Slime Smart Tube Exploded when I put it on mountain bike I bought a basic Apollo Mountain bike from a charity shop today -

The only thing that seemed amiss was a flat tyre at the back.

I took care changing the inner tube and found the culprit a couple of thorns wedged in the tyre.

Anyway I was cycling soon after and heard a noise, looked down and then saw a bubble sticking out of the tyre, I stopped straight away but it was too late - with a loud noise the inner tube exploded.

It's damaged the tyre to the extent that the metal wires on the rim of the tyre were now exposed where it had burst out.

I popped the old inner tube back in wondering if this would now be a slow puncture now that the obstructions were removed, just hoping to be able to push the bicycle home at this stage.

The exposed damaged bit of the tyre on the very edge of the rim of the tyre was placed behind the metal bit of the wheel.

I pumped it up and a small bit of the inner tube is bulging out near the rim, I was able to push it home at least.

The bike looks as new and apart from this damage to the one tyre they are both otherwise in perfect condition.

I'm fearing the worst that I'll have to buy a new tyre, if so will it have to be a 26x of the same design? Is there any way to patch up a small part of a tyre?

What did I do wrong here,is it possible I over inflated the slime/self repair tyre? It was a very impressive exxplosion/implosion anyway.

Thanks for any tips

I can think of three scenarios that caused your issue. The tire was damaged from running flat before you got it. While installing the new tube it was pinched between the tire and rim. After inflation it lifted the bead off the rim resulting in both the tire and tube failing. The tire was grossly overinflated resulting in the tire sidewall and bead separating.


Elastomer in bicycle trailer hitch: is it important? I have a bicycle trailer (Hamax Outback One). Recently I inspected the hitch as I was connecting the tow bar to the bicycle. The steel spring was getting rusty, but I do not think it's a big deal. However, inside the spring there was a black cylindrical rod which I assume is made of some sort of elastomer. That part seemed to have broken into two pieces.
I started looking for a replacement or a fix for that. There are a lot of similar complete replacement hitches sold online. However, the dimensions of the parts, especially of the coupler that stays on the bike's dropout, are slightly different, meaning I'd have to replace the whole hitch and buy new couplers for multiple bikes. Alternatively, a complete new tow bar for Hamax trailers can be found, but that is more expensive and really not something that I'd need.
On the picture below, the transparent elastomer part is sticking up out from the steel spring.

The question is: how important is that for safety that the elastomer is in one piece? I assume its role is damping when the spring gets compressed at braking.
Additional question is that if anyone has done that I plan to do, that is, to buy a no-name hitch and reuse its new elastomer alone. Or maybe there are other DIY sources of the elastomer part?

A spring, of course, is just a piece of wire.
When you bend a spring, you're just bending a piece of wire.
In a perfect world, the wire would bend evenly along it's entire (coiled) length.
In the real world, particularly during sharp or extreme bends it's possible for the wire to kink.

Either way, the kink becomes a weak spot and as with all metals when you flex them repeatedly in one place, they will break.
The flexible insert allows the spring to bend a small amount on it's own before the insert comes into contact with the spring's interior. That has the effect of spreading the bending forces across more of the spring's coils ensuring the spring bends more evenly along it's length and preventing a kink.
You could try replacing the broken polymer with a length of stiff hose filled with expanding foam. It might be weaker than the original, depending on the stiffness of the hose and foam, but they're common materials and easily replaced.
Just keep in mind: you or someone else, turned the bike so sharply you snapped the original material. Try to avoid doing it again.


Brake lever placement on a road bike I am just going to re-wrap my road bike's handlebar tape tomorrow.  Before I do that I was wondering what the proper place is to put the brake levers.  I know they should be pointed vertically, however I was wondering if there is a rule of thumb.

In the olden days one idea was that the bottom of the levers should be along a line projected from the bottom straight section of the bars. I don know why, and that was often an uncomfortable position for me. So I am a long-term follower of the "what feels comfortable" approach.

This is connected to what angle your handlebars sit at, so it's important to get that right at the same time. If you were happy with how they were before you started, leave them there.

My first step would be to attach the brake levers to bare bars, ideally without cables (it's easier if you're doing new cables at the same time). If you have a wind trainer, put the bike in that because it will make evaluating the feel of the bike easier.

Then try the two positions that matter to me - resting on the hoods, and standing up pulling on the levers. The latter is harder because it's usually something I do on hills or in sprints, not cruising along the flat. So I focus mostly on the resting position.

Sit on the bike, rest on the hoods and see how you feel. Lift the levers a little and see if that feels better. Then drop them back. Only a few millimetres at a time. Once you have somewhere that works for you, you're done.


What make and model? I have scoured the internet until I can't take it anymore. I just can't find out what make and model bike I have. I got the bike second hand and it had been repainted and had no decals or badges on it. I have put security tagging stickers on it and want to register it but need to know the make and model. The guy I got it from said he had for a few years and could not remember anything about it. Strange I know but after checking the frame number on-line I am pretty sure it's not stolen.

This is it.

The bike appears to be a low cost mass-manufactured bike sometimes termed a bike-shaped-object (BSO).

Identifying features:

rear wheel appears to have single wall steel rim.
stamped steel derailleurs
stamped, riveted chainrings with integral plastic protector
oversized, 'looks cool' frame tubes, mig welds indicate thick wall metal
non-adjustable shock absorber fork
lawyer tabs on front wheel
integral quill stem
low cost grip shifters
all of those reflectors

The front wheel looks like it may be double wall aluminum, it doesn't have the obligatory wheel reflector found on big box store bikes.

Pacific Cycles is a likely source, they make bikes under about 20 nameplates, including Roadmaster, Mongoose, and Schwinn. They also make short lived 'custom' brands; for a while they were offering a GM branded series at Wal-Mart. Finding an exact year and model name may be difficult because components would be shared between different name plates.

It looks like it's been well cared for, and if it's working for your riding habits you shouldn't have any trouble finding spare parts, especially if you've got a community bike shop around. Any big box store bike could be used to scavenge parts to replace those on this one. You could upgrade some components as they fail, but the weight of the frame and some limiting factors like the head tube would prevent you from upgrading it one piece at a time to bike shop components.


Changing the free wheel I'm thinking of changing from 8 speed to 9 speed. What are things I should keep in mind before changing free wheel?

Can the rear axle accommodate a nine speed cassette? Depending on your current equipment, you may have to change the derailer, hanger, and shifters as well.


Shimano 105 Rear Derailleur Housing Frayed While adjusting my rear shifting cables I noticed that the small piece of housing, which emerges from where the barrel adjuster is threaded in, was broken. Is it necessary to replace this or is it fine to leave it as? If I should replace it, what is the part name I should be looking for.

It's there to reduce friction when the derailleur is in its extreme positions and also to prevent contamination of the housing. It's not totally necessary, but if it's broken in a way where it can't do that anymore, replacing it will improve performance.
It's unfortunate that the first generation Shimano road 11 rear derailleurs were built to need them to perform well, but they do.
Shimano sells them. I believe their part number Y5XX38000 is a generic replacement for all the derailleurs that have it.
You can also remove it completely when the housing is out and replace it with any sufficiently long nosed shift ferrule to accomplish the same thing. It doesn't have to poke out as much as the original, only enough to route the cable around the bend that gets created in the extreme positions.


Is this a short cage or long cage rear derailleur? Is there an easy, objective way to tell?

The objective way to tell is by calculating the total capacity and matching that to the make and model of the derailleur.

This has an excellent answer for calculating derailleur capacity.


Magnetic trainer failure I never thought I'd be on the receiving end of a catastrophic failure, but I am and I am left with some questions. While reading on Wikipedia I noticed it says a con of magnetic trainers is that they are prone to breaking.

During my training this morning, my trainer failed. And it failed hard. The flywheel shattered/exploded with a sound like a gunshot. A piece of it went through the wall behind my bike, while another shot through the front of my computer (playing a great training video of course). No injuries, but I can't believe this happened! I was in highest gear during a short sprint, so the wheel was moving at a pretty good clip, but I would have thought a trainer could handle that!

The trainer is a Minoura Mag Trainer, not sure on the exact model, but it's a little older.

That said, here are my questions:

In what ways do magnetic trainers commonly fail?
Was there anything I was doing wrong that caused the failure?
Are newer trainers designed better and/or can they accommodate a greater speed?
Would another type of trainer (fluid, wind, etc) failed like this?
Can I get a replacement flywheel?

Here's some pics of the carnage:

Let's start with some quick maths. I'm guessing the roller has a diameter of 40mm based on the picture. Since it's in contact with the tyre, whatever speed your speedo reads is how fast that roller is going. But it's 40mm in diameter. So, at 72kph / 45mph we have:

Speed = 72kph = 20m/s
Diameter = 40mm = 0.04m
Circumference = π d = 0.125m
Revs per second = 20 / 0.125 = 160 Hz (9500 rpm)

The magnetic rotor is bigger, perhaps 100mm diameter, and we want the centripetal acceleration:

a =  v² / r
  = 20² / 0.05 = 800 m/s² (about 80G!)

Note that that scales with the square of the speed. So at 108kph / 70mph you're going 50% faster but the force on the outside of the rotor is 2.25 times bigger (about 180G).

1. In what ways do magnetic trainers commonly fail?

The one you care about is overspeed. Either explosion due to too much centripetal acceleration, or an imbalance causing the shaft or mount to break. It looks as though your one failed that way, either through the trainer being knocked at some point or being slightly out of balance when it was made. I've also seen bearings fail through overheating, although that shouldn't happen now because bearings are so much better.

2. Was there anything I was doing wrong that caused the failure?

Possibly going too fast, possibly going too far. If the flywheel was slightly out of balance it would probably fail eventually regardless of how slowly you went, but if you look at the centripetal acceleration, since that depends on the square of the velocity so does the "wear" caused by being out of balance.

3.  Are newer trainers designed better and/or can they accommodate a greater speed?

Possibly, and I would hope so. It's been a few years since I broke one, but I've never been a world class cyclist and I have broken two different trainers simply by putting too much power into them (one admittedly at about 1300W). The problem is, to some extent, intractable. People want cheap, light, quiet trainers, but those trainers have to somehow get rid of 500W or more of power for as long as you care to sit on them. Doing that in a light, quiet, cheap container is hard.

4. Would another type of trainer (fluid, wind, etc) failed like this?

Probably. If you bought one with a bigger fan or other dump zone, no. But that would mean the old school "bike wheel with fan blades riveted on" that people hate so much. One alternative that would work is the "pedal powered generator" setup that the green kids are so fond of building, because they usually have bigger flywheels that consequently rotate more slowly (and as I keep saying, the problems go up with the square of the speed, so twice the roller diameter means 1/4 the force). But they're big, heavy and expensive compared to a trainer, and you have to build your own if you want that power output (commercial ones seem to top out at about 200W - I keep looking because I'd like one rated to 500W).

5. Can I get a replacement flywheel?

That's up to the manufacturer.


Can I reorient my dérailleur so the top jockey doesn't hit the cassette? I was running a RD-M7000 dérailleur on my Scott E-Genius 730 and I recently received some good advice here that the Deore RD-M6000 is a drop-in replacement. I have now purchased and fitted that, but the topmost jockey wheel appears to be touching, or at least far too close, to the cassette. As a result I get a lot of unacceptable gear clatter in most rear gear selections (I also can't reach the highest gear, but one step at a time).

Here is an overview of the cassette, dérailleur, chain and crank.

I believe I've taken some six links out of the standard chain, and I think it is probably still too long. However, I don't think this is the problem. If I pull down on the main lower section of chain (to emulate a shorter chain), it pulls the lower jockey wheel closer to the crank, but it does not at all move the upper jockey wheel away from the cassette. I think that is what I need to fix.

Here is a closer view:

You can see here that the upper jockey is far too close to the cassette.

Finally here is what I want to achieve - something to reorient the dérailleur angle so the upper jockey is distanced from the cassette:

I have a suspicion I know what is wrong, though I don't know how to fix it. In the first two pictures a red connecting mount on the bike is shown. There is a black connector piece attached to that, and finally the dérailleur is attached to that. What I notice is that the two connector brackets form an angle of some 15° from each other. However in my previous post (see first link) they are some 85° from each other, and note: it is the old bracket. Not a new matching model - the actual old one from the old photo.

However I have slackened the internal hex key nut off, and tried to move the dérailleur clockwise around this pivot point, but something is preventing this bracket from travelling further. I wonder, could I have installed it back to front?

On these Shadow derailleurs, there is a tab that must rest on the bottom lip of the derailleur hangar.  (I'll note at this point that you must use the correct hangar for your bike. "Almost" like it or "derailleur has the same angle" when an incorrect hangar is used doesn't cut it. Millimeter differences create big changes in the workings of these things.  Consider how a few rotations of a fine threaded Barrell adjuster can change a whole gear.  Or if the cable is not routed just right--like say misses a small little leverage tab, the derailleur won't be able to get onto certain gears.).  If the little tab isn't touching the lip of the hangar, shifting will be compromised.  In addition, I see your derailleur's cable is not properly seated into the derailleur's housing.  That will eventually cause excess friction and poor shifting.  While one doesnt necessarily need  ferrule at this point on the external  (the derailleurs cable seat/stop can act as one)—a sealed ferrule will prevent easy contamination of the inner cable at this vulnerable spot.  Full Suspension bikes utilize the aluminum ferrule to help prevent ghost shifting when the suspension moves.

Note the things I'm talking about on these pics of my XT Shadow der.   My cassette is an 11-36. Up front I have a 2x crankset, 38-28, and I'm on the big ring.  You have to hold the derailleur just so on install so that tab gets seated in the proper spot. In this Dealer's Manual from Shimano these issues are discussed.

Finally. When a rear derailleur and it's cable are installed correctly, manipulating the B-screw moves the upper jockey wheel closer to or away from the cassette. Clockwise rotation moves the screw in and the jockey wheel away from the cassette; anti-clockwise moves the jockey wheel closer to the cassette. See photo for location and a view of the proper distance the jockey wheel should ride from the cassette.


What are the advantages of a building an electric bike from a kit vs. prebuilt I'm trying to decide on what would be the best option for me for my first electric bike. I need a way to get around, and as I live on a hill where I will have to manage a fairly steep incline coming and going I am wondering what kind of bike I should get.

There is a bike on Craigslist right now with a 36V 12amp battery and 500-750Watt motor, but as it is a Huffy bike I am pretty sure it is a kit build. They are asking 700. -- My other option is the Kickstarter kit by Barak Electric (https://www.kickstarter.com/projects/1354698863/barak-electric-bicycle-conversion-kit-electrify-yo) that has a 500 watt motor and 36V 10amph battery, and as I already have a mountain bike laying around I could install it myself and it would cost 655. I have no idea what they would be charging in a couple years when the Lithium batteries die for replacements, but I'm sure I could figure that out then. I don't have a ton of money, so going to a bike shop isn't really an option even though I would love the security of being able to return it if it doesn't work. I was looking into the Currie Electric bikes as they seem quite reasonable, but it doesn't look as though they will have enough power to get me anywhere with their small wattage and SLA batteries (not to mention to upgrade to Lithium with Currie is basically the price of the bike!)

Any advice would be greatly appreciated!

First, check your local laws. As others have mentionend, in some countries (EU), maximum power for an electric bike is 250W. Go beyond that and the vehicle will be considered a moped and will need license, insurance and and license plates. Your local laws might also require an assist-only option for your bike to be considered an e-bike. That means usually a pedal sensor, and those can be difficult to install especially with exotic or outdated bottom brackets.

Selecting a kit is not necessarily easy. If you're going to front mounted motor, check that brake type is compatible (disc or v-brake) with the kit and that fork spacing is suitable. E-bike kit should come with brake levers with a cut-off switch so the motor stops pushing immediately when braking (problem with some e-bikes).

Kits can be had cheap, but installing them takes time, effort and experience with bike mechanics. If you got all three, go for it. If you need to get up and running quickly, an entry-level e-bike is probably better option.


Spoke nipple broke, should I replace more than one? I had a spoke nipple break on my rear wheel, the threaded part broke off right where it enters the wheel.

The nipples appear to be aluminum alloy, which I believe are not as durable as brass nipples.

Since I have to replace the failed nipple anyway, is it likely that others were overly stressed after the first one failed and should I replace more than one (or all of them)? Is there any issue with having some brass nipples and some aluminum?

It's a rear wheel with 32 spoke, 3 cross lacing.

I would just replace the single nipple that is broken with a new brass nipple. It sounds like these wheels are not very expensive so I wouldn't want to invest a whole lot more time and money in replacing something that may or may not be a problem in the future.


Finding directions for Bus + bike Buses in my city have bike racks. In some cases, it is faster to use both the bus and your bike to get from point A to point B (the transit system here isn't too good). Google Maps is great for finding transit directions, or bike directions, but as far as I know, I cannot easily find directions that make use of both...
Are there any tools/websites that would help me finding such information?

OpenTripPlanner will do this, but isn't everywhere yet.  There are deployments for New York City, Portland, OR, and a few other cities.


Touching the front wheel with my foot when turning My girlfriend got a new city bike today and she touches the front wheel every time she has to make a hard turn.

Is there anyway to avoid this besides replacing the whole bike?

LATER EDIT:
I think I found my answer here.

This is a common problem, but really not a big deal. I've usually heard it called "toe overlap". I have it on all my bikes.

Basically, it's a bit shocking the first time it happens, but you get used to it. It's no big deal. If you're simply aware that it can happen at slow speeds, you'll avoid it easily enough. Since it can only happen at slow speeds, it's not particularly dangerous.

It's most common on racing-style road bikes due to their short wheelbase or on smaller frame bikes. Big tires and/or fenders can make it more likely. Big feet and shoes that stick forward of your toes very far also make it more likely.

Possible solutions include:

Try not to worry about it. It's usually just an annoyance and you get used to it pretty quickly.
Don't go slow (can't turn the wheel far enough for it to be a problem unless you're going slow).
When going slow and making a sharp turn, pay attention to where your feet are.

Don't pedal while turning
Pump the pedals instead of normal pedaling, so that only your inside foot goes forward
Get your feet into a good position (outside foot just below where the pedal overlap happens) as you start to turn.
Also pay attention when starting from a stop.

Pedal with the ball of your foot over the spindle of the pedal. This is generally considered the "correct" place, and leaves your foot only going a little forward of the pedal. Some beginners put the arch of their foot on the pedal, which is likely to be uncomfortable on platform pedals, and puts your foot more forward.

Maybe slide your foot back a bit as you're making a slow turn, so that you pedal with your toes instead. I find this uncomfortable, but it's tolerable for a few seconds.

When you're shopping for bikes, look at how much toe overlap there is. You don't even need to ride the bike, you can tell by putting the pedal forward, putting a foot on the pedal at about the right position, and turning the handlebars.

Smaller riders may find that bikes with smaller wheels give them less toe overlap. 650b or 26" instead of 700c?

Really, don't worry about it too much.


How to achieve an always clean chain My chain and cogs always look very dirty as the oil attracts dirt. It is a constant problem as you can't fully avoid stains on your trousers and hands. Also, that looks ugly and I believe it wears the chain and the cassette out as the particles stuck on chain act as abrasive.

I used to think that was unavoidable, but then I noticed that on some bikes the chain and cogs are shiny clean. Is that because their owners clean the chain daily (because honestly one day is enough for a chain to turn black after full cleaning) or because they use different lubrication solutions?

I heard about teflon-based lubricants, are they really much better in that sense than traditional oil-based ones? Also, these bikes with shiny chains were always single-speed bikes - does that mean geared system experience more traction and should be traditionally oiled?

There's lots of good info here, let me summarize my cleaning routine which combines many of the approaches already mentioned, and keeps the chain in good condition and appearance.  This focuses on getting the chain totally clean and dry (no water, degreaser, or lube) before re-oiling it; and then on removing as much excess oil as possible.  The end goal is a very clean chain with just enough oil--excess oil will quickly attracts grime.

Cleaning:

First the chain gets a wipe-down with a damp rag to remove as much sand and grime as possible.  This is just to knock the worst of it off the chain.
Second the chain gets two passes with degreaser. I use the Park Tool Chain Gang cleaner which zenbike recommended for this.  It gets filled with degreaser, and gets about 30x cranks on the pedals; then a fresh batch of degreaser goes in and it gets another 30x cranks.  At this point the chain should be quite clean except for the degreaser.
Third the chain gets washed in 91% rubbing alcohol--this is primarily to wash off the degreaser, but it also gets the last of the grime.  Sometimes this takes two rounds--the last round of alcohol should remain quite clean.
Fourth the chain is left to dry for ~5-10 minutes (just long enough for the alcohol to evaporate off).  At this point the chain should be totally clean and dry with no degreaser left anywhere on the drivetrain--move quickly onto re-oiling, as a dry chain is vulnerable to corrosion.

Lubricating:

First the new oil goes on,  1x drop per chain roller.  After applying I let it sit for a couple minutes without turning the cranks to let the oil seep into the internals.
Second I spend a few minutes slowly running the chain through a clean rag to remove most of the excess--maybe a couple-minutes worth.
Third I let the bike sit for a few minutes, then wipe the chain again, and repeat a couple times.  The oil inside the links will slowly seep out of the next day or so--so this step is just to remove that excess oil as it appears.
Finally I give the chain a wipe before and after the first couple rides.  Again just to remove the excess oil as it seeps from the internals.

I usually do this routine every 100-250 miles, depending on how fast the chain grimes up.  The goal is to have a very light layer of oil over the externals of the chain, and as much oil internally as it will accept.  If you notice the chain is staying too dry, but not dirty, then you can re-oil without cleaning and repeat the process of cleaning off the excess.


Measuring chainline without cranks? I just bought a 1970s Peugeot Mixte UE-18 for $10 at my local bike co-op. It's in great shape, but is missing the bottom bracket and cranks. I'd like to upgrade to a cotterless crankset. However, I don't know how to measure the chainline without cranks installed. I was thinking of getting these BB cups (with French threading) and finding a spindle of the right size. How do I figure out the right spindle length? Has anyone encountered this issue? Am I going about it the correct way? I would just like to keep the cost of the bottom bracket under $50.

Thanks in advance!

You can measure the chainline at the cassette as well as at the cranks.

Park tool Company has a nice article on measuring chainline at both the crank and cassette.

https://www.parktool.com/blog/repair-help/chainline-concepts#article-section-3

It's my understanding that bikes sometimes have the chain further offset from the  frame centerline at the crank than at the cassette, to avoid the chain rubbing on the next bigger ring when small ring - small sprocket cross-chaining (triples especially).


Terminology: Is there a technical term for the paired wheels on tricycles? Are there standard technical terms for the location of the wheels on tricycles? I was writing up an answer to another question and was using clumsy terms such as front-wheel on a delta and rear wheel on a tadpole for the singleton wheel that isn't part of a pair. I assume we could just call the singleton the drive-wheel or steering wheel, depending on the configuration although that doesn't always work.

I'm particularly interested if there is a configuration-neutral term for the wheels that are paired (front wheels on a tadpole; rear wheels on a delta). They are what make tricycles unique in being located side-to-side of the rider and they are unique in having single-sided hubs, etc. Are they collectively called the paired wheels, side wheels, or something else? Or is there no agreement and we have to specify the configuration (tadpole/delta) and location (front/rear) each time?

I have been in the recumbent business for over 10 years and have not ever heard a technical term to distinguish the pair of wheels versus the single wheel. As there is so little standardization it would be difficult to describe the wheels without ever running into someone misunderstanding. I used to manufacture front wheel drive two wheeled recumbents and already got into problems since 'my' front wheels were really rear wheels (135mm hub spacing) and 'my' rear wheels were actually front wheels (100mm hub spacing). Then I started to experiment with trikes where I used a delta setup with a single powered wheel on the front (still 'my' front wheel that was still actually a rear wheel) and two single-sided hub wheels.

Whenever I had wheels made I found it best to describe as much detail as possible (and still sometimes got reversed quantities) and I did the same in my shop.


Which type cycle should I choose. Need Help Hi I'm looking for a cycle for long distance(50-60 km) riding in Delhi, India. I'm confused to choose between Road and Hybrid bike. If we consider roads then Hybrid is best option and if we consider distance then Road bike is best option so I'm confused between these two.

PS: I'm a beginner for gear bicycles. I used to ride non-gear bicycles for 30 kms.

There are pros and cons to each type of bike:

Road bike advantages (imo):

Light weight
Less rolling resistance/easier to maintain higher top speed
Easier maintenance in some cases (less paniers, fenders etc. That can get in the way of things
better looks?

Hybrid bike advantages:

Pre installed fenders (you won't get dirty when riding)
More mounting points for locks, lights etc.
Wider tires meaning less pinch flats (especially on rougher roads)
More options for mounting racks for carrying luggage (often these racks are pre installed)
Dynamo mount or hub dynamo (on some models) meaning you won't need batteries for your lights
bigger tire clearance (distance between tire and frame) which is useful for mounting fenders but also to prevent the space between frame and tire getting filled up with mud when riding on dirty roads
+option to install wider tires due to frame clearance
more comfortable riding position
some hybrid bikes come with belt drives/internal gear hubs which require less maintenance/cleaning and internal gear hubs will have a longer lifespan than a derailleur system, It is said that belt drives also last longer than chains (but I have no personal experience with this)

It all depends on your situation...

do you use the bike for cycling to work (if so can you chainge clothes at/near work?)?

Have you ridden road bikes before/are you comfortable with the riding position (bent over to the front; which is more aerodynamic than the position on for example a hybrid bike)?

How rough are the roads you ride on? Are there many potholes and such? Will you risk getting pinch flats when riding on narrow (road bike style) tires?

Do you often ride in the rain/muddy roads? If so fenders would be a good thing to have on the bike.

Where do you store the bike? Do you need to carry it up stairs (if you store it inside)? If so weight is important.
How many hills you climb is also important regarding this (the bike's weight)

If the roads are muddy then if you use rim brakes you might risk wearing the pads/rim brake surfaces very fast due to the sand acting as a sandpaper in between brake pads and rims. When using disc brakes (which are present more on hybrid bikes than on road bikes) this problem will be greatly reduced or even illiminated (much less mud will get on your brake disc than on your rim wall, also brake discs can be easily replaced without rebuilding the wheel(s) and if you have to rebuild the wheel or replace the wheel it will most likely cost you a lot more money/time.


New Shimano TX55 Not Shifting I am having a problem with my rear derailleur. I installed as per instructions, adjusting the H and L limits to what I believe is proper. The problem I am having is that when I am in 7th gear, shifting down doesn't actually shift. The cable tightens, but it just pulls the derailleur back instead of sideways along to the next gear. I have tried both tightening and loosening the cable in various amounts. I also noticed that I can push the derailleur from side to side (as if it were changing gears) while the cable remains at the same tension.

As this is the first derailleur that I have installed myself, I really have no idea whats wrong. Did I install it wrong? Is it broken? I'd appreciate any help.

EDIT Added a newer video that hopefully shows the problem better.

Here's a video of the problem

Thanks for all the help! I had a friend take a look at it in person. Turn out the cable housing between the frame and the derailleur was too short. The derailleur was cocking back until it caught the cable housing, then working as normal. After a replacement with longer housing, the bike is now working perfectly.

Thanks again to all who helped!


Gates Carbon Drive vs single-speed chain, long term lifespan and maintenance I'm looking to get a new bike which will require the smallest amount of maintenance.

The bike will have an internally-geared hub and I have the choice of single speed chain or belt drive.

I have been looking at the Gates Carbon Drive and investigating maintenance costs:

A CDX belt is around 8 times more expensive than a chain where I live.
Also the chainring and rear sprocket are round 4 times more expensive.

What is the lifespan of a Gates belt against a Single Speed chain? I've looked up online but peoples opinions are conflicting. Some say in similar conditions a belt will have a similar lifespan, while others claim up to 10 times longer use.
What is the actual lifespan of a belt compared to a well maintained single speed chain in similar conditions?

I understand a belt drive is not maintenance free but much less than a chain.
If a belt can last 4 times longer than chain then I would consider this worth the investment.

Also is there an expected life difference between 11 speed and single speed chains? As comparison to my current bike.

On single sped vs. 11 speed chains. A SS chain should last a lot longer than a derailleur chain. SS chains will have wider side-plates and therefore larger bearing surfaces. The big difference is that SS chains are run with the chain ring and sprocket aligned. Derailleur chains spend most of their time being run with the chain ring and sprocket offset so the chain has to cope with lateral forces.


Should you hose down your bicycle after having used it on salty roads? When using your bicycle on salty road, if you can opt for hosing it down or not hosing it down after a commute (without re-lubricating the drivetrain at this point!), what should you do? Do you cause more harm than good, by spraying water into the drivetrain and chain? I could see this removing oil, but I can also see it removing salty water. I don't know what is best.

I realize this would depend on the type of road, the type of bicycle, does it have fenders, or not? Hence, I'm looking for a rule of thumb answer. However, in my case, to make it specific I can state that this is a hybrid bike with fenders.

Here's how I understand the situation generating the question:

While riding to work on a salty wet road the drive train has become a salt water saturated mess. Now you are at work and have access to clean water but no ability to clean and lubricate the drive train.

If that's the case...
Running some clean water over the drive train to wash off the salt water so that it does not sit on the drive train all day makes sense.
Clean water is better than salt water.
Clean water and then drying the drive train is better yet.

From an article on the effects of saltwater on metals

  The combination of moisture, oxygen and salt, especially sodium chloride, damages metal worse than rust does. This combination corrodes, or eats away at, the metal, weakening it and causing it to fall apart. Saltwater corrodes metal five times faster than fresh water does
  sciencing.com

Both salt water and fresh water corrode metal. Salt water corrodes faster so drying the drive train helps.
Once you get home it would be best to clean and lubricate.


Replacing an 8-speed cassette with a 9-speed one to make my bike faster I'd like to make my 8-speed tokyobike Classic Sport city bike go faster so I'm considering replacing the 8-speed cassette with a 9-speed one which can be found on the tokyobike Sport. The bike has smaller 650c wheels and is without a front derailleur.

My question is:

Is it a good idea? Or is there another, better way to make the bike faster?
How much faster will I actually be able to go?
What other parts beside the cassette will have to be replaced?

As Blam and Batman have already suggested you will not go faster.

The main reason is that your top speed is determined by the number of teeth on the smallest rear cog.

The smallest cog available on a normal cluster / cassette has 11 teeth.

If your smallest cog already has 11 teeth, then you will definitely not go faster with a new one. If it currently has 12 or more teeth then a new cluster can help you go faster.

But the main way of going faster is simply to pedal faster. With practice, you should be able to pedal at 90 to 100 rpm. I venture to guess that this is at lease half as fast again as your current pedaling speed.

The problem with pedaling slowly but getting the 11 tooth cog (if you don't have one already) is that you'll put a lot pressure on your knees and back, which often leads to pain and injury.

The advantage of switching to a higher number of gears is that the steps in between the gears is smaller. That can help you find just the right gear for the situation. But it doesn't change your top speed.

So my recommendation is to save you money for now while you practice pedaling faster. See also questions tagged cadence, especially What is the optimal cadence?.


Steering Dynamics Question as I contemplate reducing reach by either 1/ shortening my stem or 2/ shortening my dropbar's reach, I have some questions about whether approach 1 or 2 will have a greater difference on my bike's handling.
So, would love the group's opinion on this theoretical question: Will all 3 of these handlebars steer the same? All have the same vertical and horizontal distance from the stem.

From a naïve geometry point all three options are equivalent.
For real systems material properties and 3d geometry become relevant. For instance, your model (A) could not be made with a single piece bar. The double 90 degree bends needlessly increase stress.
On the level of one dimensional line figures there's no reasonable answer possible. To answer this question you need the actual dimensions and materials in a CAD model and then run an finite element analysis (FEA).


Can you run a quick release skewer with a SON dynamo hub? Regular SON dynamo hubs come with a hex key skewer rather than a QR. That's not a big deal, but it's probably simpler for the other 2 riders on the household who are running these hubs to deal with a QR skewer, since it's easier for them to get a feel for a tight QR than for "8-10 Nm" on the hex key, especially using a crank brothers multitool by the side of the road.
I haven't seen any admonition not to use a QR, and I doubt they could get a QR cam to put more tension on the skewer than 10 Nm on the hex skewer would pull, but I'm not sure.
I'm wondering if the hex skewer is supposed to just be a security thing, since it requires a thief to have a 5mm hex head rather than just fingers. I'm not sure that's much in the way of security. I did get some pentagonal key skewers that would provide more security, since few people are carrying one of those around, but at present these bikes don't get out of anyone's sight.

Yes, they don't care, you can use any QR you want. I've used an early SON28 with the stock one, a Pitlock, an external cam light skewer, and various Shimano skewers, and a current SONdelux with the stock one and a Shimano QR. It doesn't matter.
I don't know the numbers but I believe internal cam skewers develop quite a bit more clamping force than bolt-down skewers, so in other words it's conceivable to make a hub that could care about this distinction. But Schmidt hubs don't.


Disc brake just a little too tight I have pushed the hydraulic pistons fully out, but after a single firm squeeze of the brake lever, they ride slightly too tightly, such that rear wheel doesn't spin freely. It rubs a little bit. How can I permanently adjust the pistons to a wider default set point whenever the lever isn't being squeezed?

Bike is 4 months old, so brakes, rotors, and fluid should in theory be new enough, and visually look good.

When I finely align the brake, then manually push the pistons out, the wheel spins very freely. It's only after the first firm squeeze that it goes back to lightly rubbing.

There is no adjustment for piston position on hydraulic brakes.

Hydraulic brakes have a built in mechanism to retract the pistons slightly when the brake lever is released. The pistons are mounted in flexible rubber seals that deform as the pistons are pushed forward. The seals then pull the pistons back as fluid pressure is released. The pistons also slip through the seals to automatically advance as the pads wear.

What you need to do is adjust the calipers with the pads advanced up to the rotor. If you push the the pistons back and adjust the caliper position you wont be able to align the pads accurately enough.

A good trick is to loosen the caliper bolts, then hand tighten them so the caliper will still move. Pull the brake lever so the pads grip the rotor, keep it pulled while you tighten the bolts enough so the caliper wont move, release the lever and tighten bolts to proper torque.

Park Tool video on how hydro brakes work:


10 speed chain skipping on 9 speed cassette I have recently replaced a 9 speed chain with a 10 speed one on a 9 speed cassette. I read this is compatible. Shifting is fine and quieter but it is now jumping on the smaller cogs 6-9. Is this a common occurrence? Never had any skipping on 9 speed chain though it was a lot noisier.

This feels like a new chain on a worn cassette problem.  The fix is to replace the cassette, and soon before your chain suffers accelerated wear.
Assuming you have 9 speed shifter and rear mech still, the slightly narrower chain won't really make any difference while pedalling, and shifts might be slightly sloppier.
I run a 10 speed chain on a 9 speed cassette without issue, because its what I had at the time.


Weight distribution while cornering for maximum grip on road bike Road bike on tarmac. What should the optimal weight distribution between the front and the rear wheel be for optimal grip while cornering on a descent?

If the frame fits you properly, getting in the handlebar drops should give you the proper front/back weight distribution.  This is of course a generalization,  if you have your road bike set up with and extreme handle bar height then this might not be the case.  For example, if you have a very high stack height (e.g., all your spacers under a high rise stem) with compact bars (i.e., the amount of drop is low) you may have really bend your elbows to get the trunk of your body low enough and enough weight on the front tire.

The geometry of the frame and fork will also affect this as different head tube angles and trail numbers (which affects wheel flop - how hard the bike turns in with weight on the front wheel) will have a different idealized weight distribution for aggressive riding.

Because a lot of this is rider and bike specific you will have to do some experimentation (i.e., empirical approach).  Try taking the same set of corners at the same speed (something safe but still spirited) in different body positions.  Too upright and you should notice the bike pushes through the corner. Too low of a body position and the bike will feel like turn in too hard and may feel somewhat uncontrollable or very slow to react to rider input changes.  In the sweet spot and the steering should feel aggressive, yet still react well to input. You will feel the most confident at this weight distribution.

If you can also find corners that changes in their arc or have multiple apexes this can be a great way to find a setup that turns in well, but is still reactive to corrections (ideal for descending where you may have to make multiple corrections).

Finally, if you find yourself overshooting (pushing through a turn or a bad line going in), drop your inside shoulder towards the ground, this will add weight to the front wheel, which will interact with the wheel flop and turn the bike in harder.  I used this trick many times in criterium races, but will only work if you are not at the edge of your tire traction.


Worn out chainring or missing tension This is a follow-up to the question I need to replace a cassette for CS-HG500-10 but want to go XT
Yesterday I replaced the cassette, as well as the chain and the jockey wheels and went for a ride. The problem has not disappeared.
I'm thinking that the chainring is completely worn out, but I'm also starting to think about the tension of the chain.
I'm using the biggest chainring almost all of the time, and was in the bad habit of using it with the biggest sprocket of the cassette, cross-chaining the entire range. I've used this chainring about 7500 km (maybe 3/4 of that distance).
When I use the middle chainring (it has 3 chainrings at the pedal), the problem is pretty much gone.
Here is a YouTube video which I made today, where I'm fully breaking and then putting pressure on the pedal, you can see the chain jump.

Here are some photos of the chainring:

I have already ordered a replacement, but I wonder if chain tension could also be a factor with this.
Could this problem be removed by increasing the chain tension, or does it look like I generally should increase it after replacing the chainring? How could I do that?

Update: The new chainring arrived today. I took pictures of both and compared them. Here is the result:

I will focus on the chain tension part of the answer, as your big chainring is clearly worn out. However, do note that increasing the derailleur spring tension wouldn’t stop the chain skipping on the worn chainring. Therefore, this answer is mainly for the sake of interest.
By chain tension, I believe you actually mean the tension in the rear derailleur spring. This spring takes up slack in the chain. If your spring tension were too low, the chain could be slack in some or many gears. However, I don’t believe that it’s a setting most users need to manually change, as the factory tension is likely sufficient. From this Park Tools page on overhauling rear derailleurs, Shimano and Campagnolo RDs appear to have one setting for increasing the cage tension from the stock setting. SRAM appear to have one setting higher and one lower. I actually don’t know of any clear reasons you would want to increase the cage tension, but it is possible to do so. I suppose that if you were converting to 1x without a clutch equipped RD, you might consider increasing the cage tension, as discussed in this previous Q&A. (If you do this, you might consider using a chain guide as well.)
Less relevant to you, I recall that Friction Facts, an independent researcher later bought by Ceramicspeed, showed that all else equal, higher cage tension meant slightly more drivetrain friction, although manufacturers objected that the cage tension was necessary to ensure good shifting. I believe that Ceramicspeed’s oversized pulley cages contain at least one position which lowers the cage tension from the stock Shimano or Campagnolo setting. The amount of drivetrain friction at stake is quite small, likely considerably less than 1W.


How to get my feet out of SPD pedals? I just bought some SPD shoes and pedals last night and I was trying them out (on one foot) while balancing in my living room. I ended up falling over because I couldn't get unclipped. What suggestions do you have for breaking out of the clips? Do you simply twist your foot strongly to the outside or will that damage the cleats?

Make sure the release tension is low at first (should be a little screw on face of pedal).  Generally you will get to a point of looseness where you are popping out unintentionally, go just tigher than that.
Cleat placement also can be a factor.  The closer to the toe it is, the easier it tends to be to get out.  Be careful about moving too far from the balls of your feet, it could end up with achy toes!
Lastly, see if the sole of your shoe is interferring with the pedal.  If it is dragging, you can get little spacers that go between sole and cleat.
Don't worry about damaging the cleat, you will do more walking around on concrete.  Also, you will probably fall at least once while getting used to them.  It is almost a rite of passage.


Does price have a huge impact on the quality of road bikes? I want to buy a road bike but I have never had one. I have a limited budget and want to try triathlons. The good brands old bikes are really expensive. Even for a 25 years old bike I have to spend at least 450 Euros.

Surfing in the net, I found this bike on Amazon, which is in my price range.

The problem is that when I have asked "experts" they told me that you cannot buy a decent bike for that price, and this isnt a good bike. Can anyone give an advice? Can this bike be good or is the price determinant for a good quality bike?

Search some more for secondhand bikes. EUR 300,- should get you a nice enough used bike from a couple of years back.

A tip I was given when searching for my first bike was to search the bike or racing bike category on ebay and similar sites for "ultegra" or the name of some other sufficiently high-end groupset rather than the brand. This filters out a lot of bad bikes, and a high quality groupset is very desirable in a secondhand bike because it is expensive to replace yet wears out very quickly (unlike (most) frames that are also expensive to replace but don't wear out so much). This search on the dutch e-bay equivalent gets you a few good options in your price range.

As to your question, I agree with Daniel R Hicks' comment that beyond about 1000-1200 euro's you are mostly paying for weight reduction (which might even impact durability) rather than 'just' for quality. I also agree with your "experts", you cannot buy even a descent new bike for that price, secondhand is a whole different story however.


Help! Want to convert 8 speed Kona road bike to 1x drivetrain I currently have a 2015 Kona Rove AL with Shimano Claris 8 speed drivetrain; running double FSA tempo chainset in front. This is the link to Kona’s specifications for the bike: http://2015.konaworld.com/rove_al.cfm

I am wanting to convert this into a 1x drivetrain. Any tips on how and what parts? I figured I would need a clutch rear derailleur, which I was looking at Shimano XT 9 speed as a replacement? I’m just unsure on the cassette size, single chainring size and cranks that I would need. I mostly ride flat trails with just a bit of low grade climbing within the city. Any advice, ideas or experiences shared would be great.

I think you need to ask yourself why you want a 1x drivetrain. What is that going to do for you that your current system does not?

Presumably you want more rear derailleur gears than your current 8 (why would you want an upgrade otherwise?) That means you will have to get new shifters as well as rear derailleur, cassette and chainring. You can run a single ring on a double crank but you'll end up cross-chaining on either your highest or lowest gears, so a new crank is advisable.

It's likely that the cost of all that, plus having a shop install it for you or buying the special tools required if you do it yourself can be significant compared to the purchase price of the bike.

If you really want to do it you have a few choices:

Lower level of dedicated 1x11 system such as SRAM Apex 1. Obviously the best but most costly option. Note, this option may also require a new rear wheel in addition to the items listed above as 11 speed road cassettes generally need 11 speed compatible freehub bodies.
9 or 10 speed mountain derailleur with a 9 or 10 speed road right hand shifter. I believe Shimano mountain and road systems used the same cable pull ratio up to 9 speed. SRAM mountain and road systems use the same pull ratio throughout (at least for older systems).
Road 9 or 10 speed rear derailleur and right hand shifter, use a derailleur hanger extension to enable running a larger range cassette. (Road derailleurs usually support a 28, 30 or sometimes 32 tooth max sprocket. You will probably want 34 or larger.) This is a bit of a hack but ensures compatibility between derailleur and shifter at 10 speed. See this recent GCN Tech video for info on this method.

By the way, for road riding you will not need a clutch derailleur as the chain will not be bounced around. You could use a narrow-wide chainring for better chain retention, or just leave the front derailleur in place to keep the chain on the front ring.


Should I leave bolts in frame when I've removed component (mudguards for example) I've just remove my mudguards from my Ti frame and as usual I have put the bolts back into the frame where the thread goes into a tube - for example in the chain-stay bridge and brake bridge.
I used anti-seize on the threads and did not do them up tight.

Should I be doing this?

I do it because it looks a bit neater and I suppose to stop water getting int but I thought that maybe I am just risking ruining my frame if the bolt gets stuck in there.

Thanks

I usually plug the hole with appropriate size hardware. I add a dab of anti-seize   compound. My reasoning (other than appearance) is that while the frame is aluminum or carbon the threaded insert is typically steel and there fore subject to rust.


Imprecise shifting on a Shimano 9 speed set Edit: Jeff’s answer - replace the cable housing - fixed the problem. I made sure the highest and lowest alignments were correct, that the cogs lined up with the gears, and then replaced all cable housing for the rear gears. It’s now shifting as expected.
I have the following rear components:
Shimano ST-4500 shifter, Tiagra
Shimano RD-M591 rear derailleur
They’re both supposed to be 9 speed. The rear derailleur is long cage. For completeness, I have a 3x front chainring set and that works mostly Ok.
The problem is when I shift from one direction to another, it takes two clicks to make the change. If I’m shifting in the same direction, one click works after that. I’m kinda-sorta used to it, but it’s annoying when I want to change just one gear in the other direction. Sometimes, after shifting twice to change directions, it’ll shift spuriously one more in that direction and then I have to reverse it to get it where I want it. It’s like one of the components is meant for 10 speeds and the other is for 9, but the manuals say they’re both 9.
Any suggestions? I’ve seen elsewhere that a Shimano RD-M592 would be compatible with the ST-4500, but I’m not sure why the M591 wouldn’t be as well.
Oh, cables are new; components have been cleaned and seem to work, otherwise. The cable housing from the shifter is somewhat old, and could probably be replaced, but the cable seems to slide through it well enough.
Thanks!

There is no compatibility problem.
If the direction you have to shift twice in is downshifting (pulling cable, going to bigger cogs), that can indicate not enough cable tension. If it's upshifting, it can indicate friction in the cable/housing.
It sounds a lot like one or both (could be both) of the above are true. Misalignment in the derailleur hanger can also add to the finickiness of the adjustment, i.e. making it harder to get the chain to shift right and then stay in place without the ghost shifting. Excess pulley and pivot slop in the RD can also contribute to sluggish shifting. So can a B-tension screw that's too far out.


Safety of taking a bicycle to a country where they drive on the other side of the road? Bicycles are different in countries where people drive on the other side of the road.  Suppose I have a bicycle and I am moving to a country on another continent where people drive on the other side.
I have these obvious options:

Sell my low-end bike and buy a new (to me) bike in the new country.
Ship my bike and reverse the brake controls.
Ship my bike and continue using it unchanged.

What is the safest option?  Are there ever legal requirements?

In my opinion it is actually safer to bring the setup you are used to even if it theoretically might be less optimal on the other side of the road. Such a difference is very small. Sometimes you have to indicate to the left and sometimes to the right anyway.
When I lived in the UK for 2 years I had problems getting used to the reversed brakes and I was more or less only able to brake with both levers in the same way. I would suggest to bring your own bike instead if you do not remain in the new place for very long.
As far as I know there are no legal requirements to which brake is which. The bicycle just needs to have the brakes it is required (often two independent brakes, some countries or states may allow just one).


Freewheel or sprockets? I ride a MTB with Shimano components and increasingly when I pedal there is a slippage (no noise or resistance) occurring. Might I Need to replace the freewheel mechanism or is this just the sprocket/cassette that I am planning on changing soon anyway. Just trying to take the wheel off ONCE rather than find out after the sprocket change that the problem is still there.... Thanks!

You may need to clean up your terminology to make the question more clear.  There are two common setups a freewheel OR a freehub and cassette.  The answer will vary greatly depending on which setup you have.  If you have a freewheel both items (gears and free mechanism) are one item and essentially you should just replace the freewheel and you would be done.

If you have a freehub (free mechanism is built into the hub which is more common/modern) you will need to determine if the issue is the hub or cassette and replace accordingly.

If you do have a freehub|cassette setup, I would lean (based on your description) to having a damaged freehub which you have likely damaged more by continuing to ride (based on your increasingly description).  Depending on the price of your wheel, you may choose to replace the whole wheel, rebuild the wheel with a new hub, or find a way to fix the freehub (possible if the hub body itself is not damaged AND it is an expensive hub).


Campagnolo Record C9 / Shimano CS-HG200-9 incompatibility I drive cheap Shimano cassettes together with Campagnolo Record C9 chains. Yesterday I installed a new C9 and a CS-HG200-9. But the chain sort of slips over the sprockets, not unlike really worn parts, but exactly once per revolution and under all loads. Has anyone else experience with this particular setup?

This Campagnolo chain is not incompatible with Shimano 9 speed cassettes in general: I've gone through a couple of these, and had overall good experience. I cannot remember when I changed to the last pair, but it's been more than one year - that means at least 11000 km, much of it commuting under all weather conditions with lots of acceleration and partially steep, fast ascension + some tours over some of the Swiss alps passes.

Might be a spec change by Shimano - I know that there is no change to the Campag chain. As they are not designed to be compatible, if Shimano have changed something they will have done so only referencing their own 9s HG type chain which is slightly narrower than Campagnolo's.

The other things to look at are a stiif link or a chain rivet protruding slightly at the join.

If it's once per crank rev (rather than once per full chain rev) it would be more likely to be related to the rings - if you are doing 11000km per chain / cassette I'd guess the rings might be getting pretty tired unless you are changing once every couple of chains - depends whose rings, riding conditions etc ...


Pitted rust on frame Hello I have some small pitts of rust on my 1980 Raleigh royal frame. I don't want to strip the paint and sand blast it are there any non invasive treatments? Some of the chrome surfaces also appear to have been eaten away is there anyway to repair the chrome or is it a lost cause?

Answer:  No.  There are no good quick and easy top-coat treatments for your situation.

The problem is that pitting is a loss of material.  The metal is gone already, and the non-smooth surface will hold and hide moisture even when it looks and feels dry.  The corrosion will not stop because you've painted it even with anti-rust paint.

Not-Good Answer You can paint on rust-converter, which will transform the red/brown rust oxide into a more stable black oxide with a white foamy layer on top.  Once its converted and dried, wipe off the white stuff and then paint.  This is only a slowing action, but if it slows the rust down by 10 years then that may be all you require.

Stripping the paint at a bead blaster or sandblaster will remove all the paint and decals and chrome.  You need to take everything off the frame and forks, and protect head-tube bearing races with wood bungs or take them out, optionally replacing them with new.

Since you've gone to all this work to clean the frame, may as well finish it properly too.   Fill any holes and sand and prime it, then paint with many thin layers of good paint, lightly sanding between layers and let it cure properly before the next coat.

Another option is a full-on powder coat paint job by a pro.  However the costs keep going up, so you need to weigh the value of the bike to you against the time and effort required.

I can't speak about chrome - never really had to deal with that side.  There are chrome spray paints in rattle-cans but they seem to be cosmetic only, and not shiny.


Why has indexed shifting displaced traditional friction shifting? I really don't like indexed shifters, at least on the front. They're harder to adjust, more sensitive to cable stretching, and limit the number of gear combinations you can use (because you can't adjust the front derailleur cage manually to not rub on the chain).

So.. why are they impossible to find these days?

There is no 'conspiracy' to keep friction shifters off the market just so that you have to buy the index shifters. It is simply a matter of supply and demand. Nobody in the OEM market wants friction shift gears because bikes with friction-shift simply do not sell. That leaves the after-market and you have a similar position there - the demand does not exist amongst people building up bikes/repair old bikes.

One reason why the replacement part market does not exist is that friction shifters rarely break, even 'back in the day' they were not a common spare for shops to stock in depth.

As for your front-shifting problem, you do have the outer cage 'flat-bit' parallel with the chainset and clearing the outer ring by all of 1-3mm? Without that accurate positioning it is unlikely you will get your front mechanism to work. New cables help, and if you follow the Shimano/SRAM/Campagnolo manual to the letter, making sure no dropouts or derailleurs are bent, you will have a chance of getting optimal shifting.

I know that a simple shift-lever adjustment would be easier, but that is progress for you.


Is this level of rusting removable by sandblasting? Is this rusted steel frame still salvageable? The local bicycle shop does sandblasting before they powdercoat a frame. Do you think the sandblasting alone would be enough to remove the rust?

I'm aware that all traces of rust must be removed, or the corrosion will continue under the new layer of paint. I'm just not sure if it would be possible in this case.

Any amount of rust is removable by sandblasting or chemical means. That's not the problem here though, the real concern is how much frame material have you got left after the rust is removed. The top tube walls may be too thin for the frame to have structural integrity. Remember the steel may be rusted on the inside too, and there may be rust 'pits' that go all the way through.

If enough frame material remains, it looks like you'll have to fill and sand the top tube smooth  otherwise it will look horrible when painted

I think at this stage you have to ask yourself if all this work is worth the time and money. If the frame is a rare, classic or means a lot to you it may be worth restoring,  but would it cost less to just by another used bike?


Does riding high gear up a hill damage a recumbent bike? I have a recumbent trike with 26 gears. While normally I would shift to a low gear when going up a hill, I found that I can go up hills in the highest gear, the configuration that gives me the fastest speed on a flat. This may be because the bike relies on pressure between the seat and pedals instead of pressure from gravity, so I can put more force into the pedals.

Does riding a bike in high gear up a hill put unusual stress on the parts? It does not have high-end parts. E.g. the front and back derailleurs cost $75 together and many of the other parts can be found at Walmart. Does riding up a hill in high gear put too much pressure on a bike that the bike's parts are not designed to handle?

The bike will be fine -- the riding conditions are within the specifications of the bike components.

The bigger issue is you -- you don't want to end up damaging joints and what not by overexerting yourself.


I need some help identifying a bike I just acquired I need help identifying this bike.

The frame is Yeti A.R.C. 1992. Source. You can tell by distinct rear triangle tubing/dropout and top tube cable routing.


How accurate are altimeters in bike computers? I bought a bike computer with a pressure-based altimeter (Sigma 14.16 STS). It gives gradient of current hill with 1% resolution, current altitude with 1 meter resolution, and total climbed amount with 1 meter resolution.
How accurate are these readings?

The bike computer is based on the relationship between altitude and air pressure. Even though it has 1 meter resolution, it is still constrained by the air pressure around you. About 11.3 Pascal difference in air pressure is counted as one meter.
One thing to consider is that most houses have a slight 10 Pascal negative pressure caused by the ventilation system. Thus, if you bring the bike indoors, you may see its altitude raised by 1 meter and if you go out of your house with your bike, you may see its altitude reduced by 1 meter even though your house does not have a 1 meter ascent in its doorway.
Another thing to consider is that pressure can drift over time. I rode for 1.4 hours (1 hour 24 minutes) when pressure was drifting 40 Pascals per hour. This was 56 Pascal total drift. It should theoretically cause a 5 meter difference in the altitude (the endpoint of the ride was the same as the starting point). It gave exactly this difference. (Actually, I started the bike computer outdoors and when ending the ride outdoors, it gave the 5 meter difference; when I brought the bike indoors it gave 1 more meters of difference due to the 10 Pascal negative pressure I explained.)
This 40 Pascals per hour pressure drift is typical for changing weather. I looked at a one month long historical graph of air pressure and only twice in this month did the pressure drift faster than 40 Pascals per hour. So my example ride of 1.4 hours did have a truly changing weather. Most rides of 1.4 hours give less than 5 meters of altitude drift.
There are some ways the cyclecomputer is helping you to avoid unintended pressure drifts.
Firstly, good cycle computers (such as this Sigma 14.16 STS) store the current altitude when going to sleep and recalibrate automatically when waking up from sleep. Thus, you will not get pressure drift if the bike is parked for a long amount of time (my example 1.4 hour ride actually had a 2.5 hour long time being parked inbetween at another location than my home -- I didn't count it for the ride length).
Also, good cycle computers allow you to set several home locations and their altitudes. This Sigma 14.16 STS has two such home locations. I set one to the altitude of my home and the other to the altitude of my workplace. It is very easy to reset the current altitude to be any of these home altitudes. Good cycle computers also allow you to set the current altitude to be anything albeit with a bit more button presses than resetting to one of the home altitudes. So if you know your current altitude and are willing to take some time to enter it to the cycle computer, you can do so.
However, the total climbed amount is a very ill-defined and inaccurate concept if riding in a non-mountainous area.
For my 1.4 hour long ride, a local map service gave 471 meters of climbing. Google Maps gave 188 meters of climbing. The cycle computer measured it as 301 meters of climbing out of which 1 meters was the outdoors-to-indoors drift and 5 meters was the ambient air pressure drift so without drifts it gave 295 meters.
Why the difference between local map service and Google Maps? Why the difference between a map service and cycle computer?
The difference between local map service and Google Maps is probably due to Google Maps having less accurate altitude data in my area. If it is using a coarse altitude grid, it is not measuring every single small hill. Thus, it gives less total climbed amount due to the inaccuracy of the data.
If we take the 471 meters of total climbing given by the local map service as accurate, why does not the cycle computer measure the total climbed amount as 471 meters but rather measures it as 295 meters (plus drift)?
The reason is what you count as a hill. The cycle computer having 1 meter resolution cannot count hills smaller than 1 meters as a hill. Also, counting a 1-meter hill as a hill could cause some minor variations in local air pressure to increment the total climbed amount counter even though the terrain was completely flat!
Thus, the cycle computer must set some threshold. I don't know what the threshold of this Sigma 14.16 STS is. The cycle computer then counts only hills larger than the threshold. If riding in a mountainous area, it gives very accurately the total climbed amount. If riding in very flat terrain, you might want to count even the smallest hill which the cycle computer doesn't do.
Also, air pressure varies between 96 000 Pa and 104 000 Pa typically near the sea level. Thus, the maximum amount the cycle computer can reasonably drift is about 700 meters. Of course this can only occur if the variation between 96 000 Pa and 104 000 Pa occurs when riding the bike. If it occurs when parked, the cycle computer doesn't count it. So it is extremely unlikely to ever encounter this 700 meter altitude drift, but in theory it is possible.


Can my bike do enduro/AM racing? I would like to ask if my bike is able to do enduro/AM racing.

Specs:

Giant Stance 27.5 2
Deore 2014 RD 10spd (with switch)
Deore 2014 shifters
Deore 2014 brake set
FSA Comet 24/30/40 crank set (stock parts, already hollow tech)
Alivio 2015 FD Highband
Rockshox gold tk 30 solo air 2015 fork 120mm travel (with rebound adjuster and lockout)
Rockshox Monarch R rear suspension 120mm travel (rebound only)
2014 ZTR Crest rims
origin 8 hubs
pillars spokes
Schawlbe nobby nic evo tires
Tubeless setup (stans sealant)
Deore 10 spd sprocket
Deore chain 10 spd(not sure if deore or just shimano non series)
Giant Cockpit(HB - 720mm, stem - 90mm +-6 degree, stock giant seatpost)

If I need to upgrade any parts then I'm open to suggestions, opinions and flames.

Yeah, that bike is more than adequate for that type of riding.  The only thing you might consider tailoring for your riding styles would be the tires.  The trail you posted looks pretty smooth.  If you got into some trails that were looser or rocky then you could go with something more knobby and/or higher volume.

I say just ride the bike and enjoy the trails.  If you haven't already, figure out how to dial in your suspension and you should get tons of great riding out of that bike.


Mismatched rims, and tires that may be too wide? I am currently most of the way through a 1x10 conversion of an old (early 90s) mountain bike. As part of the process, I had to replace the rear hub, and the only one I could find locally came installed on a rim (Equation aluminum, labelled 559x16, measured 16.25mm interior width). The old rims were larger (Araya, labelled 26x1.50, measured 20.25mm interior width). I own two nearly-new (well, 15 years old, but never really ridden) Maxxis tires, labelled 56-559 as well as 26x2.10.
I understand that tire and wheel sizing is a deep, dark hole, but from Sheldon's chart, it looks like these tires are probably too wide even for the wider of my rims, and definitely too wide for the new, narrower rim.
So I'm wondering what my best strategy is:

Just run with the tires and mismatched rims I have, the difference is too little to matter
Run with mismatched rims but replace the tires with either a matched set or two individual tires that match their respective rim
Move the new hub to the old rear wheel and run with the tires I have (noting that I have none of the equipment I'd need to properly build a wheel)
Replace the front wheel with a rim that matches the rear wheel and run with the tires I have
Replace the front wheel and both tires because those tires are way too wide for 16mm rims
Any other novel, clever suggestions you might have

The thing that confuses people about all the newfangled inner rim width to tire width compatibility charts is that while the effect they're trying to steer you away from is real, it's not binary. It gets more squirrelly, floppy, and prone to blowing off the narrower you go. The point where there are major issues in practice depends on rider weight, inflation pressure, riding style, the fit of the tires, and other factors.
A 2.1 on a 16mm inner width rim is somewhat extreme by rational standards, but when rims like that were trendy there were a lot of bikes running around with such a combination. It will probably be fine, but it's on you to decide whether you want the risk, and how reasonable it is depends completely on your application.
Transplanting the hub makes sense as wheelbuilding practice if that's what you want and if the rim and hub in question are in good condition. That kind of job makes little sense from a time/money perspective if all you want is a functional bike, but it's also how skills are built. Use new spokes and nipples.
There are many times when using a rim that narrow creates some hoops to jump through when setting up the brakes on a frame that predates the trendiness of super narrow 26" rims. Eighties and early nineties MTB frames often had rims and post spacing that were about as wide as they should have been. Brake and pad models differ in their ability to get the pads in so far. That in practice is a thing you need to try and see.


Are deep rims more durable for a heavy rider? Since I weigh quite a lot (~115kg), and ride on bad roads with many holes and cracks, I am looking for rims that would be able to cope with bad conditions without getting out of true or breaking. My tires are 37x622, maybe I will go to one size wider in the winter.

My first instinct is that deeper rims should be more durable. Am I right? Are there some down sides to deep rims? Are they equally easy to true and put tires on?

For instance, which one would be better choice in my situation, DXT 337 or DXT 221

I'd actually lean toward a shallower rim, but the important bits are going with a high spoke count and either 3x or 4x pattern (both drive and non-drive sides). With a deeper rim, you are changing the angle in the cross patterns and reducing the length. This means that the spoke has to deflect more to handle the cross.

This is more noticeable with really deep rims, with the slight differences in depth for the rims you listed, the difference would not be that much.

I've built some race wheels and training wheels for a customer that's on the heavier side and competes in Ironmans. I've built the fronts with 3x both sides and the rears with either 3x both or 4x drive with 3x non-drive and haven't had any problems.

With your size and the road conditions, you will still need/want to true your wheels on a fairly regular basis, they will go out of true. If you get in the habit of giving them a quick check and true on the bike, you'll soon get where you are comfortable maintaining them.

Happy Riding!


Howto design a route in Google Maps on the pc and navigate on the android device I would like to do the following:

Create a route in Google Maps on the PC and save it under my account

Set Start and Target and let google maps create a route for my bicycle. Change the route and insert via-points to optimize the route. (Avoid ways with a lot of cars)

Save the route under my account

Open the route on my Android Device (Google Maps App?) and navigate with the route. The route should have the via-points.

I only managed to create the map on the PC and opened it in a special app called 'Google Maps Engine' on my Android device, which only shows the route. I can't navigate.

Is this possible?

I don't know that you can do this with the apps you are talking about.

However there is hope. Going back to first principles, you have a pc on which you want to create your route, and you have an android device which you want to stick on your bike and use for navigation. Correct?

If you accept that you need to abandon Google Maps altogether, there are whole companies such as RideWithGps who offer this kind of thing. You create your map through their site (as it happens one of the options is to use Google mapping, but there are other options too - including bike path mapping which may be useful for avoiding cars). You save your routes on their site, under an account that you create.

I use this part of their service a lot and I know it works well.

As regards tracking, they offer an Android app designed for exactly that. I have not tried it.

I have a pay subscription with these guys and it didn't cost a lot. But I know they also offer a free account so you might be able to do what I've said for free. I know the Android app is available through the Google App Store but have no idea whether it costs.

Probably worth saying that there are a bunch of known issues with using phones for this kind of thing. Two that immediately spring to mind are battery life (GPS and screen are always on) and a way of securing the phone to the bike without the risk of it flying off.

In the interest of fairness, other companies which offer this kind of thing include MapMyRide and Strava but I only really know of these in passing - in particular I'm not sure how they handle the tracking side. Also Garmin Connect, which I know quite well (and you don't need a Garmin computer to use), and which also has a complementary Android app. Any of these might be better than RWGps in doing what you're looking for.


Please describe what an integrated bottom bracket is The article on bottom bracket terminology at Park Tool and the Wikipedia article do not say what an integrated bottom bracket is and other resources online assume the reader already knows what one is. What is it? How does it differ from a BB that is not integrated? What is "integrated" about it?

There is no such thing.

The only mention I can find is the Wikipedia article where it is used to describe the setup that is commonly known as two piece crankset. Wikipedia does not cite any sources for the term, so it is most likely that the editor simply invented a word to describe a setup similar to external bearings where the bearings might be inside bottom bracket shell.


Outer chainring with two sizes I see outer 130 BCD chainrings with 52T/39T.
Why the the 39T in the label?
How does the outer care or know what the inner ring is?
What would be different about  52T/42T?

Does the 39T care what size the bigger is?

I have a 52T/39T that I want to take down to a like a 48T.

Front derailleurs are optimized for certain gaps between the rings and are limited to that - for example, the FD-6700 series from Shimano has a 16t front chainring difference (relating the outer and inner chainring size). There are also size constraints on the chainrings which determine the maximum and minimum size of chainrings you can use due to the shaping of the cage. If you're below the difference, within the chainring size limits and the derailleur clears the chainrings, you're good. So 52/42 should work. As should a 48 for the large ring on most road FD's.

In the olden days, people had "half step gearing" which the front chainrings were close in size and they would crosschain (partially to get closer gearing and partially because old derailleurs couldn't shift 16t chainring differences). You can still do this now.

52/39's are probably marked that way since a lot of people run that combination (and probably put it in the search bar for either chainring).


Why is it easier to balance a non-moving bike standing up than sitting down? When I arrive at a traffic light that is red I usually just stop the bike, stand up and balance it for a minute or two before going on, without ever putting a foot on the ground. Learning to balance a bike like that was easy, I estimate it took less than hour before I could stand indefinitely (well, the static load is quite high so I probably won't stand more than 5-10 minutes due to exhaustion). With some effort and luck I can also release one hand.

BUT, now I have tried to learn to balance the bike sitting down on the saddle and that is basically impossible. Why is that so much harder? Any hints on how to do it?

Just speculation, but I suspect that when we balance standing up, we move our hips laterally to make fine adjustments to the relative position of our center of mass over the wheels. When doing so, we push laterally from our feet on the pedals, which are low enough and far enough below the center of mass to make adjustments relatively easy to accomplish.

With your backside planted on the seat, the main mechanism to laterally adjust your center of mass is to move your shoulders and chest relative to your hips. Now you have a smaller mass on a relatively short lever anchored relatively high up. So a movement of the shoulders mostly results in a countermovement of the hips in the opposite direction. That makes it not only fairly difficult to get much movement of the center of mass relative to the wheel-ground contact, but also difficult to do so in a controlled manner.


Adjusting Gear Actuation I recently brought a second hand bike with Shimano Deore gears on it and  when I switch up a gear on the chain-ring it requires a significant amount of actuation pressure on the 'flappy' paddle  (almost reaches travel limit before changes).

I was wondering how I should adjust this to reduce actuation pressure?

I'm not sure what you're comparing the effort to, but typically the front derailleur requires more cable pull to actuate, in comparison to shifting in the rear.

Adjusting Shimano Front Derailleurs

Adjusting Shimano Rear Derailleurs

It could be that you need a bit of slack removed from the cable, but without photos, it's hard to say.

Front shifting explained


Is it ok to mix 23 and 25 tyres My road bike comes with 25 tires. They both seem to be slick smooth ones with little resistance.    Recently I had couple of punctures in the rear and I decided to change the rear tire to a 23 which was more puncture resistant and better grip.

Is there a problem in using 23 in the rear and 25 in the front?

There isn't a problem with it, though you may find your ride quality to go down a bit by moving to a smaller tire (but 23 and 25's don't really have much cushion to begin with so this won't matter too much). There is also a slight change in gearing due to the change in diameter of the tire. Generally though, I'd expect a bigger tire in the rear than in the front due to where you sit.

In general, you can mix tires so long as they go on the rims and clear the frame + brakes. Here is everything you want to know about tire sizing, including recommended rim widths for given tire widths.


Will changing suspension fork travel change geometry of bike? Assuming that the sag of the new 120mm fork will be set to the same as the old 100mm fork and headset spacers will remain constant, will the geometry of my bike change moving from a 100mm travel fork to a 120mm of travel?  Is this as easy as adding 20mm to the height of the front end, or does the "height" vary by make and model?  Thanks.

Since the headtube is at an angle, it will not raise the bike as much as if it was perpendicular to the ground.  How much height that would add will depend on what angle your headtube is at, probably something around 70d.

Now, adding travel will cause your bike to have slower handling.  It will make it more stable in a straight line, but more effort will be needed to change direction.  It will also move you farther back in the cockpit with may make it lift the front wheel more on steep climbs.

Also, by adding this travel, it will probably void the warranty on your frame because it is putting stresses on the frame that are outside what it was designed for.  There is also a possibility that you could stress the headtube to where it breaks, but 20mm probably wouldn't do it.


Using an 8 speed cassette on an 10-11 speed Tiagra FH-RS400 I'm trying to build a new set of wheels for touring trip (2 months) I have planned and can only find a Tiagra FH-RS400 hub. The issues is that my shifters are Claris 3x8 ST-2403-L and cannot support 10 or 11 speed.

Can I use an 8 speed cassette on the Tiagra hub and if so what size spacer would I need?

Thank you in advance!

The hub for 8 to 10 speed are the same. You are good to go. You should not need any spacer for them.

However, if you mean this hub https://bike.shimano.com/en-US/product/component/tiagra-4700/FH-RS400.html they say it is a 10/11 speed hub and hence you need a (1.85 mm, as mentioned in a comment) spacer for 8 to 10 speed for this one. Those are included by some shops.

Because it is a Shimano hub you can also verify the compatibility in the official chart https://productinfo.shimano.com/#/com?cid=C-453&acid=C-454

A similar hub which is simply 8/9/10 speed would be (Sora) FH-RS300. It could also be cheaper.


What type of tires have tubes inside? Don't judge me as stupid just yet, I'm not sure if mine's a tubular or tubeless tire but everyone says tubular tires are glued to the metal wheel. However, mine isn't. It consists of a smooth, inflatable tube inside, covered by a rough, durable cover. There is absolutely no glue used so I'm pretty confused. The way it stays on the wheel is because the wheel has a rim that keeps it from falling off. If it helps, by bike is a GMC Denali with 700C wheels. Please help, I really have no idea.

A normal clincher tyre will have a "bead" as shown in the following diagram.

It's possible you have a "tubalar clincher" like this:

If none of those quite look right, could you provide a photo?


how to remove oil from mtb disk brake at home My cycle has got an front disc brake I not know how but unfortunately few drops of oil got on my disc brake now it was making a very bad sound like a violen and and could even not able to stop my cycle at all now I have only one way to fix it,s you please help me

I use Carplan Brake and Parts Cleaner, purchased from my local auto parts shop. This contains about 30% IPA (isopropanol) and 70% Naptha.

If you don't have many bikes, it may be easier to visit your local car mechanics' workshop and ask to use a little of theirs.

If you have contaminated the rotor, you will also have contaminated pads. There is a procedure to restore pads using brake cleaner, an oven and a blowtorch... This isn't worth the effort and risk, so buy new pads.

You don't have to buy your caliper manufacturer's own pads, so long as they're the right shape; I've had no problems using Clarks and Ashima pads.


Are replacement MTB tire studs compatible between brands I have a set of nokian gazza extreme studded tires, sometimes replacement studs can be difficult to come by at retail. Are the studs interchangable between brands typically or should I stick to only the studs sold by the same manufacturer as the tire?

This article measures the sizes of studs between manufacturers. The upshot of the article is that if you have Nokian, Schwalbe, Continental, Innova studs, the dimensions are essentially the same and can be swapped around.

In any case, I'd expect Nokian (Suomi) studs to be the easiest ones to find these days anyway...

For reference, the essential from teh article linked above is that the studs are approximately:
"Overall height: 5.8mm (pointed), and 5.5mm (domed)

Base height: 1.0mm

Base diameter: 6.5mm

Shaft diameter: 3.4mm

Tip diameter: 2.0mm"


How can I teach an 18 year old girl to ride again? (Not ridden since 7) How can I teach an 18 year old girl to ride a bicycle again after she has stopped riding at the age of 7 due to crashing into a tennis net and getting scared about cycling. She's 1.6 m (Approx 5' 3"). She's scared of getting on the bike and is scared of falling off. Finds it hard to balance.

How can I also get her over the fear of crashing on a bicycle?

I would go for the same way I taught my kids to ride. Take the pedals off and let her scoot around until she gets comfortable with the balancing part. Put the seat low enough so that she can touch flat footed. This will allow her to gain confidence and not worry about falling. Once the fear is gone, the rest should come reasonably quickly.


My back wheel will no longer spin freely im new to this site and don't know anything about how to repair bikes.
My Problem is
I put my bike into my shed (the shed is cold and damp) and never used it for 3 weeks, it was ok when I put it in but when I took it out to use it the back wheel has become very stiff, you're not able to spin it freely its just stiff. Im not sure where to start, is it the brakes or can it be something else ???

Any help would be great, the bike is less than a year old so not sure why this has happened.
Thanks

This is my bike

I am pretty sure the issue comes from your disc brake.
Check the brake pads first : there must be something wrong here because you say it was worse after you removed and put the wheel back.

I guess your brakes are hydraulic : sometimes when you store your bike in a humid place for a long time, the braking fluid will kind of "dilate", resulting in less space between the two pads, hence rubbing on the disk even if you don't press the lever.

Another test you could do is removing the caliper : if the wheel spins freely, that confirms my theory.

In that case, you need to push the pistons back to their initial position (using something to pry them apart, without damaging the pads). If you cannot, you might need to remove some fluid from the hose (there should be a small screw at the lever), but be careful not let some air go in the hose.


Low tire pressure causing fall in corner? I recently fell in a corner. My front wheel lost traction (slid out from underneath the bike, what they call a 'lowsider' in motorcycling iirc).

I was running quite low tire pressure (front wheel) to improve front wheel grip, which worked wonders to improve the grip when braking (front brake) in wet weather. But I was wondering if a front wheel tire pressure which is too low can cause one to fall in a corner.

Note: the tire did not roll off of the rim (the tire was still fully on the rim after the fall).

My front tire wasn't worn excessively and is quite new (a year old, plenty of thread left, Schwalbe big ben 26x2.15" folding tire (using inner tubes, so not tubeless). My rim's outer diameter is 26mm (if this makes any difference). My wheel was in good condition before the crash (properly tensioned, no cracks in rim). My bike had some luggage (on the rear rack) on it weighing approx 30kg, the bike with all the luggage weighs approx 45kg. my weight is 80kg. The bike is a hardtail mtb using 120mm travel rock shox reba suspension (in good condition), 26 inch wheels.

I wasn't braking (in the corner). It was dry (temp approx 15 Celcius, surface was tarmac with some loose pieces laying on top (not sure how much, I was distracted by my tacoed front wheel so didn't look very closely, but judging from the pieces of tarmac in my hand there was some loose stuff :P).

I was going approximately 25-30kph (a bit fast for the corner's radius). Here is an image of the corner:

Here's a picture taken standing on the road approaching the corner (sorry I couldn't find a better photo..):

Location of corner on google maps:
https://goo.gl/maps/9x4xXEWvxYZk8TwE6

Questions:

I would expect lower tire pressure to give larger contact patch also when cornering so should equate to more grip in corners (assuming the tire stays on the rim).
Is this assumption wrong? Does the cornering grip decrease under a
certain amount of pressure? (still assuming the tire stays on the rim
under this low pressure)?
if such low tire pressure is detrimental to cornering grip, what is the reason the cornering grip is decreased?
what could i have done to prevent this accident ? (apart from taking the corner slower)?

tire thread condition:

Note: I just noticed from the last picture that can be seen above (the photo taken from the bridge deck approaching the corner) that the first part of the bridge has an incline of approx 5 degrees but just before the corner starts it appears as if the incline decreases or disappears completely (aka bridge deck becomes horizontal in the corner), which could perhaps be an explanation as to why I lost grip (front tire may have momentarily lifted due to the decrease in incline, which combined with the lean angle required for taking the corner caused the accident. What are your thoughts on this? It could be an optical illusion though, I did not pay much attention to the exact angles of the bridge after the incident occurred. could go back to check once I get a new wheel.

Any input is greatly appreciated. Thank you!

Wheel after crash:

(NOTE: wheel 'folding in half' was caused by front wheel hitting fence posts of the bridge after losing traction/front wheel sliding sideways, as can be seen from the two dents in the rim highlighted in red in the last photo).

I presume you were riding in the direction you came across the bridge and down the ramp.
I doubt tire pressure had anything to do with it. On a moutain bike sized tire, unless rolling tires of rims, too low tire pressure tends to cause imprecise handling and a general 'sloppiness' in the front end. "wiping out" as you did is not typically caused by low pressures.  Check the rim for scrapes that would indicate you rolled the tire off the rim and had the rim hit the ground.

The weight on the back of the bike, and the change in angle that coincides with the corner probably unloaded the weight off the front wheel. The amount of friction you get is directly proportional to weigh, so the wheel 'wiped out' from under you because it was not far off hanging in mid air.

When learning to mountain bike one of the first skills you need to learn is to load the shock before the corner and maintain pressure on the front wheel though the corner, letting the shock do its job of maintaining wheel contact with the ground. In this case if you had loaded the front shock, the change in angle coming onto the ramp would have be absorbed by the shock as it extended to maintain wheel contact pressure with the ground.

Things that could contributed to the crash are rider position - too much weight too far back into and though the corner. This means not enough weight on the front wheel to maintain traction and not enough preload on the fork for it to hold the front wheel on the ground.  The solution to this problem is enter the attack position, move body weight forward (not lean) to load the front fork with plenty of weight to hold the front wheel down.  With 30kg on the rear, there is very little risk of putting so mach weight too far forward you go over the bars. Just how far forward you can go is much further than most people think, and is very unnerving for a novice until they have practiced doing it many times.

The other thing that could easily contribute to the crash is the fork settings - damping, rebound and air pressure are all available on the Reba. Getting this set correctly will make a big difference to hold the front wheel on the ground. With these set correctly, maintain a good weight distribution with you body well forward becomes easier as you learn to trust the fork to work for you. With these set wrong, the fork can feel like its working against you and you are less included to load it.

All that said, the speed you went though the corner with that bike setup and weight was fairly ballsy, and the outcome not entirely unpredictable. If you don't want to crash, you may need to slow down.