Does weight and climbing cause strain on bike? I‘m a heavy (260 pound) male rider using my 2011 NORCO 24 gear hybrid to commute to and from work. It’s a 6 mile trip each way with a +450 foot climb in the last 2-3 miles coming home. The ride is all on hard surfaces with an occasional curb. I have ridden this commute about 80-100 times.

I have been having issues with the rear-shifter and chain. Also with spokes on the rear rim. Started with the rear-shifter breaking off but despite three visits to the dealer’s shop and one to a different place, new cables, replaced spokes and so on I still have problems. After a couple of rides the spokes rattle and the gears go out of sync. The issues with the gears seem to happen when going up the hills (when I assume the most pressure is on the bike).

Two questions:
If I assume the two repair shops are competent then what might be causing the gears from going out of sync 3-4 trips after I get them adjusted? What’s causing the spokes to loosen up? I suspect the strain on the bike climbing (taking in mind my weight).
What type of bike would be appropriate considering the combination of climb and level riding plus the weight?



To answer some questions and some further info:

What do you mean by "the gears go out of sync"??:
The gears don’t correspond to the setting I have. I gear but see the chain hasn’t moved. I might have to switch back and forth before I get the desired setting. Chain falls off the gears. There is also a lot of creaking and groaning (and not from me!).

Do you change the gears while climbing / fast pedaling?
Not so much while fast pedaling but definitely while climbing. It’s not a steady climb so I try to gain as much speed as possible and then drop the gears fast while climbing.

have you replaced the chain and rear cluster yet?
No. I probably need to change the chain. There is a chink in the chain after the last fail.

I’m ready and willing to replace parts if required. However if the cost start mounting I wonder if I’m better off getting a more robust bike. 



Thanks for all the great suggestions and ideas! 
Since it’s a rather spread and open question I can’t really pick any one as best but I wanted to post one final question and my action plan:
I will go back to the dealer and replace the chain and rear rim with higher performance items, plus have the bike overhauled. Think his mech is competent but will insist on talking to him directly. So yes – I intend to extend the life of my NORCO.

For my type of riding – paved roads, occasional curb, hill climbing… is the hybrid the ideal bike-form?
The spokes and gears are likely unrelated issues. 
You have done 2000km on the bike - have you replaced the chain and rear cluster yet? At you weight and those hill climbs, I would not be surprised if they are just worn out. It is also possible that at your weight and that distance the spokes have come out of adjustment, and/or now have fatiguied to the point of breaking or stripping threads on the nipples. I would also be checking for a broken axle and the bearings not being adjusted properly.  

The bike shops should have picked up all these issues, however, are they aware of the distance you are riding? Many such bikes do 50 miles a year and they may be servicing it based on that assumption. It is a mistake to presume that any LBS is competant, servicing is and art and a passion, and (putting it politely) some mechanics are better than others.  

What to do - ask around for recommendations on bike shop. If you are comfortable, take it back to one you have used, but make sure you let them know how much use the bike has had. Talk to the mechanic directly, don't be fobbed off by front counter salesmen (And walk out if you cannot get access to the mechanic). Ask him to measure the chain and check the cluster and chain rings. Check the spokes/bearings and axle. Be prepared to replace parts.