What do I get by paying more for a bicycle? I am not experienced with bicycles, although I have been using them for years to get to work, as well as to go out in the countryside (dirt trails) to take nature photos.

I have used affordable B'twin bikes and I was generally happy, but after my last bicycle was stolen I am looking to step up a bit. There are countless articles on the internet suggesting not to spend too little. But I find it very difficult to find anything tangible or easy to understand about what precisely one would really get by paying more.

Take for example the Rockrider 520, 540 and 560. (I am linking the English Decathlon site so people here can read it, but I do not live in the UK.) I am looking at these: all of them are better than what I had. The price more than doubles when going from the 520 to the 560. I look at the specs, but I am unable to translate them into what I could do with the 560 that is not possible with the 520, or how the experience would be different.  I am looking for help with this, especially advice that I could translate to other models as well, although it is these three that I am looking at now.

All of these are marked as:


  Not suitable for XC, All Mountain, Enduro and BMX.


This restriction seems to cover all forms of mountain biking (which is puzzling) and some websites suggest to dismiss all of these bicycles from the start because of this note. However, the cheapest model from Decathlon that does not have this note is 50% more expensive, way more than what I can afford (where I live, it's actually 2x the price of the discounted 560).

To sum up:

For any bicycle I pick, it is easy to find another one that is two or four times as expensive. How can I better understand what one gets in practice for paying more? The specs often just mention components of a certain brand, but it is hard to even see which component is better, not to mention how having a better component translates into riding experience (please see the specification lists I linked).

When looking at the three choices above, my spouse asked me "Even the cheapest one is better than what you had. What would you gain by paying more than that?". And I could not answer. What I really wanted (bigger wheel, better gear range and theoretically better brakes) is indeed present in the 520 already.

As to the question "why a mountain bike", I would like to be able to go on rougher trails (rocks, roots) without too much worry. I would like to learn how to do that safely and efficiently. However, I am not young and sporty or physically skilful person. I also keep thinking that my own physical limits may be reached much before that of an expensive (for me) bicycle.
With so many good answers I hesitate to say anything.

But, in an effort to add something useful to the conversation...

The Value Curve
Part of the reason it's hard to understand the difference between more and less expensive bikes is that you do get what you pay for, but cost increases faster than value. 

What is Value?
For the purposes of this answer I'm defining "value" as some measurable improvement.
For example, a $15 steel chain that will last 3,000 miles vs an $80.00 stainless steel chain that will last 8,000 miles (made up numbers - this is only an example)

Why is There a Curve?
The cost to manufacture increases faster than value. Each improvement cost more to manufacture than the last one.

For Example
It's easy to see a difference between a $50.00 bike and a $400.00 bike.
It's harder (not impossible) to see the difference between a $800.00 bike and an $1200.00 bike.
As price goes up it gets harder and harder to see an increase in value.

I would argue that at some price point there is no value increase and you are paying (hopefully) for craftsmanship, like extra polish or fancy lug work or exotic materials that are expensive but don't contribute to a measurable difference.



Suppose I agree that there is a value curve - what should I do?
There is a "sweet spot" in the curve. A place where you get the most bang for your buck. The problem is that I can't tell you exactly where that is because it changes over time and it depends on the individual's situation - finances and type of riding.
Bike shoppers have to balance their budget with the desired level of performance and decide where their sweet spot is.  

Always test ride bikes before buying. Always ride more than one so you can compare.
A parking lot is not a great way to compare ride but it's much better than nothing. Bike feel matters.