I am a heavier rider, whilst still reducing, I am over 120kg or 260lb.

I have broken many spokes on the rear of my 26er sub-$500 mountain bike. Broken at the elbow. There could be many factors for this from being a cheaper bike to not maintaining the spokes. This is just background for this question.

I am going to purchase a new hard tail bike.

Given a choice of the same bike brand and model coming in either 27.5 or 29 where the wheel is also the same brand and model. Which is going to be a stronger wheel and less likely to break a spoke and last longer?

  • 3
    Broken spokes are more about build quality and maintenance than wheel size and weight. Cheap bikes break spokes because the wheels are poorly build or they are not maintained, not because they are weak. (expensive bikes probably have weaker spokes and rims, but when assembled well these are made into stronger wheels). – mattnz Feb 3 '15 at 3:27
  • 4
    There is a slight advantage to a larger wheel, especially if you have an oversized hub (as with an internal gear hub). Unless the wheel is radial spoked, the spoke always approaches the rim at a slight angle, and the smaller the wheel, for a given size hub, the greater the angle. That angle places more stress on the spoke, which will manifest as spoke failures at the nipple. So if you get any spoke failures at the nipple end larger wheels will definitely help. (But likely a big part of the problem is simply poor quality spokes and maybe a poorly built wheel.) – Daniel R Hicks Feb 3 '15 at 3:28
  • @DanielRHicks: most helpful. I can look more in to this. – Valamas Feb 3 '15 at 4:05
  • Please note that the many near duplicates of this question have additional information in the answers. – Móż Aug 21 '15 at 4:16
  • hey I think there is simple solution is using more holes, what you think? – Shoao Feb 26 '17 at 14:59
up vote 8 down vote accepted

I've heard before that a smaller wheel is actually stronger, and this site states the following.

Because a 26-inch wheel has a smaller circumference than a larger 700c wheel, the rim is structurally stronger and resists deformation from impact. Wheels that are 26 inches excelled at handling hard drop-offs and even crashes without losing their true.

The way I understand it is that a 26 inch wheel is shorter, and therefore has a shorter lever arm when stressing the spokes. Imagine you had an enormous wheel. Because it's so big, you'd need very little force along the rim of the tire to deform the rim. Now imagine a smaller 20 inch or even smaller wheel. You would required a lot of force to deform the rim because it's being applied closer to the hub. Also, assuming the same number of spokes, the smaller rim will have the spokes closer together on the rim.

I was able to find a couple other sites that agree that smaller wheels are stronger.

700c vs 26inch Wheel Size for Touring

This site states, among other information

Not everyone can afford the highest quality wheel and tyre parts. If this is you, a 26inch wheel will offer more strength for your buck.

Wheel size facts Part 1.... Dimensions, Weight and Strength

If comparing like to like wheel builds (same rims, hubs etc), smaller wheels will always inherently be stronger than larger wheels. This is due to wider gaps between spoke eyelets and poorer spoke triangulation etc. So strength to weight ratio is something that will always be won by smaller wheels.

  • 4
    @DanielRHicks If your only concern was a strong wheel and whether or not you could ride over bumpy surfaces, then a small metal cylinder like the hub would be actually quite appropriate. – Kibbee Feb 3 '15 at 20:07
  • Good to see a counter-argument! – andy256 Feb 3 '15 at 21:01

The stronger wheel is going to be the stronger wheel. Hub, spokes, rim, and build are more important than size.

I don't get the question on size? You need to buy a size that fits the bike. Everything else the same in theory the smaller size is stronger. Buy the wheel size that fits the riding you want. If you are also tall then 29" is probably a better fit.

You are not going to get a strong wheel on sub $500 bike.

You need to pay more like $500 alone for a good set of wheels. You can pay $400 for single hub. Look for downhill wheels. They go for strength over weight. Not going to name brands but most all of the majors make downhill wheels. People (and pros) downhill on 29".

You might be better of buying a used bike and putting new wheels on it.

Larger wheels tend to last longer, partly because they are less stressed by bumps and holes. A smaller wheel hitting the same size bump or hole gets "caught" in it more, so the impact and stress on the wheel is greater.

Four other factors count also. One is larger tires. 29ers can have larger tires, which also insulate the wheel rim from impacts. The second extra factor is spoke count. More spokes equal greater strength. The third factor is material quality, but I can't help on this one (apart from recommending stainless steel spokes). And the final factor is build quality.

You pay extra for every one of those.

Addendum. The excellent counter-argument by @Kibbee made me realize that a point is missing here. It's not just the wheel strength that needs to be considered. Wheels work by levering the vehicle over obstacles. Larger wheels mean longer levers, which soften the ride for you and the vehicle. Smaller wheels don't smooth out the shocks from the terrain, so those shocks are transmitted to the frame and you.

The result is a rougher ride and earlier frame failure, especially without suspension.

26" wheels are stronger than 28" wheels but I think you can get 28" wheel suitable for your weight that will last.

Whatever size you choose I would advise you to invest in your rear wheel instead of using stock wheel you get from the shop. Buy strong rim suitable for 36 spokes, find a reputable wheel builder in your area, and ask him to build a wheel with quality spokes.

Also if you are buying new bicycle, make sure your position on it is ok. If you are for instance sitting to far back, that will affect weight distribution, and your rear wheel will have to bear even more stress.

There are more options to make stronger rear wheel, like using 40 or more spokes, wider rear axle, non dished rear wheel with internal hub, etc But all these require significantly larger investment than just getting strong well built rear wheel.

I had the same problem as you: My spokes were breaking at an incredible rate, something like a spoke a week, or so. In my case, I'm pretty strong at acceleration, and commuting in the city requires many accelerations, so a lot of stress on the spokes. They always broke at the elbow like yours.

I finally found the problem, and solved it without using any different material: While my wheel was true, the tension of the spokes was not even enough. If you allow the tension of your spokes to vary too much, the differences will grow over time due to use, and the tension of some spokes will rise. It doesn't take long for the first spoke to break, which again changes the tension of a lot of spokes instantly, exaggerating the problem.

My solution was to get really strict on applying even tension. As someone with musical training, I found it easiest to just let my computer play a constant tone, and tune my spokes to it. Apply several passes until there is no spoke that's significantly out of tune anymore. I alternate tuning passes with truing passes so that I get a result that's both true and in tune.

Since I'm using this method to build my wheels, my spoke problem has literally vanished (I still use exactly the same material!). A good bike mechanic can probably produce an equally even result; if you let someone build your wheel, and you get breaking spokes afterwards, you should probably go to someone else the next time, until you find someone who can make your spokes sing...

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