A big motivator for Hardtail Canada is sharing lessons learned over the years.
If there is a single component that has caused me the most time, money, and frustration, it’s mountain bike wheels.
As a beginner mountain biker I could not understand the hype surrounding expensive, after-market wheels.
They’re just wheels, dammit, how big a difference can they make?!
As time went on, I learned why: wheels are where manufacturers cut costs on stock builds. In other words, they’re the part of your new bike most likely to lack in quality.
I was lured by fancy high-end components with recognizable names, like XT and Fox 36, not knowing that weak mountain bike wheels were going to have the single, biggest, most eye-watering impact on my time, wallet, and nerves.
Many stock builds come with either proprietary wheels where specs are difficult to find, or low-end low-quality wheels. I believe the reason for this, and I’m proof, is that unless you know the industry and have experience, most people will not give a second thought to wheels. They’re round and hold tires–good enough, right?
In this article I discuss my personal trials, lessons learned, and some advice for you.
Although aimed at Sasquatch Mountain Bikers, these are fundamental principles for any rider. The focus here are the problems with wheels; in a later article I’ll discuss the performance improvements of proper mountain bike wheels.
If this information saves you even half the time and money I’ve spent on bad wheels, then mission accomplished.
Sasquatch's Mountain Bike Wheel Woes
Freehub Problems
A Raceface Turbine R freehub. The first image is the “wheel side” of the freehub internal. Notice the pawls/ small teeth. The second image is the cassette side, with the ratchet.
When I started mountain biking I had no idea what a freehub was.
Now, after blowing multiple freehubs, ruined trips, interrupted seasons, and untold hours searching for replacements because many bike companies don’t post their proprietary specs, I know freehubs better than any other bike component.
They are the first thing I learn about when buying a new bike or mountain bike wheel and my first point of advice for fellow Sasquatches speccing out a new ride.
The topic is deep enough that I’ll only touch on the main points here. I’ll produce a freehub specific article in the near future.
Basically, the mountain bike freehub connects your cassette to your rear wheel. It transfers power when you pedal and spins freely when you don’t.
The connection between the pawls and the ratchet inside the freehub are the last contact point between the power you put into your pedals through to making your wheels turn.
Freehubs have tiny metal teeth (pawls) that bite into a ratchet groove system. When the wheel is freely spinning the teeth don’t engage. As soon as you put the power down, the teeth engage, and you start moving forward.
Freehubs are not a flashy piece of equipment. You can’t even see them from the outside. But for strong, powerful riders, those little teeth transfer a lot of torque.
Cheap setups use generic pawls held in place by a weak lock ring. Often times the teeth won’t fully engage, and when this happens they either shear or completely blow up, ruining a ride.
High-end pawls are built of robust material and have stronger engagement systems.
Bottom line for powerful/ heavy riders: order an extra pawl set, complete with extra engagement springs/ lockrings, and freehub grease…especially if you have a proprietary wheelset or a lower end stock build. Pull your freehub apart once a month and check for any damage or wear.
If you ride a fat bike, make doubly sure you have extras. I have heard of Sasquatch Fat Bikers who’ve made it a ritual to blow up and swap new pawls mid-ride. Fat bike freehubs are especially susceptible due to the greater torque on wider fat bike hubs.
Freehub failures are catastrophic: pedalling doesn’t move your wheel and your cassette engages erratically even when you aren’t pedalling. You’ll know when it happens because you’ll hear a pop and it’ll feel like you broke your chain.
Your only optional is to shamefully stride your bike back to the parking lot.
Checking Spoke Tension
This is another good practice, especially on new or custom built wheels. As a heavier rider, or someone regularly catching air, you’ll put more direct pressure on the spokes. Keeping their tension consistent prevents spoke failure or a loose spoke falling out.
Squeeze your spokes and pluck them: the tension and “ping” sounds should be roughly consistent around your entire wheel. If a spoke is soft or produces a dull sound, gently tighten until it sounds like the others.
This advice is not scientific and I’m not a wheel expert, so if you want further detail I recommend consulting other sources or a bike mechanic.
I had a custom wheel built. A new hub was laced into a rim I owned. After a few rides the spoke tension was consistent except for one that sounded a little “off.” I didn’t think too much about it at the time, as the tension felt OK.
The next ride I was straight lining a chattery rooty section and heard a dull smacking. The nipple had wiggled itself loose and the spoke was banging around the rim’s spoke hole.
I had to pull off the tubeless tape, recover the nipple, have the whole wheel partially re-built, then re-taped and re-sealed.
Time and hassle I would’ve save had I took the time to address the problem when it first sounded “off.”
Mountain Bike Wheel Out of True
The stock Suntour Raidon 34 on the stock Growler 40.
This is another problem related to spoke tension. You hit a big bump and now your mountain bike wheel is wobbling.
For minor corrections, put your bike on a stand (or, better yet, put your wheel in a truing stand), let the air out, then identify the “high point” where the wheel wobbles as it rotates.
You can do this by holding a pen, or other soft firm object, against your rim and then spinning your wheel. Where the rim ”wobbles” and touches your indicator is the high spot that needs correcting.
Gently, evenly, tighten the 2 spokes pulling away opposite the high point and give your wheel a spin. Hopefully, the high point is less obvious.
Mountain bike wheel truing is a technical skill. If done incorrectly it can cause issues with your entire wheel system.
If you want more information, I recommend consulting expert advice available elsewhere on the internet. Park Tools and GMBN have great resources for everything mechanical.
Dented Rims
This is a problem I have not (yet) experienced any catastrophic issues with. Just a few small dings here and there from rim hits.
Although, with riding my Rocky Mountain Growler enduro/ DH style, not having dented rims is likely due to my use of rim inserts.
Rim inserts, of any kind, protect your rim and take the impact from hard hits. Your first line of defence are proper tire pressures, but after that, inserts take plenty of the force.
For more information about rim inserts check out my other article: Mountain Bike Inserts: Do You Need Them.
I ran Nukeproof ARD and Cushcore tire inserts this past season, and they made a big difference. The difference with Cushcore especially was night and day.
To read more about Cushcore, and if they’re for you, check out Cushcore: How They Live up to the Hype.
Checking Bearings
Like any other bearing in your bike, check the ones in your mountain bike wheels. Give them a spin with your finger, checking they rotate smooth and aren’t clunky.
Smooth bearings lead to better wheel performance.
On my old Giant Reign the bearings in my front wheel became noticeably grindy. This meant the wheels spun slower and lost energy quicker. Had I kept this bike for longer I would have looked into a proper bearing service.
My current wheelset, the Race Face Turbine R’s, are ones that I plan on having a long time and when the time comes for a service, I’ll produce a separate article on the process.
The nice thing about investing in a proper wheel set is that the components are significantly higher quality, which means it’ll be a while before the bearings need to be done!
Sasquatch's Mountain Bike Wheel Woes
Heavier, stronger riders are more likely to experience wheel issues by the simple fact their wheels are enduring more powerful direct forces. But these are problems any mountain biker can, and probably will, eventually face.
Mountain bike wheels and their maintenance is an entire technical discipline on its own. Here, I’ve used my experience and countless hours dealing with problems (and what I’ve learned from knowledgable friends) to give you guidance on how to avoid the same errors and assumptions I’ve made.
If you have any info to add, or want to share your own mountain bike wheel nightmares with readers, feel free to comment below!
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Nice article Dan! I’ve had my share of wheels woes too.
I snapped the axle on a 148×12 NS Rotary hub. Took my wheel out one day and the cassette and freehub just fell off. Half the axle was still inside the freehub and the other half was still in the hub shell in the wheel. Not a common issue but not unheard of, especially on a hardtail, where the rear wheel takes more of a beating. The cost of an axle was about a third of the cost of the hub!
My fat bike came with an alloy axle and the manufacturer did a voluntary recall to replace the axle and pawls after seeing so many pawl failures from bending of the axle. The new axle was steel and much stiffer (and unfortunately heavier). I suspect that’s a major source of freehub failures in fat bikes. The axles tend to be alloy to save weight and they are also much longer. The axles bend and deflect more than they would in a 148 mm hub as a result of that longer span and the freehub sees that deflection as angular misalignment between the pawls and teeth. The pawls get worn down, chipped, and eventually fail.
Dented rims… I’ve had my share. Nothing beats a crescent wrench for bending dents back out but eventually the rims will get egg shaped from trying to true them back to round.
My experience with broken spokes is that sometimes they are a one-off thing but more often a sign of an improperly or unevenly tensioned wheel. If you’re popping multiple spokes on a wheel, it’s worth having a shop look at it to assess whether a rebuild is required.
I’m not a heavy rider but some folks swear by steel freehubs for durability. I get by with alloy but I do wish I didn’t have to knock the cassette or individual cogs off with a mallet sometimes! Those alloy freehubs get chewed up so easily.
And my last point, a truing stand seems like an expensive purchase but spending $100 on a decent entry level model has been a great investment for me. I use it all the time. Have built a couple wheels, trued many more and I use it even just for taping up a rim or spinning sealant around on a freshly mounted tire.
Yep that is all great info Adam, thanks for adding! The bit about the axle itself flexing enough to cause general hub damage is really interesting…pretty gnarly you snapped it the way you did!
I still run 8/9 speed. The durability of the freehub is one of the main reasons. Just saying….
Hey that’s something new! Thanks for posting. Does it last longer because there’s less range and therefore less torque?
I’m sure other readers are keen to hear more too!
Could be less torque…unsure of the math. Replacement parts are cheaper but getting harder to find