So, you own a sweet road bike, a nice MTB bike, a cyclocross bike and you just popped for a Fat bike. What's next for your cycle stable? Well it seems we've rediscovered long forgotten rail trails and old farm roads and the new cool roads are not paved with gold but with gravel. Terms like "hard pack" have entered our road vocabulary. The new do all machines for these funky roads are affectionately known as a gravel grinders.
So, what kind of wheels should you be thinking of building for your new gravel machine? I have been getting more enquires of late about wheels suited to rough road riding than any other cycling discipline. The other night I was out on my Tuesday night club ride and I shared an in-depth conversation with a club mate about his new gravel bike and what kind of wheels would best suit his new machine. That chat begat this blog entry.
I'll start by sharing a few important aspects of a well designed gravel wheel set. Most gravel bikes take advantage of thru axle set ups much like MTB's. 142X12 thru axle rear hubs are quite common as well as 100X15 front thru axle hubs. The other common feature will most likely be disc brakes and therefore will demand rims that are properly suited with no rim brake surface.
Since you'll likely be on some challenging terrain a higher spoke count will be the order of the day. 32 hole front and rear wheels will stand up to pretty much anything you will come across. I would highly recommend a 3 cross lacing pattern for optimum strength and resilience. This is especially important for wheels coping with the inherent stresses of disc brakes.
What about spokes? I would steer clear of ultra light spokes. These wheels are not where you should be trying to shave off a few grams. For most of my off road wheel builds I usually recommend Sapim Force spokes. They are triple butted and build up to very strong wheels. Their profile is 2.18mm X 1.8mm X 2.0mm. The strength of the middle section of that particular spoke is 1400 N/mm2. That's impressive. Another ultra strong Sapim spoke worthy of consideration is the CX-Ray. The CX-Ray is a bladed spoke often regarded for it's aerodynamic profile, but that's not it's only positive attribute. It's a great spoke for any application where extra strength is needed. It's middle section strength is even greater than the triple butted Sapim Force at 1600 N/mm2.
Nipples? Definitely brass. Alloy nipples are quite light and come in a boat load of eye popping colours, but can be prone to corrosion so they shouldn't end up on your all road wheel set. Personally I prefer brass nipples with a dual interface, like the Alpina ABS2 5.5mm HEX head. There is no stronger nipple made, with the exception of titanium at 5 times the price.
Ok, so what hubs are major contenders for conquering gravel? Luckily there are a number of respectable choices. Your selection will be narrowed down to disc hubs with well sealed bearings and preferably a titanium or steel freehub for ultimate durability. An alloy freehub will save you a bit of weight but it can't match the bombproof nature of either steel or titanium. Many of the hubs that are perennial favourites for the MTB crowd will work well for the gravel grinders out there. Some of my top recommendations would be Onyx, White Industries, Hope, Hadley, Project 321, Industry Nine, Trailmech, Syntace, Chris King and Stealth. Admittedly that's quite a lot to choose from! All of these hubs unique features are dealt with in detail in my previous blog entries.
The other consideration for any rear hub is it's engagement. The degree of hub engagement can very significantly and it's worth looking at each manufacturers specs. For instance Onyx hubs boast near instant engagement with their unique German made sprag clutch.
Another thing to think about is noise. Do you want your hub to growl, purr, or run silently. On a quiet farm road maybe you're looking forward to silence and you don't want your hub to speak it's mind. A dead quiet Onyx hub might be your cup of tea. On the other end of the spectrum is a bee buzzing Chris King hub that announces itself to the world in a very loud and proud way. Something to contemplate before buying.
What about rims. Should you be thinking classic alloy or carbon fibre? To be honest you could go either way and be happy. Since these wheels might be exposed to a bit more of a beating than your fancy carbon road machine, you might be perfectly happy with a set of nice alloy rims that won't break the bank should they suffer some unintentional damage from traversing gnarly roads. If you have some extra cash set aside and you want a pair of uber cool carbon wheels you could also go that route. The carbon rims will provide some desirable compliance that will help smooth out those aggressive road surfaces and your disc brakes will ensure confident braking. . If you are confused on which way to jump we can talk about the pros and cons of both types of rims in detail. Whichever rim material you decide upon you'll want to choose a model that exploits a wider internal dimension to take advantage of all the new wider tires that are now on the market. This is where the fun begins on your new gravel bike. Running wide tubeless tires at reduced pressures for a completely different feel. More rubber on the road for added confidence and improved cornering. It's all good!
Tire choices are expanding all the time, and with the growing popularity of taking "the path less travelled", there will be even more in the future. Many of these new tires are tubeless friendly and that's likely the way you'll end up going. A myriad of widths and tread patterns abound so you are already spoiled for choice. Your gravel bike should have tire clearance for up to 44mm tires if you want the real deal experience.
The number of gravel grinding gran fondos and similar style events is growing exponentially. You might not be signing up for the Dirty Kanza 200 anytime soon, but gravel is the new frontier so dig in, get a little dirty and enjoy. If you think you might want a pair of hand built gravel wheels I'd be more than happy to design and build you something special. Give me a ring and we'll sweat the small details until you are proudly riding some killer gravel crushers.