Ever since building some 30mm wide Salsa Semi rims for my single speed I’ve been enamored with wider (but not quite fatbike width) rims on normal mountain bikes. I feel that so long as the tire remains ~20% wider than the rim itself the benefits are great: more sidewall support, less tire roll when cornering, and higher volume of air all while rolling resistance seems the same. I recently played with building up a Velocity Dually-based front wheel for the El Mariachi Ti. At 45mm wide it made a 2.4″ Schwalbe Racing Ralph about 63mm wide and felt great to ride, but the heavy rim was noticeable. For me the holy grail would have been a wide wheelset that isn’t any heavier than a more-typical XC set, like the Shimano XT / Stan’s NoTubes Arch EX set that came with the El Mariachi Ti.
With the recent XT freehub failure I got to thinking seriously about new wheels, and after a few months of trawling eBay I found myself with all the parts needed to build up just what I wanted at a sane price: 35mm wide carbon fiber rims from China, high-quality hubs from Switzerland, tires from Germany, and spokes from… wherever spokes come from.
At the same time I was able to switch to a 142×12 rear through axle, which is something I’d been wanting to do for a while, since I’m quite fond of the positive engagement and installed-straight-or-not-installed-at-all nature of a through axle. They can’t become skewed like a traditional quick releases which can be a bit skewed.
In the end they came out great, and even though I only have an hour and a half of riding on them, I’m quite content. Read more about the build below the fold…
Part List
The build for this wheel set came out as follows, with prices (including shipping) listed:
Hubs: DT Swiss 240s Centerlock: Fifteen (Front), 142×12 (Rear) – $383.83 (One was missing a lockring which cost $20.)
Rims: Light-Bicycle 35mm Hookless Carbon Fiber, 29er, 32 Hole, UD / matte finish – $396.50
Spokes: Ritchey-branded DT Swiss Competition (80 Spokes) – $45.62
Nipples: DT Swiss Standard Alu – $40.78
Front Tire: Schwalbe Racing Ralph 2.4″ HS391 (Old Pattern) – $51.07 (Already had)
Rear Tire: Continental Race King 2.2″ Protection – $50 (via Erik)
Rim Tape: Velocity Velotape 24mm – $15 (Already had)
Valve Stems: Stan’s NoTubes 44mm Valves – $14.84
Valve Stem Caps: Red from Q-Tubes SuperLight Tubes – $0 (From spares pile)
Everything added up comes out to $977.64, but a few of the parts were needed anyway (new rear tire), and others were sitting on the shelf unused (front tire, rim tape), so out of pocket, not-already-purchased was $861.57. If things go as planned I’ll no longer need the the Stan’s wheelset and will be able to sell that, further offsetting the cost.
Contrary to Light-Bicycle’s claim of 589mm, I measured the the ERD on these 35mm rims as 592mm. With the DT 240s hubs this resulted in spoke lengths of 288mm (left) and 289mm (right) for the front wheel, and 289mm (left) and 287mm (right) for the rear. I was able to get Ritchey-branded DT Swiss Competition spokes (photo) from Ben’s Cycles’ eBay store in exactly the lengths needed. These spoke lengths worked out very nicely and the wheels came together great.
DT Swiss aluminum nipples in black were chosen for light weight and appearance, and since I’ll mostly be riding these in fair weather corrosion shouldn’t be an issue.
Tire Width / Volume
After allowing the finished wheels to sit with the tires at ~30 PSI for a couple of days, the tire casings (excluding protruding knobs) measure at 61.3mm and 59.2mm (front and rear). When compared to the 56.6mm and 53.0mm size of the previous Arch EX / 2.25″ Racing Ralph / 2.1″ Kenda Small Block Eight setup (photo) the front is 4.7mm wider and the rear is 7.2mm wider. Presuming a 622mm radius of the center of the tire, this is a 17.3% increase in volume on the front wheel and 24.6% on the rear. I suspect this’ll do very nice things for the feel of the bike, even though I’m still using fast-rolling tires.
Weight / Mass
The main concern with going to wider rims is usually an increase in rotating mass. With the advent of low-cost, wide carbon fiber rims much of this has been mitigated. The Light-Bicycle rims that I received came in at 420g and 422g (front and rear), which is about 40g each lighter than the Stan’s NoTubes Arch EXs they are replacing. Combined with lighter weight hubs, even using heavier, wider tires resulted in an overall lighter set of wheels.
Because of the aluminum freehub body on the DT Swiss hubs I chose a Shimano XT (CS-M771-10) 11-36 cassette (photo), as its solid aluminum carriers should mitigate damage to the splines. The old cassette was getting near 3000 miles and due for replacement, so buying a new one at this point wasn’t much of a bother. At 339g this is is about 27g lighter than the SRAM PG-1050 previously used on the bike, which also helped to save weight.
Overall, the bike is just a bit lighter with these much-wider wheels than it was when originally built (26.00 pounds w/ Garmin Edge 510 + blinky light mount vs. 26.10 w/ Garmin Edge 500 and no light mount). This meets my desire of wider rims without much additional weight.
Here’s the breakdown of mass for each part:
Front Hub: 126g
Rear Hub: 228g
Front Rim: 420g
Rear Rim: 422g
Front Tire: 634g
Rear Tire: 644g
Rotor Lockring: 8g/ea
Cassette: 339g
Valve Stems: 8g/ea
Aluminum Nipples: 9g for 32
Rim Tape: 8g/wheel (estimated)
The final result for each each complete wheel, with sealed tire, rotor lockring, and cassette (but without rotor) is:
New Front: 1.49kg
Old Front: 1.55kg
New Rear: 1.93kg
Old Rear: 2.18kg
Total Savings: 0.31kg / 0.68 pounds
Along with going to wider rims, the new wheelset allowed me to switch to a 142×12 rear axle using the Salsa Alternator Dropout Set 12×142 w/Maxle set. This appears to weigh a bit more than the previous quick release (I didn’t measure), but this is offset by the lighter wheels. I’m really happy with how the Salsa set went together. Installing the rear wheel with the SRAM Maxle Lite was extremely simple, I just slid it into place, held it while inserting the axle, then tightened the axle down. There was no need to hold the wheel up in the dropouts while tightening down the axle like with a traditional QR.
The Ride
Most importantly, the ride. This afternoon I headed out for a shakedown ride with the wheels, heading from home up through River Bends, over to Holland Ponds, through Bloomer, then up to some friends’ place in Rochester Hills. In short, it went quite well. At first I was a little hesitant, but upon hearing no spoke pings and after a few small curb drops feeling fine I headed into River Bends and started riding the single track.
The ~27 PSI that I’d initially filled them to was a bit much, so after washing out in one corner I dropped the pressure a bit, and things got better. I still have to play with the pressure a bit more, but riding through familiar trails the wheels felt just like what I was hoping for: wider, with a bit more traction, and still great rolling resistance. I even set a couple Strava PRs on otherwise familiar pieces of trail, and I didn’t feel like I was pushing particularly hard.
Tomorrow I’ll take them out to Potawatomi and see how they fare there. I have high hopes for them.
More Photos
Additional photos of the building of the wheelset, through axle setup, and complete bike can be found in my photo gallery: