The line of carbon wheelsets from Ibis Bikes gets the bulk of the attention in cycling media. However, the entry level 738 and 938 wheels equipped with alloy rims may be the best value going today.
Rim width and tire sizes have been all over the place for the last few seasons; if you haven’t been keeping up, all the new sizes and standards can be overwhelming. And that’s not even considering the addition of new hub standards. It’s easy to simply ignore the reviews and new releases and stick to what’s been working, but after spending time ripping trail on the wide 938 wheels from Ibis, we’re loving the crazy amount of grip in turns.
Our initial foray on Ibis wheels was almost two seasons ago now, riding the Ibis Ripley equipped with their carbon 941 rims. With a 140mm travel fork, the bike was extremely capable, easily traveling at speeds normally reserved for bikes with more travel. Test rides on foreign places isn’t the same as hitting your local trails though.
Carbon rims put a hurt on the bank account though, and when sourcing wheels for a new 29″ project bike, I was looking for something that hit a sweet spot between value and performance. The Ibis 938 wheels stood out with an MSRP of only $549.
At this price, the wheels come in at $100 less than many other wheels in the category, while weighing in at only 1935 grams. Considering the width of the rims, add it to the value and you have yourself one hell of a bargin here.
The 938 designation refers to wheel size as well as outer rim width: “9” for 29″ and 38 being the outer width in millimeters. That said, when comparing the width of rims these days we’re more interested in the inner width, and the inner width of the 938 rims measure 34mm.
Other notable specs include:
- Rim material: 6066 aluminum
- 32 hole, 3x lacing
- Tubeless compatible
- Pillar double butted 14/15 g spokes
- Listed rim weight of 530g.
- Available in Boost or Non-boost hub spacing
- 1935 grams listed weight
- Rim strips and tubeless cores included
- $549 wheelset MSRP.
When going with a rim this wide, tire profiles completely change which makes choosing the right tread crucial. The wide width also presents the opportunity for potential compatibility issues. Case in point: the 2.4″ Continental Trail King (Protection casing) tires I initially chose was so big it didn’t fit the Evil Following frame it was going on. The Trail King is known for a large volume casing and mixed with the short as-can-be Following chain stays, it was a complete no-go.
Sizing down to the 2.2″ version of the tire was the solution. It saved a bit of weight, (29 x 2.2″: 850 grams. vs 29 x 2.4″: 990 grams) but with tires and wheels this wide, saving weight shouldn’t be the priority, given the higher speeds easily reached with the voluminous treads. ( 850 grams is by no means a feathery tire)
Installation went much more smoothly than one might think. I managed to seat one of the tires using a high volume floor pump, but gave up and used a compressor for the second. I also utilized the aid of a compressor to seat the 2.2″ rear tire when I swapped it out several days later.
The gang at Ibis are big fans of Maxxis Minions. They’re favorites of ours as well, but unfortunately they weren’t available when I was sourcing tires.
On the trail
When it comes to wheels, there are two things I’m most concerned with; stiffness and durability. However, both those metrics were overshadowed by the riding experience that comes as a result of the expanded tread footprint. Like other 29″ wheels, the larger hoops feel like they have more flex than 26″ or 27.5″ wheels; most of this flex appears to be a result of the longer spokes. It isn’t noticable to me at the moment; as tires are over riding my sense of feel.
Big tires on 29″ rims are fast as hell. In a straight line, in turns, wherever. Attacking trail with this setup has been ridiculously fun, whether climbing or descending, clipped in or riding flats. I’m officially sold on the new “wide” standard.
I had a rocky start though, as I went through a bit of a learning period. The initial shake down ride in a local park didn’t go well, burping the rear tire and limping back to the car. After that I kept my pressure at 22/ 25 psi, and never felt the need to run more. I could have probably run less, but the thought of burping the tires again kept me in conservative pressures all summer. At 22/ 25 I felt comfortable blazing down rock gardens at speed without being concerned. That said, that’s much lower than I’m used to running, as I generally stay closer to 28-32 psi in the front with 30-35 psi in the rear on my 650 Enduro rig.
I recognize many riders would advocate for running even less pressure, but I prefer a slightly stiffer feel for aggressive cornering as I load tires and wheels solidly in the turns. Now that we’re coming into the wet season, I’m starting to experiment a bit more with lower pressures; I doubt I’ll try running less than 20 psi, as I’m already running into issues with the tire becoming unseated at 20 psi when squaring off turns. It could also be time to add a bit more sealant to ensure a solid seal.
Tires mounted on rims this wide have a different profile due to the additional width, and when leaning the bike over, I was finding there was a defined point where traction is released. While it’s fairly predictable, at some point I’ll be swapping out tires to experiment with different tread profiles. Ibis recommends Maxxis Minions, and while they’re a favorite of ours as well, they weren’t available when I was initially sourcing tires.
29 Plus-ish vs 650b+
I’ve taken to calling the 29er with these wheels and the 29er they’re mounted on the “cheater bike” due to the unreal traction on the trail, which made it feel like I could climb up anything. To get a better sense of how much traction I was getting, I swapped bikes with my brother on a ride, to compare the traction to a 650b+ tire. The 2.8″ b+ tire had the edge in terms of pure climbing traction, but the 29″ tires had a better feel and in corners once the trail pointed down. Though I’m loving big rubber and the big contact patch of plus-ish tires, I’m not sold on b+ yet, as I felt I could ride much more aggressively with confidence with more air pressure. The downside is both bikes/ tires felt like slugs on rides where pavement climbs were involved. As with anything, its a trade-off, and the trick is to find a balance that provide the optimal riding experience you’re looking for.
29 Plus-ish vs 650b Regular
The litmus test was going back to previously loved “mid-size” wheels for comparison. After spending time on the wide Ibis 938 wheels, my 650b Nomad felt downright sketchy in comparison, even with a 2.5″ Minion mounted on the front. “Standard” width rims (23-24mm internal) are never going to feel the same again. In fact, I’m already looking into options for going wider on my “enduro rig” (a Santa Cruz Nomad), and I’m considering a set of the 738 wheels. I can’t think of another wheelset that offers more bang for the buck.
I’m looking forward to experimenting with different treads, and I can’t wait to mount these things up on my hardtail. I imagine that will be a transformative experience for that bike. One thing is certain; after the wide rims of the Ibis 938 wheels, going back to the old standard has been disappointing. All my bikes in all wheel sizes are going to need wider rims.
Though I’m admittedly late to the party, the ride on these rims is amazing. I’m still learning how much traction I actually have with these wheels. They offer significantly more grip in turns, and while they roll slowly on hardpack or pavement, on the trail they just feel like regular wheels. Unlike previous experiences with plus tires, I didn’t feel like I was giving up anything terms of playfulness or fun factor. The roll-over effect of 29″ wheels is amplified with the additional tire foot print, and I forgot I was on a bike with only 120mm of travel a few times. They’ve proved durable as well – I’ve logged a few hundred miles to date, and the wheels have only received minimal truing.
The 938 wheels are one of a number of recent releases from Ibis. Several new models feature carbon rims, with 2 models (a 29″ and 27.5″) in aluminum. The new 735 carbon comes in at a very reasonable (for carbon) $1799.00, but for the money, the 938 aluminum wheelset are worth taking a close look at. For riders looking for maximum traction, the Ibis 938 alloy wheels make sampling the waters a very affordable proposition.
Learn more about Ibis wheels at Ibiscycles.com