Ibis 941wheels

This is my first carbon wheelset. I’ve been pretty much scared of carbon components because I remember when they used to catastrophically break (i guess they still do but less often).  I had one of the first LP Components carbon riser bars around 1994. But since then I’ve avoided carbon like the plague. But last year I bought an Answer Pro Taper 20/20 bar and loved it.  I bought XX1 cranks and the’ve held up well.  When possible I’ll go with Titanium but I’m becoming more open to carbon after seeing it succeed in places I never thought it would or could.  So when I saw Ibis was going to release a fat-rim wheelset I kinda got excited.  The current list of rims available for 29+ bikes are all relatively heavy because they’re…fat! The rotational mass of the bigger rim, tire, tube all makes for a more sluggish ride.  With a steel frame the bike was weighing in at around 29lbs with a Fox Talas 32.  So…hell, why not.

Rear wheel weight is almost a full pound lighter than my Rabbit Hole with a DT-Swiss 250 hub.

The rims appear very nicely made and have a hookless bead design which supposedly is stronger when you inevitably get a rim shot when running low pressure.  Time will tell.  I have the SRAM version of the wheel, one driver is included in the cost of the wheelset.  BTW, I offer these with complete bike-builds if you are purchasing a frame from me.

The one hangup i had was when I swapped the Maxle rear axle caps for the quick-release caps they supply (at an additional cost).  When I tightened down the cassette the axle stopped turning. It turned out (pun intended) that the QR cap flange was too wide by over 1mm, and the inside of the threaded cassette nut (that is integrated on the SRAM 11-spd cassettes) was pushing against it enough to stop the driveside bearing from turning.  Aron from Victory Velo in Auburn figured it out by backing out the cassette a little and then the axle would turn just fine.  So I went back to my shop and turned down the cap in the lathe so it’d pass through the hole in the cassette. Reinstalled it all worked just fine and I have several hours on it with no issues.

The Trax Fatty’s sealed up well with Stan’s.  One held air right away, the other needed some more Stans and a few days to hold air (2.5 cups of sealant).  I’ve been running 10-15 PSI depending on terrain and here are some initial thoughts:

– i notice the lateral stiffness of the rims. More rigid of a ride but running tubeless it can feel cush at the same time. But…

– I like the feel of wider rims better and the 41’s are on the short end of the spectrum. It’s the quality of the ride, not really sure how else to put it, is better on the wider Rabbit Hole rims. The tire tracks better with lower pressure with wider rims and feels more cush. Lower pressure feels better on a wider rim, simple as that.  To be fair, these wheels were designed to be use with 2.5″ tires max, they probably didn’t think about 29+ or 27.5+ riders when designing these.

– Even with the bike being 1.7lbs lighter I can’t say i noticed the lower rotational weight while pedaling. Mostly I noticed it when I picked up the bike over stuff and while steering – turning the front wheel to place it or pop it up/manual.  The lower rotational mass was definitely apparent while turning the wheel side to side, less of that “29er effect” where there’s more resistance from the added wheel’s diameter. But as far as breaking any of my previous personal bests…not so sure it’s going to matter all that much.

2 Responses

  1. Looking forward to hearing how these hold up in the long run with the occasional rim strike etc.

    • Me too John, ive heard a few stories of riders if the enduro sort riding and hitting them really hard and not doing a thing to the rim. I’m hoping thats the case for me. The rear hub issue i had bugged me, and the bearing is still dragging. Will try to swap the driveside bearing soon to see if that helps.

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