WTB i76 Fat Bike Rims: Quick Review

Note: Guitar Ted was provided a set of WTB i76 Fat Bike Rims as part of a wheel build he was contracted to build. WTB is not sponsoring this review in any way. All opinions are Guitar Ted's.

Cross-section of the WTB i76 rims. (Image courtesy of WTB)

N.Y. Roll has purchased a set of these WTB KOM Light i76 rims and had sent them home with me to build up a set of wheels for him. So, I figured why not give you all an overview of these rims?

What It Is: WTB now offers these in 27.5" and 26" diameters. They have an "open cavity" design which should enhance rigidity. WTB makes these rims from 6069 alloy and uses a pinned construction technique to join them. Either diameter is available in 32 hole drillings only and costs $159.95 USD each. The inner rim width is, as you might guess, 76mm. These are tubeless ready as well. 

 First Impressions: The i76's do not have big holes drilled in them, or an open design in between the bead seats, as some of the original fat bike rims did have. The i76's look more like solid, single walled rims which are generally cheaper and of lower quality. Do not mistake these rims for those!

The solid, single wall section in the middle of the i76's should allow for easy tubeless rim strip installation. "Should" being the operative word here. More on that in a bit. Furthermore; the section where the spokes sit is double walled, further making a rim strip installation easier and more efficient. 

I have the 26"er versions here and they weighed in at about 800 grams a piece. For comparison, Surly "My Other Brother Darryl" rims, which are of similar width, weigh in almost 100 grams lighter and have a welded seam. Of course, those Surly rims are true single wall construction and have huge cut-outs.  

The channels where the spokes sit help keep those spoke's nipples from extending into the rim well area. This should allow for much easier taping off of the rim well area for tubed or tubeless usage. 

Those channels also theoretically make this rim stronger laterally and torsionally. I've built up single wall fat bike rims, and I have worked on several which displayed twisting of the rim cross section which you cannot true out. 

The one thing I did notice which I wasn't very impressed with was the rim joint. These WTB fat bike rims are of the "pinned and sleeved" type, meaning that where the extrusion ends meet they are joined by "pins" to keep the ends aligned. A good pinned and sleeved joint is barely noticeable, however; on these rims there is a noticeable gap.

This gap may narrow up when a rim is tensioned after building up the wheel, but it wouldn't be a bad idea to run some glue in the joint (I've had Super Glue suggested for this purpose), which would make setting up the rims tubeless a much easier task. This is not an unusual thing with fat bike rims and especially with the earlier efforts in fat bike rims, this was commonplace. It would have been nice had WTB made these like the Surly offerings and had these welded, but that isn't always done perfectly well either.

Notice in the image to the left here that the rim join is allowing light through. Also note the spoke nipple and how it sits down below the inner rim well surface. (Spoke not properly tensioned in this view) Finally, you might note the venting holes in the extrusion near the bead seat. These would have to be covered by rim tape also.

Build Process: These rims went together well. As well as any rim, really. As long as you calculate the spoke lengths properly, there should be no issues with these as far as the process goes. You might want to be a little extra careful about scratching the wide rim surface with your spoke ends as you lace the wheel though.

Conclusions: I think these are fine rims. They compare favorably with DT Swiss' fat bike rims and others in this width range which feature single wall construction and big cut outs for weight savings. You can get cheaper rims, but those are going to be solid single wall rims with much heavier weight. 

The dual channel extruded into this design is where I think these rims set themselves apart from the herd. So far I feel as though these make the WTB i76's stiffer torsionally and I would think radially as well. Not that you couldn't ding them up. These are aluminum after all. But I think these will hold up a bit better than others in this category. 

The price seems fine. You would have to spend considerably more to get lighter, stiffer rims, and they likely would be carbon Nexties or another similar Chinese brand fat bike rim. There just is not a lot to choose from in terms of rims for fat bikes, in comparison to other types of rims.

Thanks to N.Y. Roll for the opportunity to check tehse out and build up a set of these into wheels.  

Notice: Tomorrow an embargoed press release post coverage will make its debut at 11:00am CST. I will have an early post up for my morning readers, but do check out the Gravel Grinder News post tomorrow at 11:0CST.