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Just Ask Matt: WTB KOM and Off Shore Carbon Rims

January 16, 2015

@fietser writes:

“Currently I am looking at piecing together wheels. Found a good deal on KOMs but I am not sure if they are what I am looking for in a rim. They are touted as being as light as carbon but without the price tag (my kind of language). However, does the lack of weight come at a cost (i.e. strength)? The rim profile looks very similar to the Frequency with the exception of the I Beam running down the middle, the KOMs do not have it. WTB claims these are an Enduro/ Trail rim which is what I am in the market for.”


I have never owned a set of KOMs myself, but I have been riding Frequencies for years now. I actually ran the Frequency i25s on my downhill bike last season. The rims have a couple small dents, but that’s to be expected from a solid season on any downhill rim I think. I don’t think I’d go as far as to trust the KOMs for this application, but certainly they would be reasonably tolerant of all-mountain riding, and a perfect choice on a mid-travel trail bike. I have had great results from the riders I’ve put out on these rims, and they will definitely be the next rims I buy for my trail bike. It is also worth noting that Santa Cruz specs a similar rim (The WTB Asym, which is the same as the KOM with offset spoke holes) on nearly the entire range of their bikes, including the beefy, 165mm Nomad.

One feature I absolutely love about the WTB rims is the TCS tubeless design they use. The TCS rims feature a bead profile that UST certified, but obviously requires tubeless tape to seal the spoke holes. Though the tire choice plays a factor here, this makes for a bead that hangs on to the tire remarkably well, and permits using low pressures without burping. I run my front tire at 17psi and I have never burped it. Even with the tire completely deflated it is somewhat of a fight to unseat the bead by hand.

Forum Discussion here:  https://www.ridingfeelsgood.com/topic/wtb-kom-i23-any-experience/


@flow_rider writes,

“I’ve been tossing around the idea of a chinese carbon wheel build (something I saw over at mtbr). Basically, these rims: http://www.carbonbicycle.cc/proshow.php?cid=62&tid=8&id=142#.VLA4XGTF-3i plus DT350 hubs and Sapim Laser spokes. Seems to be a really cost effective way to get carbon wheels. Feedback over at mtbr has been good. What do you think?”


It’s hard for me to comment on Chinese carbon rims. I’ve seen some that are of good quality, but some real flops, as well. To most common issue I see with them is that the spoke bed thickness varies along the rim, and the rims aren’t particularly straight. This makes it very difficult to achieve a good build. However, this is not the case on all of them. Some also seem to not have impact strength that is much beyond a good aluminum rim. It’s hard to argue with the price, as they come in barely above the costs to a top quality aluminum rim. However, whether even the slight price increase is worth it over a great aluminum rim is totally up in the air. The rims in the link you posted seem frighteningly light to me. They are both lighter and wider than Enve’s comparable 29er rims. If you want to play it safe, and the terrain you are riding isn’t too gnarly, then the aforementioned WTB KOMs are a great option.

DT350s are my pick of hubs in that price range. When I don’t feel like splurging on Chris Kings, these are the hubs I buy. They have proven to be durable, the Star Ratchet assembly is a great freehub design, and they are easy to service.

I cannot recommend Sapim at all. I have seen such an astronomical amount of failures on Sapim spokes that I now refuse to build wheels for customers with Sapim spokes or nipples. I have been building wheels almost exclusively with Wheelsmith spokes for about four years now, and I don’t know that a single spoke has broken on any of them. DT spokes are excellent, as well. I also don’t recommend running the extra-thin 1.5mm butted spokes on anything by the most light-duty XC bikes. I experimented with DT Revolutions a couple years ago and found the thinner spokes sacrifice stiffness quite a bit.

Forum Discussion here: https://www.ridingfeelsgood.com/topic/off-shore-carbon-rims-just-ask-matt/

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Matt Faulkner was born in North Bay, Ontario, where he started mountain biking and racing downhill at the age of fourteen. He completed a diploma in Mechanical Engineering Technology at Georgian College in Barrie. After spending a few years in the engineering departments of mining companies, he switched over to the bike industry. He now lives and works as a bike mechanic in Downtown Toronto.


  1. Thanks @Matty-f excellent information as always.
    I had actually noticed that the Santa Cruz bikes all seem to be rolling on WTBs but didn’t realize that the Asyms were in the same league as the KOMs – interesting.

  2. Is there a Wheelsmith spoke that you’ve found best? Straight Gauge vs Double Butted?

  3. I only build with double butted spokes. They are lighter and stronger than a straight gauge spoke, and still sufficiently stiff. The only advantage to a straight gauge spoke is that they are slightly cheaper.

  4. The weight weenie 1.5mm spokes actually work quite well when used on the lower tension side of a wheel (drive side on front, disc side on rear). I have a couple rear wheels that are identical except for the spokes, one is all DT comps while the other is DT comps on one side and Revolutions on the other. As far as I can tell they feel the same, and both have stayed true equally well.

  5. When I asked WTB about it, they told me the Asym rims are actually kind of in between the Frequency Teams and the KOMs. They are lighter than Frequency rims because they don’t feature an I-beam style structure inside, but they’re still a bit heavier than KOM rims.

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