Derby Rims lightweight wide carbon fiber mountain bike rims

Derby Rims is a new brand designed by Ray Scruggs in Marin, CA. They, like so many of our favorite things, were born of necessity. Quite simply, Scruggs wanted a wider carbon rim. So he started making them.

Besides the width, the key feature is the bead lock ridge, which holds the tire’s bead against the sidewall and prevents burping. He also says that helps them seat up quickly, sometimes even with just a floor pump. They have 10mm deep center channels, which he says means you shouldn’t need a tire lever to get them on.

The other interesting feature is the lack of a bead hook. He says you don’t need it and it lets him make a thicker bead wall overall, about 1/2 a millimeter compared to most other carbon rims. Roll through to see the inside profile…

Derby Rims lightweight wide carbon fiber mountain bike rims with no bead hook

Considering the widths, they’re pretty light:

  • 29er – 35mm external / 29mm internal / 32mm deep – 465g
  • 650b – 40mm external / 34mm internal / 32mm deep – 450g

He recommends using the thinnest tubeless tape and only running it over the center channel, just enough to properly cover the spoke holes.

Derby Rims lightweight wide carbon fiber mountain bike rims

The matte black featureless finish is pretty tasty looking, letting them fit into any color scheme you’ve got going on. The deep round shape does mean you’ll need 44mm valve stems.

He’s been selling them direct for about a month now, check them out at He’s looking at EN testing to be able to sell them abroad, and is considering a lighter weight race version that would have about a 180lb rider weight limit. The current version caps out at a more-than-adequate 250lb rider limit.

Technically, he’s not making them, just designing them. They’re made in China by a manufacturer that produces for others and their own house brands, but says these are his design. He says they’ve only had one failure so far, under big rider that cracked one edge, causing a bit of air leakage but still letting him ride out. Since then, Scruggs modified the layup a bit and added a couple layers of carbon reinforcement.

Retail is currently $379 per rim, but he’s got them on an introductory special as of this post. That deal could end anytime and standard pricing could go up, so check ’em out now if you’re interested.


  1. @copycat I’m with you… I don’t know why so many companies are pushing out the 26″ format, the forgot that the starting point for those companies making money was the 26″ wheel. For me any company not producing any 26″ wheel part now and previously promoting the 26″ wheel heaven will be banned from my list. Sorry industry but paying with the same coin is fair.

  2. Please stop using the terms “Super, Ultra, Mega, Massive” or any other terms that have absolutely no bearing on what the product actually is or does. If these are Super wide, what are the 44mm rims 80mm rims, or 100mm rims?

  3. @blake: I agree. I guess 100 mm would be stupidly-humungous-eye-poping wide if 40 is super-wide? These rims look tempting. I understand that 650b / 29er probably make the most business sense, but funny enough I still have a 26″ mtb that I still ride and I’m looking for new lighter rims (I also have a 29er). Too bad Derby Rims isn’t an option.

  4. @Fabricio, @copycat, @wheelz:

    If you need rims for a DH bike, these ain’t gonna do it. If you insist on 26″ wheels for any other use, you can find all the hardware you need for almost-free any time of year on ebay.

    At this point, bitching about a lack of new 26″ product is a lot like pointing out that none of the new frames and forks work with rim brakes. All it does is reveal the fact that you don’t want to buy a new bike – which is fine – yet you’re somehow still interested in blowing four digits on new wheels.

    Run your current bikes into the ground. You will replace them with a bike that has the biggest wheels that can work well for a rider your size, and if you’re any taller than 5’1″, that bike will have 27.5″ or bigger.

    These rims are cool. They address an important factor in wheel dynamics: width. Tires get bigger, rolling resistance drops, tire pinches decrease, and traction improves with extra rim width. If I had $1k to throw at a new wheel build, I’d be all over them.

    Big thumbs up to Derby for axing the 26″ size. 26″ may yet become a kid’s bike again, as it was in the beginning.

  5. I’m not so sure about the hate here. The guy is filling a market demand for cheaper carbon rims. The equivalent aluminum rim, like a Stan’s Flow EX which is still narrower, is 60 grams heavier per rim. 120 grams of rolling weight is pretty significant and the stiffness benefits should be obvious to all. Would we all rather have a set of Roval’s or ENVE’s? Sure, but upgrading your wheels to carbon for $600 or so, is pretty solid value for money.

  6. Wow those look nice! Nice to see a rim with a deep center section. If they where 60-70grams lighter they would kill most competition in the XC segment.

  7. “These rims are cool. They address an important factor in wheel dynamics: width. Tires get bigger, rolling resistance drops, tire pinches decrease, and traction improves with extra rim width. If I had $1k to throw at a new wheel build, I’d be all over them.”

    Yup. I’m not too fussed about rim weight but at ~300g a set less and potentially stiffer and more durable than my P35s, I’ll bear these in mind for my next wheelset.

  8. And I was really hoping that all the whining about the lack of 26″ new tech would not migrate from PB to BR.

    I guess I had better complain to BBS and Michelin that they don’t make the wheel and tire size I want for my car either.

    And yes, I do own a 26er.

  9. @Chainwhipped: 26″ wheels are far from being a thing of the past. I am still riding 3 26″ wheeled mtbs and don’t plan on going 27.5 or 29 in the future. Around me and in my club (more than 150 members), most people still ride and enjoy 26″ wheels. If you don’t realize that 27.5″ is just another arrow in the quiver, that’s your choice, but remember how manufacturers hoped aboard the 29″ wheels train a few years ago, claiming they would be superior to 26″ wheels? It was a new epiphany! Now, the same manufacturers (except Niner, of course) are pushing the same messages about 27.5 wheels. I’m not against progress, far from it, but phasing out 26″ wheels is the worst move a manufacturer can make, IMO. Time will tell, but the ones who did (or will do) won’t have my money.

  10. When it comes to carbon rims, being lighter is not the point. Carbon rims are Waaaay stiffer than aluminium and therefore provide more accurate steering and less wheel deflection.

  11. He makes 26″ rims, I just ordered a set. I’m putting them on a brand new “Divinci Dixon”.Here is a link to his spec page & the specs on the 26″ rims.


    26” x 40mm
    Heavy Duty & Downhill layup options
    Weight +/-10: 440g [Heavy-Duty] or 465g [Downhill]
    BSD: 559mm
    Outer width: 40mm
    Inner width: 34mm
    Channel depth: 8mm
    ERD: 522mm

What do you think?