Why carbon rims?

[Baron Blubba]

Originally Posted by prototoast

Other than all the benefits of carbon rims, which I don't care about, why should I buy carbon rims?

"Knock it, don't try it."

[mattscq]

I imagine if you hit something hard enough to crack a carbon rim, you'll also crack an alloy one. Sure there's some degree of deformation in alloy and it'll dent instead of shatter but if it's going to be a stiff rim, it's also going to be a (relatively) brittle rim.

It's crazy that they made 1300g alloy wheelsets but the high end alloy market is basically dead now. Then again, those wheels were like $2k new so it wasn't like it was any cheaper than carbon today.

[nmrt]

My 40 mm carbon disc wheelset with carbon-ti hubs are 1240 g. That is a lot of savings from the HED rims.

Yes, I agree 1600 g was not "heavy"...6-7 years ago. Now, you can build really light wheels. Would one want them is another question. But 1600 g is heavy IMO.

Originally Posted by flying

If I recall correctly the HED's are not heavy for a 40mm at under 1600gr

But that aside the weight penalty for carbon is also that the bike industry next claimed due to carbon wheels it was necessary to move to disc brake as carbon not stopping well in the wet with rim brakes.... so I guess we could say ultimately carbon wheels added a bit of weight there of the "total" package

But mainly as I said development stopped so we will never know how far it could have gone.

[MikeD]

Originally Posted by HowardCosellsPR

I find that carbon withstands way more abuse before failing. Period. That said, I don't ride ultra-weight weenie wheels and... im little (135-140lbs). I might still ride aluminum on road (though I don't), but the value proposition for me especially gravel and dirt favors mid-range carbon. Simply less maintenance and durable as it gets (for me). As for braking, I also don't understand why anyone who lives in places with hills and/or rain doesn't ride discs... but... I suppose burying one's head in the sand can be relaxing at times.

I cracked my first carbon wheel while 'road' biking two weeks ago. Hit a baby-head at 30mph while descending a very rocky jeep track in Arizona . The sidewall was crushed/cracked, but the wheel was totally solid/true otherwise. I rode out after installing a tube. Oops. Had that wheel been aluminum, I likely would have taco'd the wheel and gone over the bars. That said, the same wheel had taken so many hits, over the last 6yrs I was kind of shocked that it hadn't happened sooner.

Perhaps apples to oranges but.... I raced mtbs fairly seriously between 1989-1999. In that time, I tacod, cracked, bent, and dented a countless aluminum rims. Some of these wheel incidents resulted in injury, some did not. I've never broken a carbon rim while mtb'ing and, now, only one while gravel-riding. So... my score is 1 carbon fail than required putting in a tube vs like 100 alu failures that resulted in anything from hospital visits to long walks home.

Hell, I can count on my hand the number of times ive even had true my gravel or mtb carbon rims.

100 failures? BS

[Pastashop]

https://youtu.be/VfjjiHGuHoc?si=W_wFBO7m_Q1XkTei

[Mark McM]

Originally Posted by nmrt

My 40 mm carbon disc wheelset with carbon-ti hubs are 1240 g. That is a lot of savings from the HED rims.

Yes, I agree 1600 g was not "heavy"...6-7 years ago. Now, you can build really light wheels. Would one want them is another question. But 1600 g is heavy IMO.

Well, it's a bit of an apples/oranges comparison, to compare recent all carbon disc brake wheels to a carbon/aluminum rim brake wheels from a few years ago. Particularly since the wheels don't move on their own, they have to be part of a complete bike.

The primary reason for the aluminum brake tracks on the HED wheels is braking performance. As has been noted, the recent move to disc brakes has been largely fueled by the issues with braking on all carbon rims. Since carbon disc brake wheels need, well, disc brakes, you have to also consider the extra 600 grams or so of weight added to the bike due to disc brakes, and not just the 360 gram reduction from the wheels alone. Which means that when you look at the big picture, those 1240 gram carbon disc wheels may result in a heavier bike, by total weight.


Just for yuks, I weighed a couple of my bikes for comparison. I have a Specialized Aethos (disc brake) with Roval Alpinist CLX wheels. The wheels have 33mm deep carbon rims, and weigh 1260 grams. Total bike weight, 14 lb. I also have a set of HED Jet 4 wheels (aluminum/carbon rim brake) which weigh 1600 grams, which I installed on a Trek Emonda (rim brake). This bike with the HED wheels had a total weight of 13 3/4 lb. So the bike with HED Jet aluminum carbon wheels was lighter than the bike with the 1260 gram all carbon wheels, while still maintaining the good braking performance of aluminum brake tracks.

[LadyDog]

Originally Posted by ridethecliche

The specialized roval alpinist slx wheels are al and light if you're interested in that sorta thing.!

And our Baron has some for sale. Sorry lazy with the link, but easily found.

[nmrt]

I agree with your analysis -- a lighter bike can be built with a rim brake bike with less effort and less botique parts than a disk brake bike, especially the recent ones where they have AXS gruppo on it.

All I am saying is that while the overall bike weight has become heavier (AXS, integrated front end etc.), it is common to see wheelsets weights for disc in the 1200 g-ish range. This used to be the vaunted rim brake tubular wheelset weight realm from the yester years.

In this respect, 1600 g is h.e.a.v.y. if you want disc brake wheels.

Originally Posted by Mark McM

Well, it's a bit of an apples/oranges comparison, to compare recent all carbon disc brake wheels to a carbon/aluminum rim brake wheels from a few years ago. Particularly since the wheels don't move on their own, they have to be part of a complete bike.

The primary reason for the aluminum brake tracks on the HED wheels is braking performance. As has been noted, the recent move to disc brakes has been largely fueled by the issues with braking on all carbon rims. Since carbon disc brake wheels need, well, disc brakes, you have to also consider the extra 600 grams or so of weight added to the bike due to disc brakes, and not just the 360 gram reduction from the wheels alone. Which means that when you look at the big picture, those 1240 gram carbon disc wheels may result in a heavier bike, by total weight.


Just for yuks, I weighed a couple of my bikes for comparison. I have a Specialized Aethos (disc brake) with Roval Alpinist CLX wheels. The wheels have 33mm deep carbon rims, and weigh 1260 grams. Total bike weight, 14 lb. I also have a set of HED Jet 4 wheels (aluminum/carbon rim brake) which weigh 1600 grams, which I installed on a Trek Emonda (rim brake). This bike with the HED wheels had a total weight of 13 3/4 lb. So the bike with HED Jet aluminum carbon wheels was lighter than the bike with the 1260 gram all carbon wheels, while still maintaining the good braking performance of aluminum brake tracks.

[zmalwo]

the difference between a deep carbon wheel and a shallow allow wheel is so small that it's only noticeable more than a single percentage during descent. on uphill deep carbon wheels do not offer any advantage at all. for safety reasons allow wheels for training is a no brainer imo.

[fogrider]

Originally Posted by prototoast

Other than all the benefits of carbon rims, which I don't care about, why should I buy carbon rims?

Then don't buy them! I went through aluminum wheelsets every couple of years. I was truing wheels and replacing spokes every month. Carbon wheelsets rider smoother, stay true and take a beating. For all those the want to ride aluminum wheels, that's great, I'm not hear to convince anyone. But if anyone ask, I'm happy to say carbon wheels are better in every way.

[KonaSS]

Originally Posted by zmalwo

the difference between a deep carbon wheel and a shallow allow wheel is so small that it's only noticeable more than a single percentage during descent. on uphill deep carbon wheels do not offer any advantage at all. for safety reasons allow wheels for training is a no brainer imo.

Well, the difference depends on which wheels you are comparing. Which carbon wheel and which aluminum wheel? The difference between any decent aero carbon wheel and say an old box section aluminum wheel is probably close to 10 watts at a fast group ride pace. And you get some portion of that benefit the entire ride, not just on descents.

People who train and care about performance know that 10 watts is huge. Some people will follow a detailed training plan all year and will be happy to gain 10 watts. So in that perspective, a pair of carbon wheels looks like a great value.

[callmeishmael]

At the top level, the aero benefit is such that you're just not competitive on an alloy wheel. It's as simple as that. A box section alloy is giving up 20-30w to a high end, 45-50mm depth carbon wheel at pro speeds. That's a game changer.

The same comparison is probably 10-20w at decent amateur speeds. A gain of 20w at CP would be a really good year's training for me, and isn't far off my January vs July fitness disparity.

Moreover, given that rim vs disc is now a done debate (at least on mainstream, off the shelf bikes, and certainly at the pro level, the major disadvantage of carbon (wet braking) likewise disappears.

Ok, carbon is a bit more expensive (though less and less so as more manufacturers offer 'affordable' carbon models and higher end alloy ones move in lower and lower volumes) but it's also tougher at the same weight, too.

Finally, and though this is chicken and egg, there's just not much development going into alloy rims: what you've got is likely what you'll get. In contrast, carbon wheels have arguably seen the fastest and most significant developments in bike tech of the last 5 years (perhaps after tyres, on reflection).

I've got alloy rims on my (turbo) trainer/occasional commuter/spare road bike, and when I'm out for a bimble or cafe ride they don't affect my riding enjoyment one iota. But whenever I've taken it out and ridden it hard, it's definitely slower.

[El Chaba]

Data point: Nobody can drop me on the local group ride when I am using box section tubular wheels. Many of these wheelsets are twenty years old and sometimes as old as forty years. It really doesn’t matter to me what the pros are using or how many watts I am “giving up” or whatever. I understand that my findings are in contradiction to what the industry and its adherents are pushing. I would write that I don’t care, but that is not true…It gives me a great deal of satisfaction.

[RoosterCogset]

Originally Posted by bfd

I recently bought a set of BTLOS carbon rim brake wheels and love them! They hold up to my 200lb weight, are aero (45mm deep rims), and super light (the wheelset came with a listed weight of 1305g (729g rear and 576g front)! That's tubular wheel weight!

The weight was a surprise as the estimate they gave when I finished selecting the parts was 1325 +/- 25g, so I was expecting 1350g!
Good Luck!

Aren't you worried about where they left out the 25g of material?

[NHAero]

I've been on carbon disc wheels less than 3 years on my all road bikes. What I've noticed, vs. the alloy disc wheels on my FS29er and old 26er, is that even though the wheels are lighter and lower spoke count, they are still true. And they've taken some real hits. Now for the first time I have some lightweight rim brake carbon wheels (thanks to Clean39T) and it will be interesting to see how they fare. I have to say the sound the pads make (Swissstop) when braking isn't lovely, it makes me think they're scratching up the rim, but when I look everything looks fine.