Carbon Wheels with Rim Brakes - Obsolete?
 

I just purchased a cheap road bike (Trek Emonda ALR 5 2018) with rim brakes and plan on upgrading it with a used CF wheelset, to get the best bang for my buck.

Of course I've watched a bunch of videos and read articles beforehand, but I'd still like to know what the community thinks.

In the interest of a balanced discussion I'll present common arguments made in favor and against rim brakes with CF wheels.

Pro: maintenance, weight, affordability
Cons: outdated, degenerative, ugly

https://cimg4.ibsrv.net/gimg/bikefor...c82b110a47.jpg

My daily driver and MTB are certainly modern regarding all the latest tech trends, however my race bike and soon-to-be-upgraded TT bike are still 11sp and mechanical. And I think I may keep it that way specifically for the affordability reason. Lots of good used wheels out there. And Giant still makes rim brake frames, including the Trinity, which I have my eye on for a new rim brake TT rig. Don't wanna get new TT wheels if I don't have to.

I have Di2 12sp and hydro disc on my daily driver (a 2022 TCR Advanced Pro) and I don't intend on regressing with any of that tech. Instead I will wait a while to get my race bike and TT more modern.

At any rate, my actual opinion is that disc is better. Is it required? Probably not in most areas, certainly not around here. I can get up and down any of our mountains on rim brake just fine.

The ease of maintenance thing is certainly an objective benefit in favor of rim brake, but many modern riders or MTBers are not really fazed too much by disc, so its not a huge disadvantage for lots of people. I haven't actually check components weights, but I can't imagine it's actually impactful. I'm a racer and outside of TT I don't really pay a ton of attention to my equipment TBH, not nearly as much as many here.

Just remember you should get carbon rim brake pads as well. Generally most real complaints about rim brakes stem from ancient steel rims in the wet, or carbon rims in the wet. Admittedly I haven't ridden carbon rims but if you can get them for a good price and you are looking to try them out it still seems viable.
You could also have the carbon rim brake wheels for racing/spirited rides only and keep the stock aluminum wheels for training. There are decently light aluminum rim brake wheels too, but most are older then the carbon rim brake wheelsets.

^
yeah the pads can matter a lot. I like the Reynolds blue.

By "degenerative," do you mean dropping cash on a structural component -- the brake track -- that wears out?

The lack of clearance on road rim brakes also means you have to run pretty narrow tires to actually get the most aero benefit out of the wheels, meaning less comfort and potentially higher rolling resistance if you can't run lower pressure due to risk of pinch flatting.

Yeah exactly, the brake track will wear out and the entire thing may run the risk of delamination.

I think with variable mainline rim brakes like Shimano 105, Ultegra, Tiagra etc. clearance shouldn't be a major issue if reasonably sized tires are used.

Here's a CON for you (from someone who had rim brake CF wheels with the correct pads) - They don't stop in the rain. Heck, they don't stop that well in the dry.
How about a nice, lightweight set of inexpensive alloy wheels? Rouleur Alloy Rim Brake Wheelset – Boyd Cycling

Yes, I've heard conflicting reports about reduced brake performance in rainy conditions, thanks for sharing.

Apparently, as already pointed by slow rollin, the pads need to be specifically rated for use with carbon. That "should" resolve the issue, however I myself cannot comment. Can you confirm?

I spent a lot of time finding the cheapest but lightest bike/frame possible, so I want to add the maximum amount of value/performance by getting CF wheels.

Modern aero disc brake rims are most often optimized for 28mm and wider tires with external widths in the 31+mm range. I have doubts that many rim brake frames and brakes have clearance for that, so the options for rim brake wheels with decent aero shapes will be accordingly few and far between. Being able to make wider and more aero rims is one of the biggest gains that disc brakes enabled.

I have over 6k miles on rim brake Enve SES 3.4 wheels that came with my road bike, that I bought used. Not sure how many miles the previous owner had, but he was an active racer, so probably quite a few. For me, the biggest limiting factor is that I can't use tires larger than 26mm due to brake arch clearance.

Yes, I used the pads recommended by the rim manufacturer. They *sort of* worked dry, but definitely weren't as good as the old pad / alloy wheel combo they replaced. I tried two other brands of CF pads, not much better. I eventually bought a disc brake bike and upgraded to CF wheels. :)

On my Emonda ALR 5 (2018) with rim brakes and 58cm frame height, I can fit 28mm tires no problem. The previous owner had installed them and there's about 3 - 4mm of clearance between the tire and the fork. It's a tight fit, but it works. And this ALR 5 is almost 6.5 years old.

I think reasonably new race/road bikes with rim brakes have frames that can support it.

I very rarely see claims of rim brake carbon wheels being ugly simply due to them being designed to stop with brake pads touching the rim.
...actually the only times I can think of are from hard-core c&v folk. Even a lot of c&v people think carbon wheels on old steel frames look cool.

As for carbon rim brake wheels being outdated...they are no more outdated than aluminum rim brake wheels. As such, I don't see why that should even be a consideration.

Wider external width rims will also have wider internal widths and 28mm nominal sized tires will be closer to 30mm actual width. Like I wrote before, I doubt there are enough rim brake models with that much clearance for wider tires and rims to warrant many good modern aero wheel options.

I wanna say that there are plenty of 25 mm wide external rims out there that would match well with many race tires. I have some random novatech's that visually look good with the 24c turbo cottons, not sure though

When one already has a rim brake frame, whether rim brake CF wheels are obsolete is beside the point; the more relevant question is how much one would be willing to spend on CF wheels for that frame.

I ride FFWD F4R FCC (CF) wheels with SwissStop Black Prince pads and see no noticeable difference in braking distance compared to Mavic Ksyrium Elite (alloy) wheels with Shimano R55C4 pads. However, brake modulation is definitely worse because the initial bite is a bit grabby, which took a few rides to get used to. (Continental GP5000 tires on both wheelsets.)

I can't tell what this discussion is supposed to be about, but I'd suggest, if buying used, to buy the newest models you can afford, in hopes of landing stuff like higher TG resins, textured brake tracks, and wider internal widths. Pay attention to brake track width so that you aren't having your calipers to wide open to clear the rim and degrading brake performance.

I have one bike left with rim brakes which I bought in 2016, my Emonda ALR and I run carbon rims in a 50mm, but I live in Florida, so flat, wind, and rain. If I know rain is a guaranty at some point during the ride, I generally would take one of the disc brake bikes, but these days, I try to avoid riding in the rain as much as possible, that is what my trainer is for. I went with the deeper section wheels to deal with the wind as uber shallow climbing wheels were wasted on me, having no climbing to do here. I personally like the aesthetic look of the deeper wheels on the bike, and since I don't have hills, the brakes over heating is also a non concern. I use the Black Prince pads and if you do get caught in the rain or ride through any deep puddles, just make sure to check your wheels and pads after the ride for excessive dirt and grime so you are not grinding the brake surface off.

I run the Bontrager Aeolus Pro 5's with Pirelli P Zero Race TLR tubeless and with these rims, they measure right at 28mm. Had them for a couple of years, and they have been great wheels. I do not get pushed around in the wind or by trucks when they blow by me. They are 19.5 internal, 27 external. With Trek trying to clear out some inventory, they are also on sale, get a set of the Pro 5's or Pro's 3's (30mm I think), for $1200 and they have a lifetime warranty. I know they have the hub body for both Shimano and SRAM, I want to say, you can get a Campy one, but you'd have to inquire.

I personally think if you like the bike, why not get what makes you happy and makes your ride more enjoyable. I put SRAM Force AXS 12 speed with a spider based power meter on it at the beginning of 2023. Was there anything wrong with the 11 speed Ultegra I had on it? Nope, worked like a champ, but I figured as a present to myself for surviving another year, why not and have enjoyed riding that bike even more.



https://cimg6.ibsrv.net/gimg/bikefor...42c20bb9fd.jpg

I wonder if you will be able to find carbon wheels that will provide improvement at a price that makes sense for that frame. Seems you have to go over $1K to find carbon wheels that are both aero and lighter than mid-pack alloy.

Why not just get these? They aren't even heavy.

https://hedcycling.com/collections/r...ormance-series

My big argument against carbon wheels with rim brakes is mostly just the braking. I still have 1 road bike with carbon wheels and rim brakes...it's not my "daily driver" bike so it caught me off-guard when I took it out for a ride this winter, and it started raining while I was on a descent. I was able to just dry the brakes enough to slow down for a hairpin turn. After that, I stopped riding it unless the roads were perfectly dry....I've got disc-brake bikes that I'll ride in the rain/snow.

Even in dry weather, I can't say the braking performance is especially good. I'll say it's merely tolerable and not even comparable to my disc brake bikes or even my rim brake bike with alloy hoops.

As far as tire clearance, it hasn't been a big issue for me. It's tight, but I'm able to run 28mm tires on that bike. I'm up to 30mm wide tires on the back of my disc brake bikes, but 28mm works ok for me.

Don’t know why the carbon rim mfgs, for rim brakes, don’t inbed aluminum or steel braking bands for additional stopping power. It wouldn’t be rocket surgery.

2muchroad is debating whether to spend money on CF wheels for a rim brake Emonda ALR 5 that he/she picked up for a pretty good deal to replace its stock 2,200 g wheels.

Used Trek Emonda ALR 5 - Good Deal? - Bike Forums

Well, no; see: Lún Routte 45mm Rim Brake Wheelset – winspace.cc

Currently $799 / € 747, and they were $100 off just a little while ago.

That's why I posted those Heds.

But all the aero wheels had aluminum braking surfaces in the past, until that wasn't light enough. Then that didn't brake well enough, and now we have disks. And if anyone complains that discs weigh more, it is pointed out that weight isn't all that important. I guess alloy braking wheels weren't light enough, but now it doesn't matter, and the cool bikes don't have rim brakes anymore.