Carbon rim brake wheelsets - worth the risk?

[booge]

Have moved away from eyeing off kinlin wheelsets from aliexpress.
Now seriously contemplating chinese carbon wheelsets....
Tuff, yeoleo, lightbicycle and farsports....around $1k aussie dollars
Are carbon rim brake wheels OK now?
Most of the horror stories seem to be a number of years old now. But I'm still a little wary of them.
With Raoul Leuscher describing carbon rim brake wheels as a bad design and shimano not even making carbon rim brake wheels for that reason.
Is it worth it? I'm a regular recreational rider, 76kg, not a brake dragger but no daredevil either.
How have your carbon rim brake wheels been?

[foo on patrol]

I have two sets of Zipp 404 Speed Weaponry and have no problem pulling my 108kgs mass up from speed into a round about when racing. They are okay in the wet also.

Foo

[booge]

I believe they're the gold standard aren't they? I've read about zipp stopping as well as any rim brake wet or dry

[g-boaf]

Have moved away from eyeing off kinlin wheelsets from aliexpress.
Now seriously contemplating chinese carbon wheelsets....
Tuff, yeoleo, lightbicycle and farsports....around $1k aussie dollars
Are carbon rim brake wheels OK now?
Most of the horror stories seem to be a number of years old now. But I'm still a little wary of them.
With Raoul Leuscher describing carbon rim brake wheels as a bad design and shimano not even making carbon rim brake wheels for that reason.
Is it worth it? I'm a regular recreational rider, 76kg, not a brake dragger but no daredevil either.
How have your carbon rim brake wheels been?

I've ridden three brands, Bontrager (Trek), Xentis (Austrian made things) and Mavic.

Bontrager ones supplied with cork pads and were pretty bad in the rain. But perfectly good in dry weather. Used those with Ultegra rim brakes and also Magura RT8 TT hydraulic rim brakes.

Xentis ones (Xentis 2.5 SL at $3.2K) were supplied with Swisstop for Xentis pads and were not particularly better in the rain. I had an occasion where I was stuck commuting home in three huge downpours and lost all proper braking ability. On the plus side they are super, super, super light!

The Mavic wheels with their own Mavic brake pads (and Mavic tyres) I can't talk about for wet weather because it was dry and sunny but I did take them up and down some big mountain passes in France at fairly high speeds and they were okay for that. In the wet I'm not so sure. They were on a Canyon Aeroad CF SLX with Shimano Ultegra 8000 rim brakes. The wheels and bike were given to me by Mavic. With hard use they screeched a bit but no real drama. But I've also seen reports of poor behaviour with those wheels as well (from a very skilled rider).

I'm much lighter than you however.

No idea about the Chinese carbon wheels how they behave. Last set of rim brake wheels I purchased were alloy Fulcrum Racing Zero Competizione and they were excellent trouble free wheels. I used them for commute rides and even up and down mountains. Now they don't get much use because I have a disc brake bike.

[warthog1]

I have 3 sets of rim brake carbon wheels
85mm token tubular.
Zipp firecrest 404.
Prime rr50 v3.
All have been fine.
The zipps are no better than the others tbh.
None brake very well in the wet.
I don't ride them in the wet by choice however.
Use carbon specific pads and don't drag the brakes.
Pulse the brakes if required on a steep hill.
Dragging brakes generates excessive heat and is not advised to avoid damaging the rim with heat.
Not hard to avoid damaging them ime.

[open roader]

With a budget circa AU $1,000 for carbon rim brake wheels I'd be asking a custom wheel maker like Greg Ryan from TWE or others wheelmakers.

If it were my money I'd be looking for a 2nd hand set of Bora 1.

Easy enough to switch in a Shimano freehub if required and the braking surfaces of even the original model Bora wheels is better in both wet and dry than anything you will buy new for $1k.

I have the 2nd generation Bora 1 in a 35mm rim - a wider rim than the original model but not the current AC3 brake track surface - my Boras stop like no other carbon rim wheel I've ridden before and I've ridden plenty of fancy carbon rim brake wheel sets like Zipp, Xentis, Corima, Madfiber, Mavic and Lightweight.........

[Duck!]

With Raoul Leuscher describing carbon rim brake wheels as a bad design and shimano not even making carbon rim brake wheels for that reason.

This paragraph excludes one critical detail: clincher (which in context includes tubeless). Shimano do produce rim-brake carbon rims, but only for tubular tyres. Luescher's criticism and Shimano's non-manufacture relate specifically to the extended sidewalls of the clincher profile, which can bulge under pressure from the tyre. Tubulars are not subject to the same pressure, so eliminate one of the perceived problems.

That said, the horror stories are largely historical; advancements in rim surface coatings and brake pad compounds have made rim failures a very rare occurrence, as well as drastically improving braking performance. Various ceramic rim treatments reduce heat transfer into the carbon laminate. Modern synthetic pad compounds brake much better in the wet than cork, but in order to reduce heat build-up in the dry are considerably faster-wearing than normal rubber-based pads.

Technique still plays a part though. You don't have to go full daredevil, but carbon rims are best treated with short, hard braking efforts; the laminate structure is a poor thermal conductor, which cuts two ways... Hard braking generates high surface temperature, but the low conductivity resists that heat soaking into the rim. However, that low thermal conductivity also means the rim won't shed accumulated heat as rapidly as a metal rim, so it needs some breathing time. Short version, you have to be pretty abusive on the rims to have problems. A more likely failure source is a low-mount platform-type rear carrier which may place a wheel close to the car's exhaust for an extended time.

[Retrobyte]

I have a carbon rim brake wheelset from Farsport/Wheelsfar that I've used since February. They came with the carbon specific Swissstop pads and so far there's not a mark anywhere on the braking surface. I'm not as big as Foo, but not a lightweight either (95kg), and I don't race, but they perform well for me and so far have been reliable and durable. Having said that, if it does rain while I'm on a ride things do become pretty hairy when braking - braking distances increase exponentially in the wet.

[familyguy]

With Raoul Leuscher describing carbon rim brake wheels as a bad design and shimano not even making carbon rim brake wheels for that reason.

This paragraph excludes one critical detail: clincher (which in context includes tubeless). Shimano do produce rim-brake carbon rims, but only for tubular tyres. Luescher's criticism and Shimano's non-manufacture relate specifically to the extended sidewalls of the clincher profile, which can bulge under pressure from the tyre. Tubulars are not subject to the same pressure, so eliminate one of the perceived problems.

That said, the horror stories are largely historical; advancements in rim surface coatings and brake pad compounds have made rim failures a very rare occurrence, as well as drastically improving braking performance. Various ceramic rim treatments reduce heat transfer into the carbon laminate. Modern synthetic pad compounds brake much better in the wet than cork, but in order to reduce heat build-up in the dry are considerably faster-wearing than normal rubber-based pads.

Technique still plays a part though. You don't have to go full daredevil, but carbon rims are best treated with short, hard braking efforts; the laminate structure is a poor thermal conductor, which cuts two ways... Hard braking generates high surface temperature, but the low conductivity resists that heat soaking into the rim. However, that low thermal conductivity also means the rim won't shed accumulated heat as rapidly as a metal rim, so it needs some breathing time. Short version, you have to be pretty abusive on the rims to have problems. A more likely failure source is a low-mount platform-type rear carrier which may place a wheel close to the car's exhaust for an extended time.

I've had my Token to a point where they're very hot to the touch after a quick, steep descent and a red light at the bottom (here: https://www.google.com/maps/(AT)-33.792686 ... 384!8i8192). Not as in 'burn yourself on a hot disc' hot, but certainly noticeable. The first time also gave off a slight smell of something, but I think it was more the pads than the rims. Certainly no tyre swelling or sidewall bulge or popping tubes like the tales from early days of carbon rims. Thought it might be an issue, but the consensus seems to be that you need serious heat to damage carbon rims now. Sustained heat, too, from what I read of this reply?

An older set of FSE wheels had a caveat on the labels that you had to run the brake pads low on the sidewall to put it more over the meatier part of the rim. Those got hot a few times, too.

Jim

[booge]

So would a deeper rim be better for any heat disippation? I'm looking at either 40mm Tuff rims or 25mm rims from Light bicycle, both clinchers.

[blizzard]

So would a deeper rim be better for any heat disippation? I'm looking at either 40mm Tuff rims or 25mm rims from Light bicycle, both clinchers.

I can't imagine it would. I would go for the deeper rims personally.

[warthog1]

I fail to see the point of shallow carbon rims sorry.
You buy them for the aero advantage primarily and a lower depth compromises that.
25mm is going to do bugger all.

“Our development at Enve has shown us that you need a minimum 35mm rim depth to start to control and improve the flow of the air, while at higher depths it’s all about trading weight for aero.”

https://roadcyclinguk.com/gear/buying-g ... heels.html

[booge]

Primarily looked the 25mm rims from Light bicycle was merely due to the weight being close to the Tuff ones. The Tuff wheels are extremely light at a tad under 1300g in the 40mm rim version. Probably leaning toward Tuff due to weight and aero

[Mr Purple]

Light Bicycle do also offer a 'flyweight' version of the 25mm. I think it was about 1260g in 25mm with Bitex hubs when I priced a set. They don't have it as an easily selected option but you can request it when ordering.

I agree in principle that deeper rims (40mm minimum) suit carbon better but if you're doing a pure lightweight climber build there is some justification for 25mm. My plan was to do a rim brake 25mm build for windy days.

[Duck!]

I fail to see the point of shallow carbon rims sorry.
You buy them for the aero advantage primarily and a lower depth compromises that.
25mm is going to do bugger all.

Superior handling over similar profile aluminium rims is a pretty big point for carbon.

[warthog1]

I fail to see the point of shallow carbon rims sorry.
You buy them for the aero advantage primarily and a lower depth compromises that.
25mm is going to do bugger all.

Superior handling over similar profile aluminium rims is a pretty big point for carbon.

I have raced crits, road races, tts.
Not noticed it at all.
Handling in what form?
I accept a lower profile rim is going to be less affected by cross winds.
Yeah I've noticed that.
Not a huge issue though and the modern wider rim profiles are less affected by cross winds for a given height.

I have these;
https://www.this link is broken.au/prime-rr-50-v ... c-wheelset
Done about 15k km on them.
Never noticed them blow around at all. Nothing.
Great wheelset. Better than the 404s I also have and a fraction of the price.

The 85mm tokens I have do blow around but what the hell.
They were the only aero wheelset I had at the time. Never took them out for a race and put shallow aluminium in. Free speed

[Duck!]

I have carbon rims on my MTB, where aero is very low on the scale of importance. The rims are about 300g lighter than the aluminium set they replaced, so more responsive to braking, accelerating and steering. They're a lot stiffer laterally, which improves tracking, and because carbon absorbs vibration, they're better at ironing out trail buzz that the suspension is not sensitive enough to deal with.

On a back to back test, the difference is very apparent.

[warthog1]

I have carbon rims on my MTB, where aero is very low on the scale of importance. The rims are about 300g lighter than the aluminium set they replaced, so more responsive to braking, accelerating and steering. They're a lot stiffer laterally, which improves tracking, and because carbon absorbs vibration, they're better at ironing out trail buzz that the suspension is not sensitive enough to deal with.

On a back to back test, the difference is very apparent.

Fair enough
Never used them on gravel.
The lighter weight would improve feel too.

[foo on patrol]

I have a carbon rim brake wheelset from Farsport/Wheelsfar that I've used since February. They came with the carbon specific Swissstop pads and so far there's not a mark anywhere on the braking surface. I'm not as big as Foo, but not a lightweight either (95kg), and I don't race, but they perform well for me and so far have been reliable and durable. Having said that, if it does rain while I'm on a ride things do become pretty hairy when braking - braking distances increase exponentially in the wet.

Well I never, are you saying that I'm a fat bastard?

Foo

[warthog1]

^^

[g-boaf]

Light Bicycle do also offer a 'flyweight' version of the 25mm. I think it was about 1260g in 25mm with Bitex hubs when I priced a set. They don't have it as an easily selected option but you can request it when ordering.

I agree in principle that deeper rims (40mm minimum) suit carbon better but if you're doing a pure lightweight climber build there is some justification for 25mm. My plan was to do a rim brake 25mm build for windy days.

Pretty much you go for the low profile lighter wheels if you are building a very very light bicycle. We are talking UCI illegal weights. But that’s also needing other changes like cranks, cassette, bars and stem, seat post, etc. and it costs serious $$$$, you could buy any entire bike for that price.

The Xentis 2.5 SL wheels I have are lovely for going uphill, just feels outrageous, but they are poor in the rain and on descending. Sometimes I do have to ride in heavy rain so that’s a consideration.

[Mr Purple]

That was exactly what I was half planning - Chinese carbon frame, 25mm wheels, SRAM Red and sub 6kg.

Then I added it up. And plugged the 2kg saving into the bike calculator for my favourite climbs. It's worth about 4 seconds on Gravatt and 10 seconds on Cootha Back.

I'm buying a gravel bike and training harder instead.

[MattyK]

^That's pretty much why I ended up choosing some heavy Kotavelo R42s (that should be arriving today yay me) - they'll be going on my cheap TT build that won't see any hills anyway. Which ironically makes the need for aluminium brake tracks somewhat moot... but they were still cheaper than all of the used carbon wheels that I've seen, without the downside of being used.

[g-boaf]

That was exactly what I was half planning - Chinese carbon frame, 25mm wheels, SRAM Red and sub 6kg.

Then I added it up. And plugged the 2kg saving into the bike calculator for my favourite climbs. It's worth about 4 seconds on Gravatt and 10 seconds on Cootha Back.

I'm buying a gravel bike and training harder instead.

Try the 11 speed SRAM Red mechanical instead of the E-tap, that was very light. Basically go and find the specifications of the old Canyon Ultimate CF Evo SL (the carbon/orange one) and use that as your blueprint for what components to go for (or find equivalents of them). Or the later version of it:

Rim brake build:

Wheelset: Zipp 202 NSW Carbon Clincher
Drivetrain: SRAM RED eTap AXS
Power Meter: Quarq DZero
Brakes: THM Fibula - $$$$
Seatpost: Schmolke 1K
Saddle: Selle Italia SLR C59 $$$$
Weight: (Size M, w/o Pedals) 5.68 kg
Price: $12,299 AUD

Looking at that price back then, it's pretty decent considering what bikes cost now. Even the disc brake version was pretty well priced too and also illegally light.

Half of the appeal of having such a light bike is that they feel light and fast to accelerate, especially against something heavier like the S5 (in my signature). But the penalty is that it is expensive when you get to 6kg and going less than that starts getting very costly.

[booge]

Would there be issues mounting a 23mm tyre with tubes or tubeless on a 26mm ext width rim? The internal width is 19mm.
Tuff have said it's fine, after other opinions from people not trying to get a sale!