Carbon clinchers in mountains

mercia_man

Anyone here with practical experience of using carbon clinchers in the mountains?

I'm buying a high end bike to take on holiday in my new camper van to my favourite parts of the Alps and Pyrenees. Most of the models I'm considering are fitted with carbon clinchers as standard. I want to know whether these wheels will be safe.

I know there have been reports of carbon clincher rims overheating and deforming, causing potentially lethal accidents. But companies such as Enve and Reynolds claim to have solved past problems with new rim and pad developments. I fancy the idea of wheels that will be as light as my Neutron Ultras but which will also give an aero boost on flat or rolling roads.

I've got more than 20 years experience of riding in European mountains, mostly on a touring bike with 15kg of camping gear, and am a confident descender. I don't want to descend like a novice because braking is not up to scratch on my new bike. I plan to use it for fair weather solo rides rather than sportives.

I don't want to start another handbuilt v factory wheels debate. But I would really appreciate hearing from people who have actually used carbon clinchers in the high mountains and know what they are talking about.

ugo.santalucia

Reynolds, Enve and Mavic have developed improved resins, which resist higher temperature and dissipate heat better. Mavic C40 are particularly safe, as they have also an internal aluminium bed (against blow out)

http://paolocoppo.drupalgardens.com/con ... u-buy-them

I have built a few Gigantex rims (although they were tubulars) and WOULD NOT advise to use them in the mountains... braking is just OK at best and delamination has been reported by others on this forum. So that rules out Planet X wheels, which use the same rims.

bigpikle

I rode several days in the Alps with a mate who had Fulcrum carbon tubs while I had alu clinchers. While his were a lot more noisy when he needed them, he had no issues at all and neither did I. Having said that it was dry throughout and having ridden with him on the same wheels in the UK in the wet, I wouldnt have fancied his chances it if had poured down....

Grill

Took my RZR's to the mountains with no problem. Would never take a carbon clincher though...

cycleclinic

Not many have the budget for those kind of wheels ugo. Better of with alloy rims for big mountain work alot cheaper unless you are an elite racer and have a team with sponsership.also most folk going up a mountain do do not fast enough to get the benefit from areo wheels and coming is guided by gravity and you top speed is function of how hard your balls are not how aero your wheels are.

ugo.santalucia

thecycleclinic wrote:

Not many have the budget for those kind of wheels ugo. Better of with alloy rims for big mountain work alot cheaper unless you are an elite racer and have a team with sponsership.also most folk going up a mountain do do not fast enough to get the benefit from areo wheels and coming is guided by gravity and you top speed is function of how hard your balls are not how aero your wheels are.

OK, but you are completely off topic

robbo2011

I do not have experience of carbon clinchers, but do have quite a bit of experience of riding in mountains. The only point i will make is that you clearly have doubts in your mind about using them which is why you posted here. Having doubts in the back of your mind when descending is a bad idea, worst of all it can be dangerous and less seriously it can spoil the excitement and exhileration of a fast mountain descent due to being over cautious.

Get some decent alloys, put the doubts out of your mind and enjoy the descending

rolf_f

ugo.santalucia wrote:

thecycleclinic wrote:

Not many have the budget for those kind of wheels ugo. Better of with alloy rims for big mountain work alot cheaper unless you are an elite racer and have a team with sponsership.also most folk going up a mountain do do not fast enough to get the benefit from areo wheels and coming is guided by gravity and you top speed is function of how hard your balls are not how aero your wheels are.

OK, but you are completely off topic

And logic hardly applies when the OP already has a perfect set of wheels for the task but doesn't want to use them

mercia_man

My query is not whether carbon clinchers are value for money - each potential purchaser will make his or her decision on how much they are willing and able to spend. What I want to hear about is their braking performance in mountains.

I enjoyed ugo's favourable blog on the new Mavic Cosmic Carbone 40c. I've also seen Mavic's informative video on the development and construction of that wheelset. And I've read good first ride reviews from journalists who tried them out at the press launch in the mountains above Nice.

Of course, positive reviews following a freebie in the south of France are not the same as long-term assessment. But it seems to me that the CC 40c is the best attempt yet to make a safe braking carbon clincher. They have been developed and tested on the very roads, such as Ventoux, on which I'm planning to take my new bike. And, as ugo says, they do look very attractive.

I've also been impressed by company promotional videos and first ride reviews of the updated and improved 2014 Reynolds Assault SLG and Attack wheels.

Robbo2011 makes a very valid point but cycleclinic has misunderstood me. My point is I am buying a new high end bike and the models I am considering mostly come fitted with carbon clinchers as standard and I want to hear from people who have used such wheels in the mountains. It's not a question of me not wanting to use my Neutron Ultras - I plan to take them with me on my hols as a spare or alternative.

ugo.santalucia

Mercia Man wrote:

My query is not whether carbon clinchers are value for money - each potential purchaser will make his or her decision on how much they are willing and able to spend. What I want to hear about is their braking performance in mountains.

I enjoyed ugo's favourable blog on the new Mavic Cosmic Carbone 40c. I've also seen Mavic's informative video on the development and construction of that wheelset. And I've read good first ride reviews from journalists who tried them out at the press launch in the mountains above Nice.

Of course, positive reviews following a freebie in the south of France are not the same as long-term assessment. But it seems to me that the CC 40c is the best attempt yet to make a safe braking carbon clincher. They have been developed and tested on the very roads, such as Ventoux, on which I'm planning to take my new bike. And, as ugo says, they do look very attractive.

I've also been impressed by company promotional videos and first ride reviews of the updated and improved 2014 Reynolds Assault SLG and Attack wheels.

Robbo2011 makes a very valid point but cycleclinic has misunderstood me. My point is I am buying a new high end bike and the models I am considering mostly come fitted with carbon clinchers as standard and I want to hear from people who have used such wheels in the mountains. It's not a question of me not wanting to use my Neutron Ultras - I plan to take them with me on my hols as a spare or alternative.

Which wheels are fitted on the bike you are considering?

chris1967cycling

I was on Ventoux in July and saw multiple rim/wheel issues - all clinchers.

These included alloy rims overheating and blowing tubes/tyres off the rim. In one case the rider didn't stop soon enough and wore the alloy rim down to the spoke bed.

The carbon clincher failures shocked me. I'd expect cheap Chinese carbon clinchers to fail but I saw top brand CC's fail catastrophically.

All caused by the same fundamental issue - heat transfer from the rim into the inner tube which caused it to expand and destroy the rim.

I was approx 10km from the top and on one corner near us saw 3 rim failures. One guy had both front and rear destroyed. His wheels were a top American brand which I myself have always considered as market leaders.

You don't have to take my word for it - just google carbon clincher failures/issues - plenty of scary pics, articles.

Both myself and my friend (who manages a top bike shop) rode Tubulars and had no issues on the same decent.

Based on what I saw I would not use any clincher wheel (alloy or carbon) for prolonged descending/braking in hot weather. You may be ok on cooler days but heat transfer will still occur.

While an alloy rim may still be intact after an overheating issue you may not have a useable tyre or worse still end up on your face.

Tubulars are more hassle than clinchers but I've not seen any carbon tubular rim failures due to heat issues - my rule of thumb is look at what the pro's use and where possible (cost etc) follow their example.

mercia_man

To ugo: I've been looking at the new Look 695 Light and Aerolight, Scott Addict and Bianchi Infinito CV. The Scott comes with Syncros RL 1.1 or 1.0 carbon clinchers and the Bianchi with Vision Metron 40 carbon clinchers. The Look is the front-runner for me at the moment but I am shortly going to have some test rides so will make my decision after that. My LBS Epic Cycles is doing a good deal on the Look with Enve 4.5. They also big up the Reynolds Assault SLG which are fitted to their sponsored women's race team Addicts. Another possibility is the Mavic Cosmic Carbone 40c which seems a big improvement on Ksyriums.

My original thought had been to get a Look with a Campag custom build and Neutron Ultras as a fine weather climbing bike with safe alloy rim braking. But then I thought why not try different wheels rather than duplicating - perhaps trying some Shamal Ultras. And now I've been thinking why not try some carbon clinchers with a bit of aero benefit as I can always use my Neutron Ultras on it as well. They are currently on my six year old Orca.

To Chris1967cycling: your account is really shocking and is just the sort of info I was after. I have never suffered problems with alloy clinchers in many years of mountain riding on my road bikes or tourers. Stopping a tourer loaded with 15kg of camping gear in four panniers while descending Ventoux at 45mph does need care. But I know how to use the brakes so the rims don't overheat. I suspect some problems are caused by relative newcomers to cycling constantly dragging their brakes down steep descents while riding in a group of riders rather than at their own pace.

I have suffered blowouts in the Alps while descending on my Bike Friday Pocket Rocket - a performance folding bike with 20in alloy aero wheels. The small wheels obviously heat up more than full size and my problems were exacerbated by a worn out rim tape allowing the tube to go into a spoke hole.

ugo.santalucia

Mercia Man wrote:

To Chris1967cycling: your account is really shocking and is just the sort of info I was after. I have never suffered problems with alloy clinchers in many years of mountain riding on my road bikes or tourers. Stopping a tourer loaded with 15kg of camping gear in four panniers while descending Ventoux at 45mph does need care. But I know how to use the brakes so the rims don't overheat. I suspect some problems are caused by relative newcomers to cycling constantly dragging their brakes down steep descents while riding in a group of riders rather than at their own pace.

I have suffered blowouts in the Alps while descending on my Bike Friday Pocket Rocket - a performance folding bike with 20in alloy aero wheels. The small wheels obviously heat up more than full size and my problems were exacerbated by a worn out rim tape allowing the tube to go into a spoke hole.

Lowering the tyre pressure helps... never run more than 100 PSI and if it's the last descent before heading home let some air out.
When you choose a a mountain to climb, go up the steep side and come down the more gentle one... there are a lot of things you can do and most people don't bother with, but ultimately if you are not enjoying your riding as you live in fear of the tyre exploding, well it spoils the all experience, doesn't it?

Monty Dog

Not mentioned here is never use latex tubes with carbon clinchers, they can't withstand the heat.
There's a reason why many stick with tubulars with carbon rims - high speed blow-outs being one.

mroli

chris1967cycling wrote:

just google carbon clincher failures/issues - plenty of scary pics, articles.

To be fair - if you google tubular glue melting, you also get plenty of scary stuff. If you know how to descent properly and it sounds like the OP does, that is going to assist with the overheating issue greatly.

redjeepǃ

Sounds like an argument for disc brakes to me :-).

mroli

Aren't discs meant to be even worse? Due to the relatively small surface area?

markynulty

The hire bike I had in Mallorca this September had a set of Zipp 404 clinchers on it.

I did around 40,000ft of climbing over there and no issues on the descents. Granted, the mountains are not as high as some of those in mainland Europe, but the descents are still quite technical.

mercia_man

Thanks for that, markynulty. I simply want to hear from people like you with real life experience of using carbon clinchers in mountains before I make my new bike choice.

markhewitt1978

mroli wrote:

Aren't discs meant to be even worse? Due to the relatively small surface area?

But they aren't anywhere near the tubes so at least won't cause your tyres to explode.

Monty Dog

In terms of the OP's question, you are not likely to get a response from the numpties that dragged their brakes down an alpine descent, cooking their rims and blowing their tubes. There's plenty of evidence out there to suggest that carbon clinchers suffer from poorer heat dissipation - this will be made worse in a sportive situation where due to the wide variety of rider skills, you often find yourself caught behind slower, less confident riders and therefore have little choice but to 'ride' your brakes.

chris1967cycling

Interesting article on carbon rim heat build up with comments from all the major manufacturers - ignore the VS car exhaust, the article is below this

http://velonews.competitor.com/2013/05/ ... ing_286605

mercia_man

Thanks, Chris. Good article. It confirms that short sharp braking on mountain descents - a practice I have always followed whether descending the Burway on the Long Mynd or the Tourmalet - is the right one. And when I'm touring with camping gear, I play ultra safe by stopping occasionally to look at the view and to let my rims cool. I know how hot rims can get after foolishly feeling them with bare hands after a descent of Asterton Bank on the Mynd.

It seems to me that poor braking technique plays a big role in carbon clincher failures. I haven't done any sportives for several years but I can remember being surprised at the over cautious, brake dragging technique of many slow descenders in the Maratone dles Dolomites.

chris1967cycling

No problem. One question though - why the aversion to tubulars ?

Is it just the convenience of the the clincher you are after ? I had this dilemma a couple of years ago and after weighing up all the pro's & cons decided tubs were best for me.

They tend to be cheaper than the CC version, they weigh less, lots more choice and finally the obvious lack of worry about overheating.

The other benefit of tubs which I don't think has been mentioned is that if and when you do puncture a well glued tubular can be ridden to a safe halt - clinchers may part company with the rim under rapid deflation and you're back on your face again !!!

Another consideration is availability of tyres/tubs etc. I've been able to buy tubular tyres even in french supermarkets before - try finding a correct 700c style tyre in a matching size etc - almost impossible in my experience

Good luck with the decision

mercia_man

No aversion to tubulars although I've never tried them. Maybe tubs would be best for me. It's just that I'm buying a new bike and carbon clinchers are a standard fitment on most of the ones I'm considering.

Safety and powerful braking on mountain descents are important to me and I want to weigh up the pros and cons before I buy. A forum like this is a great way to pick up information from people with real life experience - while ignoring the occasional armchair pundit with more opinions than actual knowledge.

The more I hear, the more I'm moving towards alloy or Mavic CC 40c.

rolf_f

Mercia Man wrote:

No aversion to tubulars although I've never tried them. Maybe tubs would be best for me. It's just that I'm buying a new bike and carbon clinchers are a standard fitment on most of the ones I'm considering.

With the Look at least you spec every component (which, I'd have thought, would be a bit essential if you are spending a big wodge on a bike) so no worries on that at least.

I'd have thought that tubulars is the only way to go to get a wheel that will perform better than your Neutrons (and, of course, if you got the Look you wouldn't need to spec any wheels at all!).

robbo2011

Mercia Man wrote:

It seems to me that poor braking technique plays a big role in carbon clincher failures. I haven't done any sportives for several years but I can remember being surprised at the over cautious, brake dragging technique of many slow descenders in the Maratone dles Dolomites.

Too right. Last year, One of those slow descenders almost took me out by suddenly veering across the road and knocking into me for no reason while i was overtaking. And someone elses carbon wheel blew up in front of me due to over cautious braking. Quite dangerous when you think about it.

cycleclinic

tyre pressues will be important too. If the rim can get to 700 F that 357 C peak then let assume the air in the tube can get to 270C that would represent a doubling of the absolute thermodynamic temperature. This means air pressue woud double. If you start of with 110 psi in your 23mm tyres that means over 200 pi peak pressue that cannot end well.

If a pressue of 70 psi was used at the start then peak pressues would be alot lower and tyre could survive them. Of course a 110kg rider may need wider tyres to run low pressures and the frame may not have the clearance.

This also why tubs survive when clinchers don't. Even 22mm conti spinter have a max operating pressure of 170psi but you would never run that 100 is enough.

Disc brakes will mean carbon rims will not heat up but dragging a disc brake may cause fade or worse a long lever. Shimano's use of mineral oil avoids the long lever issue to a certain extent as the fluid is not hyroscopic but brake dragging is bad. You don't have to go to a sportive to see people drag there brakes I see it all the time on club runs in Suffolk, no mountains here.