Carbon clinchers, with or without aluminium brake surface?

leloby

Since the date this forum thread started we have experienced an unusual rising trend in emails from concerned potential customers worried about the braking qualities of our rims. It is safe to say that there is a direct correlation. It is causing us a lot of time and stress and putting people off a perfectly good product.

This is how the "PilotPete" encounter happened:

We get an email about some "uneven wear" on a carbon rim from PilotPete - no hint as to exactly how it happened was given although we did get an email from him applauding the merits of these rims following a trip to the Algarve some 3 months prior to this - with a brief description of some heroics on a descent.

I asked for the wheel to be returned for inspection. The emails went backwards and forwards with me putting up possible reasons for the irregularities in the rim. We were about to concede that it might actually be a flawed rim when I did a quick search and found a BikeRadar post from the man himself:

I have 50mm carbon clinchers from Wheelsmith. They are lighter, stronger and much better to ride than the stock wheels they replaced. These wheels are STRONG, so all the nay sayers should take note. I hit a massive pothole (I'm talking 6" deep at nearly 45mph in a descent in the Algarve in November. Both tyres blew and I thought I had shot the wheels. After stopping and inspecting there wasn't a mark on them....I could not believe it. That impact would have destroyed most alloy rims - my back wheel bucked over 18" in the air according to my ride buddies. I took some couple of hundred metres to come to a halt and it still didnt damage the clincher rims.

So let's stop making mass generalisations about how 'weak' carbon fibre is and how it will surely fail when using a tyre lever etc...it's horses for courses, much depends on quality and design. Wheelsmith has got it right with Gigantex rims that's for sure, I couldn't comment on other carbon rims.

Full transcript here: viewtopic.php?f=40042&t=12825710&p=17426303&hilit=wheelsmith+gigantex+algarve#p17426303

So, not having heard of these rims in riding conditions as extreme as this before, nor any previous issues with them until that time, the balance of probabilites suggested to us that this was not just simply a flawed rim.

Any conjecture of this being a "not fit for purpose" claim is nonsense.

The emails continued until I called PilotPete on the number given and mentioned the BikeRadar post. It was then agreed that the rim would be replaced at cost with only that and return postage charged. The job was done and we haven't heard from him since. He had 3-4 months of use out of these wheels before any post-incident damage was noted.

The general consensus here at the time amongst ex-pros and experienced riders was that following the Algarve incident the wheels should have been sent to us for inspection - or even the rims replaced as a matter of course. Any self respecting cyclist who's crash helmet suffers impact would replace it, even without any noticeable damage. After all - "..that impact would have destroyed most alloy rims".

Given the circumstances, how anyone could be disappointed by the performance of these rims, let alone have a complete change of heart and feel they should let the world hear on a largely unmoderated forum, remains a mystery.

We have encountered 3 similar issues with these rims since then. 1 from a customer involved in almost exactly the same circumstances during a mountain descent and who owned up straight away, one from using totally inappropriate brake pads - and one with a badly mounted rolled tub on a tubular rim, again during a mountain descent. This is from more than 4 yrs of using full carbon clinchers and 8yrs of using carbon tubular rims in all shapes and sizes. They get used in anything from trips to the high mountains to Cat1 racing and Cyclocross. Most people familiar with the braking performance have no issue with them whatsoever - wet or dry. Any who do, are made nervous about using them simply from reading misguided information and idiocy found these forums!

Make of that what you will. The way I see it, from PilotPete's original findings, these rims could save your life.

leloby

Post updated here also:

viewtopic.php?f=40042&t=12879488&p=17992288&hilit=wheelsmith+gigantex#p17992288

napoleond

:shock:

Wasn't aware of that! Bloody hell, pilot Pete is lucky he is able to post at all! Strong wheels indeed.

amaferanga

It's the forum way. People with no experience of something whatsoever that once read something, somewhere, they can't quite remember where, etc. claiming that it's crap or dangerous. Or people who have used something and had unrealistic expectations (i.e. that it should survive a massive impact that would destroy an alloy rim and be completely unscathed) claiming it's crap or dangerous.

ugo.santalucia

amaferanga wrote:

It's the forum way. People with no experience of something whatsoever that once read something, somewhere, they can't quite remember where, etc. claiming that it's crap or dangerous. Or people who have used something and had unrealistic expectations (i.e. that it should survive a massive impact that would destroy an alloy rim and be completely unscathed) claiming it's crap or dangerous.

What's negative about the process?
There was an alleged issue, the builder took some time to come and explain the situation, we are all a little better informed.
These things don't just happen on forums... Remember the issue with the Mercedes class A that capsized in the Moose test years ago?

pilot_pete

I completely agree about the strength of these wheels, which is why I made the original post. Their strength and rigidity is certainly not questionable. However their braking performance is in my opinion.

Braking performance with the supplied cork pads was none existent from new. I rode them twice, first ride in the wet, where wet braking was seriously dangerous and I cut the ride short. Tried them in the dry and again just not good enough. i did not ride the again until I had changed the pads to Swiss Stop yellow which improved both wet and dry braking, but wet braking was still not good.

We have a difference of opinion over the brake track issue which started to chew the pads up. We seemed to agree that the resin had changed in certain areas, most likely due to overheating. There was no evidence of delamination whatsoever, the rim was sound (a testament to its strength). There has been no link demonstrated to me that a vertical hit of a pothole caused delamination, which lead to overheating of the braking surface. The rim was not delaminated.

This is where our opinions differ. My braking technique is now called into question and used as a causal factor. No discussion of this technique ever took place and I have explained my technique in previous posts. My argument is that if you cannot descend a hill and brake at the bottom without the rim structure being damaged due heat in some way then the rim is not suitable for such use. I am not talking long 'Alpine descents' here, I'm talking UK and Algarve. My technique is NOT at fault, I rode west to east across the Pyrenees this summer on stock aluminium clinchers and had no brake overheat (anywhere near) or pad wear issues. However, a statement concerning 'over-exuberant' braking was added to Derek's website subsequently.

So, we have our difference of opinion and that is where it appears we will remain. I accepted the rim change at cost but will NEVER use these wheels in hilly terrain again. In my opinion, the braking performance is not up to it. And just for clarity I think the build quality was superb and the vertical strength unbelievable. I have no issues at all in those areas.

PP

napoleond

To be fair, the braking is an issue with any carbon wheel. I've noticed weaker braking on Planet X (Gigantex), Zipp and Campag Bora Ultra 2. Used with Swissstops. You are never going to get the same level of braking as with an aluminium track.
Furthermore, when in the Alps I was braking less than on the UK's short steep descents...

leloby

To reiterate, the original post advised us:

Braking is accepted as being worse on carbon rims in the wet, for sure. BUT, put a set of Swiss Stop Pro Race pads in and it is good, if not quite as good as an alloy surface. My riding style has adapted and to be honest I don't notice them as being worse in the wet now. As for dry performance I have found braking exceptional.

They are definitely faster than my stock wheels too, so it does depend on what you are replacing. My stock Most Chall (truly awful) wheels flexed all over the place when climbing and the spokes pulled through the rear rim in less than twelve months use. They were heavy too. So let's get some perspective. My wheel choice was instantly noticeable upon first riding them, they transformed my bike and I mean transformed the ride. It felt like a new bike, I could not believe the difference.

My cycling has progressed and I rode a fast 65 miles undulating yesterday at an average of just under 19mph. Now I know some of that average is down to the wheels.

So, choose carefully would be my advice, but do not be too put off by all the nay sayers. When I was looking at replacement wheels I liked the look of Campagnolo Shamals, but in the end got hand built carbon wheels for similar money. Do I need them? No. Do I need some kind of wheel? Yes, obviously. I had a budget of £700 and got hand built wheels which in my opinion are MUCH stronger than factory built. And of course, if I ding a spoke it is easily replaced. When the rims wear out Wheelsmith will fit a new one.....jobs a goodun!

pilot_pete

Further interesting reading for those interested.

http://redkiteprayer.com/2012/07/carbon-clinchers-are-they-ready-for-prime-time/

http://forum.slowtwitch.com/cgi-bin/gfo ... st=3014846

http://roadbikeaction.com/Tech-News/content/71/4808/Tech-Report-The-Real-Story-Behind-Carbon-Clinchers.html

That's just the first few results of a google search about carbon clincher problems. They all seem to come to the same conclusion as me in that braking on the downhills can cause heating/ braking issues, even with a correct braking technique and riders should seriously consider if this sort of rim is appropriate for that kind of use...

PP

Edited to reply to the post above. Yes, once I had put Swiss Stop pads on braking was significantly improved over the supplied cork pads. I made a typo and should have put "I had changed the pads to Swiss Stop yellow which improved both wet and dry braking, but wet braking was still not as good."

My opinion of the braking ability of these rims has obviously changed over time due to my experiences of these rims, I don't claim otherwise. And that's the problem. In order to get braking of a safe standard you have to fit different pads and there would appear then to be a heat issue which over time affects the integrity of the rim. THAT IS MY SOLE ISSUE WITH THESE RIMS. We can keep quoting forward and backward all day, the fact is my opinion has changed and it would appear that industry wide there are braking/ heating issues with carbon clincher rims. I will leave the discussion now as I feel I have made my point, others can decide on the suitability of a product for their needs based on this and any other research they choose to do.

PP

amaferanga

ugo.santalucia wrote:

What's negative about the process?
There was an alleged issue, the builder took some time to come and explain the situation, we are all a little better informed.
These things don't just happen on forums... Remember the issue with the Mercedes class A that capsized in the Moose test years ago?

The negative is the fact that people are forming opinions based on 3rd hand information. On the issue of carbon clinchers it seems everyone has an opinion on them, mostly that they're bad, without ever having used them. Like I said, it's opinions based on reading something, somewhere once that said they were bad that end up with forum threads turning into absolute drivel full of ridiculous generalisations (e.g. Kinlin rims are rubbish - remember that one? ).

leloby

Pilot Pete wrote:

...I will leave the discussion now as I feel I have made my point, others can decide on the suitability of a product for their needs based on this and any other research they choose to do.

We have a pair of similar wheels here if anyone wants to try them out. They are off-loaded by our sponsored rider after a heavy season so are pretty hammered having been in the Rás na mBan and the Scottish National Road Race - but they will give you a idea of how "crap" the braking is before you splash the hard earned. A deposit is required and you'll need to pay for brake pads and courier both ways.

Here's what they've been through:

http://www.britishcycling.org.uk/points ... &year=2012

ugo.santalucia

amaferanga wrote:

ugo.santalucia wrote:

What's negative about the process?
There was an alleged issue, the builder took some time to come and explain the situation, we are all a little better informed.
These things don't just happen on forums... Remember the issue with the Mercedes class A that capsized in the Moose test years ago?

The negative is the fact that people are forming opinions based on 3rd hand information. On the issue of carbon clinchers it seems everyone has an opinion on them, mostly that they're bad, without ever having used them. Like I said, it's opinions based on reading something, somewhere once that said they were bad that end up with forum threads turning into absolute drivel full of ridiculous generalisations (e.g. Kinlin rims are rubbish - remember that one? ).

That's true of life in general... You don't need to get on a forum to find third hand information.

Re the kinlin... This is first hand... I have built a couple of sets which are still around. My impression is that hey were very mediocre rims, in line with their price. I don't really die for using them again.
I have also had direct experience of three friends with kinlin made rims cracking after give or take a couple of years. I have still to see an open pro or ambrosio rim cracked

leloby

Open Pros !?! - they are possibly the most dangerous rims on the market - people need to KNOW about this sort of poor manufacturing. I was just riding along when THIS happened.....

http://www.wheelsmith.co.uk/open-pro-fun

il_principe

I've been riding on a set of Zipp Firecrest CC's since May, they've done just under 2000 miles without any trouble. Rides have include long descents in the Pyrenees, and a ride in Cyprus that involved 35 miles of almost continuous climbing followed by a descent back the same way. They've performed very well. You do notice some fade on long descents, and the rims have got quite warm, but it's never been an issue. They do screech a bit on long descent though.

I'm a pretty nervous descender and probably ride the brakes more than most. Thought they would be less than ideal for the mountains, but as it turned out they were completely fine. I also have a set of FFWD's with an ALU brake track, but they are a damn sight heavier and looked wrong on the new bike. Both sets can be seen in my sig pics. I freely admit that they were purchased for tartiness reasons...

amaferanga

ugo.santalucia wrote:

That's true of life in general... You don't need to get on a forum to find third hand information.

Re the kinlin... This is first hand... I have built a couple of sets which are still around. My impression is that hey were very mediocre rims, in line with their price. I don't really die for using them again.
I have also had direct experience of three friends with kinlin made rims cracking after give or take a couple of years. I have still to see an open pro or ambrosio rim cracked

Well at least your info is 1st or 2nd hand. I have 3 sets of wheels with Kinlin rims and all are round and have remained true for many thousands of miles.

ugo.santalucia

leloby wrote:

Open Pros !?! - they are possibly the most dangerous rims on the market - people need to KNOW about this sort of poor manufacturing. I was just riding along when THIS happened.....

http://www.wheelsmith.co.uk/open-pro-fun

So now Bitex hubs are excellent quality and Open Pro are dangerous to ride... It is getting a bit surreal. Looking at the state of corrosion of that rim, I am surprised it was even rideable.

Shooting a rim with a rifle might be a fun stunt to impress some, but does not say much on how rims behaves in relation to metal fatigue, which is how rims die In the real world, typically we don't get shot at... Certainly not aiming at the rim.

napoleond

The reason that problems with carbon clinchers comes up on searches is that people post the same horror stories vicariously and repeatedly. The same happened with one set of post recall mavic r-sys. That one set was posted about hundreds of times. The rsys spokes actually have the highest deflection strength of mavic's entire range...

trek_dan

Just to change the subject very slightly, would people with experience of both say that there is actually any major advantage to going for a carbon clincher with alu brake surface ahead of say a 30mm deep aero alu rim?
Say with a budget of £400 - would a set of PX 50mm carbon clinchers weighing about 1800g have enough of an aero advantage over say a set of handbuilt IRD Aero's with Sapim CX spokes on Novatech (or similar) hubs, presumably weighting about 1500g? Or am I comparing apples and oranges - or am I missing the point and are cheap carbon rims were there is no weight advantage just bling...

napoleond

The 50s would be more aero (except on a crosswind).

leloby

The update on this is we have a number of sets of carbon clinchers from a coaching company in France who have traded them in for the new wider tubular sets. They have seen a lot of mountain miles and show various states of wear so buyer beware. All are true and very little brake track wear. They'll be given a once over before establishing prices.
Contact us via website info for further details.

leloby

All now gone. Cheers.

FlacVest

We wouldn't have so many of these posts if people realized how little they really save at a sustained 25 mph.

Regardless, if people also just stopped taking what people post on a forum for gold, it wouldn't be as bad either.

cougie

What are the wheels for ? If you're worried about the weight then why go deep Rim ?
If they're to be bling wheels then go for the alU brake surface. Much better in the wet.

Gabbo

How they look (not mine - these are from the WS site). An anodised braking surface would have finished them off superbly imo



All this talk about wheels is scaring me!

pride4ever

Lol carbon

ernestovicencio

My non-firecrest zipps have never let me down.