Braking with Carbon Tubular Rims & Tub Security

Sergeant Rock

Hi

I recently acquired a lovely set of wheels - 50mm ultralight carbon deep section Gigantex tubular rims built up on Royce Hubs with CX-Ray spokes. Great wheels which run very quick and lively. I'm new to carbon and haven't ridden tubs for many years but I wanted a set of reliable out and out lightweights.

I went with Enve carbon specific brake blocks which give good stopping power and modulation. However a couple of times, when under heavy braking in the hills, I can detect an overheating kind of smell from the rim / blocks and there is some brake block residue on the rim. My question is how normal is this smell and am I overheating the rim. The main concern of course is rolling the tub. I am using Tufo S3 Lites with Tufo tape, the universal tape that they now do - they have dropped the extreme version.

Another consideration I have with regard to tub security is running pressure, which I am running at fairly low pressures, for Tufo 110 to 120 psi, to improve the ride suppleness - they still roll perfectly well. Will these lower pressures affect the adheredness of the tub under hot braking?

Thanks in advance

rick_chasey

The smell - wouldn't worry. If in doubt, brake less. It sounds flippant but I mean it. Only brake when you absolutely have to, and keep it hard (within reason) and brief.

The Psi - 110 isn't low - and as long as they're properly glued/taped it won't be a problem. To put it into context, pretty much all pros run tubs at Paris Roubaix, and they run them as low as 60psi.

keith57

Don't ride the brakes, use them when necessary, on, then off, it's the same for alloy too, especially on long Alpine descents.

I really like Zipp cork pads on my carbon rims, excellent modulation and no grabbing at low speed.

Velonutter

I ride my tubs at 130 on the front and 140 on the rear and they are more comfortable than my clinchers.

I use Zipps dual compound brake pads, they wear quickly though, but are perfect for my type of riding, i.e braking hard on downhills and group riding with my club.

andy_wrx

According to Tufo
http://www.tufo.com/s3-lite-215g/
S3 Lites are 21mm and run at 8–15 bar (115–220 p.s.i.) !!!

Personally I'm running Conti Podium 19mm and Conti says 160 to 220psi.
I'm experimenting running at 140psi or 120psi on Cheshire TT courses to see what's fastest and doesn't shake your teeth out : on rough surfaces (Cheshire...), too hard will be slower

Sergeant Rock

Thanks for the replies so far. Regarding the tubs I went for the Tufo S3 Lites partly because I was chasing a super light build but also because they seem very robust, and these wheels are for use in all conditions, and because there would be no issues using Tufo tape with them. However, reflecting on these points, I've cured myself (partially) of the extreme weight weenies bug I have recently had, and Tufo tub tape would probably have worked fine with any decent tub brand.

This leaves the fact that they are very tough and fast for their weight, but like andy_wrx, I live in Cheshire and ride in The Peaks a lot and the roads are appalling - worst in the lanes actually, especially when riding in a group. The ride of these tubs on the 50mm rims is not actually that bad but compared to my Dura Ace tubeless it is somewhat firmer so the use of minimum pressure was an attempt to improve things. However, like I said in the OP I was concerned that working right at the bottom end of the recommended pressure range might make tub adherence more iffy under high speed cornering or heavy / hot braking on carbon rims with softened glue.

Having seen the initial responses and doing more looking around myself I think I will continue with the low pressure regime and the Tufo's for but I may invest in a pair of Zipp Platinum or Cork pads since they seem to have the best reputation for minimising heat build up. Oh and I will brake less which is good because in general going down hills fast is half the the point of going up them in the first place.