Continental Competition Pressure. Tubs

b0dski

Just got a set of wheels with 22mm Continental Competition Tubulars on them.

I've never used tubs before. What pressure would be recomended for them. The wheels are Shimano Dura Ace C50's. I weigh 190Lbs, and the bike is used mainly on "normal condition" british B roads

Thanks.

chrisw71

The tyres should have the recommended and maximum inflation pressure printed on the side but I believe, for 22mm it is 110 psi and 170psi respectively.

b0dski

Yeah they do. I'm used to running clinchers at around 110 psi. A tub will obviously run higher pressure. Does that mean I should be around 150-160? So around 10 psi short of it's maximum like the clinchers are at 110 psi.

andyrr

'Normal' ie some fairly poor surfaced bits, I'd run close to 110 psi, prob no more than 120psi - I'm nearer 150lbs so maybe you could go higher pressures but I wouldn't go near 170psi on the road, 150 too much even for lovely smooth roads.

Yossie

Agree - 160psi is horrid - bouncy and skitty on the road. I run them at around 130/140psi with no problems at all and a really nice (to me) hard, solid feeling on the road.

There is a big debate about whether a higher tyre pressure actually means more or less efficiency on the road (ok, the harder they are the less rolling resistance but is this countered by the fact that they may kick up off the road everytime you hit a bump and therefore lose speed).

Someone at sometime has said around the 125/130psi mark in the dry is the way to go, but I can't remember who or when or where or why. Drop this down to around 110psi for when its rainings/Paris - Roubaix racing.

A lot of it will also depend on how much "feel" you like from your bike/tyres: I like everything to be as stiff and hard as possible (oooeeerrr Missus), some people like a bit more "give" - personal choice and very, very subjective.

andy_wrx

chrisw71 wrote:

The tyres should have the recommended and maximum inflation pressure printed on the side but I believe, for 22mm it is 110 psi and 170psi respectively.

See Sheldon Brown
http://www.sheldonbrown.com/tires.html#pressure

Most tires have a "maximum" pressure, or a recommended pressure range marked on the side of the tire. These pressure ratings are established by the tire manufacturers after consultation with the legal and marketing departments.

The lawyers want the number kept conservatively low, in case the tire gets mounted on a defective or otherwise loose fitting rim. They commonly shoot for half of the real blow-off pressure.

The marketing department wants the number high, because many tire purchasers make the (unreliable) assumption that the higher the pressure rating, the better the quality of the tire.

Newbies often take these arbitrary ratings as if they had some scientific basis. While you'll rarely get in trouble with this rote approach, you will usually not be getting the best possible performance.

Savvy cyclists experiment with different pressures, and often even vary the pressure for different surface conditions.

A variety of other tyre myths debunked here too
- tread patterns on tyres for use in the wet, swapping front-to-rear to equalise the wear

b0dski

Cheers guys.

Andy, with a username like that are you on Scoobynet too ???

andy_wrx

No, I should really be ex_wrx

Shame, I could get my bikes in the back of the 'wagon without removing the wheels

b0dski

Wagon's the way to go. Can only get the frame on the backseat of my Blobeye and the wheels in the boot. Sucks really :x

markos1963

Unless you are racing why use such high pressures? I use 90psi on the front and 100psi on the back. I weigh 90kg. You get a lovely smooth ride and being tubs there's no risk of pinch punctures. If I'm TTing on a nice smooth duel carriageway then I pump them up to 110 and 120 respectively. If the tyres are too hard then they bounce around and you end up going slower.

andyrr

B0DSKI wrote:

Cheers guys.

Andy, with a username like that are you on Scoobynet too ???

but I am ! lol
Still got my '03 wagon, back seat folder takes a bike with both wheel still on.

Re Paris - Roubaix - I'm sure the pros drop to pretty darn low pressures sometimes - since tubs don't suffer pinch flats due to the rim shape they can drop to really low pressures for traction, not sure what but I'm sure it's under 100psi.
On the roads I've ridden on I really would never ever go above 130psi, just too hard. A glass-smooth TT on a DC I might go to 130+ but I doubt I've been lucky enough to see such a road surface ! Depends on your own weight but 110 - 120'ish psi should be good for good drip in the dry, closer to 100 if the surface is slippy. I spoke to PX when I bought a pair of their ex-pro team wheels and they quoted a tdf mechanic stating that they normally ran tubs at 110psi, no need to go harder. Harder feels faster but is a sensation that belies the truth.