Disc wheels

[Ivor]

Any comments/things to look for in disc wheels?
Is there any benefit to the convex type (e.g. planetx) as opposed to the flat ones (e.g. corima)?

[Snoop Doug]

you can try a corima disk and a corima tri spoke if you know who to ask

I think the corima disk has a campag cassette on ye back of itte...

[Ivor]

[quote="Snoop Doug"]I think the corima disk has a campag cassette on ye back of itte...

[quote="Ivor"][quote="Snoop Doug"]I think the corima disk has a campag cassette on ye back of itte...

[Jon H]

I've used a HED, Corima and Zipp and not noticed any difference between them at all in terms of performance/speed.
But the HED didn't seem particularly well made (and was heavy), and the Zipp was very tight for clearance between the chainstays, so I just use the Corima now. A plus point for the Corima is that the valve cut-out is big enough to get a normal track pump head onto the valve without farting about with one of those 90 degree adaptor widgets.

[quote="Snoop Doug"][quote="Ivor"][quote="Snoop Doug"]I think the corima disk has a campag cassette on ye back of itte...

[Andrew G]

I asked about at various places and folk and the majority answers were comfortably:

The best disc is the Campag Ghibli - costs an arm and a leg and won't fit your Shimano set up. If you're feeling flush though then go for the Fulcrum which is probably very similar.
Second best was the Corima - You want the CN which is the one for normal bikes, the C+ is double layered and heavier and designed for track or tandem use.

My so far limited use of the Corima is that it is excellent quality and very nice to use. As Jon points out the valve hole is sensibly sized for easy tub inflation.

At a TT on Sunday the Zipp hole on someone's disc was so small that it took two of us with an L shaped adaptor ages to get any air in to it and we had to partially close the valve to get the pump head on. I don't think I could ever buy Zipp anyway as I don't think I can get past their ludicrous marketing bull.

With the Planet X I asked GBs about them and they said that unlike all the other PX kit they had had some returns with build problems with them, as they're the same as Karbona the same would apply for them and other Gigantex made stuff.

I'd take up Snoop's offer of a trial. There shouldn't be a problem as with 10 speed the spacing is so small that there is very little that it can be out. In Mallorca when Andy's spoke broke (Shimano wheel) he borrowed Marek's Cosmic with a Campag cassette and it ran without any problems.

[George]

I wouldn't worry about getting a disc until you can go sub hour on a 25, you'll save yourself loads of money and the benefits are only felt nearing 30mph anyway.

Ask Mark Mclaughlan if he uses a disc to go sub hour

[Jon H]

I disagree George. Contra-intuitive as it may seem, aerodynamic benefits have a greater benefit at lower speeds. This is because once you're up to racing speeds the main battle is against air resistance, and the power required to overcome this is proportional to the cube of the speed. So an aerodynamic saving (which effectively gives you a % gain in power) will give you a bigger gain in time if you're doing 20mph than at 25mph or 30mph.

[Dominic]

Save yourself a load of dosh and get wheel covers.

[Ivor]

[quote="George"]I wouldn't worry about getting a disc until you can go sub hour on a 25, you'll save yourself loads of money and the benefits are only felt nearing 30mph anyway.

Ask Mark Mclaughlan if he uses a disc to go sub hour

[Ivor]

[quote="Dominic"]Save yourself a load of dosh and get wheel covers.

[tel]

Being an old fart and one of the slower testers I would agree with Jon and say that as you are on the road for longer periods a disk wheel would be of benefit for the slower rider.

I`ve used a Hed and now a Zipp-I believe a disk makes around 30secs difference on a 10mile tt to someone of my limited ability.

Terry

[Dominic]

[quote="Ivor"][the other idea is perhaps a 101/82 combo on it.

[Andrew G]

Don't waste money on a 101/82 combo. Either get a disc or don't you never have a problem with the wind at the back (bike stability not your own) unless it's force 9.

Most of the stuff I've seen George says that the disc is effective from about 15mph which is why people use them on sporting courses too I guess.