Tubulars - 21mm or 23mm

Dangerous Dave

I'm planning on buying a stock of tubs for next year (Vittoria Corsa CXs all the way) but was wondering what the general view was out there on 21mm vs 23mm. I'll be sticking them onto a set of campag Bora Ultra. Is the 21mm too thin?
Any thoughts Boardies?

Morgan

I don't like the sound of either of those - can you get a 22?

sy

23's By the way I assume you are racing on these? 21's ok in dry for TT

CheGuedara

Can't say I run tubs, but 21 is pretty narrow though and might not give a lot of leeway on any road you might call iffy. From what I understand thy're less comfortable, a bit more aero, and have a slighly lower rolling resistance (RR) to wider ones so long as they're up to pressure. I suspect in the real world the increase in RR between 21mm & 23mm won't be significant unless you're TTing @ 35mph.

Check this link out this, it's old but makes the point. The CXs come in a good position but you could only be looking at as little as 2w of resistance between 21 & 23 (something like 1w = 4s per 25miles is the rule I think).

Nice hoops though, how would they compare with the ever-popular Zipp 404s (I'm saving for a pair of deep section carbon wheels for a spring purchase, so open to opinions)

blorg

Wider tyres actually have lower rolling resistance at any given pressure but you can inflate the thinner ones to higher pressures. From what I can gather there is no RR benefit to a 21 over a 23 but you might have a slight aero benefit.

Good article on it here, there is plenty more stuff on the web if you search. Note on the list that Che links above the tyres with the lowest RR are a 22 and a 24mm while the 19mm is quite far down the list.

Dangerous Dave

yeah, looking at these for racing
I've always ridden CXs and not really interesting in riding anything else at this stage, but unfortunately they don't make a 22. I'm getting back on tubs now after a few years in clincher, so just wanted to get others views rather than just sticking with 'habit'.
I had a set of new 404s and sold em to get these. I reckon at that level of wheel there is no difference to be honest. The deal-clincher for me was the Record standard bearings in the Bora Ultra.
If you're on a budget, I also just bought a second-hand pair of Flashpoints, and for the money, you can't argue with them.

Twinksno1flan

I recently bought a pair of 3-4 year old Bora tubs and they are brilliant,I also got a single rear from another ex-time triallist. Veloflex is my man although I have a few used Conti's.The tyres wont last to long but the difference is so good that I will move up a category next year, stunning wheels that make racing a lot more fun.