TT wheels

pedalbasher

Appreciate there are LOTS of variables and other considerations, but very generally, how much advantage is an 80mm front wheel (e.g. Zipp 808 FC) likely to give over a 38-40mm front in a TT?

I'll be doing a combination of sporting courses (i.e. hilly TTs) and flat, fast TTs. Not sure whether it's worth looking at an 808 to complete my armoury - and whether it would be sensible to use it all the time, even in hilly TTs.

pedalbasher

...this is with a disc rear, btw.

ugo.santalucia

Is this a change of heart from the other thread or an addition to the fleet?

You can do your own calculations based on the numbers quoted by manufacturers... try FLO numbers, plot them against your current result and you should be able to work out how many seconds you will save

These are fairly basic, but the numbers are not far off mark

https://whosatthewheel.com/2016/11/06/c ... and-power/

aberdeen_lune

Not much. Why not get a trispoke?

pedalbasher

Thanks Ugo, I'll take a look.

This is an alternative... I ruled out the race-only tubs as a bad choice, and thought I'd make do with current clinchers as my go-to wheels, with a standalone new front wheel for TTing (paired with my current disc). Now I'm questioning whether it's even worth going for a new deep front!

aberdeen_lune

Depends on the wind. There is a marginal gain to be had but it depends what it's worth to you and how many float days you encounter.

Grill

If you get the right wheel and tyre/tub then quite a lot. It's hardly marginal.

pedalbasher

@Grill, looking at clincher front. I'm thinking Vittoria latex tube and a Corsa G+ tyre (23mm). Rear is a Zipp 900 with Corsa G+ tub (also 23mm).

Grill

Corsa Speed is faster. A lot faster.
http://www.bicyclerollingresistance.com/

pedalbasher

Thanks. Two reasons I'm thinking G+

1. The rear tub is a G+ and it's near new, so for aesthetics' sake it would be nice to match it.

2. More importantly, I'll be doing a series of sporting courses on some dubious lanes / road surfaces, where a tiny bit of puncture protection will make me feel better.

Grill

Use sealant on fast tubs/tyres if you're worried.

aberdeen_lune

Even Flo wheels table states around 20 second saving on a 25TT. For an average rider that's around 0.5% so a gain to be had but depends on conditions for handling.

For what's it's worth I vary between an 808 Firecrest on less windy days and a Corima 50 for other days. Not sure myself on how big a difference it makes because I always go faster when it's less windy. Is it worth it that's up to you on your own cost benefit analysis. Not sure why you'd go clincher front tub rear though.

ugo.santalucia

Aberdeen_lune wrote:

Even Flo wheels table states around 20 second saving on a 25TT. For an average rider that's around 0.5% so a gain to be had but depends on conditions for handling.

For what's it's worth I vary between an 808 Firecrest on less windy days and a Corima 50 for other days. Not sure myself on how big a difference it makes because I always go faster when it's less windy. Is it worth it that's up to you on your own cost benefit analysis. Not sure why you'd go clincher front tub rear though.

I guess it depends what 20 seconds mean to you. Personally, I wouldn't spend a penny for 20 seconds... but that's because I don't know what to do with them. To be competitive I'd need more like 20 minutes.

However, in your case 20 seconds might be the difference between finishing 5th and 3rd... in which case it matters... it's your call
The number per se is meaningless, unless it means something... if you know what I mean... :roll: