Disc wheels

[xrayspecs]

I know this is one of those how long is a piece of string questions but will a disc wheel make much of a difference to my time trialing and if so what to go for, there also seem to be clincher (my pref) or tubular options. What sort of front wheel should they be combined with? Also is second hand a good idea as they seem to be carbon. Just some thoughts from the experts.
CG

[Andy H]

Could be of interest.....

http://cyclingtips.com.au/2010/04/biggest-bang-for-your-buck-in-time-trial-equipment/

Think the fact that they look good and make you 'feel' faster is as good a reason as you need!

[Rob Jones]

 of all the aero gadgets this one I think is one of the least proven in terms of performance and value. Definately depends on conditions and on course too...extra weight not good on a lumpy course. If you have money to burn then a deep rim front wheel will be more beneficial in good conditions. A low weight rear disc will cost a bomb. A lower cost one will weigh a ton!

Mine is a budget one - clincher but carbon rims. Don't think allu rims is important as in tt you hardly use rear brake. Its very heavy but I still think helps time a bit, even on the wick course. The noise it makes is great! I see no reason not to get a 2nd hand one, so long as you can check bearings are smooth and it spins true. Its unlikely to have done that many miles given limited utility.

[stevelandeg]

Chris, here's my attempt at muddying the water.

In 2003 I set my course PB for the R10/22, 24:27 on a float night.
Road bike with clip ons, 30mm alloy clinchers & 23mm tyres, road helmet, no real structure to training.
Last night was a TT bike, skin suit, pointy hat, 50mm carbon front & 100mm rear with tubs @130psi, training plan to record 24:51.

[traine]

11 years is the difference Peter Pan ! ! !

Tim

[Rob Jones]

Just 30 seconds lost in 11 years of decline is a great tribute to current echnology 

[Chris Reed]

That table is useful but would be interesting to understand the marginal gains,

Eg, difference between
Hoods vs Drops
Drops vs Aero bars
Aero bars vs tuned aero bars

Similar,
Normal rims vs 30/40mm
30/40mm vs 80/100mm
80/100mm vs Disk

I get that the biggest improvements I can make is weight down & power up! But what can I say I love data!

[traine]

Choose your wheels for the conditions (and audio stimulation), but a pointy hat and aero bars are worth a minute in a '10'.

I reckon pimply tyres are better than slicks (the golf ball effect) and the front wheel aerodynamics are more important than the rear wheel. My tri-spoke front wheel is really 'flat' and fast.

I thinks it stands to reason that a disc must be faster than a spoked wheel. Why else do track cyclists use double discs ?

A fewer spoked wheel is faster than a much spoked wheel e.g. 22 spokes are better than 36. Just take a single spoke and swish it through the air fast and note the sound it makes. That's all air resistance ! Flat tapered spokes must be better than round.

An aero rim must be faster than a flat rim but the depth that the rim needs to be is debatable. Perhaps because a deep rim shortens the length of the spoke it may be better.

Since you need ears and shoulders, you cannot shave them off or tape them down, the bike is the only factor to concentrate upon if you already have a skin suit but, I am told, the position on the bike is critical and that is something to concentrate on - and losing the odd pound or two in weight !

Tim

[Davey C]

That table is useful but would be interesting to understand the marginal gains,

Eg, difference between
Hoods vs Drops
Drops vs Aero bars
Aero bars vs tuned aero bars

Similar,
Normal rims vs 30/40mm
30/40mm vs 80/100mm
80/100mm vs Disk

I get that the biggest improvements I can make is weight down & power up! But what can I say I love data!

The comments about weight are misleading I think...in a TT aero comes first, power just behind and weight way down the list (assuming the course is flattish).

Even on a standard road bike deep section wheels (50mm) are worth the small sacrifice in weight as aero trumps a couple of grams every time. I'm sorry I can't but my hands on the article right now but please take my word for it that this isn't anecdotal or 'gut feeling' opinion!!

[Rob Jones]

Ita a shame so many TT courses are flat and non-technical

[xrayspecs]

Thanks guys thats really helpful and very interesting reading. I'll be investing in a skin suit next club kit order then. Will double up as a onesie when the weather gets cold then.

[ron b]

Every little bit helps but Bowen did his PB on his Road bike yesterday but with non UCI head gear.