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Re: Reducing weight of TT bike for London 2012
Posted: Tue Jun 12, 2012 6:19 am
by SuperDave
LiveFastRideHard wrote:A custom geared set of aero rings from Fiber-Lyte would do the trick. I find gearing to be just as important as tyres. I use the Vittoria Evo-Tri and it has a much better puncture resistance than the chrono. The first generations of the Evo-tri were under 200 grams and very fast. I still have a couple sets I use for races. I also used the aero Fiber-lyte rings and was pleased with their performance. I used the Felt DA through three different models and found tapered ti bolts, shortened seat post, stem face plate swap, ceramic bearings(headset hard to find) brake pad holders, arm cups and pad swaps and housing were the best ways to deal with the integrated frameset. Good luck with the training and preparation.
Pardon my ignorance, but are the Vittoria Triathlon tyres still using Butyl rubber inner tubes? If so I wouldn't advise using them for such a key event.
-SD
Re: Reducing weight of TT bike for London 2012
Posted: Tue Jun 12, 2012 6:19 am
by Weenie
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Re: Reducing weight of TT bike for London 2012
Posted: Wed Jun 13, 2012 4:34 am
by thisisatest
i believe the main (only?) difference between the evo triathlon and evo chrono is that the triathlon version uses the butyl tube. this is so one can pump up the tires the night before the event and leave it in the transition area without the tire losing significant pressure. the chrono, with the latex tube, is faster though.
Re: Reducing weight of TT bike for London 2012
Posted: Wed Jun 13, 2012 8:46 am
by Pokerface07
The tri version of the tyre weighs 230g vs 165g for the Crono. 65g extra per tyre. Not a huge amount, but when looking ways to drop the overall weight, tyres is an easy choice.
thisisatest wrote:i believe the main (only?) difference between the evo triathlon and evo chrono is that the triathlon version uses the butyl tube. this is so one can pump up the tires the night before the event and leave it in the transition area without the tire losing significant pressure. the chrono, with the latex tube, is faster though.
Re: Reducing weight of TT bike for London 2012
Posted: Wed Jun 13, 2012 3:41 pm
by odin99
this is an awesome thread. what's the current weight of your TT bike poker? and how much have you reduced its weight? (sorry if i missed this)
Re: Reducing weight of TT bike for London 2012
Posted: Wed Jun 13, 2012 3:55 pm
by KWalker
Also changing rings will change the SRM calibration, which I personally wouldn't want to deal with mentally speaking.
Re: Reducing weight of TT bike for London 2012
Posted: Wed Jun 13, 2012 4:07 pm
by Pokerface07
No idea on the weight. But it was heavy! Possibly in the range of 9kg+ if I recall from a recent UCI event where they weighed it.
Once I get all the new parts, I'll weigh it again and post it up.
Re: Reducing weight of TT bike for London 2012
Posted: Wed Jun 13, 2012 4:50 pm
by Pokerface07
KWalker wrote:Also changing rings will change the SRM calibration, which I personally wouldn't want to deal with mentally speaking.
Yes - this is true. In fact, I had considered going to a larger chainring just for the TT (I use the same chain set for road racing as well) but was worried what it might do to the calibration by switching. Accurate power readings is very important in a TT for me.
Re: Reducing weight of TT bike for London 2012
Posted: Wed Jun 13, 2012 5:25 pm
by ross
Pokerface07 wrote:The London course is mostly on Brand's Hatch - which is a lumpy race circuit (think they used to hold the F1 there, now used for motorbike racing). Wind conditions likely to be variable (but it's a twisty course so it's gonna hit from all angles).
Brands Hatch has 2 layouts, the Indy sprint circuit and the longer GP circuit.
I've never done it on a bicycle but have tons of trackday experience there as it was my local circuit for 8 years. There are two places I can imagine would be braking points on a bike
1. Into Druids hairpin, although this is uphill so you may be able to scrub speed here
2. Graham Hill bend coming down the hill again from Druids
On the GP circuit
In addition to the above, Surtee's is uphill so that should be fine. Stirlings would be the only other point as that's a downhill 90 degree left but the track's pretty wide there
Paddock Hill should be a blast on a bike at top speed
Best of luck