Handling of those TT bikes

[weiyun]

With all the crashes in Stage 13 of TdF, the commentator blamed it on the poor cornering performance of those TT bikes. Is it true that they handles poorly on cornering? Or was the wet road/high speed/tyre to blame?

[mikesbytes]

Both, a wet road simply has less grip and those TT bikes are setup to maximise aero. which sacrifices handling

[weiyun]

The key question I guess is how was the handling affected? Wheelbase? Trail? Seat tube angle? Rider fit? And how did they affect the handling in the wet?

[T-Bone]

There are a few things i can think of. Disc wheels generally don't like going around corners too much, and they especially don't like a crosswind. On time trial bikes frames, the steeper seat angle would put the riders weight forward which could make it less stable. Positioning on the aero bars also provides less control, if you think about it a small movement at the centre of the steering axis would give a greater reaction than a small movement at the outside of regular drop bars.

Since riders do train a bit on their time trial bikes and would be used to them, i believe the greatest issue is the wet road. Especially going downhill, and with the riders trying to minimise any possible time loses the favourites have to push to the limit. All the minor time loses, such as slowing down slightly too much for a corner (not to mention the extra energy required to accelerate again) will all add up, just think 1sec every km doesn't seem like much, but in the end it's almost 1min.

[weiyun]

Thanks James. I think that makes sense. I'll take a closer look at those TT bikes next time, especially their bar handle position etc.

It was interesting listening to Evans' interview at the end of the ITT. He mentioned that he was going at 1/2 of his usual speed on those corners and taking extra care. And he ended up coming second. Slowing down really have paid well with little penalty in the scheme of things.

[Glenno]

Guys it was very wet at times, but I think a few of the accidents come down to nerves.

There was not much wind, so the aero wheels were not being impacted on that count.

The cobbles were very wet and the roads don't train well but some of the accidents were a results of tyres slipping.

these tt bikes made horrible noises going over the cobbles especially those with aero wheels. there is not flex in them at all.

also some guys were using their normal road bikes, these must been the lower placed riders

[mikesbytes]

Unlike a crit circuit, in these races you can't know the limitations of every corner. Many of the accidents happened on corners that tightened up on themselves.

[T-Bone]

Millar's rear Mavic disc certainly didn't help his time trial. Looked as though the aluminium rim seperated from the rest of the carbon fibre disc.

[mikesbytes]

Yes it looked that way to me too.

I would of thought they would of used a full carbon wheel, so why the aluminium ?

[weiyun]

Millar's rear Mavic disc certainly didn't help his time trial. Looked as though the aluminium rim seperated from the rest of the carbon fibre disc.

I thought there were mentions that the chain broke and somehow the wheel disintegrated after. He looked pissed.

[mikesbytes]

Yeh, they mentioned the chain brake in the repeat.

At a guess, after it broke, it jammed itself between the frame and the rim, causing the rim to break.

[T-Bone]

They said he had to change his bike twice, so maybe the chain broke in a second incident, though it could have just been a change back to the original bike with a new rear wheel. I guess we'll find out tomorrow.