/ Bad weather, hills Tour of Britain, tyres

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j0ntyg on 16 Sep 2013
I know nothing about biking so I must ask the biking community to inform me. The Tour is going through Cumbria today. The weather is terrible, heavy rain and 50mph winds. The riders will go over Honister pass, which, being west facing will attract both the N.W. wind and the rain, although the wind will have been behind them.
Those conditions will have made things difficult. So do these cyclists ever stop to change tyres as Formula 1 does?
balmybaldwin - on 16 Sep 2013
In reply to j0ntyg:

No. Essentially a road bike tyre is so thin that traditional tread patterns are not required, and make virtually no difference.

That doesn't meant that manufacturers don't produce them e.g. Continental 4 seasons has more tread than their GP4000s - but that doesn't provide any more grip in real terms (if anything it lowers it due to a reduced contact patch)

Compound will probably matter so they use a compound that performs well at the temperature of the road (i.e. cooler here than say the Vuelta)
dale1968 - on 16 Sep 2013
In reply to j0ntyg: They will drop the PSI, so there's more contact with the road when cornering
j0ntyg on 16 Sep 2013
In reply to balmybaldwin:

>> Thanks for that. Would I be right in assuming that a thin tyre has the advantage of being compressed down through the water on the road surface,
to the road surface itself? There will be an incisive tyre plus the weight of the rider.
Guy - on 16 Sep 2013
In reply to j0ntyg: The tyre pressure is high and the contact patch is small which means the irregularities in the road surface play a bigger part in allowing the water to escape than tread does.
Blinder - on 16 Sep 2013
In reply to j0ntyg: they might run more puncture resistant tire ( tub's) as the rain will wash more grit and stuff onto the road. But they will not change mid race. Don't forget a team is composed of nine riders ( I think). Which will mean 18 spare wheels plus spare bikes and spare wheels in case of puncture.
adam11 - on 17 Sep 2013
In reply to dale1968:

I know nothing about pedal bikes, but would they lower the pressure to get more heat into the tyre - as well as increasing the contact patch?
stewieatb on 17 Sep 2013
In reply to j0ntyg:
> (In reply to balmybaldwin)
>
> >> Thanks for that. Would I be right in assuming that a thin tyre has the advantage of being compressed down through the water on the road surface,
> to the road surface itself? There will be an incisive tyre plus the weight of the rider.

It's that sort of thing, yes. When a car aquaplanes, it's because the pressure the car's weight is exerting on the contact patch is low enough that surface tension can momentarily support the car's weight. Deep tread helps displace the water before this can happen, provided speeds are low enough.

On a bike, the contact patch is much smaller and is only two wheels, leading to a much higher contact patch pressure. Hence, it's impossible for a pedal bike to aquaplane.

Wet roads are of course more slippy, but getting more contact rubber on the floor is more important than having measures (tread) against something that can't happen (aquaplaning). Dropping the tyre pressures slightly gives you a slight increase in contact patch, hence increasing your limit of friction on corners and for power transmission.

There's a really good Sheldon Brown article about all this somewhere.

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