TDF Stage 5 - question about tyres

[Salad Dodger]

I have only ever watched the TDF via the "highlights" TV programmes, but this year, due to current lack of work, I have been watching the live coverage, and finding it fascinating.

I am not knowledgeable about road cycle racing, so can I ask a genuine question please?

I understand that most riders probably used wider than normal tyres yesterday, to give more durability over the cobbles. But why so many falls on the tarmac? Is this the norm when a peloton races in the rain? Or are they likely to have used more knobbly (and therefore maybe less grippy on tarmac) tyres?

Also, do the riders have the option of "wet" or "dry" tyres, like in motor racing or motorcycle racing, or do they normally use the same tyres for all conditions? Obviously yesterday's stage was outside the envelope of normal tarmac racing conditions....

Any explanation to an interested novice spectator would be appreciated!

 

[MisterStan]

Interesting article here on the bikes and tyres used yesterday.

 

[adscrim]

My view was that most of the non-cobble related offs happened at junctions or RABs. These areas are often covered in fuel/oily substances from exhausts and are treacherous when wet - especially when traveling at the speeds they were going yesterday.

 

[Beebo]

Interesting article here on the bikes and tyres used yesterday.

wow 50psi for the front tyre!
I even saw someone yesterday with a clip on rear mud guard.
top bar brakes could have helped Froome with his damaged wrist, but I doubt it would have made much difference if his wrist was that bad.

 

[MisterStan]

I know, 50 psi is less than the Mrs runs on her hybrid!

 

[oldroadman]

Over pave, it's good to ride slightly wider tubs - 27 instead of the (now normal for road) 23 or 25. Inflation at only just over 3.5 bar is something I've never heard of - perhaps it was a misread/print/quote, or someone having a little practical joke. 5 bar would be as low as anyone needs to go, otherwise a danger of flatting due to compression and the horrible discomfort on pave. The technique, wet or dry, is big gear and push on, relax upper body and let the bike track naturally. Sean Kelly mentioned not over correcting, dead right, that is a cause of falling. Some makers do have "wet" versions of tubs, which are a bit softer tread.
On "smooth" roads, it's the road paint that's the big problem, crossings, lines, they always seem to be on a bend, and the wheels can just go from underneath. One other cause of falls, using front brake too hard in the wet - often not much to be done if avoiding others or poor handlers. Which is a good argument against disc brakes on the road, far too easy to lock. For the gent who asked about tread pattern, it's slick or minimal - knobblies are strictly for those funny MTB things! One things for sure, wet pave is zero fun and just something that has to be done as part of the job.

 

[w00hoo_kent]

On "smooth" roads, it's the road paint that's the big problem, crossings, lines, they always seem to be on a bend, and the wheels can just go from underneath.

And for some reason continental (French definitely) road paint is particularly slippy. I guess we use a different formula in the UK, ours tends to sit prouder, but be more forgiving.

One other cause of falls, using front brake too hard in the wet - often not much to be done if avoiding others or poor handlers. Which is a good argument against disc brakes on the road, far too easy to lock.

I'd question that, disks shouldn't be easier to lock than rims and I've never found them so (although I've not ridden much with modern rim brakes so am willing to be proved wrong). All the science points to disks being easier to brake progressively with.

 

[laurence]

oddly, late last night when my mind was racing, i did wonder if the change in bike settings and lower tyre pressures caused some of the accidents as riders wouldn't be used to it

good post. chapeau.

 

[Pro Tour Punditry]

On the R5 commentary, they were talking about how the riders basically get no choice over brands of tyres as its dictated by sponsorship.

Interesting article here on the bikes and tyres used yesterday.

In the embedded article it mentions Garmin were riding Mavics with FMB Paris-Roubaix tubulars. The pics I saw have the sidewalls "blacked out" with marker pen as FMB are not "sponsors"

 

[Andrew Br]

I'd question that, disks shouldn't be easier to lock than rims and I've never found them so (although I've not ridden much with modern rim brakes so am willing to be proved wrong). All the science points to disks being easier to brake progressively with.

I agree with this; discs can be easier to control than rim brakes especially when it's wet. At the very least, you've a good idea what's going to happen.
Another factor that occurred to me when I heard the squeal of braking during the live coverage today; carbon rims are reported to be "grabby" under braking so is that another factor ?
Interesting that a couple of (FDJ ?) riders unclipped when they were braking heavily; it looked like it stopped them going down.

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