Professional Cycling - What size chainrings do tdf riders use?

on mountain stages, what size small chainring do they use? (I assume all are on doubles)

I think it depends. I can't throw any numbers your way (maybe someone else can?) but on stage 17 of the Giro I remember some the riders saying that they were going into Mountaion Bike territory it terms of gearing...I also have an interview with Dave Z where he says that he used a compact to get up Brasstown.

The compact wouldn't surprise me at all... Why cook your legs when you still have 1000+ miles left to race?

They use doubles, yes. 39t or 36t. Quite a few riders are on compact cranksets this year for mountain stages. I'm quite sure they aren't using a 34t inner ring though, at least not yeat - but I may be way wrong.

I would guess that with ten speed cassettes, they wouldn't need compacts.

And with compacts, they couldn't get a high enough gear for descents. I'm guessing 53/39 in mountains.

The ones with 36s are the ones that finished way down on the stage Menchov won last week?

Was watching repeats of last week tonight on OLN, and they were showing Mercado and Dessel pedalling very slowly on the easiest back gear. (on the stage they won). The hill didn't seem huge, and I couldn't help thinking that they could be spinning my granny gear to go the same speed while sitting down.

I would guess that with ten speed cassettes, they wouldn't need compacts.
Why? 10s cassettes don't get you additional high or low range. They only add finer increments.



nd with compacts, they couldn't get a high enough gear for descents. I'm guessing 53/39 in mountains.
A 50 with an 11T gets you fairly high. Higher than 52x12 or 53x12. Not higher than 53x11 obviously but if a guy wanted to "compromise" by using a compact for the mountains, he could mitigate the high-end losses by using a cassette with an 11T cog.


That all being said, I would still guess many (most) are on 53/39 for the mountains and probably 53/42 for the flatter stages. Cassettes with 27T for the steeper mountain stages. Maybe only 25.

That all being said, I would still guess many (most) are on 53/39 for the mountains and probably 53/42 for the flatter stages. Cassettes with 27T for the steeper mountain stages. Maybe only 25.
Thats what I meant to say, but you said it right.

You guys have no idea. For the alps - a 39 and a 25 at the very very most.

The first few hairpins on Alpe d'Huez are ridden at over 20 mph. The average speed up this climb for the winners is around 13 mph. 13 mph is a cadence of 90 with 39/21. To get that speed with a 39/25 they would need a cadence of 120!

13 mph is a cadence of 90 with 39/21. To get that speed with a 39/25 they would need a cadence of 120!

Or shift up a click or two.

Or shift up a click or two.
In which case there's no need for the 25 - so they are geared higher than what everyone here is saying.

Bobke was asked this question yesterday. His answer was 39/21 or 39/23...

At the Tour of California at least some pros were using 39/27 on Sierra road. I do not find it out of the question to think that some might use a 25 or 27 cassette on the steeper mountain stages of the Tour (which L'Alpe d'Huez is not).

At any rate the question is on chainrings and I believe we have that covered.


Bobke was asked this question yesterday. His answer was 39/21 or 39/23...The question he was asked was what gear they were in, not what gears they have on their bike. It was funny because immediately after he answered that question they had a camera shot of someone's bike and you could very clearly see that they were not in the lowest gear of the cassette, they were up...yep, a click or two. Making a 25 feasible and quite possibly 27 for the non-climbers.

The question he was asked was what gear they were in, not what gears they have on their bike. It was funny because immediately after he answered that question they had a camera shot of someone's bike and you could very clearly see that they were not in the lowest gear of the cassette, they were up...yep, a click or two. Making a 25 feasible and quite possibly 27 for the non-climbers.

I never claimed Bobke was being accurate (God love him!)...:D

I never claimed Bobke was being accurate (God love him!)...:D

It's quite possible he was accurate, i.e. they very well could have been in 39x23 or 39x21 for that section. My point is, the gear they might have been in at the time probably wasn't the lowest gear on the bike. I paid close attention to that segment, with this discussion in mind. Given the speed they were going and their cadence, that gearing would be pretty close to right. But it wasn't necessarily the lowest, which was backed up by the camera shot of the bike with the chain very obviously NOT in the largest cog of the cassette.

On a 27 cassette (stock, anyway), the next lowest gear is a 24. On a 25, the next lowest is a 23. On both, the next after that is 21. As such, those cassette choices are not inconceivable. I have my doubts that the stronger climbers had anything that low, but don't forget there are 150 or so other riders that are not getting camera time.

I would guess that with ten speed cassettes, they wouldn't need compacts.

Five cogs, six cogs, ten cogs...the number of cogs has nothing to do with cycling. What is important is to have precisely the CORRECT cogs needed for a given ride. Thirty years ago, it was customary for a pro rider to put on the cogs that matched the needs of a given day of racing.

Today, it would be foolish to assume that because a bike has twenty speeds that it has the correct gears for a given day of riding. Many current road bikes with ten cogs have only about 12 distinctly different gears with reasonably straight chainlines. And, of those 12 gears, only 1 or 2 might be suitable for the sort of brutal climbing through the Alps that the Tour de France imposes.

I read somewhere recently that they use the same gearing most of us use. 53/39 in the front and either 11/23 or /25 in the rear in the mountain stages. I also read in the Giro some riders were planning on using a compact on that killer mountain stage but most stayed with the standard gearing.

burp