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I'm amaze that Contador or any pro would us 34-30 set up on Plan de Corones. I know 24% is steep but I thought they had the strenght to use 27 or better yet 25. According to Cyclingnews "It was a new experience for me," said Contador. "I had to use a 34x30 gear." I believe they're on Sram. would the Red rear derailer work or would they use mtb derailer such as X-O? And who makes a 10 speed cassette that end w/ 30?
 

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There are a couple reasons that they'd go with a small gear on a TT like that, but the biggest is probably that they're on dirt. Getting out of the saddle on an unpaved section of 24% isn't an option - the rear tire will slip - so instead of using a "normal" gear that they'd mash and might force them out of the saddle for longer, they put on smaller gears that let them keep their weight on the saddle and turn a reasonable cadence. 90rpm is 8mph in a 34x30 combo - that's pretty damned fast on a 20% + grade. Pelizotti's average speed (including the less steep initial slopes) was less than 12mph.

SRAM doesn't market a 10 speed cassette with a 30 on it, but I'm sure they can piece on together using MTB cogs and 10 speed spacers. That's the sort of thing component sponsors will do for pro teams from time-to-time. I don't know with SRAM, but a 9 speed cog and 10 speed cog are generally the same, the only difference is the spacing in between them.
 

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gray8110 said:
There are a couple reasons that they'd go with a small gear on a TT like that, but the biggest is probably that they're on dirt. Getting out of the saddle on an unpaved section of 24% isn't an option - the rear tire will slip - so instead of using a "normal" gear that they'd mash and might force them out of the saddle for longer, they put on smaller gears that let them keep their weight on the saddle and turn a reasonable cadence. 90rpm is 8mph in a 34x30 combo - that's pretty damned fast on a 20% + grade. Pelizotti's average speed (including the less steep initial slopes) was less than 12mph.
Contador or anyone I saw didn't use TT bike. From the picts, the rear derailer lools like a short cage so he was probably still using the Reds stuff instead of the X-O. Levi said he use a 26 http://www.cycleto.com/girovideo.html?bcpid=1551054974&bclid=1543290355&bctid=1571653424. I didn't see him struggle w/ those gears but I also didn't see him stand up either. Not to say he didn't climb out of the saddle.
 

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spongebartstatepants said:
perhaps the 34-30 was the size of the two chainrings. that cassette doesn't look THAT big.
Definitely not, he's riding at least a 50tooth big ring... It's probably possible (although a bit pointless) to run a 34x30 chainring combo, but the shifting from "big ring" to small ring would be pretty crappy.


The cassette looks like a 30 to me - a 30 tooth cog really isn't that big and on a 700c wheel, it isn't that noticable. The diameter of a 30 is only about 23% more than a 23 tooth cog.. about 3/4" wider.
 

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SRAM MTB derailleurs, unlike Shimano varieties, are not compatible with their road shifters. It had to have been a short cage road derailleur, or an experimental mid-cage, as there are no longer options currently available from SRAM for their road groups.
 

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MaestroXC said:
SRAM MTB derailleurs, unlike Shimano varieties, are not compatible with their road shifters. It had to have been a short cage road derailleur, or an experimental mid-cage, as there are no longer options currently available from SRAM for their road groups.
Ya, I think it has to do with the "pull ratio" of the shifters. Something like that.

Completely off topic, but I'd like to try SRAM, but I run Campy and really don't want to get into having different types of wheels laying around.
 

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Old_school_nik said:
Heras used a triple for in the 23% grade in the Vuelta a few years back

Was it on the L'angrilu [sp?]

Nik
Triples were pretty widely used the last time the Vuelta hit the Angliru, but that was before compact cranks became mainstream. I don't think any pro would be embarassed to use a triple on a steep enough climb, but a lot of the gear combinations on a triple are redundant and the relatively poor shifting makes a triple a less-than-ideal choice - especially for a TT.

A 50/34 with a 13-30 gives a pro everything he needs for an uber-steep climb and will be a good pound lighter than a triple with more predictable shifting. Also, SRAM doesn't make a triple so Astana, Saunier Duval et al wouldn't even have the option.
 

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Sram mtb groups use a 2-1 ratio which is different to ShimaNo's road and mtb groups also different to srams road groups although sram could meld a road mech with a mtb mid cage. this should work on a 30.
 

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slowdave said:
Sram mtb groups use a 2-1 ratio which is different to ShimaNo's road and mtb groups also different to srams road groups although sram could meld a road mech with a mtb mid cage. this should work on a 30.
I believe SRAM MTB groups are 1.1:1 ratio (claimed 1:1) while Shimano is 1.7:1 (claimed 2:1) ratio. Not sure WHAT the SRAM road grouppos are, ratio wise, but they're not compatible.
 
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