Pros/Cons of Using MTB cassatte / mech for the Etapes?

Von2

Hi

52 and feeling it! ... and heading for the Etapes in July.

On a different thread someone suggested that I use a MTB cassette / rear mech in order to get over my problem of having Dura Ace 53/39 and 11-23 - putting a 11-34 on the back.

What do you think?

WHat are the pros / cons of doing this?

Thanks for your help

Steve

vorsprung

three issues

1) Road derrailluers have a capacity limit and a 34T sprocket is going to be greater than this. So you would have to replace the derrailluer as well

2) a MTB 11-34 will have big gaps in the ratios which might make pacing with a group less comfortable

3) If you are really so unfit that you need a 34T sprocket you might be unable to achieve the minimum speed to get over the climb with out getting swept up by the broom wagon. Hmm ,on second thoughts this is probably not the case. 39x34 gives a gear of 30.1". Which is a bit lower than a "typical" 34x27- 33.1"

Hoopdriver

Couldn't you just use a compact chainset and a 11-28 and achieve that too?

I'm 52 as well - I've a road bike with a compact chainset 50-34, and 13-29 on back (it's Campagnolo; they make a 13-29) and I can't imagine much I couldn't get over with that set up.

elcani

Hi - I suggested this and have just posted again on your other thread. Just to reiterate, the only 'true' con to doing this is the wider gap between ratios that comes as a result of the larger jumps in teeth number on the MTB cassette.

In terms of functionality, it will be fine as long as you change the mech and chain (as your current one is unlikely to be long enough).

Whether it comes within your budget depends on the size of your budget and the price you can get the kit for. You could try borrowing cassette + mech from a mate with an MTB if you're really strapped.

Whether you actually need to do it at all, only you can know - despite people telling you that 'with X x Y combination you should be able to get up anything'. Sheldons gear calculator (linked to in the other thread) will allow you to compare various options with what you've used in the past.

Good luck, and let us know what you settle on.

Cheers

Hoopdriver

I meant to add in my previous post that I do not believe an MBT mech will work with STI shifters - something else you may want to consider.

John.T

Hoopdriver wrote:

I meant to add in my previous post that I do not believe an MBT mech will work with STI shifters - something else you may want to consider.

It will work fine. It may be listed as 9sp but it does not know this.

Hoopdriver

Yes, I know that mechs are the 'dumb' partner in the shifting sequence as regards the number of speeds, in other words it just does what it's told, but i was under the impression there was an overall incompatibility between MBT mechs and STI shifters that has nothing to do with the number of speeds involved.

John.T

Hoopdriver wrote:

Yes, I know that mechs are the 'dumb' partner in the shifting sequence as regards the number of speeds, in other words it just does what it's told, but i was under the impression there was an overall incompatibility between MBT mechs and STI shifters that has nothing to do with the number of speeds involved.

Only front mechs. Rear all have the same cable pull (other than some old Dura-ace ones).

Von2

Guys

Thanks for your input

I have decided to put a compact on with as high a normal cassette as possible .. still searching (can I mix and match with a COmpag cassette and DUra-Ace mech / derail?

A fall back will be for an MTB cassette (plus mech)


And final option ....... big bag of Pringles, loads of beer, and a big Flatscreen in line with other root vegetables!

Steve