Front shifting problems

neilob · Post by **neilob** » 7 Feb 2008, 11:04am

Some advice please from the many clever people out there! I am changing my Thorn Club Tour to straight bars for various reasons (sacrilege I know...). I've bought all the bits including a new Deore MTB chainset to replace the Ultegra triple. I've got the rear mech (Deore XT) changing sweetly using the new shifters but somehow can't get the front shifting properly. Do I need to change the Ultegra front mech as well? I thought there was compatibility??

Thanks
Neil

PW · Post by PW » 7 Feb 2008, 12:15pm

Front changers have different cable pull per click for road & mountain. If you're using MTB shifters get an MTB mech, it should fit if the c/set's an mtb type.

gaz · Post by **gaz** » 7 Feb 2008, 12:53pm

neilob · Post by **neilob** » 7 Feb 2008, 4:30pm

Aaaah! It's all clear now. Thanks for the responses. Bottom line is I need a Deore front shifter as well. More expense, unless the old one off :lol:

my tandem works. More excitement for tonite!!!

ianr1950 · Post by **ianr1950** » 7 Feb 2008, 4:43pm

Are they MTB shifters or the flat bar shifters for road bikes you have got?

thirdcrank · Post by **thirdcrank** » 7 Feb 2008, 4:45pm

neilob

Problems with front shifters can be caused by several things.

Although you cannot use road STI levers to shift for an MTB chainset because they do not pull enough cable, it should be OK the other way round - just use the stops to ensure the mech., does not move too far. (I speak as one who is normally strict follower of rules and manufacturer's recommendations but I do have a bike with flat bars, road mech and XT triple.)

The problem may be with the position of the cage. A modern triple cage has a sort of shoulder on the inside for the shift inner to middle, and if that shoulder is at the wrong height, you have no chance.

The steps between the rings can affect your ability to get the position right. Shimano road triples are optimised for 52-42-30, not a compact triple, but it can be done.

neilob · Post by **neilob** » 11 Feb 2008, 3:49pm

My shifters are (I think) MTB 7-speed 'Rapidfire'. The front mech is an Ultegra (for triples) and the chainset is a compact Deore. Do you think this can be made to work? Was just about to dust off the credit card and buy a new front mech......

thirdcrank · Post by **thirdcrank** » 11 Feb 2008, 4:11pm

I think I mentioned before I speak as a confirmed non-experimeting conformist but I have a Cannondale bike with flat handlebars with MTB controls and road mechs. The back is a 105 and the front has a model number, not even a group name. The bike originally came with a Cannondale road chainset 52/42/30. This creaked and groaned from new and eventually Cannondale agreed to a new chainset. Not wanting a repeat, I got the shop (SOWERBY BROS; MIRFIELD) to fit a compact XT chainset, once they had assured me it would work. (I had read all the if's and buts and had my doubts but it does work 100%.)

I would emphasise that it was the shop that did it. Having previously switched the rings on my 9sp Ultegra from 52/42/30 to 48/38/26 - preserving the gaps exactly and still having spent a lot of time cursing the Japanese in general and Mr Shiman in particular - it is something I would be slow to attempt myself.

CJ · Post by CJ » 11 Feb 2008, 4:37pm

neilob wrote:My shifters are (I think) MTB 7-speed 'Rapidfire'. The front mech is an Ultegra (for triples) and the chainset is a compact Deore. Do you think this can be made to work? Was just about to dust off the credit card and buy a new front mech......

Get out the credit card. I assure you the Ultegra mech cannot be made to work with a flatbar "Rapidfire" control. It pulls about 30% too much cable, which overshifts the mech about 30% too far.

flobber · Post by **flobber** » 12 Feb 2008, 7:56pm

Sorry for jumping into the thread, but similar question.

Would I be OK to use road chainset (105) with a MTB frontmech (deore) with MTB (Deore) shifters?

PW · Post by PW » 14 Feb 2008, 12:21pm

Probably not. The Deore series front mechs are designed for a gap in middle-outer ring sizes of 12 teeth. If the size difference is smaller than this then the inner cageplate will foul the middle ring when you try to change up. If your outer is more than 12 teeth bigger than the middle then fine.