44-32-22 chainset with sti road shifters

[magical_mouse]

hi, has anyone successfully fitted a 44-32-22 shimano (or other) chainset to use with sti road shifters on a normal road frame - with or without frame braze-on for front mech (may determine the frame i buy)?

is shifting as good as 50-39-30 shimano?

thanks

david

[Vantage]

The change in chainring size won't make any difference to how your gears work. What you will have to do is lower the height of the front mech or derailleur.

[Wesh-Laurence]

Yes I have a Shimano SLX chainset with 44/32/22T being operated by Shimano 4503 (Road) STI brake/shifters.

The chainset is a mountain bike chainset and to obtain clean (a quick click) shifting I've also used the SLX MTB Front Mech. The issue with this set up is that the Road STI Levers doesn't pull sufficient gear cable to operate the MTB Front Mech. To increase the cable pull I have used a Jtek Shiftmate device (model no 7?).

Others on this forum will say that you can use a road front mech with an MTB chainset but I couldn't get clean shifting with that combination.

The Shimano MTB rear mech (long cage) works perfectly with the "Road STI Levers".

This shows the Shiftmate fitted, it needs to be anchored on a cable stop.

[531colin]

If you really need to gear that low, I think you should avoid a frame with braze on F. mech. mount, as its unlikely to get the mech. low enough.
Other points to consider are (to the best of my knowledge!).....
10 speed cassettes** don't come with sprockets as big as 9 speed or even 8 speed....unless you build your own cassettes. 10 speed mountain R. mechs. don't index with road STI ( but 9 sp. do)
Only Tiagra STIs now come in 9 speed.
22 T chainrings only come in 4 bolt, you might be better off using 5 bolt 74/110 BCD, where more ring sizes are available.....they only start from 24T, but you could have for example 24, 36, 48 T, which would bring the outer ring much nearer the curvature of a road mech.
And finally.......why let STIs dictate your gearing choices? http://forum.ctc.org.uk/viewtopic.php?f=5&t=57027&hilit=skinflints&start=150

edit per Brucey....square taper 74/110 chainset
** sorry, I think that's road cassettes....wide geared mountain cassettes are available.

[Brucey]

you can often use a road front mech made for larger chainrings, quite happily.

However you can only do this if you have a 'road' chainline, which an MTB chainset won't give you.

And of course you cannot adjust the chainline in the traditional way if your new chainset is an H-II design or similar.

cheers

[RickH]

This one from Spa (& proabably others - I haven't looked) with the right length BB would give you the right chainline. 46-34-24 would give you access to a wider range of chainsets but you would lose a bit at the low end of the gears unless you can run bigger rear sprockets.

As has been said earlier, a clamp on front mech will give you more scope for movement. A braze on one with an adapter would give more scope if position of bottle bosses might be a problem as you then have a range of clamp positions for any given mech height, which might be more likely to need consideration if you are using a non standard mix of kit particularly with smaller frame sizes.

Rick.

[CREPELLO]

However you can only do this if you have a 'road' chainline, which an MTB chainset won't give you.


cheers

What is happening with all those mass produced tourers that are fitted with Deore chainsets and operated with road front mech's and STI's? Dawes, Ridgeback etc wouldn't do this if it didn't work - or does it not? I've not heard or read anything about this being an issue, albeit these bikes use the larger 48/36/26 chainsets. I know that Shimano say you can't do it, but that's different from what we (should) know actually works.

Am I missing something?

[freeflow]

Works quite well. My wifes bike has r600 sti (think ultegra for small hands) with XTR chain set and rear mech with a 12-36 cassette. The front mech has to be moved down and consequently a bottle cage boss influences the final position. The rear mech must be an older style 9 speed. The cassette is a standard 10 speed cassette. The chainline did need tweaking so in practise the pedals are spacer shifter to one side. However at the level my wife rides at this is not an issue. I wouldn't recommend this set up for racing but for day to day pootling or even touring its fine.

[CJ]

What is happening with all those mass produced tourers that are fitted with Deore chainsets and operated with road front mech's and STI's? Dawes, Ridgeback etc wouldn't do this if it didn't work - or does it not? I've not heard or read anything about this being an issue, albeit these bikes use the larger 48/36/26 chainsets. I know that Shimano say you can't do it, but that's different from what we (should) know actually works.

Am I missing something?

They do work, but they don't shift quite as cleanly as one would like. And the problem shift is the most urgently needed shift, from middle to inner.

The over-wide chainline may be part of the problem, but the main one is the 12 tooth outer-middle difference, that puts the middle ring even further away from the part of the mech that's trying to derail the chain off it.

Most road triple mechs are designed for an 11-tooth difference, but can tolerate a 10-tooth difference if outer and middle are both a lot smaller than they're designed for. I have a Tiagra mech on a Stronglight chainset (closer chainline than a MTB/Trekking chainset which may also help) with 46,36,24 rings and it's never failed to shift from middle to inner. The inside of the cage clears that 36 by only a whisker though. The 38 on 48,38,?? does not, so I hear. 44,34,22 might be okay but by then the discrepancy between the gentle curve of the mech and the much sharper curve of those much smaller rings may causing other problems. This discrepancy seems likely to make downshifts from middle even worse if you try to use a road mech as the OP did, on the usual MTB arrangement of 44,32,22.

The OP's solution is the best solution, if you want to shift a MTB or trekking chainset with Road STI.

Dawes don't do it that way because big companies don't spec widgets from little companies, probably on account of the small company lacking the throughput to offer a cheap enough price, plus the logistics of getting US-made bits to the factory somewhere in Asia that actually makes these bikes. And apparently there's a chap in Shimano's European HQ who knows even better than I do, what actually works with what and why, and whose job it is to advise the likes of Dawes about what they can get away with. The wheeze of using a good quality 9-speed MTB mech with a 10-speed road STI in order to shift a super-wide-ratio 10-speed MTB cassette originates there, within Shimano, so I was reliably informed the other week.

[Brucey]

further to that; some bottom swing 'road' mechs will (just) reach out to an MTB chainline. As well as the middle to inner shift issue, the movement of the front mech isn't quite right any more.

The reason for this is that the shift ratio of the mech (cable pull vs lateral movement of mech) varies through the stroke. Another side effect of this is that the mechanical advantage of the cable over the mech gets lower and lower the further out the mech reaches. This often has the effect that the lever force required to shift onto the big ring can become excessive.

Although the extreme mech positions are governed by the mech stop screws, the other positions are not; thus the altered shift ratio may mean that the 'nudge' settings don't work out quite right.

In theory the problems associated with the shift ratio onto an MTB chainline could be cured by making a widget that alters the cable position on the front mech; with a bottom pull, bottom swing mech, moving the cable mount position upwards by about 3-4mm would usually do it.

This would however still leave the issue of shifting middle to inner.

There is a further possibility of (on a very small chainring) the front mech clashing with the chainstay. the included angle between the chainstay and the seat tube can easily be ten degrees less with a slack-angled 700c wheeled tourer vs a more MTB-like frame.

cheers

[Valbrona]

1/ Don't buy a frame with an FD bracket.
2/ Shimano MTB front mechs do not work with Shimano STI levers, as you probably know, but note that they will work with bar end levers.
3/ Get a 'road specific' crankset if using a 'road specific' FD, on account of chainline.

[CREPELLO]

Of course, a MTB chainset will work with a Shimano MTB front mech and Campag ergo's. Another good reason for Shimergo.

[jackdaw]

I saw an interesting article about STIs and triples here:

http://janheine.wordpress.com/2013/03/2 ... i-triples/

May be of interest...

[georgew]

I saw an interesting article about STIs and triples here:

http://janheine.wordpress.com/2013/03/2 ... i-triples/

May be of interest...

Many thanks. Interesting article.

[Ayesha]

Dawes Giro 500.

OE BB 115mm, new 110mm.

Reduces MTB chainline from 47.5 to 45.

Works a treat.

I fitted a DOG FANG !!