48-38-28 to 42-32-22

[Aravis]

I've been looking forward to making this switch for a while. With my chain and cassette having reached the end of their lives, now is the time to give it a go. Changes like this always throw up unexpected challenges, some of which I've overcome.

Where I'm still struggling is with the front mech. The bike I'm using came to me as an old hybrid with a 42-32-22 chainset and Shimano STX changer, but I never used it in that form. I converted it to a light tourer using a 48-38-28 chainset, Shimano 2203 front changer and Sora Flightdeck triple shifters from my previous bike. That all worked well, although I did have to manufacture a shim to mount the changer.

I'm not sure whether the 2203 front mech ought to work with a 42-32-22 setup, but in any case it looks as though I can't mount it low enough. So I was hoping to use the STX changer. But when I attach it, I find that my shifters aren't moving the cage anything like far enough to operate a triple. If I put the the 2203 back the difference is obvious. I'm quite certain I'm not doing anything silly - the adjuster bolts aren't restricting the movement at all.

So my main question: is there a shifter/mech compatability issue I'm unaware of? Clearly the one I'm trying to use could be defective, but I don't want to buy another one only to find I have the same problem.

Any suggestions gratefully received!

 

[Cycleops]

Most mechs will handle two or three rings. Have you checked there isn't more adjustment on the limit screws?

 

[DCBassman]

Might have some insight. Please clarify: shifters are Sora Flightdeck, 3303s on drops? If so, the shifter and STX won't match. Front shifters are far less cross compatible than rears, have discovered all this while converting a Sora-equipped roadie into a light hybrid.
No easy answer I can see for using the smaller rings, they need an mtb compatible shifter and as far as I'm aware (not necessarily very far...), there's nothing that fits drops that will do it.

 

[Aravis]

Might have some insight. Please clarify: shifters are Sora Flightdeck, 3303s on drops? If so, the shifter and STX won't match. Front shifters are far less cross compatible than rears, have discovered all this while converting a Sora-equipped roadie into a light hybrid.
No easy answer I can see for using the smaller rings, they need an mtb compatible shifter and as far as I'm aware (not necessarily very far...), there's nothing that fits drops that will do it.

Yep, that sounds exactly like it, as I was starting to fear. But there must be people using smaller rings with drop bars, surely?

I suppose my next question is whether I can find a road-style mech that will work satisfactorily with the smaller rings. I can understand that mechs might be optimized for a particular ring size, or range of sizes, but it's not obvious to me why they should suddenly stop working when you go below a particular size, as some of the descriptions seem to imply.

 

[raleighnut]

Yep, that sounds exactly like it, as I was starting to fear. But there must be people using smaller rings with drop bars, surely?

I suppose my next question is whether I can find a road-style mech that will work satisfactorily with the smaller rings. I can understand that mechs might be optimized for a particular ring size, or range of sizes, but it's not obvious to me why they should suddenly stop working when you go below a particular size, as some of the descriptions seem to imply.

If the mech is too far from the ring you run the risk of the chain un-shipping outwards from the big ring.

 

[Nibor]

Fit a bar end shifter that will work with any mech

 

[raleighnut]

Fit a bar end shifter that will work with any mech

Or downtube shifters.

 

[Crackle]

I think you're looking at some bodge because I found the same thing on a front triple. I couldn't put a smaller than 48 top ring on and have reliable shifting but I have a mtn bike with pretty much the same ratio as you're suggesting which works just fine.

 

[Tin Pot]

Ah. Not confusing body measurements then.

 

[Levo-Lon]

Id think a mtb mech will sort this out.
You can get them cheaply

 

[DCBassman]

MTB mech won't work with road shifter - that's the problem.

 

[Aravis]

Or just a downtube shifter for the front, and a brifter for the rear. IIRC Lance Armstrong rode with such a setup at some point. Not that that's a great recommendation!

Edit. And here's a picture. This could be you.
View attachment 415547

I have a pair of 3x8 trigger shifters which I bought a few months ago for another "sometime" project; I could stick one to the end of a handlebar - that would work wouldn't it? TBH you're tempting me with the Lance impersonation.

But back to reality, thanks guys for all the advice, especially the steer away from persisting with the MTB mech, which saved me a lot of thinking time. I'm up and running now, as I have the road mech working adequately today, a big advance on yesterday. A few subtle changes, in particular angling the cage outwards slightly to the rear, may have made the difference.

I now find that the rear mech won't shift onto the smallest cog. This may have been happening for a while since I haven't needed the smallest cog, or even the one next to it, since like ever. Even now it's a non-problem really since 42/13 is as high as I'm likely to use, but it may need nothing more than a thorough clean.

The whole idea of this is to spend rather more than 1% of the time on the big ring. With any luck, Monday should be the day I find out if it works for me.

 

[pawl]

If you are on drops would bar end shifters work?

 

[Levo-Lon]

MTB mech won't work with road shifter - that's the problem.

Ahh misread it

 

[mcshroom]

Is it a mounting issue? Does the clamp on the SLX mech sit below or above the cage on the derailleur?

Assuming you can mount it so the derailleur is close enough to work properly, and it can clear the chainstay in the granny ring, the 2203 derailleur should be able to handle a 42-32-22 as I've done it before on my tourer. It works, I've used that setup, or the same with a 3403, touring for years, but it will always be a bit vague shifting IME and you will probably need to keep the gap between the big ring and the cage to be a bit larger than normal.

The problem comes with a frame designed for the top swing derailleur. I've had the problem recently with my hybrid-drops conversion. That bike is designed for a top-swing front derailleur and I couldn't fit a bottom swing one because the bottle mount is in the way. I don't think there's a road derailleur that is top swing.

To get this to work with drop bars and a MTB derailleur, you have three options that I can think of: -

1. Fit a downtube/bar end shifter as mentioned above. I went for bar ends on the hybrid conversion and I'm actually very impressed with them. It also allowed me to fit brake levers which can handle full v-brakes
   
2. Fit a Campagnolo Ultrashift left shifter that uses microrachets instead of indexing. I've not tried this but apparently the shimano MTB front ratio is pretty close to the powershift models of campag shifters too - https://jefaisduvelo.wordpress.com/...on-campagnolo-veloce-10-spd-powershift-ergos/
   
3. You can get a shiftmate that fits inline and lets you use an MTB derailleur with a shimano STI shifter - https://www.sjscycles.co.uk/cables/jtek-shiftmate-7/

As you also have trigger shifters, I suppose the other option is to fit flat bars or butterfly bars instead. Good luck, whichever you choose