Matching shifters and front mech

[jessand]

Hi All

I have Shimano 4700 triple 10 speed shifters, can I use them with double chainrings using the stop screw to prevent overshifting?
2 If I can do the above, can I use any shimano 10s front derailleur or should it be the specific 4700?

Many thanks

[Brucey]

the FD-4700 (double) mech has a completely different pull ratio to the triple FD and it basically won't work. Some older double FDs had a shift ratio that is similar to the FD-4703 (triple) which you presumably have, so these might work.

However it depends on the double chainset in question. If you are thinking of a 'compact double' then you will almost certainly have to adjust the shift ratio of the FD to get it to work with your shifters; the reason is that the throw of a FD for a compact double is more than an (older, i.e. with 10-12T range) 'standard' double, because the chainrings are spaced differently (by virtue of the dish on the big ring being different to allow you to run small-small).

So with the right FD (which might as well be FD-4703) and a ~11T range, and the correct chainrings etc, you can run a double chainset with your shifters. Or you might be able to do something clever with the shift ratio of an (older) double FD and make it work with a compact double. Otherwise you are in for little more than a bunch of indexed-front shifting induced misery.

IMHO a 3x10 system can nearly always be arranged to provide more, better gears than a 2x10 system, so I almost certainly wouldn't change it in the way you are intending to. Why are you thinking of changing it?

cheers

[jessand]

Thanks Brucey

Reason I considered changing was that I rarely use the big ring, I thought I may slmplyfy things by losing the big ring (46t) and fittng a bigger 'middle' ring of about 42t. From what you say I don't think it's worth attempting, my 26,36,46 works.
EDIT: I was looking at a super compact chainset of 26/42 or similar.

[Brucey]

changing to a compact double will save you about 100g and it might be simpler in use (*) but getting there won't necessarily be simple.

(*) the annoying thing about supercompact doubles is that the doubleshift is massive and very disruptive. Whenever I use one I keep thinking I wish there were another chainring between these two so that the doubleshifts are easier to manage.

We all use different gearing; If I had your triple the 46T ring would be the most used.

An easy change might be to use different rings (assuming this is a 74/110BCD chainset) and go to 24-34-44....? Would this suit you better?

cheers

[jessand]

Ah yes, would my 4703 fd cope with rings that small?

[Brucey]

probably yes. It won't be perfect though. It'll have to be set 4mm lower so check this is OK (and it doesn't hit the chainstay for example)

cheers

[jessand]

Many thanks Brucey, I'll give it a try.