Front mech options................

[sittingbull]

I'm looking at a "new" build running 2 x 9spd with a 34/50 crank.

Of the four mechs I've considered (Tiagra FD4500 & FD4600 and 105 FD5500 & FD5600), only the FD4600 has sufficient capacity for the chainwheels.

Note: the FDx500's are 9 speed and the FDx 600's are 10 spd.

Techdocs quotes the capacities as 15 teeth or less for all but the FD4600 which is 16 teeth or less.

So I'm wondering:
Will a 10spd mech work with a 9spd chain (I assume the 10spd mech is narrower)?
Are Techdocs being overly cautious and either of the 9spd mechs will be fine?

Any help appreciated

 

[PatrickPending]

Yes, I'm 99% sure my commuter has a 10 speed front mech - and its a 9 speed rear

 

[Smokin Joe]

What you suggest will work. I can't see any mech having a problem with 50/34 chainrings, they are more or less standard now on most bikes and you'll see them with all makes of mech including 105. As PP says, a ten speed front mech will work, I've run one with a nine speed setup without issues.

If you want value rather than bling the Tiagra mech will work just as well as the 105. The gearshift quality is all in the shifter, the mech is just a slave unit.

 

[youngoldbloke]

105 FD5700 = 16 teeth

 

[sittingbull]

Thanks guys

I've bought the 10spd Tiagra FD4600.

It's a "New other", removed from a new bike, just under £11 posted

 

[inkd]

Similar dilemma whether to upgrade my 9speed sora to a higher groupset but will it make any difference? also will sram 10speed still work with my 9speed sora? there are some real cheap ones on ebay, only asking because I have got to replace my cable as its starting to fray and a few strands snapped.

 

[evo456]

Similar dilemma whether to upgrade my 9speed sora to a higher groupset but will it make any difference? also will sram 10speed still work with my 9speed sora? there are some real cheap ones on ebay, only asking because I have got to replace my cable as its starting to fray and a few strands snapped.

Sora FD will be fine, as mentioned earlier, the cable pull / shift is determined by the shifter. All you need to make sure is the FD can accommodate the range and size of the chain rains, if you are using the same chain ring sizes and maintaining the chain line it'll be fine. A ten speed rear cassette - at least for shimano is the same width or slightly narrower than a 9 speed cassette (but a 1mm washer can sort that out), so same principles as the FD, you can keep the old RD if the new cassette is the same or within the min/max sprocket sizes of the old.