when in gears 9 & 10 (smallest cogs at back) in the middle front ring, the chain always seems to snag/catch on the front mech guide…..when i run it in 1st gear middle ring, there is the correct clearance 0.5 – 1.0mm and that doesnt catch…..

i always thought in middle ring you were suppose to have no clearance issues at all in any of the rear cogs?

im sure i must have done something wrong, as ive just gone 10 speed, and it was exactly the same with my 9 speed setup!

if im just sitting and spinning it doesnt do it too bad, but if i stand up it really makes a racket catching

any ideas?

all other gears seem absolutly fine…

God…didn’t you know….
Front mechs are the work of the devil. 👿

They do seem to be evil…..

Bumpidy for the daytime mechanics if you are about!

One of my bikes has always done this, never been able to fix it despite adjusted the front mech height and angle umpteen times. If I manage to get clearance for middle ring & cogs 8 and 9, the chain just fouls the front mech at the other end of the range.

I just see it as a reminder that I really should be changing up into the big ring.

cheers spooky – interesting im not alone!

i know it didnt used to do it, or im pretty sure it didnt…

then i started to fit groupsets myself and its always done it 😆 still think ive done something different somewhere, will at worst get a shop to check it over…..funny cos the gears all go in fine and dandy with no skipping/slipping…

exactly the same as you, if i try and eradicate the clearance on the low cog, i get the chain rubbing on the top one 😆 use the top gear more so i tend to endure the 2 bottom ones being catchy…

your rear mech should be set up so that when its in the middle ring and the middle of the cassette the chain runs through dead centre of the guide. This is easy to see on a 9 speed set up asyouput chain on middlering and 5th sprocket on rear – adjust front mech so you have equal distance either side of chain.
With a 10 speed its slightly more tricky as middle of cassette is between 5th/6th -so put chain on middle and 6th adjust so its slightly over to the 5th (5th been the smaller of the two) shift to 5th and adjust so gap between is same distance over to 6th as 6th is to 5th.

Don’t worry about the lower and higher gears catching in middle ring – your gears are duplicated – have a look at a gear chart and work out what you have on each ring and then see how they cross over
gear calculator

eg on my 9 speed set up I find that on the big ring gears 1-4 (with 1 been the smallest) middle 3-7 and granny 6-9 gives me thefullspread of gears available to me – on a 10 speed i should imagine big 1-5 , middle 3-8 , granny 7-10

Hope this makes sense

cheers stan – very interesting that, ill have a look into trying the setup like that, though to be honest, im sure its probably more so the positioning of the front mech somehow, im sure its something ive done incorrectly there as, as i said it didnt do when the shop set it up first time around…ive since done 2 groupsets and they were/are both the same….thanks for the input though, interesting ideas!