Author Topic: super compact problems  (Read 798 times)

super compact problems
« on: January 30, 2019, 11:33:54 am »
I am trying to convert a stronglight  triple chainset 48/38/28 ( on the cheap) in to a super compact . I have fitted an old  plain  40 tooth chainring  on to the middle position . But I can not get  front triple shimano 105  derailleur  to lift the ten speed chain from the inner 28 to the 40 . Do i need to invest in a more modern ramped and pinned  44 t chain wheel . Or am I being too ambitious , and should also fit  a 30 t or 32 t inner .  Am currently using a  11/28 t cassette so can fit a 11/32 or 11 /36 if required  thanks colin .
Four wheels move the body, two wheels move the soul !!!

Re: super compact problems
« Reply #1 on: January 30, 2019, 11:40:31 am »
I think this might be a problem with indexed front changers.  I have 40/24 but use Campag Ergo levers so therefore not indexed and I can easy the chain up or down by feel.  My chain rings are absolutely plain, no ramps or pins, but I imagine these will help with an indexed front changer.

Re: super compact problems
« Reply #2 on: January 30, 2019, 12:18:04 pm »
a 'middle ring'  in the 'middle position' (and either  nothing or a chainguard in the outer position) will give the best shifts with a 10s chain and your shifters. The other thing is that  I suspect that you ought to be using the 1-2 clicks in the (triple?) shifter not the 2-3 clicks.

You might be better off with a different FD which is meant for a double, too; the inner plate of a triple FD often has features on it that are designed to help the shift along when you are using the recommended chainring sizes etc; these can be a positive hinderance when you start varying charing sizes and FD height.

BTW you can look to use an outer ring in the 'middle position' but the bolt counterbores will be in the wrong side of the chainring, so the bolts may protrude and interfere with the shifts/chainline etc on the left side of the chainring. Hence I suspect that buying a 'middle ring' may be the path of least resistance.

cheers

Re: super compact problems
« Reply #3 on: January 30, 2019, 06:08:02 pm »

You might be better off with a different FD which is meant for a double, too; the inner plate of a triple FD often has features on it that are designed to help the shift along when you are using the recommended chainring sizes etc; these can be a positive hinderance when you start varying charing sizes and FD height.


I found this in the past when swapping out a 105 triple for a double: I needed to change the front mech as the triple front mech physically fouled my new chainrings.

Re: super compact problems
« Reply #4 on: February 04, 2019, 01:13:48 am »
My guess would be that the lack of ramps/pins is the issue - you're only 1T over the standard middle ring. Might be worth trying a larger pinned middle ring. I have a 26T inner ring on my 105 setup, so there is probably a bit of leeway there to raise the fd a bit for a larger middle? TBH I can't see any real-world advantage to your proposed setup vs your triple, so if you can't make it work it's not the end of the world, just a wasted £20 for the chainring?

Re: super compact problems
« Reply #5 on: February 09, 2019, 10:01:40 pm »
Thanks for your replies . Well I have totally lost the plot on this one . I have never been happy with the sti  front gear change on the triple .But buying a new inner ring ,chain guard , front mech ,chain and cassette ( last two because the old ones are a bit cattle trucked ) for less of a gear range  and having to double change when drooping in to the granny ring  didn't make much sense to me .  So I have pulled off the triple levers, fitted old non aero brake levers & simplex friction gear levers . Put the old 48/38/28 triple crank back on . Bought & fitted a new 8 speed cassette & chain and its bloody brilliant . So easy to set up /changes gear like a dream . And should be cheaper and longer lasting than running 10 speed chains and cassettes  ( judging by the old 7  speed bike I own ). Happy days colin
Four wheels move the body, two wheels move the soul !!!

Re: super compact problems
« Reply #6 on: February 10, 2019, 01:12:04 am »
TBH having started cycling in 5s days I soon migrated to 7s (as soon as I could) but have not felt a terribly strong urge to have more gears than that. I've owned, used and worked on 10s/11s systems and they are certainly more finicky. 9s mostly seems OK and 7/8s seems very tolerant of small variations in setup.  My touring bike still wears 3x7s. I don't see any point in changing it or fitting STIs; just a lot of hassle for very little gain.

cheers