Changing from Standard to Compact (front mech issues)

herzog

Got a period of heavy climbing coming up and I've temporarily changed from my usual standard chainset to a compact. Previously when I've switched, I've adjusted the front mech height (& gear cable) to compensate for the different chainrings, however this time I've left it. The compact will only be on for a couple of days after which the standard will go back on.

At present the front mech is about 5mm above the large chainring - the shifting is fine, and I'd be interested in hearing if anyone could think of possible issues that I may encounter...

andrewc3142

All the front mech does is shove the chain across from one ring to another so if it does that fine, end of story.

However, a gap of 5mm is considerably more than an ideal set-up and maybe the time it won't shift so well is on one of those climbs, at which point you might regret the 15 mins or so it takes to adjust it ….

I changed recently from standard to compact in recognition that it's not as easy as it once was to get up the hills. Probably climate change, but they seem to have gradually got steeper over the past few decades.

I was very glad of it last week doing the circuit round the Applecross penninsular and back over the Bealach na Ba. I did max out on the descent to Applecross, but that's the first time, so for me at least I can't really see the point of changing back again.

davidof

Herzog wrote:

At present the front mech is about 5mm above the large chainring - the shifting is fine, and I'd be interested in hearing if anyone could think of possible issues that I may encounter...

I have a braze on mech, when I went compact I ended with a similar gap, a bit less maybe. The issue I have is that it won't change if I'm on extreme chain alignment so have to think to change at the rear first. It has caught me out a couple of times. It also seems more prone to derailment when changing up, which makes sense.

slowbike

I did the same change for similar reasons - also intending to go back to a standard, but never did (now utilised on my TT bike) - I didn't bother changing the Front mech height and it's been fine for 000's of miles.

herzog

Thanks for comments. Just got back and the mech functioned perfectly (even in dodgy combo). As I'll be switching back to a standard at the end of the week, I'll be leaving it as is.