Front derailleur adjust screws

Nachimir

Winter (and me rushing through adjustments) really messed up the screws on my front derailleur. I've googled and found the odd "kit" of two replacement screws for mechs for about £10. Went to a local fixings place (Butlers in Nottingham) and found replacement cap bolts for pennies.

For reference if anyone else is looking, it's an Altus derailleur and they're standard 4*12 cap bolts. There's a tiny bit of play, but they'll be fine with a little threadlock in there.

nicklouse

the reason why there is some play is that they are wrong.

you have a standard M4 bolt which is a very rare thread on a dérailleur (4 X 0.7mm DIN standard) the vast number of dérailleurs use the JIS standard which is 4 X 0.75mm

Nachimir

Thanks, I'll see how they hold up and report back.

njee20

Just go to your LBS, they'll probably have a pile of old front mechs and give you the screws out of one FOC!

Nachimir

Cheers, will try that if these give me any trouble, but they seem fine for now. No discernable change in shifting after a day at Cannock; and with the old ones I had to adjust them at least once a fortnight until they corroded.

Ultimately it's a cheap mech and I'll upgrade it, for now whatever works.

cee

when you go the the LBS...take chocolate biscuits. mechanics are far more likely to help you out with a bribe of some sort

milfredo

Not meaning to sound rude but if you need to adjust those screws more than twice in the life of the chainset then you either don't understand what they do or there is something odd like the wrong size screws fitted.

They only stop the chain falling off; either into the BB when the cable is the slackest or off the largest when the cable is the tighest. If you are turning them trying to line up your derailer to the chain position then you are not doing it right (I think this might be what you are doing)

cee

milfredo

True...but after they got fiddled with....and mashed...they did need replaced to set them correctly.

Nachimir

mlfredo, I know exactly what limit screws do, thanks. I find drops, crashes, and every day wear and tear can lead to them requiring tweaks anyway.

milfredo

Nachimir wrote:

mlfredo, I know exactly what limit screws do, thanks. I find drops, crashes, and every day wear and tear can lead to them requiring tweaks anyway.

As I said, I wasn't meaning to be rude. I still can't believe that drops and crashes would affect the limit screws. The mech hanger would be screwed long before a screw that is tucked out of the way.

Anyhow, try the adjusting technique I mentioned and you'll be sorted in about 2 minutes and spend the £20 on some new cables. Happy riding

Nachimir

milfredo wrote:

As I said, I wasn't meaning to be rude.

Appreciate it, and I don't mean to come over as defensive. Text is awkward

I found a mix of commuting and trails just meant that the chain would rub every so often. I'm sure there's a mixture of factors leading to that, not just the limit screws. Maybe it's a duff mech, but it shifts ok most of the time.

Since picking bike maintenance back up last year, I've learned to completely dismantle and rebuild a bike, and rather masochistically enjoy it. As a result the bike I have is in pretty good nick after 2500 miles in all weathers. It always feels like there's so much more to learn.