Have a older bike with Shimano derailleur, trying to understand hi and low trim settings.just have 2 gear sprockets on the front,but lots

of rubbing and noise when riding or trying to change.
looking for model number of shimano,but all i can find is the Shimano names i dont know what model, but it has a hi and low screws which when i turn them i dont see any change,lik they are not causing any difference.
any one with advice on this problem?
thanks
john

The Model# may be on the inside of the outer plate.

Start at step 1-
https://www.parktool.com/blog/repair...eur-adjustment

High and low screws only limit derailleur travel, they do not provide any trim function

Adjusting the high and low limit screws will only make a change when the derailleur is at the limit of its travel and the mechanism is contacting one of the screws. Under any other conditions they will have no effect.,

thanks i will look there
john

thanks i mis spoke, they move it in board or outboard? any way when i turn then i see nothing happening.
other posts says i have to put them at there max in board or max outboard before i would see any change,is the the correct understanding?
that may explain why i dont see any change in the box present condition.
i will look again at that park tool video
thanks
john

They are limit "stops". When the FD is either fully in or out it rests against the screw. They only adjust the limits the FD can move, as noted they are not connected to ANYTHING but get bumped up against.

Once you set the limit screws properly, and the gap between the large chainring and derailleur cage (1-3mm), and make sure cage is parallel to chain...the cable tension has to be right or your cage won't reach both high and low limit screws when you shift to big and small rings, respectively. Look for an inline cable tension adjuster to set tension. You may need to reclamp the cable at a different point if it's to far off.

https://www.parktool.com/blog/repair...eur-adjustment

Start at the top and do every step, don't just futz around with stuff.

ok thanks' a great guide, will follow to the letter.
john