front derailleur gears......

[ray316]

l have a vitesse sprint 21 speed and cannot use all the gears, l have no problem using 1 to 7 on the back but on the front can only use the small and middle rings. When l move the shift lever to the top ring (3) nothing happens. l have tried adusting the front derailleur with the low/high adjusting screws but with no joy.. Can anyone give me some advice on the best ways to get the adjust right so l can use all the front rings.
Also just a question for you bikers, which front ring is best to stay when cycling..why have 3 rings

 

[Smokin Joe]

Your cable has gone slack. You probably have a barrel adjuster on the downtube, with the chain on the small ring screw the adjuster anti clockwise till the slack in the cable has gone and you should be ok. Alternatively you can undo the clamp bolt on the mech and pull the cable tight with a pliers.

As you have fiddled with the H/L screws they will need to be reset as they are to stop the chain from overshooting the rings. Make sure each screw butts against it's stop on the mech when on the inner and outer chainrings.

Which chainring to use and how many you need is a different question and down to each individuals preference and would probably illicit passioned arguments from double/triple/compact devotees..

 

[Steve H]

Big ring for downhill, little ring for going up hills and middle for everything in between. There's more to it than this, but it's not far out.

Also try not to "cross" the chain. I.e. When in small ring on left hand side, also use the rear gears on left. When in big ring on right, use rear gears on right. When in middle use the middle. This prevents undue twisting pressure on chain

 

[ray316]

Thanks for replys and advice guys, l'll try the adjustments again tomorrow.....