Mountain Bike Gears Help Needed

[Ballistic Banana]

I recently brought her in doors a Moutain Bike (nearly New).
I new the gears needed tweaking a bit as the selector was getting over enough to get to the large cog (15th-21st Gear)
They are shimano gears and i have played about but cant get the metal gyide to go over enough.
It comes over to the frame side easy enough(maybe to close).
The cable comes down the frame underneath the bottom and up to a clamp which i have tryed moving the cable tighter/looser etc to no avail.
There is also two tiny screw with high and low written near them .What are thay for ??

TIA Biker Dudes

BB

[monkeyjunky]

The two screws adjust the range of travel. Loosen the high one about 90 degrees and that should do the trick. If the chain starts to come off the top cog tighten it a touch. They are very sensative!!!

[greeny]

their the 'stops' which limit the amount which the chain can travel so as not to overshift and fall off the other side of the chain ring - you need to adjust these

[NoisyGriff]

The little screws are the answer.
High/Low refers to which end of the travel that screw limits. Try turning the 'Low' screw anticlockwise and watching how the guide moves.

That should sort you out. Be careful, though, bikes are rear wheel drive and there's a lot of snow about...

[hut49]

Ditto re sensitivity. Didn't you get a user manual explaining the adjustment mechanism? I have one so if you've lost yours let me know and I could fax you a copy or even scan it and email. It may not be the same bike but the principles are the same.

Hutch

[campbell]

There will be two screws on the figer of 8, there are to ajust the travel of the figer of 8 to go from the large cog to the small one. Good luck but it is rather reasy when you find them and have a play

[fatsteve]

Simon,

These are the upper and lower limit screws. Best thing to do is losen both off completely whilst adjusting the front mech. Then tighten them up to stop the chain from either dropping off either side.

It's also easier to setup the front mech when the chain is completely straight, ie smallest gear on the rear wheel with largest gear on the crank and oppositely; largest rear gear on the rear with smallest gear on the crank.

Best to adjust the rear mech first, then do the front (depending on which gears you can and can't select).

Drop me a mail if you get really stuffed.

Hope this helps

Steve

>> Edited by fatsteve on Saturday 4th January 18:50

[Ballistic Banana]

Cheers all for the replys.
A little typsie now so not gonna try anything tonite.
Didnt realise the two smaller screws done that much.
It nearly makes it on to the large cog so probably fiddling withthe little screws will sort this out.


BB

[douglasr]

As others have said, its the little screws that need adjustment. Get yourself a copy of Zinn and the art of mountain bike maintenance by Lennard Zinn - excellent book.

[**999**]

New bike - used for a while - cable has stretched.
That's the principle cause of the problem and if the bike is used often you may find that you nedd to revisit the tuning advice given here on a regular basis. The only thing that cured my problem (used to race MTB's XC) was the purchase of Goretex Cables. They stretch once and that's it.
Don't forget that the gear selector levers mounted on the handlebars have a knurled fitting near where the cable enters the lever. You can make small adjustments to tweak the gear mechanisms from here...useful when out on the trail

[Mr E]

Yup. Knobs on the levers and ickle screws should sort it out.