Simple mech question

cunning-stunt

I have a dual chainring and bashring,with a 9spd cassette.

I swear blind that when I had the bike I could engage any combination of gears without the chain rubbing on the front mech,but the mech took a knock and had to be repostioned by my cack-handed self.

Just for my own peace of mind,is it possible to achieve what I describe above? I've spent hours looking for the 'sweet spot' to no avail,yet I'm positive that any combination of gears was achievable without rub before the mech got moved.
At the moment,it's all to buggery and i'm getting about 4 cogs per chainring without rubbing...losing 10 gears in the process

It's simple in theory...limit screws,barrel adjuster,height - but me and mechs don't mix and not only can I not find the sweet spot,but I can't get the majority of my gears engaged without rubbing
Read the instructions (bloody memorised them actually),followed Park Tools site,hit it with a hammer,kicked it,swore at it,checked cable tension,disconnected cable and checked movement manually..

The sad thing is,I understand exactly how mechs should work,but can't get my bugger in the right position.

I hate mechs :evil:

Bikedevil

yes it is, I used to have a dual ring and bash guard set-up on 9spd (short cage mech) rear

Basically the best way I found to get it spot on was to essentially re-fit the front mech from scratch. Also you might want to check the alignment on your mech hanger if you've taken a knock.

cunning-stunt

The rear is fine,just the front had a knock that put it out of alignment.
Thanks for replying,I just needed to know it wasn't my memory going haywire on me.

There's 8 hours of tomorrow sorted

Bloody mechs :evil:

skyliner

Obviously you've checked for damge to the cable? Or you wouldn't be asking on here. Put the chain on the 32t (middle) ring, and shift the front gear shifter to the granny ring position, loosen the collar fixing bolt,align the outer edge of the mech with the bash guard, tighten the collar fixing bolt, and then loosen the pinch bolt, and take out any slack in the cable by pulling the cable through the pinchbolt , and the tighten the pinchbolt with the cable snugly under the pinch washer.
And breathe!

baccaman21

...Frustrating isn't it...

I went through the same shenanigans recently... Did the whole nine yards, stripped and cleaned everything (including cables and pods) took it all back to the base level and ultimately conceded defeat after weeks of trying to figure it out... I even got the blow torch out at one point...

In the end I bought a new (front) mech and installed it in minutes and it ran perfectly - no buzz (apart from the biggest chainring to smallest sprocket... which is acceptable)

It's often the case that... If in doubt - splash cash out.

Get new gear and use the old stuff as spares mate - you'll appreciate it in the end.

One good thing that comes out these kind of episodes - you learn a great deal...