Do I need a front mech cable roller?

Still with the clockwork, trying to set up the front mech and having all sorts of issues. Not struggled like this with a front mech before.

M737 front mech (top pull) as came with the bike when I bought it. M737 cranks. When I was cleaning it I tried the front mech and the chain seemed to wedge itself between the top of the mech cage when on the top ring down shifting. Rhe clearance between the mech cage and the big ring was tiny too, almost touching. Easy fix I thought, just lift the front mech up a bit. With a bit of fettling the shifting is cleaner but man do you need a lot of force at the shifter. It also makes a terrible creaking noise from the cable.

When I look at the cable run the angle of the cable from the frame cable stop to the mech is quite steep. There is a boss at the bottom of the seat tube for a roller, and as this is a very small frame, perhaps I need to use a roller and a bottom pull mech. Any ideas if I should be using a roller?

While on the topic of shifting, the rear is also dodgy. When in the small ring I can't really use the largest 2 or three cogs at the back as the chain is effectively riding on the jockey and cog at the same time. Usually I would adjust the screw on the rear mech but it already at the limit. Chain too long? Mech spring not strong enough? Something else?

I only took the bike out of the shed for a bit of a dust down, it's as it came really aside from some bolt changes so maybe it wasn't set up right before it came to me? It's had very little use, I've probably turned the cranks more over the last day in the stand than it has seen actual riding, so glad I discovered these issues now, but I'm hoping to fix them to encourage some family bike rides now the weather is improving.

With the issue between rear mech and cassette... is it a short cage or long cage rear mech,? What cassette ratio is it? Short cage mechs often only reach up to 28T on the cassette (or something like that.
Can't help much with the front mech issue, I'm having similar problems, but I'm is my a front mech roller on my Prestige!

Edit: just noticed your rear mech problem arises when on smallest chainring, could be the chain too long/slack. Or indeed the spring failing.

It's not a short cage mech. I thought the cassette was an XT one but I degrease it and under the grime was a very tidy m900 12-32 cassette which was a bonus.

I suspect the chain is too long and will fit a new one anyway. I usually use the big ring to big cog minus 2 links but recently that failed me and I ended up with a short chain. How do you get the right length?

I think I'll try and get a mech roller and bottom pull mech as if nothing else, it will remove the horrible angle the cable ends up at and should in theory reduce the effort needed to shift.

What's the issue you are having with your mech?

I usually use the big ring to big cog minus 2 links

Click to expand...

!!!
+


New cable?
When I put my rock lobster together I put a bottom swing[top pull] mech on it and it was
obvious the cable line was really bad, ******* terrible would be a better description.
I don't think i even tried a cable, the cable may have been pulled at a 30 degree angle.
I put a top swing mech on as the cable has a better angle, still not great. It needs new cable
more often than the bikes with cables that run in the dirty muddy bit of plastic under the bottom
bracket, clearly a lot of thought went into cable stop placement.

Re:

When the cable routing is as bad as mine (or even worse), you really should consider it.



The weird thing is that this is the original mech. :facepalm:

Re:

Two lower cog slack is normal if the rear cog is large and so is the front on a medium or small cage mech. You have a large rear cog.
Put it in large large and if it is near taught with a hint of slack it is correct.
It is safer to have slack and a gear you would shift out of if you accidentally move in to it. You can still pedal and be safe.


Front mech, get everything lubed up, shifter, mech cables and try again, check the exit of the cable it could be on the metal. Any picture?

Might as well try the bottom pulley

A front mech outer plate should be about 3mm above the highest tooth.

Cheers. I don't have a pic as I've taken it all apart now. The cable angle is much like the one above though.

With the mech positioned around 3mm above the largest chain ring, it shifts up fine but down shifting it seems to almost wedge itself between the top of the mech cage. If positioned higher than 3mm seems to work better. I've tried 2 different xt mechs with the same result so I don't 5hink the mech is an issue.

Going to try the bottom pulley when I can get one, bold hole for it must be there for a reason right?

ishaw":18k7lg8k said:

I suspect the chain is too long and will fit a new one anyway. I usually use the big ring to big cog minus 2 links but recently that failed me and I ended up with a short chain. How do you get the right length?

Click to expand...

It's big-big PLUS two links!

For the chain riding on the jockeys and cassette simultaneously you need to tighten the B tension screw to lower the jockey away from the cassette.

I fitted a mechano roller to my clockwork and used a bp mech... Easier shidt and may do the same on my FC build!

hamster":2lqllxtk said:

ishaw":2lqllxtk said:

I suspect the chain is too long and will fit a new one anyway. I usually use the big ring to big cog minus 2 links but recently that failed me and I ended up with a short chain. How do you get the right length?

Click to expand...

It's big-big PLUS two links!

For the chain riding on the jockeys and cassette simultaneously you need to tighten the B tension screw to lower the jockey away from the cassette.

Click to expand...

Thanks, looks like I may have got it the wrong way round last time then. I've always been u sure if a link consists of the outer plate and inner link, or if these count as two seperate links?

B screw is all the way in so when I put it all back together with a new chain I'll adjust this out and see how it all hangs together.