Rear Mech doesn't go low enough?

Chrisdicko

Hi Guys,

Still attempting to build my new bike, and I'm just waiting for a chain tool to arrive.

I'm trying to set up my rear mech by eye on the cassette, the Lower gear seems almost perfect once adjusted with the small screw, but the high gear, by eye I can only get it to 10th, not 11th.

This is pushing it by hand, but even with the shifting cable connected, I cannot achieve the lowest gear, even with adjusting the other screw.

The rear mech and shifter is used but looks brand new and straight.

The frame is used and from 2009, but the hanger looks bang on straight.



Any ideas, please?



Thanks a lot

PolderRider

Interested in answers as i've just fitted a 9 speed long cage rear derailleur which doesn't move lowest and highest cogs. Suspect wiggle sent me a 7 speed derailleur by mistake...

Lagrange

Try looking at the front. The chain line - the line of the chain should be straight when it is on the front and 5 or 6 at the rear. If it is straight on any of the bigger cogs then the mech may not reach far enough to engage with 11th.

Chrisdicko

Lagrange wrote:

Try looking at the front. The chain line - the line of the chain should be straight when it is on the front and 5 or 6 at the rear. If it is straight on any of the bigger cogs then the mech may not reach far enough to engage with 11th.

Thanks for the reply. I will have a look when I get the chain on.

The mech is a SRAM 11-speed mech though, so should reach on an 11-speed cassette, or is there more to it?




Thanks a lot
Chris

keef66

The only way you can be absolutely sure the hanger is straight is with a hanger alignment tool. Mine always look straight till I use the tool and find out they aren't.

If you back off both high and low limit screws you should easily be able to line the cage up with the biggest and smallest sprockets when pushing the mech by hand with no cable attached.

@ PolderRider - should be no difference between a 7 and 9 speed mech, the respective cassettes are the same width. It's the shifter which tells the mech how far to move with each click. Have you backed off both limit screws?

The Rookie

You’ve lost me, 10th and 11th are the highest gears (smallest cogs) and then you say you can’t get the lowest gears (biggest cogs), which is it?

There are two ‘the small screw’ which one are you adjusting and have you tried the other one?

keef66

The Rookie wrote:

You’ve lost me, 10th and 11th are the highest gears (smallest cogs) and then you say you can’t get the lowest gears (biggest cogs), which is it?

There are two ‘the small screw’ which one are you adjusting and have you tried the other one?

That's why I described them as biggest / smallest sprockets

Too much confusion around high / low gear, changing up / down; people get it @rse-about face all the time.

Chrisdicko

The Rookie wrote:

You’ve lost me, 10th and 11th are the highest gears (smallest cogs) and then you say you can’t get the lowest gears (biggest cogs), which is it?

There are two ‘the small screw’ which one are you adjusting and have you tried the other one?

It won't go to the smallest sprocket.

Yes, tried both screws.

Chrisdicko

keef66 wrote:

The only way you can be absolutely sure the hanger is straight is with a hanger alignment tool. Mine always look straight till I use the tool and find out they aren't.

If you back off both high and low limit screws you should easily be able to line the cage up with the biggest and smallest sprockets when pushing the mech by hand with no cable attached.

@ PolderRider - should be no difference between a 7 and 9 speed mech, the respective cassettes are the same width. It's the shifter which tells the mech how far to move with each click. Have you backed off both limit screws?

Thanks for the reply. I have been trying with the screws backed off, and no cable.

I think I may need to take the frame somewhere to get the rear hanger checked.


Thanks a lot

larkim

If you're trying to move it to the smallest sprocket, why do you need to push anything by hand? With the cable disconnected it should sit in line with that small sprocket as the cable should be at lowest tension at that point surely?

The Rookie

The mech should go past the smallest sprocket with no cable on it.

A small bend in the hanger won’t stop that, a big enough bend would be obvious.

Either there is an issue with your setup or the adjustment. Seeing as you said you adjusted BOTH screws to try and fix it suggests your adjustment skills may be the issue.

larkim

To be clear, I meant after the screw adjustment was complete, but we're saying the same thing broadly I think (even if I was a bit imprecise!).

Definitely sounds like something is wrong! One thing I've made myself do is look through the mech to see exactly where the low / high screws are so you can visualise what it's doing to the mech. It just makes it more logical to me as I don't do adjustments often enough for me to have it committed to memory!

Alejandrosdog

OP
Take a breath and start again. Park have a good video on adjusting rear mechs.