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-   -   New Rear Mech wont Shift into 1st Gear (https://www.bikeforums.net/showthread.php?t=1220551)

Daddydgc 12-31-20 06:26 AM

New Rear Mech wont Shift into 1st Gear
 
Hi All, this is is my first post on the forum and apologies if has already been covered elsewhere.

I replaced rear wheel, bottom bracket (sram gxp) and rear mech (shimano zee) but cannot access 1st gear (largest cog) even though the limit screws are not restricting the range of movement. I took bike into local bike shop and they could not fix and changed rear cassette, chain a gear cable. LBS said to bring bike back in new year and they will have another look but I want to get out on the bike over Xmas holidays and really annoyed that ive paid out already without getting the issue fixed.

I am running a 1x 10 speed cassette (11-32) with a 32t chain ring with shimano deore 10 speed shifters.

The rear wheel (shimano) is a little wider than the alex rims i had previously and i yhought this may be causing the issue but when i put the old wheel back in i am still getting shifting problems.

Could it be that I am somehow not fitting the new rear mech properly but surely LBS would have spotted this and resolved?

Can anyone offer any advice on what the problem could be please?

Cheers

Kapusta 12-31-20 08:26 PM

When you say 1st gear, you mean rhe large cog, right?

What exactly do you mean when you say you canít access it? What heppens when you try to shift into it?

Daddydgc 01-01-21 03:29 AM


Originally Posted by Kapusta (Post 21857215)
When you say 1st gear, you mean rhe large cog, right?

What exactly do you mean when you say you canít access it? What heppens when you try to shift into it?

Yes I can't shift into the largest cog. I can get the other 9 gears no problem but not the final large cog. I have opened up the limit screw so even if I try and manually push the rear mech into the large cog it barely does this - the range of the rear mech does not appear to be sufficient although the shimano zee specs suggest it should do the job.

Other than the rear mech, I had changed rear wheel and bottom bracket so these could be the issue. My local bike shop have since changed the casset, chain and gear cable and still wont shift into largest cog.

Kapusta 01-01-21 07:36 AM


Originally Posted by Daddydgc (Post 21857496)
Yes I can't shift into the largest cog. I can get the other 9 gears no problem but not the final large cog. I have opened up the limit screw so even if I try and manually push the rear mech into the large cog it barely does this - the range of the rear mech does not appear to be sufficient although the shimano zee specs suggest it should do the job.

Other than the rear mech, I had changed rear wheel and bottom bracket so these could be the issue. My local bike shop have since changed the casset, chain and gear cable and still wont shift into largest cog.

Have you detached the cable to the RD when you try to manually push it into 1st gear?

is the issue the the RD canít push the chain far enought inboard, or that it wonít clear the large cog (as if the cog is too big).

Daddydgc 01-01-21 07:44 AM

Yes I have tried detaching the gear cable and pushing rear mech across manually but does not appear to quite have the range of movement to sit directly above the largest cog (despite the limit screw being fully released).

The issue is the RD cant push the chain far enough across to the largest cog as there is enough clearance above the largest cog.

Kapusta 01-01-21 09:35 AM


Originally Posted by Daddydgc (Post 21857601)
Yes I have tried detaching the gear cable and pushing rear mech across manually but does not appear to quite have the range of movement to sit directly above the largest cog (despite the limit screw being fully released).

The issue is the RD cant push the chain far enough across to the largest cog as there is enough clearance above the largest cog.

I am suspecting a derailleur hangar alignment issue, You may be able to detect this visually, but with 10 speed and up it needs to be more precise, and you may need a hangar alignment tool in order to positively rule this out.

It is a little odd that this would not have come up with the last RD, but it may be that the last RD had a tad more extra range available to it.

freeranger 01-01-21 10:44 AM

looked up the zee der. Is it possible you might have the DH version? "There are two versions of Shimano's ZEE RD-M640 Shadow Plus Rear Derailleur: a Downhill (DH) for 28t-max cassettes, and a Freeride (FR) for up to 36t-max cassettes."

Daddydgc 01-02-21 05:56 AM

Hi thanks for the replies.

I've checked and definately got the FR version of the Zee rd-m640-ss so should be ok.

I refitted my old shimano deore rear mech and realised that it slides onto either side of the rear mech hanger whereas the new zee mech just fits on the outside of the hanger which results in the old rear mech being around 5mm closer to the cassette with enough range to change all gears.

Do i need a different rear mech hanger for the new shimano zee mech to work with my bike frame which is a Marin Rocky Ridge 7 Four? Such a hanger may shift the new mech across by 5mm which would give me the range I need.

I'll take some photos as soon as I get to 10 posts.

Any thoughts are very much appreciated folks?

Really want to get out on the bike to shift some festive pounds!

freeranger 01-02-21 07:29 AM

Was the Deore der not working? If it still works, maybe put it back on until the LBS can figure out a solution. If not possible to mount the zee inward, and that turns out to be the problem, may need to stay with a Deore.

Canker 01-02-21 08:24 AM

without pics I'm just going to throw this out there.
https://wheelsmfg.com/blog/standard-...r-hangers.html
I'm going to guess you have a direct mount hanger and are trying to mount the RD using the b-link.

Kapusta 01-02-21 08:30 AM


Originally Posted by Canker (Post 21858945)
without pics I'm just going to throw this out there.
https://wheelsmfg.com/blog/standard-...r-hangers.html
I'm going to guess you have a direct mount hanger and are trying to mount the RD using the b-link.

I was wondering if diect mount something-or-other was involved here.

Is the reverse also possible?

Daddydgc 01-02-21 11:16 AM

Thanks for all the responses. Solution was simply to remove the link piece supplied with the shimano derailleur so it mounts directly to the rear mech hanger (this had the effect of shifting the mech towards the cassette by around 5mm) so that i now have all gears working perfectly. Only wish my local bike shop could have pointed this out to but clearly they were after some more work from me...

Thanks again all for your help with this.


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