Shifters not working after tightening clamp bolt -Help!

For discussions about bikes and equipment.
bikesandboats
Posts: 26
Joined: 9 Feb 2016, 8:17pm

Shifters not working after tightening clamp bolt -Help!

Postby bikesandboats » 15 Sep 2016, 8:46pm

Hi All,

Recently bought a tandem and it is fitted with Shimano Nexave 7 speed shifters (see the pic)

It worked fine when I bought it, then I took the shifters off to change the stem and when I refitted them they stopped working, but only after tightening the clamp bolts. The button and lever click still but it seems that the cable won't move to allow the gear to change.

I can loosen them and they work but flop around on the bar.

Any suggestions would be great!

Joe

Image

User avatar
gaz
Posts: 13904
Joined: 9 Mar 2007, 12:09pm
Location: Kent, car park of England

Re: Shifters not working after tightening clamp bolt -Help!

Postby gaz » 15 Sep 2016, 9:12pm

I'll be the first to say it doesn't make sense.

Tech docs (I think) can you confirm you're talking about "bolt 10".
2020 : To redundancy ... and beyond!

bikesandboats
Posts: 26
Joined: 9 Feb 2016, 8:17pm

Re: Shifters not working after tightening clamp bolt -Help!

Postby bikesandboats » 15 Sep 2016, 9:23pm

It does not make sense, yes its bolt 10.

Perhaps something where the cables are is being clamped somehow?

Joe

User avatar
meic
Posts: 19355
Joined: 1 Feb 2007, 9:37pm
Location: Caerfyrddin (Carmarthen)

Re: Shifters not working after tightening clamp bolt -Help!

Postby meic » 15 Sep 2016, 9:36pm

One possibility, not seeing the bike, is that you have pulled the cables (outer and inner) so tight that the outers are no longer touching the stops at each end. So when you change gear, it just makes the gap at the end of the outer smaller, rather than changing the gear.
This can also happen if an outer cable gets "hooked" on to something, preventing it from taking the shortest route between its stops.
Yma o Hyd

User avatar
gaz
Posts: 13904
Joined: 9 Mar 2007, 12:09pm
Location: Kent, car park of England

Re: Shifters not working after tightening clamp bolt -Help!

Postby gaz » 15 Sep 2016, 9:37pm

Service Instructions which seem to show this is a "reverse normal" shifting set up, where the unpulled cable position is on the large sprocket.

Whilst I can't see that this is in any way relevant to the symptoms are you setting it up accordingly?
2020 : To redundancy ... and beyond!

PT1029
Posts: 735
Joined: 16 Apr 2012, 9:20pm

Re: Shifters not working after tightening clamp bolt -Help!

Postby PT1029 » 16 Sep 2016, 8:00am

Are the levers mounted adjacent to a bend in the bars. I have known Shimano rapid fire levers (not this model though) which work, but if mounted too close to a bend in the bars, on tightening the clamp the bend in the handle bars applies pressure to the housing (or lower lever), which stops them working (in 1 direction at least). So, if by a bend in the bars, try moving away from a bend a little, secure and check the shifting.
It probably isn't this with those levers (but worth a check just in case).

Brucey
Posts: 37426
Joined: 4 Jan 2012, 6:25pm

Re: Shifters not working after tightening clamp bolt -Help!

Postby Brucey » 16 Sep 2016, 8:19am

I'm inclined to agree; my thought was that tightening the clamp may have pulled the cover round slightly, so that it now fouls a shift button, probably the one that is closest to the clamp.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

User avatar
DaveP
Posts: 3227
Joined: 9 Mar 2007, 4:20pm
Location: W Mids

Re: Shifters not working after tightening clamp bolt -Help!

Postby DaveP » 16 Sep 2016, 10:15am

If you have changed the stem then this is likely to have altered the cable run. A higher or longer stem might need longer cables to achieve the desirable gentle bends. A shorter or lower stem - you might get away with the existing, but you might also find that excess cable between bars and frame stops can produce kinks near the ends of the outer.
Not a very deep point perhaps, but worth eliminating (by inspection).
Can you tell if the inner cable is actually moving in or out of the shifter when you press the buttons?
Trying to retain enough fitness to grow old disgracefully...