Lost 3 gears out of 8

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Lost 3 gears out of 8

Postby tuco » Wed Feb 20, 2008 9:43 pm

Has anyone encountered this fault?

Bike was working fine, just finished a 40km ride and heading home and I couldn't select the 3 highest gears.
I just finished checking it out and I can't find anything wrong. I simply can't select the last 3 highest gears. I press the select and nothing happens.
I loosened the cable and now I can select the 3 highest gears but now I can't select the 3 lowest gears. I've left it like that for now because I need the 3 highest gears for tomorrows fast group ride.

Basically I seem to have lost the 8 gear range and now it's only a 5 gear range.

I hadn't hit anything or dropped the bike on the rear derauiller. It simply stopped selecting mid ride.

Everything is Shimano. Can anyone shed some light on this fault?
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by BNA » Wed Feb 20, 2008 9:59 pm

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Postby sogood » Wed Feb 20, 2008 9:59 pm

Did the high and low limit screws get bumped? If they are alright, check to see if your cable hasn't been jammed at some point, thereby not allowing the RD to return to its resting position (smallest cog). Also check your shifter to make sure the mechanism is intact.

At this stage, I suspect your RD is totally out of adjustment. The best thing to do now is to go through the full setup as shown on Park Tool site.

http://www.parktool.com/repair/readhowto.asp?id=64
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Postby tuco » Wed Feb 20, 2008 10:05 pm

sogood wrote:Did the high and low limit screws get bumped? If they are alright, check to see if your cable hasn't been jammed at some point, thereby not allowing the RD to return to its resting position (smallest cog).

At this stage, I suspect your RD is totally out of adjustment. The best thing to do now is to go through the full setup as shown on Park Tool site.

http://www.parktool.com/repair/readhowto.asp?id=64


No bumps so the H an L screws should be okay.

If it is out of adjustment then how did it get out of adjustment? One gear change it was okay and then the next I'm down three gears.

I'll have a look at it and that web site tomorrow night. Don't want to stuff it up this late at night before tomorrows ride.
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Postby sogood » Wed Feb 20, 2008 10:30 pm

Some strange things can happen.

In the first instance you shouldn't need to take it all apart. There are only two possibilities,
1) The RD was stopped from returning to the most relaxed position by out of position limit screw ie. Aligning with the smallest cog. The simple solution is to just turn the limit screw. If you dump the gear at the shifter end and the cable is really really low in tension, and the RD is still out of position, then you can bet it's a limit screw issue. But just check and make sure there isn't a little stone or something that got jammed in the RD.

2) The RD was stopped from returning to the most relaxed position due to a restriction by the cable. This could be caused by a problem in the run of the cable or, a problem in the shifter mechanism. Try pulling and relaxing the bare cable under the down tube and see if you can work out where the problem is. There's a possibility that the internals of the shifter has seized at a certain position.
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Postby DavidH » Wed Feb 20, 2008 10:30 pm

If the limit screws were wrong then loosening the cable wouldn't have allowed you select the three highest gears. I personally haven't experienced an issue like you are describing, but I was with another rider who had a similar problem. She ended up having to replace the shifter (since Shimano shifters aren't servicable). Which wasn't cheap.

Hopefully it's something simpler than a buggered shifter :) .
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Postby Kalgrm » Wed Feb 20, 2008 11:23 pm

I had a similar problem on a bike I was given for nix. It turned out to be a shifter problem which was easily solved with a squirt of WD40. Shifters are now great.

Didn't get some of that storm into the shifters by chance, did you?

Cheers,
Graeme

(PS - it was a shimano MTB shifter. Removed the cover, squirted, replaced cover, smiled.)
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Postby mikeg » Thu Feb 21, 2008 12:01 am

A frayed inner cable in the shifter or at a housing stop?

Just a guess!
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Postby mikesbytes » Thu Feb 21, 2008 8:55 am

mikeg wrote:A frayed inner cable in the shifter or at a housing stop?

Just a guess!


Yeh, that was my guess too.

Also check that the hanger hasn't come loose from the frame
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Postby tuco » Thu Feb 21, 2008 9:23 am

44km ride today and towards the end of the ride I lost another 2 high gears.

I was thinking something in the shifter area and now a few people have suggested that I more confident that's where the problem is.

I only had it adjusted at the lbs 2 weeks ago and before this week had only got in 60km. I was passing the lbs today and I thought bugger it, I'll stop and ask. The boss man said bring it and we'll have a look at it for you today.

I would have tackled it myself if I didn't lose the other gears because I could have coped with 140km on the weekend with 5 gears but I'd struggle with only 2.

I let you know later what the problem was for future reference purposes.
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Postby kukamunga » Thu Feb 21, 2008 9:36 am

Start with cable. Sitting in guides and adjusters properly? No kinks or breakages in outer? Sounds like it could be fraying somewhere unseen/ internally, just before it breaks! :shock: Know how to make a single-speeder to get home? :roll:

Other tips above all relevant. Also, hope derailleur hanger is not about to break or fall off. Is gear cluster/ cassette tight on freewheel? Hmmm..... :? LBS???
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Postby sogood » Thu Feb 21, 2008 9:36 am

Derailleur's working and adjustments aren't that difficult and it's well worth learning. Once known, you'll be able to better maintain your bike both at home and on the road.
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Postby Kid_Carbine » Thu Feb 21, 2008 10:04 am

sogood wrote:Some strange things can happen.

In the first instance you shouldn't need to take it all apart. There are only two possibilities.
Only two? Easy to see that you're no bike mechanic.

To diagnose & repair, I suggest the following
Mount bike on workstand so that cranks can be rotated & wheel can turn.
Pull up chair so you can work in comfort.

Disconnect cable from derailleur.

By hand, move deraileur [while rotating cranks slowly] through full range. You should be able to engage all gears without running off the inner or outer sprockets.
If not, try adjusting limit screws. Check alignment of derailleur mounting & repair if required.
If this does not fix it, derailleur is faulty. Repair or replace derailleur as required.

If this is all good, then pull firmly on cable-end & run your indexed shifter through all gears. You should feel full movement for each gear position. If this is good then reconnect cable after lubricating the sections where cable passes through an outer sheath, adjust & retest gear selection.

If not, then pull outer sheath from shifter body untill you can get a proper grip on inner wire at shifter body. Re-test all gear positions. If you don't feel proper movement for all positions, then repair or replace shifter [or frayed cable inside shifter] as required.

If movement is full & free, then remove sheath outer sections from the fittings on the frame & slide them along to be away from the inner wire that they normally cover. Examine outer sheath for damage & kinks. Examine inner wire for damage, kinks, fraying, rust & dryness. Lubricate, repair or replace damaged/faulty components as required.
Actually I do this first as it's the cause of the problem 99.9% of the time for me.

The most common fault that I find in our newly acquired, but pre loved, bike hire fleet is that the last segment of the deraileur cable, the part most susceptible to water ingress. It's very frequently rusty & dry & very stiff due to seemingly total absence of maintainance by previous fleet owner.

The derailleur, in normal operation, is pulled to the inner sprockets by brute force via the cable, but pushed to the outer [smaller] sprockets by a spring whose tension diminishes at it moves outward. When the resistance in the cable excedes the strength of the spring, you start losing gears. [it doesn't take much]
Clean the rust from the inner wire with a rag, then run the outer cable back over this section, back & forward a few times to dislodge as much rust from the inside as possible, then clean, lubricate, re-assemble, adjust & test.

My own preference is for stainless steel inner wire & if possible, teflon lined outer sheath, but this costs money & is not necessary if the bike is maintained.

The simple fact is this. Each element of the whole system has a job to do. If we test each element separately we can quickly find which part of it is causing the grief & we can then address the actual cause, restoring the system to full service without great cost or excess inconvenience.
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Postby tuco » Thu Feb 21, 2008 10:21 am

Good answer K_C! I must print that out for future use.

I'll let the lbs guys do it this time. After all, they did adjust it only 2 weeks ago and due to rain I've only ridden about 60km since so they may have over looked something.

I won't be over charged if there's a big problem. I'm on pretty good terms with the boss man over there.
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Postby europa » Thu Feb 21, 2008 10:28 am

Because you're in a high humidity, high rainfall area Tuco, it might be worth spending the extra for stainless cables. Sometimes the irritation of small problems easily outweighs the costs (not that I call this one 'small' or an 'irritant').

I'd also be buying a can of thin, spray lubricant (I use Joker440) and be giving the cables a quick squirt on the uphill side of the outers periodically, even with teflon coating and stainless. The factories will say you don't need it, but it doesn't take much to cause dodgy shifting and as KC pointed out, it's nearly always cable stiction doing it.

As far as I'm concerned, dodgy shifting is the most noticeable problem a bike can have and the one most likely to ruin a ride/race outside of a part actually failing.

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Postby sogood » Thu Feb 21, 2008 10:31 am

Kid_Carbine wrote:Only two? Easy to see that you're no bike mechanic.

Easy to see that you aren't able to categorize all the little potential issues down to two major categories. It is a mental process after all and guess you can call yourself a bike mechanic.
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Postby tuco » Thu Feb 21, 2008 2:22 pm

Just got off the phone to the lbs.
It was the cable fraying up in the STI level housing.

Have to remember that for next time. I'll also take Richard's advice due to the climate up here.

Thanks for the input everyone.
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Postby Birdman » Thu Feb 21, 2008 2:57 pm

Glad we got that all sorted out...or you got it sorted :roll: but it was a team effort.

How did it fray? Was it rubbing in the shifter casing or something?

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Until next time...
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Postby europa » Thu Feb 21, 2008 3:45 pm

tuco wrote:Just got off the phone to the lbs.
It was the cable fraying up in the STI level housing.


Which is exactly the area you wouldn't look for it in normal use :? It does explain why the gears went so quickly though. Good thing cables are cheap. Anyone want the rubber band that came with the rear dr on my bent?

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Postby tuco » Thu Feb 21, 2008 6:39 pm

Bike is back. Haven't tested it as the rear tyre is flat. Must have a slow leak.

Cost $10 to be repaired. They showed me the cable. It was very frayed and just holding together. I don't know where it was rubbing, it may have been just age.
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Postby Kid_Carbine » Thu Feb 21, 2008 6:57 pm

$10? Including parts? Hell, perhaps I should shop myself there when it comes time for repairs.
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Postby tuco » Thu Feb 21, 2008 7:32 pm

Kid_Carbine wrote:$10? Including parts? Hell, perhaps I should shop myself there when it comes time for repairs.


Yes, including parts.
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Postby europa » Thu Feb 21, 2008 10:12 pm

Kid_Carbine wrote:$10? Including parts? Hell, perhaps I should shop myself there when it comes time for repairs.


You're forgetting, when Tuco goes in, they roll out the red carpet, get his favourite chair, give him a beer (laced with vodka). Good customers are always remembered :roll:

Oh hang, maybe that's not Tuco, maybe that's what happens when I go into my lbs :oops:

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Postby tuco » Sat Feb 23, 2008 9:26 am

Test rode it today. Best $10 I ever spent on the bike!
I didn't realise how bad the gear changing was until I got the new cable.
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