Chainset/Chain Query

[jpembroke]

9 speed derailleur is definitely OK with 8 speed set-up. No problems there. Although, personally, I'd prefer a medium cage mech with a 29t cassette. Still, you shouldn't have problems on any other sprocket though. I reckon it just needs setting up right. Try a second opinion/bike mechanic before you spend anymore money. Changing the cable is always worth a try and won't cost much.

 

[mickle]

Ok. What are the symptoms exactly?

 

[ChrisKH]

Ok. What are the symptoms exactly?

Regardless of what front cog you use, if I try and change to the first four large cogs on the back (29 and downwards), you can't apply any pressure to the pedals without the gears slipping (ie jumping up or down a cog). The four smaller cogs on the back are better, but even then they jump occasionally.

If I use the smaller cog at the front, the symptoms appear much worse.

 

[mickle]

Are your cable outers in good nick? It's not unusual for the outers to get mashed during folding. A kink or a split would cause these symptoms.

Is the hanger bolted up tight and the mech bolted up tight to the hanger?
Is the chain within acceptable wear tolerances?
Is the hanger straight?
Is the mech straight?
Is the cable unkinked, free from corrosion and lubed?
Is the cassette within acceptable wear tolerances?
Is the 'b' adjust screw set correctly?
Does the chain have a stiff link?

I could go on..

 

[ChrisKH]

Are your cable outers in good nick? It's not unusual for the outers to get mashed during folding. A kink or a split would cause these symptoms.

Is the hanger bolted up tight and the mech bolted up tight to the hanger?
Is the chain within acceptable wear tolerances?
Is the hanger straight?
Is the mech straight?
Is the cable unkinked, free from corrosion and lubed?
Is the cassette within acceptable wear tolerances?
Is the 'b' adjust screw set correctly?
Does the chain have a stiff link?

I could go on..

I'll check. Thanks Mickle. Most should be 'yes' as the bike has only done 300 miles, if that.

 

[peanut]

I agree it sounds like it needs completely setting up from scratch Chris .Especially as you are replacing the chain.

Make sure you check from behind that the cage for the rear derailier is hanging vertically . It gets knocked out of alignment easily and needs to be spot on. Near enough is not good enough.Check that the derailier return spring is still strong or that will adversly effect changes

Also very important is the proximity of the top jockey wheel to the cassette sprockets which is adjusted by the 'B' screw.

The following Shimano guide will help you get the chain length right which isn't easy and to set the transmission up.
http://techdocs.shimano.com/media/t...RA/RD-4400/5TS0B_EN_v1_m56577569830607031.PDF

 

[ChrisKH]

Thanks Guys.

 

[mickle]

Fixed it yet????

 

[ChrisKH]

Unfortunately not. I had to paint two doors and a radiator yesterday.

I did fit some rather natty lights on my helmet though.

I'll take a look tonight and see if I can't resolve.

 

[ChrisKH]

Success! Well sort of. Had a look at the Park tools How To.......whatever and;

1. Checked the salient points over. Nothing remiss on the bike.
2. Changed the chain to an eight speed. Probably not necessary, but at least three out of four components are eight speed now.
2. Adjusted the H & L settings on the rear derailleur. These were way out (what did the bike shop do?)
3. Adjusted the D setting which was fine.
4. Gears still all over the place. Checked the indexing and it's not there.
5. Big discovery of the night, checked the change from smallest cog to next largest and it wouldn't jump. Checked the derailleur cable and it was loose. Not major, but very slightly. Tightened this up, reversed the derailleur adjustment nut by two full revolutions.
6. Indexed the gears and voila! It all works.

Except when I switched gears on the front derailleur on the way to work this morning and the chain fell off. So, need to adjust this as well, probably because of the new chain.

 

[jpembroke]

Great news! One of the joys of 8 speed is ease of setup and adjustment (I love 8 speed!). I'm sure you'll be able to keep it indexed no problem now and you won't have to pay a bike shop to do it for you (yes, what exactly did they do?).

Your front derailleur just needs the same adjustment i.e. dialing in the H and L screws to stop the chain from overshifting.

 

[ChrisKH]

Thanks all.

 

[MartinC]

Well done Chris. Sounds like it just needed adjusting properly. Give that LBS a miss now.

 

[ChrisKH]

Well done Chris. Sounds like it just needed adjusting properly. Give that LBS a miss now.

Usually they're very good. To be fair to them, they changed the derailleur cable and outer case on my request (the other got snagged in the bike's folding mechanism) and probably the major fault was the cable being loose. This probably stretched in the first month and wasn't re-adjusted.

I will try and do more myself in future though.