gears slipping in high gears

samsbike

Retro Guru
My road bike has an issue. Chain and the teeth on the cogs look fine, but going uphill in a high gear I.e. a big cog on the rear, the chain slips. It's all fine on the straights, it s poor under load.

What should I do to fix this

Thanks

Sam
 
Have you checked the chain with a proper wear indicator?

Have you looked at the chainrings?
 
cyfa2809":3nx02dag said:
Have you checked the chain with a proper wear indicator?

Have you looked at the chainrings?

+1

The chain may indeed look fine but would you spot 0.75% 'stretch' to overall length of the chain - which is all it takes for the chain to need replacing - ? If it gets to 1.0% it's prematurely wearing front and rear cogs, ie 'hooking' them. These wear figures can be identified using a £5 chain wear indicator, try an XTools one for best value IMO.

Course it might not be the chain at all!
 
Sounds like a worn out drivetrain.

If you haven't got a chain wear guage you can do a check with a 12inch ruler.

Start off on the centre of a chain link pin count 12 complete links and see if the 12 inch mark of the ruler alligns up with the centre of the link pin on the 12th link (complete link is one inner link and one outer link).

If the ruler miss aligns with the centre of the 12th link by more that 1/8th of an inch it's dead and has most likely taken the cassette and front rings out (usually just the middle ring if your MTBing)
 
thanks all

Actually its a road bike but frustrating nevertheless.

Its a pain as it was an ebay purchase and sorting out the drivetrain is going to cost more sigh.

I will do the test on the chain and report back.

The seller said the bike had only covered about 600 miles and it was a year old (which was true as the model was only launched in 2010), however it was a commuter.

sam
 
Lack of maintenance can wear out a drivetrain pretty quickly, especially if the bike has been used in the rain. However wearing it out in 600 miles is difficult.
 
Millage isn't a very good measure really as it depends on the conditions, fol. My record is wearing out a chain and cassette in one ride. That was last years kielder 100, all the rock grit mixed with the rain and mud formed a nice grinding paste that quote the chain out which then took out my cassette. it made it an expensive ride !
 
dvatcmark":yco9arfc said:
Start off on the centre of a chain link pin count 12 complete links and see if the 12 inch mark of the ruler alligns up with the centre of the link pin on the 12th link (complete link is one inner link and one outer link).

Apologies for being thick, I am simply measuring the lenght of 12 links, centre to centre, or is it from one of the pins (front or back) till another 12 links?

thanks
sam
 
I think, having never actualy measured it this way before, what the method calls for is that you go from the centre of the pin to the centre of the pin, or edge of the plate top the edge of the plate.... doesnt matter which
Just be sure that it includes 12 full links (or, in other words, 24 rollers)

I might be talking out of again, however ;)

G
 

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thanks

unkleGsif":161u2qmo said:
I think, having never actualy measured it this way before, what the method calls for is that you go from the centre of the pin to the centre of the pin, or edge of the plate top the edge of the plate.... doesnt matter which
Just be sure that it includes 12 full links (or, in other words, 24 rollers)

I might be talking out of again, however ;)

G

many thanks, will do it and report back
 
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