Chain slip

dannyharris

New chain cut and installed onto my carrera tdf. New rear gear cable attached and indexed the gears.
When turning the pedals with my hand the gear chain is really nice, no chain rattle or anything so I'm sure they are indexed correctly. When I apply a lot I pressure mainly from the start position the chain slips.
The only gear this doesn't happen on is the largest sprocket.
If I pedal with hardly any pressure it tends not to slip.
Any ideas what I am doing wrong?

marcusjb

Sadly, you've probably left it too long before replacing your chain and the cassette is also worn. It will need replacing as well.

If you replace your chain in a timely manner, you will only need to replace the cassette every 5th or so chain (in my experience)

dannyharris

Oh poo. Was planning on 120 mile ride this Sunday.

marcusjb

If you've still got the old chain, stick it back on - you've ****ed the cassette anyway! If not, get to the bike shop tomorrow. You'll be riding Sunday, no issues.

Read up on measuring chains - basically you want to change them when they are around 0.75% longer than they should be. Once you get to 1%, the chain will be wearing the cassette out too much, and will cause a new chain to slip.

As I said, if you change your chain when it's at that 0.75% point, then a cassette should last a good long time.

dannyharris

Going to get another cassette tomorrow and have it fitted. Should I go for the stock part? Could I change the gear ratio without spending on parts I don't need?
Skint so only got about £50 to play with.

k-dog

£50 is plenty. You could replace it with the same or possibly change the ratios a bit. You justice to make sure your derailleur has the capacity and your chain is long enough.

dannyharris

Thanks for the help guys. Stuck with the same ratio. Fitted myself. That's easier than getting my tyres off the rims

bikeit65

Dont want to hijack the thread,
how many miles should a chain be replaced so that cassette will not need replacing also?

k-dog

It's not the miles but the wear and that depends on conditions and lubrication.

to check the wear you need to measure the chain. 12 links should be 12". If you get to 12 1/16" then the chain should be replaced. If you get to 12 1/8" then you'll probably need to change the cassette too.

Or you can buy one of the chain measuring things - if one side fits change the chain, if it's the other change both.

You can usually get through 3 or so chains for each cassette.

Edited for a typo.

cycleclinic

Typically under normal conditions 1000-1500 miles will see you 0.75% wear you may get more though. k-dog info is spot on. No point in repeating it.

bikeit65

Will check condition of the chain tomorrow, if i need a new chain what would you guys recommend, the chain on the bike at present is a Shimano 105

dannyharris

My lbs seemed to think the slipping could have been caused by a slight wobble in the rear wheel or because he thinks my rear derailer looked bent. Seems ok after new cassette tho.

keef66

dannyharris wrote:

My lbs seemed to think the slipping could have been caused by a slight wobble in the rear wheel or because he thinks my rear derailer looked bent. Seems ok after new cassette tho.

I think your LBS is talking rubbish. The fact that the new cassette has sorted the problem seems to confirm it. A new cassette wouldn't true your wheel or straighten your mech hanger...

dannyharris

That's what I thought. Starting to get the hang of doing work myself now.
Next two jobs is to look into my rear mech. I know how to true a wheel already.

keef66

Bikeit65 wrote:

Will check condition of the chain tomorrow, if i need a new chain what would you guys recommend, the chain on the bike at present is a Shimano 105

I'd suggest the cheapest KMC 10 speed chain you can find. That way you get a new Missing link with it. Unless you're overly concerned about weight or shininess, in which case go for a dearer KMC chain with slotted plates and hollow pins and sparkly coatings.

Bozman

I was out for the first time on a new build on Saturday, brand new chainset, new chain and a cassette with roughly 500 miles on it, on my first time out of the saddle the chain slipped, this carried on for the first 40 miles and then it stopped and has been fine since.
My mate had a similar experience and that self rectified after a couple of trips out, it all seems a little odd to me especially when you've swapped components too, I've never had this issue when I've swapped just the chain.

drlodge

I've had my chain slip when standing up the pedals on a steep hill. It was due to the RD cable stretched a bit, a couple of twists of the cable barrel adjuster and all fixed.

bikeit65

Checked the chain with the cc3 park tool chain checker and on the .75mm side it will not fit between the chain links, so happy days for another while,

I7 Extreme

How can you tell the wear on cassette's? I Don't really want to spend £32 on a new cassette, I would rather spend something like 15 or 20 on one which has done low mileage such as this one - viewtopic.php?f=40091&t=12933462&hilit=105+cassette every cassette I see on ebay says good condition or very good but what I've gathered from on here is that it would only be 'very good' with their old chain, what should i look in the picture for a good cassette? thanks

keef66

Modern cassettes have shallow teeth to aid shifting. The downside is that the chain finds it easier to jump forward over them when they are worn. It's nearly impossible to spot a worn cassette just by looking, even when you have a new one for comparison. Easiest way to tell is to fit a new chain then go climb a hill.

I'd never risk buying a used cassette for that reason. Instead I buy the cheapest new 10 speed one I can find. Usually CRC or Ribble.