Slipping chain?

[RiflemanSmith]

Hi,
I bought a Voodoo Marasa the chain used to slip under extreme torque like standing up on the pedals slogging it up hill.
I have just put a new KMC chain on and now it slips badly in low gears like every stroke.
My normal gear is the middle chain ring and 6 (out of 8) on the cassette and it slips on any hard pedal stroke even sitting.
Peddling normally is fine but any torque even sitting and it slips?
What is causing this?
Any help much obliged.

 

[172traindriver]

Next port of call would be to take a look at the cassette.
I had a simailar problem with chain slip in the past and thought a new cahin would cure it, but it actually made things worse.
A new cassette was the next thing I replaced and Bingo.......problem solved!
If that fails the chainrings would be the next thing to look at, but I never got that far.

 

[boydj]

A worn chain will wear a cassette badly, so that the two continue to work together. Replace the chain, and the new chain will slip under any kind of pressure. You need to replace the cassette.

 

[Hip Priest]

I had recent difficulties of a chain / cassette nature and it turned out both were fine. I had a bent derailleur hanger. If you're not mechanically-minded, your best bet would be to take it to your LBS to get it looked it.

Don't wait 'til your chain comes off when you're out of the saddle going 15-20mph...like I did.

 

[RiflemanSmith]

It always slipped from new, but I had a spectacular lowside the other day and the back wheel came off and I have noticed that a few teeth are damaged,
Looking at 8 speed cassettes, which gearing would suit my needs, a bit of both road use and occasional off roading?
Cheers.
Mark.

 

[simon.r]

Looking at 8 speed cassettes, which gearing would suit my needs, a bit of both road use and occasional off roading?

Start with what you've got now and work from that. Do you feel the need for a lower (easier) gear? Get a cassette with a bigger big cog. need a higher gear - cassette with a smaller small cog. Do you find the gap between gears too big? Get a cassette with closely spaced tooth sizing.

The only other issue is to make sure your rear mech will cope with the difference between biggest and smallest cogs, which can be an issue if you want to fit a wide range MTB cassette on a road bike.

Edit - looking at your OP, if your 'normal' gear is one gear that you rarely move from you could consider a singlespeed conversion

 

[RiflemanSmith]

Going to change the cassette any way because of the damaged teeth but I was thinking it wont be this.
It was always slipping and surely it would be slipping in the gears that I use most frequently?
As at the moment is slipping in all of the lower gears that never get used and in the two gears that I do use it is less of a problem?

I wouldn't like a fixie, I only use the middle chainring and the top three gears for normal riding but I like having the option to change for hills and speed.

 

[betty swollocks]

The two main reasons why a chain slips is a) chain/sprocket incompatibility because one is worn much more than the other and b) derailleur not adjusted properly.
If you've checked both of these and neither is the case, best take the bike to your local bike shop and let them sort it.

 

[RiflemanSmith]

Can the chain slip because or a rear dérailleur problem but still change gear okay?
Cheers
Mark.

 

[betty swollocks]

It's possible that it'll be capable of derailing the chain from one sprocket to another, but if the chain is not aligned on the sprocket properly, it is conceivable that it will jump and skip about a bit.
So, eliminate this eventuality by ensuring that the derailleur is adjusted properly. Here's some help:- http://sheldonbrown.com/derailer-adjustment.html

Best wishes and good luck.