Bicycle Mechanics - Chain Slip - New XT Cassette

So, I popped a new wheelset with a brand-new Shimano XT 9-speed cassette on the back. Now, I'm getting some crazy chain slip, mostly on load, but not always. I'll shift into a higher gear, and it'll slip back to the lower.

Went to my LBS, and the tech said it's either:
1) Chain needs replacing. Measured mine, it's not stretched, but over a year old. Or,

2) Middle front chainring is too worn. Could very well be, I haven't replaced it yet, and most of my riding is in the middle.

So....I bought a new chain, and I'm waiting on the shop getting the middle ring in before I replace it.

My question is: Is this normal after adding in a new cassette? I had no probs with my old wheelset. Buying new parts isn't an issue, but I would like to make sure I'm fixing the prob.

When you replace your cassette, you should always replace your chain. Sometimes this will necessitate replacing chainrings too. The problem is that otherwise you're trying to match up things that have worn to different levels so they're not engaging properly. Also, you didn't mention if the chain was creeping out of gear on the front or the rear.

So, I popped a new wheelset with a brand-new Shimano XT 9-speed cassette on the back. Now, I'm getting some crazy chain slip, mostly on load, but not always. I'll shift into a higher gear, and it'll slip back to the lower.

Went to my LBS, and the tech said it's either:
1) Chain needs replacing. Measured mine, it's not stretched, but over a year old. Or,

2) Middle front chainring is too worn. Could very well be, I haven't replaced it yet, and most of my riding is in the middle.

So....I bought a new chain, and I'm waiting on the shop getting the middle ring in before I replace it.

My question is: Is this normal after adding in a new cassette? I had no probs with my old wheelset. Buying new parts isn't an issue, but I would like to make sure I'm fixing the prob.The new wheelset might have required a bit of RD tweaking. Something to check if the chain is jumping from cog to cog rather than skipping teeth on cog or chainring.

Thanks Khuon!
It's slipping out from the back. Usually fairly stable in the largest and smallest rings on the back--but everything in between seems to slip.

Makes sense that other parts would need replacing, also, at the same time.


I'm slowly replacing/upgrading worn parts myself, so I'm sure I'll be posting here lots :D

The new wheelset might have required a bit of RD tweaking

I have to admit, no idea what RD Tweaking is. Bought the wheelset (Mavics on XTR hubs) and had the tech add the XT cassette....I trust the guy, even watched him pop it on, no overtightening...

When you replace your cassette, you should always replace your chain. Sometimes this will necessitate replacing chainrings too. That's just not ALWAYS true and one is spending unnecessary money if not changing them does not create a problem.

I have to admit, no idea what RD Tweaking is. Bought the wheelset (Mavics on XTR hubs) and had the tech add the XT cassette....I trust the guy, even watched him pop it on, no overtightening...Because of differences in tolerances and dimensions,when you throw on a different rear wheel,it might require READJUSTMENT of the RD.

Bah, tweak the rear derailleur. Damn noobs. :rolleyes:

Yeah, I was thinking that. These rims are a bit slimmer than my previous ones; that could very well be it, also. Never even attempted an adjustment, but I'll have to learn sometime.

Thanks guys!

Bah, tweak the rear derailleur. Damn noobs. :rolleyes:

Yeah, I was thinking that. These rims are a bit slimmer than my previous ones; that could very well be it, also. Never even attempted an adjustment, but I'll have to learn sometime.

Thanks guys!It isn't the rims.

Rear Derailleur is the RD he is talking about.

Your both right about the chain and cassette.

If it is a good rider with multiple wheel sets You will want to keep the Chain on the bike from ever getting to much if any stretch because you never want to trash a good cassette with a old chain on a 50 mile race. With the 10’s costing $150 a $20-30 chain is nothing.

If it’s an average 2000 – 6000 a year rider it’s a question pay me now or pay me later. With one wheel set it is a matter of choice wear it all out and replace it all. Or at 1500 – 2000 miles change the chain and check the teeth. If they are a high RPM rider they can make gears last a long time. If they are low RPM power rides they can chew a cassette or ring in 1000 – 1500 miles. Add off road riding and just sandy road riding and you can’t use the mile rule you just have to look and teach the rider to watch for wear.

If is the occasional rider it is about 99.9999% that your going to a new chain on with every cassette/freewheel.

In fact I don’t remember not putting a chain on with a cassette, except for multiple wheel owners. It’s kind of like the oil filter that is good for 6000 miles but you still do change it when you change the oil at 3000.

Cheers