Replacing the big sprocket on a Shimano 11spd cassette

I have an XT M8000 cassette on my main bike. It has an aluminium 42t sprocket that’s mashed, some way before the rest of the cassette. It’s on a cluster of three cogs. Is there a cost effective way to replace this cluster, do Shimano offer this as a spare? SJS cycles don’t have it so I suspect not.

Is there an alternative that’s cheaper than a new SLX cassette at £50 that’ll do the same job, like an expander? I’ve found one but it’s $110 before shipping or taxes which sort of defeats the point. I’m loathe to throw away a functional cassette for the sake of one cog.

If you search “Rose bikes Cassette sprockets” they do parts of the cassette, both the rear group of three, and individual 11,12, 13 etc small sprockets?

i’d look on rose as above. Dave Hinde used to break up cassettes and sell indivdual sprockets, but doubt you’ll want to go there 😉

Out of interest, how much use has you cassette had?

One Up 45t includes 18t?
Link
The M7000 SLX 11 speed represents better value.

I’d get a smaller front ring at the same time too, if you’re wearing out the 42t you’re geared too highly

Agree with Steve, smaller ring needed.

The spare part is 1RK 9805. I found one shop with stock, it’s €67.50! Madison don’t seem to even bother.

Edit: €50 on Bike24. I’d still get a new cassette.

Rose don’t do them unfortunately. nor Hinde.

A normal expander is meant to work with the worn 42t rather than replace it so it won’t work unfortunately.

cp- I was just trying to figure out how much I’d used it but it looks like my Strava has been hacked so I can’t get my mileage up 😕 . From memory it’s about 1,000 – 1,200 miles almost all off road.

I run a 30t up front, which is in good condition. Surely the bigger problem is the cog being made of aluminium?

Thanks for your sleuthing njee, I’ll have to get a whole new cassette then!

Sunrace are the same, don’t think you can get those either. You can for sram but they’re so expensive, they’re more than a whole XT cassette.

I run a 30t up front, which is in good condition. Surely the bigger problem is the cog being made of aluminium?

Well yes and no, it won’t wear out unless it’s being used, that it’s worn out so quickly just further reinforces that you use it a lot, which is solved by using a smaller ring. FWIW I’ve got 2000 miles on my XX1 cassette, the 42 is fine, but I probably only use it 1% of the time, at most. Many rides I never use it.

I did spec my chainring size with the intention of limiting the amount of use I give the aluminium sprocket.

I run a 30t up front, which is in good condition.

which does kinda beg the question why a presumably ali 30t is just fine when a whopping great ali 42T is shagged….?

D0NK- it certainly does. When I say shagged, I mean proper shagged. Bent teeth. Teeth missing. It was new in January and I’ve been up maybe 8 mountains and do ride fairly steep stuff around the Peak day-to-day, but the previous 10 speed cassette on the old bike did that and lasted a couple of years including the Strathpuffer. This is the shortest time I’ve had a cassette last since I switched from SRAM 7 years ago.

but the previous 10 speed cassette on the old bike did that and lasted a couple of years including the Strathpuffer

How many chainrings did that setup have?

2x.

Just sayin.

That was 1x too, lowest gears was 32 front 36 rear. It did go through an alloy chainring in just over 18 months but I think that’s acceptable.

Im on my second one in a year. First was a 42 current one is a 40 and im pretty sure the top 3 are steel not ali. Its all to do with chain line, wears quicker on the out side most rings. My 42 went on 9,10,11 and im running a 30t front.

Thanks bigpins, that’s useful to know. I’ll try and adjust the chainline but since I’ve got BB92 I doubt I can do much about it.

It’s tough living in the future…

It was a lot cheaper than the 42t too.

How’s your chainline? Is your chainring sitting too far out?

2x

Correct answer.

The 42t sprocket is quite a but narrower than the teeth on the chainring, no?

The answer to your problem is to go back to 1×10 and use a sunrace 11-42 with the steel 42t sprocket (can’t remember the model and can’t find the email, but from Triton Cycles).

Also keen an eye on Revolution Components. They’re a small NZ outfit but I was riding with someone who had a steel big sprocket made to replace the alu one from a SRAM 10-42 cassette.

I was reading this with interest, as I’ve managed to take a tooth off my 42t cassette 🙁

Still, rides OK so I’ll live with it 🙂

The 42t sprocket on them Sunrace cassettes is thicker than all the rest, seems a good design choice!

Having said that Shimano cassettes are hardly lightweight flimsy things are they! SRAM equivalents are usually machined skeletal things in comparison.

If it’s a standard 104 BCD crankeset you can space the front ring inward. It often needs about 4 mm which is a pretty thick washer. I got some commonly available (not specialist aritisanal unobtainium bike taxed) alloy split washers that did the job. Depending on the crankset you might, most likely though, need longer chain ring bolts as well.

If you are that stressed you NEED to go to HR / occupational health and tell them – you are on the verge of being unsafe at work if not already over it. Stressed folk make mistakes

I have been transferred in a hospital reorganisation into a role that I didn’t have the skills for and the stress nearly did for me. After working the system I am now in a suitable role.

If you are that stressed you NEED to go to HR / occupational health and tell them

I never stress over the state of my cassette. Occasionally about the rear mech. Or about having STW open on too many tabs at the same time. 🙂

😆