8 speed chain on 9 speed cassette

[thenorthwind]

I have an 8 speed cassette which came on a second hand wheel. I bought a new 8 speed chain with the intention of getting some use out the cassette, before going to 9 speed later (I built the bike up with a 9 speed shifter). All but the smallest sprockets run fine without skipping except the smallest, even after a couple of weeks of commuting wearing the chain in. So I'm thinking of putting a new 9 speed cassette on, at least for a short tour, as the skipping in top gear will annoy me. Will the 8 speed chain play nicely with the 9 speed cassette or is it a no go?

[531colin]

I'm running a 9 speed triple on an 8 speed chain with no problems at all....friction front shift, don't know if it matters.
(why?....just one lot of spares!)

[Brucey]

8s chains vary in their exact width and furthermore the interval between the sprockets in a cassette can affect whether a wide chain can stick out one side or not (and thus still clear the neighbouring small sprocket).

I think it is a suck-it and see job.

cheers

[thenorthwind]

Will just have to try it then, cheers

[CREPELLO]

If you already have the 8 speed chain, just give it a go - then let us all know how it goes
If you've yet to buy the chain, the difference in price between 8 and 9 speed is so small these days, you'd probably be safer with 9.

[Jeff31]

I managed to fit a 8speed chain (SRAM) on a 9speed shimano cassette. It ran but gave a whirring noise and felt a bit rough giving a noticeable vibration through the pedals on smooth tarmac, so not very often. Can only assume I had thrown the 8speed chain in my 9speed spares box and neglected to check before fitting it. Thought it was a worn cassette during the 1st ride but after a second ride realised it was an issue and discovered my mistake. No apparent damage and the chain gave good service when fitted to a Campag 7speed drivetrain.

[Redvee]

When Shimano went 9 speed with their 105 groupset I had it on my road bike whilst still having 8 speed on my MTB so one Sunday afternoon when I was bored I swapped rear wheels around and apart from the gears not indexing up obvioulsy there were no other issues with the chain, think it was a Wipperman Connex chain on the road bike and Sedis, not Sram, PC81 on the MTB.

[Keezx]

Basically N+1 speed chain fits on N speed cassette, the other way around not.

[thenorthwind]

Seems to work fine. Can't remember exact model of chain and cassette as I buy whatever basic SRAM/Shimano/KMC 9spd stuff is cheapest at the time.

It turned out a worn sprocket wasn't the issue though, since it continued with the 9 speed cassette. After much careful examination, I found a link in which both inner plates were bent, in parallel, giving the chain a kink, so I removed that link. Never seen that problem before, but I find with bikes, the more you know, the more problems invent themselves.

It turned out that wasn't the (only?) issue either. I didn't realise a) the chain had a quick link, or b) the quick link is arced to wrap around the chainrings/sprockets (wasn't aware such a thing existed - not sure how the upper jockey wheel likes this). Sod's law dictates that I'd put it on the wrong way.