Changing from rear cassette from 8sd to 9sd

[silk186]

I bought my bike in to be looked at because I was having trouble adjusting my rear gears.
It turns out that I have an 8 speed rear cassette and a 9 speed shifter.
The solution is to buy a 9 speed cassette from Chain Reaction and I have a few choices:

• Shimano Deore-Alivio HG50 9 Speed MTB Cassette
• Shimano Deore HG50 9sp Cassette + Chain

I can choose between:11-32t and 11-34t
For the chain I can go with:

• none
• KMC X9-93 9 Speed ChainKMC X9-93 9 Speed Chain
• Shimano Deore HG53 9 Speed ChainShimano Deore HG53 9 Speed Chain

I don't know how the know whether I need 32 or 34 teeth
I also don't know how to tell if I need to change the chain or which is more suitable.

 

[Hacienda71]

What is the rear mech? This will be the limiting factor on the cassette size.

 

[PatrickPending]

KMC chain, I guess its a mountain bike/hybrid with a long cage rear mech, worth checking as in the post above as to what it can cope with tooth wise...

 

[silk186]

It just says Shimano Dear on the rear derailer, and the front shifter is a Shimano Deare 9 speed.

 

[silk186]

I washed my bike so I could look it over:

The rear derailer says: GD Shimano RD-M531 Japan VIA
The rear cassette says: Shimano HG MEGARANGE 34T CS-HG41-8ao​

I went into a bike shop today and he said the only difference between a 34T and a 32T is the last gear. He said that either would fit my bike and that it would only effect the gear ratio in the lowest gear which I never use.

He also says I would need a new chain and the the Shimano is the better of the two, after some reading I'm leaning towards the KMC X9-93:

KMC X9-93 9 Speed ChainKMC X9-93 9 Speed Chain
Shimano Deore HG53 9 Speed ChainShimano Deore HG53 9 Speed Chain
​

This is changing from a Shimano HG41 8 speed to a Shimano Deore HG50 9 speed
Can someone confirm this (the kid looked like he wasn't out of high school yet?

 

[evo456]

Your rear derailer will be fine with 32 or 34t. Contrary to what you've been told there is a difference between the two choices the 34t ratio are the same as your 8 speed with the exception of the second to last 'easy' gear. The 32t cassette have more closely spaced ratio at the 'harder' end. So if you hardly use the your current top 2/3 easy gears and/or find that on the harder side you are constantly shifting up/down to find the 'right' gear, I'd say go for the 32t it'll fit your needs more.

As for the chain, best to change as the old one would have worn with the old cassette, KMC will be fine.

 

[Nigelnaturist]

@silk186 I ran a KMC X9-93 on my road bike, no issues after 2,500 miles, picking up a little on what @evo456 says, the large 34th not only lowers the lowest gear (inner) but when its used on the middle as well.

 

[Crankarm]

The issue here is having a cassette and shifters that are matched as 8 and 9spd cassettes have slightly different spacings and 8 and 9spd shifters have slightly different pulls for each gear increment to reflect the different spacing of the sprockets of the cassette as there are a different number.

The size of the largest inner sprocket is a different issue governed by the size of the rear deraillieur cage. For 34T sprocket I would have thought a long cage deraillieur would be fine even a medium cage, but not a short. For me Shimano HG53 chains are fine and cheap and do not rust. They change just as well and last just as long as Shimano HG93 chains which I have used in the past as well as Dura-Ace. My HG53 chains last thousands of miles although I do keep them clean and well lubed. I would say 5 - 6,000 miles at a guess before I need to replace. I bought a KMC chain once. It wasn't cheap. It might even have been one of the ones mentioned above. It was ok drive wise but rusted up pretty quickly. Never again. Shimano for me.

 

[Nigelnaturist]

@Crankarm, I think the issue of 8 or 9sp was established in the second sentence, i do agree that KMC do need some looking after certainly the ones i have had, even just one ride in the wet needs attention, but longevity had one with an 8sp cassette for 7-8,000 miles only kept it that long as I was changing from 8sp to 9sp when it needed doing so I was pushing it a little, but I think also what helps is I run a triple and I run a pretty straight line from my middle to the 14-19 on the rear which is where most of my riding is done.

 

[silk186]

Has anyone else had trouble with rust on KMC chains? When I was reading reviews they tended to favor the KMC over the Shimano Chain.
I seems that living in the UK I will have to ride in the rain a lot...
I never go over 15 miles a day, typically I ride half of that so low maintenance is preferred however I would expect a few years out of a chain.

Thanks for the explanation evo456, looking at the specs I see what you are referring to:

Cassette Option 11-32T: 11-12-14-16-18-21-24-28-32
Cassette Option 11-34T: 11-13-15-17-20-23-26-30-34
​

Having read over all of your comments a few times it seems that the 32T is an easy choice for the cassette, but the chain is a bit harder. Many KMC fans in this forum however two of you have mentioned that they require more maintenance...

I will place my order later tomorrow after a bit more research.

 

[Nigelnaturist]

@silk186 I can't comment on Shimano chains as I never use them, the KMC have a quick release link making removal of the chain easy, as for maintenance it really is a matter of drying the chain if you have been out in a downpour and a quick lube, not much more than 5 mins.

 

[jack smith]

Kmc, shimano chains tend to be cr*p any chain will rist if you get it wet and dont dry/ lube it

 

[evo456]

I wouldn't over think the chain, at the end it is a consumable. Personally I would go for the KMC - it has a quick link which makes it easier to install/remove, the shimano may need a chain tool. Lastly when you do rid of the KMC you can keep the quick links for emergency uses if a chain link breaks in the future.

 

[Nigelnaturist]

Kmc, shimano chains tend to be cr*p any chain will rist if you get it wet and dont dry/ lube it

Quantify c*** as @evo456 all components on the drive chain are consumable items, chain, cassette and RD mainly then chain rings and finally the FD (FD's tend to last longer on triples), reason for this is most riding can usually be done on the middle ring, so less shifting another benefit is generally a straighter chain line and therefore less wear on the chain and cassette too, so if looked after everything on a triple should last longer than a compact double.

 

[silk186]

Thanks for all the advise, 32t + KMC it is