What cassette do/should I have?

[DaveReading]

The spec for my tourer, when I bought it a couple of years ago, listed a Shimano HG31 11-32t (8-speed). My cassette does indeed have smallest and largest sprockets of those sizes, but as I found out when I was doing some sums on intermediate ratios, the other sprockets are somewhat unevenly spaced (11-12-14-16-18-21-26-32) and don't seem to match the published Shimano docs for any of their cassettes.

I can't see any obvious branding on the it, either Shimano or SRAM, but if it helps it has a black finish and most of the larger sprockets are rivetted together (though I'm about to split them to clean them properly). The spacing and appearance seem to match that of the SRAM PG820 (see www.bikeman.com/FW6187.html).

If I do go for a more evenly spaced 11-32t, the Shimano HG31, HG40 and HG41 all come in a 11-13-15-18-21-24-28-32t "aw" option. What's the difference between these three?

 

[RebornBumbler]

There's little point having close ratios in the low gears - all cassettes tend to have closer high than low ratios.

Whether you need to change can only be determined by you - it's dependant on the cadence you like to run, your usual terrain...
If you don't need higher ("spinning-out" while pushing on down hills) or lower (having to get off and walk going up them) gears than you have currently, don't bother.

Don't worry too much about the specific spread of the ratios.

 

[Rickshaw Phil]

The difference between the Shimano cassettes you've listed is in the material quality. The HG40 and HG41 will last longer and be slightly ligher than the HG31. I haven't tried them myself yet but a few folk on here believe the SRAM cassettes are better quality than their Shimano equivalents.

Personally, having looked a lot into gear inch calculations for my own bikes I'd prefer the SRAM ratios that you currently have if I was choosing an 11-32 cassette.

Although at a glance the Shimano ratios look more evenly spaced the 3 tooth jump from 15-18 is a big step (about 10 gear inches) right in the part of the cassette where you really want smaller jumps between gears for comfortable road cruising. (That's my view at least)

 

[oldfatfool]

You should move to CD's cassettes are hard to get hold of, of poor quality and very 1980's.



I'll get my coat

 

[I like Skol]

Are you sure you need an 11-32 cassette? If you don't then you could move to something like a 11-28 or 11-30 like THESE which will reduce the jumps between gears a little.

 

[DaveReading]

Are you sure you need an 11-32 cassette? If you don't then you could move to something like a 11-28 or 11-30

OK, I admit I'm a wimp - riding up Walbury Hill a few weeks ago I started wishing I had a 34t.

 

[Rickshaw Phil]

OK, I admit I'm a wimp - riding up Walbury Hill a few weeks ago I started wishing I had a 34t.

I can relate to that. If you really want (and if your rear mech will take it) 11-34 is available: link

 

[byegad]

I tend to prefer the 11-34 Shimano 9 speed cassette to the 11-32. Mainly because the 11-13-15 of the 11-34 is a nicer combination at the top end rather than the 11-12-14 of the 11-32. Bonus is you get a slightly lower bottom gear. I find 11-12 to be rather too small a gap.

 

[Kins]

+1 for the 11-34. Made a difference to hill climbing comfort.

 

[I like Skol]

OK, I admit I'm a wimp - riding up Walbury Hill a few weeks ago I started wishing I had a 34t.

I'm not trying to ridicule you. If the gear is there and you use it then it's good for you and you should stick with it. I was just putting forward the option that you don't have to maintain the OEM set up

 

[DaveReading]

I'm not trying to ridicule you. If the gear is there and you use it then it's good for you and you should stick with it. I was just putting forward the option that you don't have to maintain the OEM set up

No offence taken, in fact I'm I'm tending towards an 11-34t, which my current mech ought to be able to cope with.

Thanks for the advice, everyone.