suitable cassette for 8 speed

monastery

I am going to upgrade my drivetrain for my 8 speed bicycle, with a view to enhancing its road performance. I have purchased a new 8 speed chainset (52-40-32):

http://www.chainreactioncycles.com/shim ... -prod40623

I have also purchased this chain:

http://www.wiggle.co.uk/kmc-x8-99-8-speed-chain/

I have decided on this cassette:

http://www.wiggle.co.uk/sram-pg850-8-speed-cassette/

However, I can't decide on which ratio. I live in Cambridge which is pretty flat, I am in reasonable shape and stay in high gears but I am no pro racer. I am more interested in improving speed than climbing hills.

The options for this cassette are:

11-28
11-30
11-32
12-23
12-26

From what I have read the 11 teeth options are not that beneficial. That leaves 12-23 and 12-26, with the latter being better for when you do have some hills to navigate, but having a narrower range has some other advantages. Does anyone have opinions as too whether I should go for the 12-23 or 12-26 cassette?

Many thanks

elderone

Personally and for no other reason I would go for the 12-26 because if you do come across hills it may be more useful than a 23.You say your more interested in speed so being slower up hills (on a 23) will reduce your average speed , as time lost going slower up hills can,t be got back.
Like I said, thats what I would do.

unixnerd

None of the above for me. You want as narrow a range as possible to minimise the gaps between gears. I'd keep the 11t as a 52x11 feels great with a good tail wind or a downhill slope. On my triple I run an 11-25 ten speed and it's great, 25 will get you up anything with a triple. So I'd search for a different cassette.

monastery

So the trade off is that with 12-26, the higher 26 cog is better for climbing hills, while the 12-23 cog means that you have more gear choices within an optimal but narrower range?

From what I have been reading only a few people can get any use out of the 11 cog. So the disadvantages as I understand it, is that with the 11-28 cog, there is a large gap between the gears and the 11 cog will give you a lower average speed (for mere mortals) than a 12 cog.

unixnerd

You won't use an 11t often, but when you can it's nice :-) Top gear on my Roubaix is 50x11 and on a nice downhill I often miss the 52x11 my Cannondale has, but you're going above 30mph and it's not often.

keef66

I have a 50/39/30 triple and a 12-25 10 speed cassette. I live not a million miles from you and I'm never thinking 'I wish I had another gear'. Most of the time I stay in the 39 chainring and use all the sprockets on the cassette.

So in your position I'd say go for the 12-26

akc42

I have only had my bike a few weeks (previous was hybrid with triple)

I have an 11-28 cassette with compact (50,34) chainrings. I have hills to climb which are 16% at the hardest and I cannot get up them completely seated - although once stood its not too bad. At the other end of the scale, I can get about 38 mph when I feel my cadence has maxed out at 50-11. I don't experience large gaps between the gears

For my current level of strength that appears to be about correct, but as I get stronger I would certainly feel that I needed a higher top gear. For me the solution would be to get bigger chainrings.

t4tomo

52-12 should high enough for most mortals not to spin out its pretty close to 50-11 which is standard "high" gear on a compact.

Given you have a low of a 32 up front vs 34 on a compact then the 23 will give you only a marginally higehr gear than a compact normal low of 34-25, which will be easily adequate for anything cambridgeshire throws at you. if you want a bit extra range if you go riding elsewhere in the Uk then go 12-26 as 32-26 should get you up anything, plus the gaps on a 12-26 aren't exactly massive you just have a couple of extra 2 cog jumps at the lower gears end. The sweet spot is still 1 cog jumps and you have 3 chainrings to play with to make sure you keep in the 1 cog jump range.

All the 11-XX cassettes are starting to get too many 2 and 3 cog jumps.

Mad_Malx

Forget the 11. Even pros seldom use much higher than a 52-12, and that's for high speed bunch riding and flat-out sprints. If 52x12 isn't low enough you need to practice higher cadence.
As others have said, 32x23 is likely low enough for anything in Cambs, but if you ever stray to the hills then the 32x26 is nice to get you up most stuff.

desweller

You've got a triple. No reason not to go for the 12-23 (unless you're using the bike for touring).

nevman

Agree .

andy_wrx

OP : You're right about the 11 - unless you are a strong rider on the flat with a stiff tailwind, or you race, you'd only use that in practice when bombing down a long hill
So you'd hardly ever use it and having it would mean you have bigger gaps in your remaining 7 gears - so go with the 12

Your triple is actually the classic 52-42-30, which I have on one of my bikes
Not sure about Cambs, but I rode in Suffolk last year and didn't find any hill where I (personally - ymmv !) needed the 30-tooth granny ring.
But it's there if you do go somewhere hilly, does give you the low options

So depends what you want - the 12-26 has a lower low gear but has bigger inter-cog gaps than the 11-23 : if it were me, and assuming flatter/rolling terrain rather than hilly, I'm more irritated by finding that the gear I want 'isn't there' and I have one up which is too high and one below, than I would be for having that low 30-26

And if you're buying your chainset at CRC, you do realise the cassettes are there than Wiggle, don't you ?