Cranksets

nonnac85

Im thinking of getting a new crankset soon. Currently I have an entry level Truvativ 8sp set. I would like to keep an 8sp casette so does anyone know of any 8sp cranksets for up to about £60?
Maybe Im missing something but I cant find much information about compatibility from sites like CRC etc.
Either that or is it possible to use 9sp crankset with 8sp cassette - if so would i need an 8 or 9sp chain?
Thanks

toasty

Do you want to keep your current bottom bracket?

If not the new Hollowtech ones are a winner.

http://www.merlincycles.co.uk/?fn=product&productId=112&categoryId=12

Fitting is easy enough, requires a tool though. Assuming it's a cheaper/oldish frame it might need facing. Failing that I'd just get an Octalink Deore one, you could even pick up a new ES51 bottom bracket in that budget.

nonnac85

no not fussed about keeping current BB because its a powerspline and its pants - an identical replacement only costs £12!

toasty

What bike is it just out of interest? If the bottom bracket has been faced a hollowtech one would go well then. You can generally see if they're faced in the factory, on the outside edges of the bottom bracket shell there should be no paint. Perhaps not something you can spot with the old one in, I'm not sure

nonnac85

its a Spesh Hardrock 07 model

this is spec of current BB...
Truvativ Power Spline, cartridge bearing, 68 x 113mm for 47.5mm chainline

im not entirely sure what im looking for in terms of facing etc having never had a proper mtb to look after before!

supersonic

9spd cranks work fine with 8spd systems.

Octalink stuff is still very good value, and lasts a bit longer than HT2.

Length of axle depends on the chainset fitted: length of shell depends on your bike, ie 68mm.

nonnac85

Does the price make a difference to the quality of HT2 v octalink i.e. is a £37 Deore octalink like this better than an Deore LX HT2 at £50?(like this).

Also if I was to upgrade the BB would something like the Hope BB be compatible with octalink / HT2. It says it works with "all common systems" including Shimano but thats as far as detail goes.
Thanks

toasty

That's a Hollowtech BB, it'll be compatible with the Shimano Hollowtech crankset, these come with a bottom bracket anyway though.

If you want to go the Octalink route you'll need an Octalink BB, I use the Shimano ES51 on one of my bikes, along with the Octalink crankset. The one I linked is completely sealed, it should last for longer without needing any fiddling compared to the Hollowtech one, once it's dead it's dead though and you need to swap out the BB.

supersonic

Hollowtech label is confusing - it refers to the hollowcrank arms, which Octalink (the bottom bracket interface) can be hollowtech

Hollowtech 2 is the crank arms with an integrated bottom bracket axle, and external bottom bracket cups. This requires the frame to be 'faced'.

HT2 chainsets come with the bottom bracket. Octalink chainsets require the purchase of a octalink cartridge bottom bracket.

As Toasty says, the ES51 is a good buy for octalink, and will last longer than HT2. This is HT2s biggest bugbear, the poor lasting bottom brackets, and paying 50 quid for a new one to work in my eyes is ridiculous.

toasty

supersonic wrote:

Hollowtech label is confusing - it refers to the hollowcrank arms, which Octalink (the bottom bracket interface) can be hollowtech

Ah I see, that explains a few things

nonnac85

so basically the £37 Deore octalink is going to last longer than a £50 LX HT2 due to BB type?
Is there any substance in rumours on other sites about octalink being fased out?

Also im confused about Shimano numbering of cranksets - M530=£37, 531,540 and 540G all £34 on CRC
Lower the better?

Thanks for all the help so far!

dave_hill

supersonic wrote:

This is HT2s biggest bugbear, the poor lasting bottom brackets, and paying 50 quid for a new one to work in my eyes is ridiculous.

That's a pretty big generalisation.

Shimano did have some major issues with bearing quality with early HT2 cranksets, but later ones are much improved. I've known HT2 bottom brackets give up the ghost within 3 months, but my own Hone unit has lasted 2 years and over 2000 miles without any issues - it's still running as well as it was when I installed it and I haven't exactly been kind to it.

HT2 gives you more flexibility, as it is compatible with Race Face's X-type BB (which ARE rubbish, BTW) and FSA's Giga Pipe system. In addition, aftermarket HT2/X-type bottom brackets are also available from manufacturers such as Hope, Superstar, etc.

IIRC, only Shimano and Blackspire used Octalink, which is now rapidly loosing favour.

For the sake of £50, I'd say that an LX M582 chainset (which comes complete with the bottom bracket) from CRC is excellent value. If you're going to fit it yourself, you'll need the correct tools (£15 for the genuine Shimano set, again from CRC) and a quick trip to your LBS to get the BB shell faced.

andy83

i have deore octaling crankset and does me fine and im really happy with it, although my entry level crank on GT agressor was a bugger to get off