Drivetrain Advice

seph_16

Hi,

I need a bit of advice about my drivetrain options.

I've currently got an 8-speed 11-32 shimano rear cassette, and a rubbish SR suntour 3 speed chainset (not sure of the no. of teeth) up front. I'm bit by bit building a new bike up but need to work out my options.

I was looking to replace the lot with:

Rear cassette: 8 speed SRAM PG850
Chainset: Shimano XT M770 hollowtech 2.
Rear Derailleur: Shimano XT Shadow M772
Chain: SRAM PC870

The front derailleur (SRAM Jobbie) and shifters (shimano rapid fire, not sure what model) were replaced last year by my LBS , they both work perfectly and i'm really pleased with them, so they're heading over to the new bike.

My first question is, is the above lot compatible (especially the chainset, as it states for 9-speed), if not, what 8-speed compatible chainset would be recommended?

Secondly, am I better off switching the lot to 9-speed but that will require new shifters as well?

Thanks in advance, I'm sorry if it's not enough detail.

supersonic

It will all work together, no probs! 8spd chains are fine on 9sod cranks - only slight prob is thhat the front mech may rub a little in some gears.

9spd will allow you to go to the higher end Shimano stuff (and better made, lighter, and slicker). Its not just about the extra gear, its that Shimano stopped making top end 8spd stuff years ago.

seph_16

Hi,

That's great thanks! Am I right in thinking that if I choose to switch over to 9-speed in the future, all I need to change is the rear shifter, cassette and chain?

Thanks

seph_16

Also, I noticed you've got a more recent I-drive. The frame I'm switching over to is a 2003 I-drive 1.0. I can't work out where the cable runs for the front mech! I see it runs towards and under the I-drive and BB section, but then where does it go? I've looked on pink bike at other people's similar bikes but i can't see clearly enough. Surely it doesn't just rub on the bottom?!

supersonic

Once you have the new crank, yes, will just need shifter, cassette and chain. 9spd chains don't like really old 8spd chainsets, but 8 and 9spd chains are fine on 9spd chanisets.

There is a plastic cable guide under the frame!

seph_16

Ah, there's no guide there! (second hand frame)...

Any ideas where I can get one?

supersonic

You can just use a short section of cable outer, but they usually screw into the frame. Best to contact the importer, Hotwheels.