Forum home Mountain biking forum MTB workshop & tech

Quick questions on fitting Hope BB and XTR M970 Cranks

dan1502dan1502 Posts: 568
edited October 2010 in MTB workshop & tech
I've just removed my raceface evolve crankset and BB (despite having the wrong crank puller but managing to improvise!) and am about to fit the Hope external BB. I don't have any instructions and the crankset isn't due to arrive until the morning. Anyway, my first question is am I correct in thinking there should be two spacers on the drive side and one on the non-drive side? The pdf diagram from the Shimano website shows this configuration as does the parktools guide but they are using a Shimano XTR bottom bracket. My guess is I should do the same but I want to be sure.

Secondly, my frame had an external BB fitted already from the factory. Looking at the edge of the frame where the BB fits in it has paint on it still. Do I need to get it faced or will it be ok as it is?

Just by way of feedback, the x type BB bearings seem to be ok but on one side the plastic shield had a bit cracked off and missing which seems to have resulted in a bit of corrosion where the bearings run on the axle but nothing that won't polish off.

I'm doing the job now so a quick response would be fantastic.

Thanks
Santa Cruz Tallboy

Posts

  • nicklousenicklouse Posts: 50,675 Lives Here
    if your BB shell is 68mm then yes.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • dan1502dan1502 Posts: 568
    I'll double check.
    Santa Cruz Tallboy
  • dan1502dan1502 Posts: 568
    It's 73 mm so one on the drive side then I guess?
    Santa Cruz Tallboy
  • dan1502dan1502 Posts: 568
    I'm pretty certain about the spacer now but what about facing? Should I worry about it or not? Like I said, there was an external BB fitted by the factory but the surfaces are still painted.
    Santa Cruz Tallboy
  • nicklousenicklouse Posts: 50,675 Lives Here
    if you have a good LBS get them to check it and do it if needed.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • dan1502dan1502 Posts: 568
    Ok, I'll have to see how quickly they can look at it and get all the other jobs done in the meantime. It's tempting not to bother but I will try and resist!
    Santa Cruz Tallboy
  • Interesting reading this, hope you haven't sorted and dumped this topic, reason being I bought a new bike a few days ago and removed the cheap Shimano SLX cranks and replaced them with my Truvativ Noir cranks off my old bike with a brand new hope BB.

    First ride today made it very obvious that my chainline is actualy out of line! My BB shell on the frame is 73mm so I put one of the spacers each side after installing the hope adapters, which you have to use with GPX cranks. Once I started having shifting problems I stopped and; visually just looking down on the chainline I could see things are not in line, when in the big ring front - small cassette ring rear (i.e. top gear) it was obvious the big ring was too far away from the BB. I need two spacers to install the cranks correctly (tight) but am going to move both spacers to the non drive side currently one each side) to move the crank rings closer to the BB which I think is the problem (i.e. too far away). All that said (sorry for the length of this) I would be very happy to hear from anyone who knows shed loads better than I do. Cheers. Ian
  • nicklousenicklouse Posts: 50,675 Lives Here
    rockandrollsuicide

    73mm BB and GPX you do not use two spacers.

    you do not use any spacers. this is just to stop the seal/bearing from being crushed.

    GPX is not the same as HT11 set up.

    as it says in the GPX manual

    http://www.sram.com/_media/techdocs/95- ... nksets.pdf
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
Sign In or Register to comment.