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  1. #1
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    Help on installing my crankset

    Alright...

    I have sitting here, a SRAM PC991 chain, a Shimano HG70 cassette, and Race Face Evolve DH X-type. All brand spanking new. The bike is the 2005 Fisher Tassajara 19" frame.

    This is my biggest project to date. I installed mechanical disc brakes (Avid BB7) and replaced some spokes in my rear wheel. So. I'm replacing the crankset and the whole thing because it's acting up (and I've tried to be nice to it, but stuff happens)

    I'm looking at the instructions for the crankset, and I need some help understanding.
    here's the statements.

    1. FRAME PREPARATION (CRITICAL):
    a) BB shell threads must be chased after welding to ensure good alignment between opposing ends of BB shell.
    b) BB shell must be face milled on both sides after paint to ensure flat parallel bottom-out surfaces for BB cups to mate with.
    c) CRITICAL!!! BB shell width tolerance after face milling must be:
    68mm shell = 65.25mm-68.25mm
    73mm shell= 72.25mm-73.25mm

    What is "chased" ?? shouldn't the frame be good to go?
    face milled? what? is this like sanding the metal?
    Bottom-out? HUH?

    I don't understand. The bike already has the Bontrager Select cranks on it... and should be just fine for replacing, correct?

  2. #2
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    If it ain't broke....

    Don't fix it! My guess is that the instructions you are reading imply that you are installing the cranks on a brand new frame. More than likely the chasing and milling they reccommend was done to your frame when your bicycle was originally built. I say take the old cranks off and install the new ones without consideration to chasing or milling as described in the instructions.

    Just my 2 cents.

    Bob
    'If Wal-Mart sold parachutes, who would jump?' Frank Havnoonian (quoting his father) Drexel Hill Cyclery

  3. #3
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    Reputation: Guyechka's Avatar
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    Ok, so here is what I have learned from having an Atlas x-type for a year:

    There's a 99.9% chance that you don't need to worry at all about chasing the BB shell, since a crank was already installed previously. If there is any paint on the shell where the cups would meet it, then you want to take it to the LBS.

    Spacers on the X-types are the most confusing thing to understand--until you install them once and it all makes perfect sense. I'm supposing you bought the proper tool for the X-type BB. If your BB shell is 68mm, then two big black spacers go on the drive side and one big black spacer goes on the non-drive side. If your BB shell is 73mm, then one big black spacer goes on the drive side, and no spacer goes on the non-drive side. Then you have these little black spacers (I think they are 1mm wide). Those go on the axle. It doesn't matter where you put them, just so long as you put them on somewhere. They are meant to adjust the chainline, but without them you won't get the crank to seat properly. That is, you can put them both on one side or one on either side, but it still means that the axle length is going to be the same.

    Finally, when you crank down that bolt, you must crank it down until it bottoms out--meaning you absolutely can not turn it any further. Once finished, spin it around and it should spin freely. There shouldn't be any play at all if you grab a crank arm and yank it back and forth.

  4. #4
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    I do belive the university bike shop has the spline tool.

    So, on the non-gear side crank, it came with the big axle thing and 4white spacers and 1 black spacers flush up against the crank. Then there is also one black spacer on the other end of the axle.
    These are all very thin.

    On the BB, there are 3 thicker black spacers. I have no idea what size my BB size is. The current BB on it states 68mm and 73mm compatible, as does the specifications sheet for the Bontrager Select cranks.

    Is my best bet to just measure it?
    Also, what does "E-type" mean?
    Last edited by J Macker; 02-09-2006 at 11:50 AM.

  5. #5
    Your bike is incorrigible
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    Quote Originally Posted by J Macker
    I do belive the university bike shop has the spline tool.

    So, on the non-gear side crank, it came with the big axle thing and 4white spacers and 1 black spacers flush up against the crank. Then there is also one black spacer on the other end of the axle.
    These are all very thin.

    On the BB, there are 3 thicker black spacers. I have no idea what size my BB size is. The current BB on it states 68mm and 73mm compatible, as does the specifications sheet for the Bontrager Select cranks.

    Is my best bet to just measure it?
    Also, what does "E-type" mean?
    Yep, either go to Fisher's website and look for the specs or measure the BB yourself. Those three black spacers that fit onto the BB are the ones you need to worry about first. You will use either all three (if you have a 68mm shell--two on the drive side/ one on the non-drive side) or just one (if you have a 73mm shell--one on the drive side/ none on the non-drive side) Check the instructions that came with the crank. There is a picture showing installation of the BB, including the spacers. Bellow that pic should be a chart telling you how many spacers on what side you should be using for each BB width. You just have to remember that one more spacer goes on the drive side than on the non-drive side.

    I forgot to mention the "spacers" that fit into the crankarm where they join the axle. (On mine, they are red.) They fit in a little groove at the base of each arm, and, when seated in the groove, are flush with top of the little groove. They are slightly thicker than the other spacers. They should already be in the crankarms, but they could have fallen out shipping/handling.

    E-type is a derailleur that fits onto the BB, between the shell and the cups. That is, it doesn't clamp onto the seat tube. If your current derailleur is clamped onto the seat tube, then it's not an E-type.

  6. #6
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    Holy cow. The difference between the cranksets is NIGHT & day.
    Simply amazing!
    Probably the best money I've spent on my bike yet!

    Thanks for the input guys!
    I installed everything just fine, and all is great!

  7. #7
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    Excellent news!

    Glad to see you got it installed and you're up and running. Enjoy it.

    Bob
    'If Wal-Mart sold parachutes, who would jump?' Frank Havnoonian (quoting his father) Drexel Hill Cyclery

  8. #8
    Your bike is incorrigible
    Reputation: Guyechka's Avatar
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    Quote Originally Posted by J Macker
    Holy cow. The difference between the cranksets is NIGHT & day.
    Simply amazing!
    Probably the best money I've spent on my bike yet!

    Thanks for the input guys!
    I installed everything just fine, and all is great!
    Yeah, ok, now you can try explaining the installation next time.

    When you've done it once, it seems really obvious, but it's so damned difficult to explain all the different spacers.

  9. #9
    Meh.
    Reputation: XSL_WiLL's Avatar
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    Quote Originally Posted by J Macker
    Alright...

    I have sitting here, a SRAM PC991 chain, a Shimano HG70 cassette, and Race Face Evolve DH X-type. All brand spanking new. The bike is the 2005 Fisher Tassajara 19" frame.

    This is my biggest project to date. I installed mechanical disc brakes (Avid BB7) and replaced some spokes in my rear wheel. So. I'm replacing the crankset and the whole thing because it's acting up (and I've tried to be nice to it, but stuff happens)

    I'm looking at the instructions for the crankset, and I need some help understanding.
    here's the statements.

    1. FRAME PREPARATION (CRITICAL):
    a) BB shell threads must be chased after welding to ensure good alignment between opposing ends of BB shell.
    b) BB shell must be face milled on both sides after paint to ensure flat parallel bottom-out surfaces for BB cups to mate with.
    c) CRITICAL!!! BB shell width tolerance after face milling must be:
    68mm shell = 65.25mm-68.25mm
    73mm shell= 72.25mm-73.25mm

    What is "chased" ?? shouldn't the frame be good to go?
    face milled? what? is this like sanding the metal?
    Bottom-out? HUH?

    I don't understand. The bike already has the Bontrager Select cranks on it... and should be just fine for replacing, correct?
    For x-type bbs, having a completely flat surface for it to push flushly against is very important. That's why the frame needs to be chased. It removes any imperfections in the material or paint.

    Bottom-out is when you run out of threads.

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