Instinct Bottom Bracket Height- Mtbr.com
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  1. #1
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    Instinct Bottom Bracket Height

    Thinking of buying an Instinct. Does anyone know the bottom bracket height? The website only describes drop. I called Rocky Mountain but they have not called me back yet.

    Thanks.

  2. #2
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    The BB height will depend on the tires you're using, since BB height is referenced to axle height on the wheel. The nominal 29" tire/wheel outer diameter is roughly 29.15" to 29.25" so half that is the reference for the BB drop, around 14.575" to 14.625".
    I'm a member of NSMBA and IMBA Canada

  3. #3
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    Quote Originally Posted by rockyuphill View Post
    The BB height will depend on the tires you're using, since BB height is referenced to axle height on the wheel. The nominal 29" tire/wheel outer diameter is roughly 29.15" to 29.25" so half that is the reference for the BB drop, around 14.575" to 14.625".
    Thanks. I guess I should have clarified by asking the BB height for the alloy with the spec tires. Are you saying the BB height or drop is around 14.5 inches? Because I seriously doubt the height is 14.5 inches.

    I like the bike and it's on my buy list, but I don't understand why I can't get this simple spec.

  4. #4
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    14.6" would be approx axle height, that's roughly 371mm. So the BB Drop is 36mm in the slack Ride9 setting and 23mm in the steep mode, so the BB height would be right around 13.1" (to the centre of the BB spindle) in the slack mode or about 13.7" in the steep Ride9 setting.

    But the net ready-to-ride BB height will depend on tire inflation and suspension sag. If you run 30% sag with 140mm travel, that will lower the BB height by 1.65" so that's going to be a net BB height between 11.45" slack to 12.05" steep.

    That's the main reason Rocky doesn't spec the BB height, there's so many variables (even without Ride9)
    I'm a member of NSMBA and IMBA Canada

  5. #5
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    Thanks. I spoke with Rocky Mountain today. The person I spoke with didn't have the answer either, but he said he would email me. Hopefully, we'll see soon. I'll report back.

  6. #6
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    Rocky Mountain got back to me. The Instinct BB height is 342mm (13.465") +/- 7mm depending on chip position.

    Thanks Rocky Mountain and Uphill.

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