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  1. #1
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    AM BB height what's considered tall / too tall ?

    Seems like a lot of riders like low BB heights for better handling. My current ride just measured 14.5" - it started @ 13.8" but w/ taller tires & a longer front fork it increased. I can feel that extra 1/2" and wonder if it is an easy adjusment ??? Thanx

  2. #2
    MattSavage
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    I like a taller BB height... Less pedal smacks more chainring clearance. 14.5" is probably fine as long as you're HA isn't too slack as a result of that taller fork.
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  3. #3
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    There's a lot of personal preference there. I like a low BB. My current bike is right around 13.75", and I wish it was lower. I can deal with having to ratchet a bunch to avoid pedal strikes, and like the low BB for handling. I may try to lower my fork a little more, and see if I don't mind the steeper head angle.

  4. #4
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    What are you riding now Zeb?
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  5. #5
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    Quote Originally Posted by SJensen
    What are you riding now Zeb?
    08' Turner RFX 140mm travel F&R, 650b wheels. Think I am going to go 29er in the near future - no more smallness.

  6. #6
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    What frame are you going to go with for the 29" wheels?
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  7. #7
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    Quote Originally Posted by Bikinfoolferlife
    What frame are you going to go with for the 29" wheels?
    Niner RIP 9, Turner Sultan would be my first 2 choices... used to save some $$$.

  8. #8
    FM
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    BB height doesn't tell you anything useful without considering amount of suspension.
    12.5" is a pretty tall height for a hardtail with a 4" or less fork.
    But that same height is on the low side for a suspension bike with 4-5" of travel.

    14.5" on a 6" bike isn't bad, with or without 650b wheels.... (I've had several 6" bikes with 14.5" BB's)...good for technical climbing, big chunk and ledgy rollers. However a lower bike with less travel can definitely be more fun on smoother faster trails. Just my .02c based on bikes I have owned....

  9. #9
    Hmmmmm
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    It's all personal.
    My 06 San An has a very high BB of about 15", but it works good for where I ride. We have lots of off camber rock and tight single track.
    It doesn't carve corners as well though.
    It's also got 6" travel, so when it sags it isn't as high as one would think.
    It's still a fast bike, just not as fast as something you'd be racing on in the downhill direction.
    It's loads of fun. It's kinda like a two wheeled Jeep. It's high off the ground, with a short wheelbase, so it turns tight hairpins with ease and pedals over all kinds of crap.
    14 - 15" is good for a 6" trail bike around here.
    If I was riding smoother, faster, single track, then I'd want something lower.
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  10. #10
    Bicyclochondriac.
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    Quote Originally Posted by FM
    BB height doesn't tell you anything useful without considering amount of suspension.
    12.5" is a pretty tall height for a hardtail with a 4" or less fork.
    But that same height is on the low side for a suspension bike with 4-5" of travel.
    .
    Exactly!

  11. #11
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    I guess the DH'er in me probably feels different then most, but I can't imagine liking a 14.5inch BB on a 6 inch bike. My 8 inch glory had a 14.5 BB with 175mm cranks, and striking my cranks was never a worry. It was way too high. Now I'm at 13.7 with 8 inches of travel and I love it. I guess I do strike pedals/cranks a bit now, but who cares. I donno, 6 inches? I feel like 12.8-13.5 depending on where I'd be riding would be a pretty ideal range for me!

  12. #12
    eBiker
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    IMHO, BB height is the rough equivilent of riding "in" the bike or riding "on" the bike.

    Which, I guess, would be personal preference, but for me "in" the bike = railing turns and increased stability in almost all situations due to a lower center of gravity.

    For me 14"+ = "on" the bike, 13" and below = in the bike. How is that for oversimplification

    P

  13. #13
    Hmmmmm
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    It depends on the amount of rocks and other things that might be embedded in the trails you ride.
    Around Bootleg, many riders I've talked to say they like a taller BB height, because we have of a lot of embedded rock that results in pedal and ring strikes.
    Otherwise I'd rather be "in the bike" instead of "on the bike".
    Also in my case, I'm 6' 1" tall and 200 lbs fully geared up, so the height of CG is relative.
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  14. #14
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    As a larger rider, 200 lbs, I bob and wallow a bike more than the average size rider while pedaling over rocks, roots, and eroded trail and so I get more pedal clearance problems than the average rider. Having a slightly higher BB, about inch higher than common these days really makes a big difference in clearing pedal strikes for me.

    I’ve found I like a 12.5 inch BB height or more when I’m on the bike and travel is at sag. For example with a 4 inch travel bike using 25% sag I like a 13.5 inch BB height so at sag it is 12.5. And my current 5.5 inch travel bike using 650b wheels with about 30% sag (about 1.75 inches sag) makes an ideal for me 13.75 BB height (topped-out) and 12.5 inch when sagged.

    I’ve experimented with even higher BB height when sagged, up to 13 inches sagged, but found no additional pedaling benefits and so I added more sag when riding such a high BB to keep my weight center from becoming awkwardly higher than about the 12.5 inch sagged BB height that is optimum for me.

    I wish there was an easy way to adjust BB height without affecting suspension travel and handling geometry. If a larger BB shell and adjustable asymmetrical BB housing were standard for bikes, such as single speed BB’s, it would give riders the option to adjust BB height for conditions and preferences (also effective seat angle). Of course such an adjustable BB height would slightly alter suspension anti-squat performance from the low to high adjustment, but a good suspension designer could deal with it.

  15. #15
    Bicyclochondriac.
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    Quote Originally Posted by derby
    As a larger rider, 200 lbs, I bob and wallow a bike more than the average size rider while pedaling over rocks, roots, and eroded trail and so I get more pedal clearance problems than the average rider.
    I don't think the issue is that you are 200lbs, I think it is because you run your suspension soft. Aren't you running a soft spring in your Pike?

  16. #16
    Hmmmmm
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    Body weight is definitely an issue, even if the bike is sprung correctly for a person's weight.
    I used to be over 230 lbs and now I stay between 185 and 195.
    I'm having a lot easier time riding technical terrain at the lighter weight.
    "I thought of that while riding my bike."
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  17. #17
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    Quote Originally Posted by derby
    As a larger rider, 200 lbs, I bob and wallow a bike more than the average size rider while pedaling over rocks, roots, and eroded trail and so I get more pedal clearance problems than the average rider.
    Sounds more like a poorly designed/set up suspension than a weight problem.

  18. #18
    arc
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    Quote Originally Posted by D34ThL0rd69
    Sounds more like a poorly designed/set up suspension than a weight problem.
    Its easy to throw more spring at shocks and forks, but getting more compression and rebound damping to match the new spring rate is the hard part.

    Derby had a good point about bottom bracket height, talking about static BB height doesn't tell you much if you don't account for sag.

    It's good to run a tall BB if you do much night riding, the stuff guys ratchet over in the daytime will smash toes once it gets dark.

  19. #19
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    Quote Originally Posted by kapusta
    I don't think the issue is that you are 200lbs, I think it is because you run your suspension soft. Aren't you running a soft spring in your Pike?
    Yes, I do tune to use full travel when I ride. I run softer sprung suspension than most riders I guess. My interests are tight slower rough single tracks trails near home and when I travel I go to slower rock crawling trails, Moab, Goosberry Mesa, Arizona, etc. I'm getting too old to really push bigger jumps or riding as fearless as when younger to use firm suspension springs full time.

    I never feel harsh bottom out so I'm not under sprung. When I do get in higher ride speed or more step up and down big rock (and wallow) situations I can compensate by adding a few clicks of compression damping. It's not optimum for those rare situations for me, a step up in spring rate would balance better, but firmer compression damping works pretty well to stabilizes the high speed handling for those temporary situations, especially now using PUSH'd forks and shocks.

    BTW, I sold the Pike (a great fork!) and went to a rare 160 - 130mm wind-down travel Nixon Elite coil and really like the slacker handling options for some situations, especially in the desert or long downhills. I miss the stiffer Pike, having a little less stiction too with it, and am looking for a good used Lyric U-turn coil. For my ride interests I wish the Pike was 160 - 130mm, I think it's plenty stiff, I guess the Lyrik is another pound heavier.
    Last edited by derby; 03-14-2009 at 12:45 PM.

  20. #20
    ay Diablo!
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    Quote Originally Posted by derby
    BTW, I sold the Pike (a great fork!) and went to a rare 160 - 130mm wind-down travel Nixon Elite coil and really like the slacker handling options for some situations, especially in the desert or long downhills.
    Derby,

    At your weight I would think you would need a stiffer spring then the stock Nixon spring. I have the exact same fork and love it, but weigh 160 lbs. I heard that finding the stiffer spring for the 160mm Nixon is difficulty, just wondering where you found one for future reference.

    To stay on topic, I like a taller BB ht, I'm in southern Nevada and spend a lot of time in southern Utah and perfer the higher BB for pedal clearance. I'll also like a more slack HA.

    Bunk
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  21. #21
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    Quote Originally Posted by farmboybunk
    Derby,

    At your weight I would think you would need a stiffer spring then the stock Nixon spring. I have the exact same fork and love it, but weigh 160 lbs. I heard that finding the stiffer spring for the 160mm Nixon is difficulty, just wondering where you found one for future reference.

    To stay on topic, I like a taller BB ht, I'm in southern Nevada and spend a lot of time in southern Utah and perfer the higher BB for pedal clearance. I'll also like a more slack HA.

    Bunk
    The Nixon Elite firm springs are impossible to find, I tried tried to find one for a few weeks before mounting it on my bike and before I found out I lucked out when I bought my Nixon Elite 160 - 130 wind down coil. I found out after buying the fork it came with a firm spring kit in it for a guy 30 lbs heavier than me. But even with the firm spring set at 140mm height the Nixon still has a little more plush compliance than my Pike with the softest spring! I could never bottom the softest spring in the Pike even using lighter damper oil but I can occasionally bottom the Nixon with the same sag and travel. I got my fork in unused condition on ebay from a private seller.

    In my opinion BB height preference is personal and, like steering head angle preference and spring weight preference and bike preference, it depends on what you are used to and what kinds of rides are most important.

    When I'm slow climbing in the lowest granny gears I hate loosing precious momentum back-pedaling or grunting to spin faster approaching every rock, step-up, or rut to be able to back-pedal if needed to "time" pedal clearance. I guess if I was a much faster climber or climbed smooth trails all the time I'd want a low BB too. With a 1/2 inch higher BB than common I still have to back-pedal and time some step ups for sure, but far, far fewer times.

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