Bottom Bracket hits on 29ers

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    • #84910

      Somebody needs to help me out. I have been reading reviews of the Specilaized Stumpjumper FSR Comp 29 and there are several complaints about peddle hits and bottom bracket hits while riding over rocks/obstacles. So I start thinking it is an issue with that bike. I talked to Specialized and the guy I talked to said they just didn’t have the rear suspenion set up correctly. I read one that said the rider took the time to set up the rear and still was hitting.
      I looked at reviews of the Gary Fisher HiFi Deluxe and there were similar complaints from riders about peddle hit and BB hit. So I am wondering if this is an issue that some of them have? Or is it that people have an unrealistic expectation on what a 29er can do? Like it would happen on all 29ers. Some reviews don’t mention it as a problem at all? I am a little concerned because I am hesitant to spend $2500 with that doubt. Thanks for any info.

    • #84911

      How does someone hit their BB on anything? I have hit my bash guard on stuff… but BB? I don’t think the SJ 29 would be any different than any other bike. If i try and ride over something tall enough to make contact with a part of my bike…it makes contact. Is there a reason why the bike should not make contact with these objects?

    • #84912

      It’s likely that people are just overestimating the clearance of their 29er… 29ers aren’t magical – they aren’t gonna make you roll over EVRYTHING without contact.
      Like fat-boy says, if you ride over a rock/log that is just too big, you are gonna make contact.

    • #84913

      I have the exact bike your speaking of. I have an 09 Stumpjumper 29 comp, and I have not hit the bottom bracket on anything, yet that is !! The way I see it, with any 29er, you have 3" higher ground clearance on a same model bike with 26’s. I have hit my pedals a few times though, but that was cornering when I should have had them parallel, so that was my mistake. I am with the others. I guess it all depends on how gnarly your trails are 😬 I love me stumpy and have no regrets. Good luck !!

      PS: I only paid $1700 for mine at the LBS a few months back.

    • #84914

      There’s an incorrect assumption about 29ers floating around out there.

      "The wheels are larger so the frame must also be higher off the ground."

      Most people think that making a 29er bike is akin to simply putting big tires on your truck. Bigger tires=taller truck and higher center of gravity. While this might have described some of the very first 29er bikes, it’s a thing of the past on newer frames. Frame builders quickly recognized this issue and began altering the lengths and angles of the tubes and chainstays to lower the bottom bracket (BB) height. This also resulted in a lower center of gravity in relation to the wheel axles than that of a 26" bike. Most new 29ers have about the same BB height as their 26" brothers but some are actually a tiny bit [i:2wo7jzao]lower[/i:2wo7jzao] rather than [i:2wo7jzao]higher[/i:2wo7jzao] as assumed. I’d check the specs on the model you are looking at and compare it to your current 26" bike if you think it’s a frame design issue.

      It’s more likely though that it is a riding style issue. Leveling out your pedals over rocks is a much better way to prevent hits than going out and buying a higher bottom bracket. For the most part, you’ll hit the same rocks with your pedals if you are riding a 29er or a 26er.

    • #84915

      I believe a 29"er would have an extra 1.5inches of clearence not 3” as previously stated.

    • #84916

      Thanks for the info. That definately clears some things up. I have an 08 FSR Comp XC right now and the owners manual says the BB height is 321mm. The Specialized website says the 10 Stumpy FSR Comp 29 has a BB height of 338mm. So the 29er is 17mm higher. Not a huge difference but it is a bit higher. I have to say that I have had pedal hits all the time but I have only had a BB hit once. I guess the reviews made me a little uneasy is all.

    • #84917

      GoldenGoose is right – in general, 29ers should NOT have higher BB heights than 26ers. I guess the best advice is to test ride the bikes if you can to see how they feel. Oftentimes a higher BB can have adverse consequences on things like cornering and stability which is a big tradeoff.

      In the end, getting over rocks and logs of any size is all about technique. Check out this video we made a while back and you’ll see that if you’re doing it right, your crank height doesn’t really matter.

      http://www.singletracks.com/video/LogJump.mov

    • #84918

      The BB height of my Niner RIP 9 is 13" – pretty much exactly what I had on my old Trek Fuel. That is why 29ers are more stable – your center of gravity is lower with respect to the bikes.

    • #84919
      "Beaker" wrote

      The BB height of my Niner RIP 9 is 13" – pretty much exactly what I had on my old Trek Fuel. That is why 29ers are more stable – your center of gravity is lower with respect to the bikes.

      That and the gyroscopic effect of those big wheels spinning.

    • #84920

      My ’08 Specialized FSR Stumpy 29 has no higher BB than Any 26, No Lower either.

      The roports you are ready are probly a riding issue.

    • #84921
      Somebody needs to help me out. I have been reading reviews of the Specilaized Stumpjumper FSR Comp 29 and there are several complaints about peddle hits and bottom bracket hits while riding over rocks/obstacles.

      I could swear that when I was looking into buying my Specialized Sumpjumper I read some tech stuff on the specialized bikes that explained that the specialized bikes are built with a little lower bb’s in order to acheive a lower standover height.Just a characeristic flaw that is to be expected with those bikes.

    • #84922
      "steve32300" wrote
      Somebody needs to help me out. I have been reading reviews of the Specilaized Stumpjumper FSR Comp 29 and there are several complaints about peddle hits and bottom bracket hits while riding over rocks/obstacles.

      I could swear that when I was looking into buying my Specialized Sumpjumper I read some tech stuff on the specialized bikes that explained that the specialized bikes are built with a little lower bb’s in order to acheive a lower standover height.Just a characeristic flaw that is to be expected with those bikes.

      Steve, I think tyou are correct. I ride a stumpy. But I have no real issues with Pedal Banging

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