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  1. #1
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    1/2" taller BB height ?

    I have an 08' RFX and the current BB height sits a smidge below 14". I am toying w/ the idea of trying a 650b wheelset. The 650b / Neo-moto combo is 1/2" taller putting my BB height @ almost 14.5" - Anyone think this would upset my bikes geometry / handling ? Thanx

  2. #2
    TNC
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    We don't have many Turners around my area. Would you consider the RFX a little light in the front end with your current fork setup? You know...tries to lift on a climb or requires a lot of of front leaning body english for the front tire to bite? If not, you probably won't notice any loss in front end stability or traction. Now, I wasn't clear on your original statement, but if you're indicating that your RFX will take a 650B front and rear, then I don't think you'll have any issues. I have all the fixin's to do a rear 650B to match the front that is already on my '99 Bullit, but laziness has ruled for building the wheel up to this point. 14.5" for a long travel bike BB height isn't too crazy IMO. It seems the bulk of bikes talked about with 650B seem to be hardtails and shorter travel XC and trail bikes. Personally, I think the bigger impact of the 650B concept can be realized on long travel AM bikes where you get to retain 6 or more inches of travel with the tallest possible wheel/tire combo.

    keen, what kind of fork on your RFX?

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    Quote Originally Posted by TNC
    We don't have many Turners around my area. Would you consider the RFX a little light in the front end with your current fork setup? You know...tries to lift on a climb or requires a lot of of front leaning body english for the front tire to bite? If not, you probably won't notice any loss in front end stability or traction. Now, I wasn't clear on your original statement, but if you're indicating that your RFX will take a 650B front and rear, then I don't think you'll have any issues. I have all the fixin's to do a rear 650B to match the front that is already on my '99 Bullit, but laziness has ruled for building the wheel up to this point. 14.5" for a long travel bike BB height isn't too crazy IMO. It seems the bulk of bikes talked about with 650B seem to be hardtails and shorter travel XC and trail bikes. Personally, I think the bigger impact of the 650B concept can be realized on long travel AM bikes where you get to retain 6 or more inches of travel with the tallest possible wheel/tire combo.

    keen, what kind of fork on your RFX?
    Thinking about going 650b front and rear. Have a Pike up front... I know why not a Lyrik, 55, 36, 66 etc. I really like the Pike Dual Air and I also run a 2" rear shock for 5.6" of rear travel. I talked w/ someone @ Turner bikes and they thought 1/2" rise in BB height would really upset my bikes handling. My last few bikes, Bullit aside, had sub 14" BB heights. I used my Bullit for DH and had a 14.6" BB height which was great for lessening pedal strikes. The Bullit did feel like a slacked out high chair though . If I am going to drop $$ on a 650b wheelset I just want to make sure its all positive. I want to feel a noticable difference. I measured a 1/2" difference between a 26er 2.35 Nevegal and a Blunt Neo-moto combo.

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    TNC
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    Interesting. I would be curious to know if the person at Turner has ridden a 650B equipped bike to make that assessment or if they're just assuming such. You and I were/are Bullit owners and have definitely experienced a tall BB bike, and frankly I was surprised how the massively tall BB didn't result in a tippy bike. Yes, it felt tall...very MX dirt motor kind of tall...but not really sketchy on the trail. For me it was more of an issue of my 32" inseam than any handling issue. Sometimes I think many in the bicycle world gets a little stuck in the conventional approach when looking at things.

    That said, I think the beauty of the 650B concept is the fact that it doesn't go to the extremes of something like the 29'er concept which is huge. It just takes the conventional MTB wheel/tire setup to a level that maximizes height without making massive impacts in suspension design or geometry manipulation. Bike and suspension design has gotten so good that it will probably be subtle but positive incremental improvements in the basic equipment that moves MTB performance forward. We've been using the 650B setup at our shop for everything from XC racing to bigger hit AM applications. I would bet that if one could snap one's finger and turn every wheel and tire available into 650B instead of 26, no one would miss the 26'er. 650B would just represent the logical and biggest improvement that could be made without the relatively large change in design and equipment that the 29'er brings. Understand that I'm not slamming the 29'er concept whatsoever. It's a great size for the place it suits the rider and/or applications in which it is popular. I'm just saying that 650B is probably the size that would have been chosen for the modern era of MTB'ing if everyone had started with a clean sheet of paper. But we didn't, so there will obviously be resistance from a standpoint of manufacturing, existing marketing, and just the plain old issue of "fear of change". A lot of people comment that "if it ain't broke, don't fix it". We wouldn't be where we are now with the amazingly great MTBs we have now if we all lived by that concept.

    keen, I think if you bought a good 650B wheelset...tried it...didn't like it...that you'd have no trouble in selling it without a painful wallet hit. There are more and more people each day who are realizing the benefits of 650B, so I think you'd find an easy market to sell the wheelset...even in today's economy.

  5. #5
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    Did the folks at Turner know about the fork you are using and the fact taht you are using a shock that only gets 5.6" of travel out of the RFX platform?

    I doubt you'd notice that half inch increase out on the trail. But, with that said, are you sure there would be ample room for a 650b rear wheel with suitable tire (Neomoto) for the RFX? I don't think you'd ideally want to "compromise and run a Quasi Moto in back on the bike would you?

  6. #6
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    Quote Originally Posted by MMcG
    Did the folks at Turner know about the fork you are using and the fact taht you are using a shock that only gets 5.6" of travel out of the RFX platform?

    I doubt you'd notice that half inch increase out on the trail. But, with that said, are you sure there would be ample room for a 650b rear wheel with suitable tire (Neomoto) for the RFX? I don't think you'd ideally want to "compromise and run a Quasi Moto in back on the bike would you?
    Turner was aware of my combo. They really discouraged running a BB height taller than 14" . I am really into large volume tires so anything less than the Neo-moto would be a buzz kill.

  7. #7
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    Quote Originally Posted by keen
    Turner was aware of my combo. They really discouraged running a BB height taller than 14" .


    RFX's are (and have always been) listed above 14" BB height on the Turner website. Weird.
    Extreme stationary biker.

  8. #8
    TNC
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    geo, I think he mentioned something about running a sub-OEM length/travel rear shock and a Pike fork which I'm guessing contribute to the listed BB height he stated.

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    Quote Originally Posted by TNC
    geo, I think he mentioned something about running a sub-OEM length/travel rear shock and a Pike fork which I'm guessing contribute to the listed BB height he stated.
    Ah, of course....with the reduced travel, the sag will also be reduced, leaving an overall higher BB.
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  10. #10
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    Quote Originally Posted by geolover


    RFX's are (and have always been) listed above 14" BB height on the Turner website. Weird.
    I mentioed a 14.5" BB height to Turner and that was too high in their opinion. My current BB height is 13 7/8" . My Pike's a-c height is 520mm vs. 535mm Turner spec. - less than a 1/4 " from stock. I am going to try a 650b up front then both if the front feels ok.

  11. #11
    TNC
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    Quote Originally Posted by geolover
    Ah, of course....with the reduced travel, the sag will also be reduced, leaving an overall higher BB.
    LOL!...sorry, geo...I thought your comment was about the "stock" BB height compared to his current setup...fuzzy internet perception on my part.

  12. #12
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    Quote Originally Posted by TNC
    LOL!...sorry, geo...I thought your comment was about the "stock" BB height compared to his current setup...fuzzy internet perception on my part.
    No apologies necessary...your perception was spot on...I WAS considering the stock geometry. My response to you was my "ah-ha!" moment. I get it now.
    Extreme stationary biker.

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