Results 1 to 11 of 11

Thread: 4" FS 650b

  1. #1
    Moderator Moderator
    Reputation:
    Join Date
    Jan 2004
    Posts
    3,833

    4" FS 650b

    Just thought folks might like to see the first FS 650b bike I've done - this was finished about a month ago for my friend Martin, who is really happy with it. Ventana 650b specific rear end (~435mm chainstays), Notubes 355 rims/DT hubs, lots of fancy XT (brakes, cranks, derailleur) and XTR (shifters, pedals, derailleur) and 4" front and rear suspension provided by Fox (at bottomout with no air in the chamber, the F100 fork crown just barely clears the tops of the knobs on the Neo-Moto). The frame is True Temper OX Platinum and weighs about 6 pounds with the RP23.

    The whole bike weighs about 26.5 pounds with the big 2.3 tires, and would probably be close to a pound lighter with the newer 2.0s, but those big guys are just too much fun so he has no immediate plans to swap.

    I haven't personally ridden the bike, as it's unfortunately WAY too small for me, but Martin assures me that he notices a significant difference between his old 26" wheels and the 650b setup.

    In any case, kudos to Ventana for jumping in with both feet and making this rear end. The lateral stiffness on the quad bearing setup is awesome, IMO, and it's much better than futzing around with a 29er rear end or trying to stuff the wheel into a 26" setup.

    -Walt
    Attached Images Attached Images
    Waltworks Custom Bicycles
    Park City, UT USA
    www.waltworks.com
    waltworks.blogspot.com

  2. #2
    Only dead people are old
    Reputation: Super E's Avatar
    Join Date
    Nov 2004
    Posts
    619
    That is so sweet! I'm drooling all over with racing thoughts of riding one...

  3. #3
    mtbr member
    Reputation: MMcG's Avatar
    Join Date
    Jul 2003
    Posts
    9,024
    That is one sexy bike! I really like the aggressive slope of the top tube Walt! Well done!

  4. #4
    slow up hill
    Reputation: sennaster's Avatar
    Join Date
    Sep 2006
    Posts
    424
    want

  5. #5
    Sail On!
    Reputation: Waterat Pat's Avatar
    Join Date
    Mar 2007
    Posts
    237
    It sure is nice to see an XC 650B FS bike. I noticed you shortened up the head tube a bit like a 29er. Well done. Can we get some geometry for that baby?

  6. #6
    Moderator Moderator
    Reputation:
    Join Date
    Jan 2004
    Posts
    3,833

    Sure...

    Here are the basics (all numbers are without sag)
    Toptube: 56cm (22") effective
    HT: 70.5 degrees, 90mm long
    ST: 73.5 degrees, 42cm center-top
    BB: 20mm drop
    Chainstays: 435mm
    Trail: 85mm

    If there's something more esoteric you'd like to know, just aks. It's really just a straightforward XC geometry.

    -Walt

    Quote Originally Posted by Waterat Pat
    It sure is nice to see an XC 650B FS bike. I noticed you shortened up the head tube a bit like a 29er. Well done. Can we get some geometry for that baby?
    Waltworks Custom Bicycles
    Park City, UT USA
    www.waltworks.com
    waltworks.blogspot.com

  7. #7
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    335
    Looks like a great bike. Can't wait to hear the ride report.

    And Walt, what do you charge for one of these babies?

  8. #8
    mtbr member
    Reputation:
    Join Date
    Apr 2007
    Posts
    48
    Quote Originally Posted by Walt
    Just thought folks might like to see the first FS 650b bike I've done - this was finished about a month ago for my friend Martin, who is really happy with it. Ventana 650b specific rear end (~435mm chainstays), Notubes 355 rims/DT hubs, lots of fancy XT (brakes, cranks, derailleur) and XTR (shifters, pedals, derailleur) and 4" front and rear suspension provided by Fox (at bottomout with no air in the chamber, the F100 fork crown just barely clears the tops of the knobs on the Neo-Moto). The frame is True Temper OX Platinum and weighs about 6 pounds with the RP23.

    The whole bike weighs about 26.5 pounds with the big 2.3 tires, and would probably be close to a pound lighter with the newer 2.0s, but those big guys are just too much fun so he has no immediate plans to swap.

    I haven't personally ridden the bike, as it's unfortunately WAY too small for me, but Martin assures me that he notices a significant difference between his old 26" wheels and the 650b setup.

    In any case, kudos to Ventana for jumping in with both feet and making this rear end. The lateral stiffness on the quad bearing setup is awesome, IMO, and it's much better than futzing around with a 29er rear end or trying to stuff the wheel into a 26" setup.

    -Walt
    Awesome bike Walt!
    The thing i don't like in Ventana bikes is that the main pivot of the rear end is too low, too close to the BB. A slightly higher pivot would perfectly mate with a Sclumpf Speed Drive, or a Schlumpf Triebwerk or a Truvativ Hammerschmidt.
    Walt, what do you think about that? is a higher-main-pivot/Schlumpf (or Hammerschmidt) combo a viable configuration?

  9. #9
    Moderator Moderator
    Reputation:
    Join Date
    Jan 2004
    Posts
    3,833

    I actually built one...

    I have just such a frame in my shop now, but I screwed up the shock mount position and have to fix it before it sees the light of day. Pivot is about an inch higher than the Ventana standard, for a more rearward/neutral axle path. It's otherwise almost identical geometry to the bike pictured (2cm shorter seat tube being the only difference) - intended to be a travel bike (no derailleurs to worry about when packing) since it's easy to unbolt the rear end and put it into an S&S travel case.

    Of course, with this pivot position you cannot use a front derailleur. I may install an ISCG setup to use a Hammerschmidt, or just do a Rohloff.

    The unfortunate thing (beyond me realizing *after* powdercoating that the shock mount wasn't right) is that it was for my wife, who has decided full suspension is (in her own words) "for sissies" and no longer wants it. So I'm trying to decide what to do with it now. If anyone is interested in such a bike (at a significant discount), feel free to drop me a line to discuss.

    -Walt
    PS In general I agree with you on the pivot position on Ventanas, but for lower travel (ie, 4" or less) I've found that the slightly forward axle path doesn't bother me at all. The rear end feels very plush, IMO. I've had rave reviews from customers, as well. Might be a different story for DH or freeride apps, but then again I do a different design for those situations.


    Quote Originally Posted by lavolpeeluva
    Awesome bike Walt!
    The thing i don't like in Ventana bikes is that the main pivot of the rear end is too low, too close to the BB. A slightly higher pivot would perfectly mate with a Sclumpf Speed Drive, or a Schlumpf Triebwerk or a Truvativ Hammerschmidt.
    Walt, what do you think about that? is a higher-main-pivot/Schlumpf (or Hammerschmidt) combo a viable configuration?
    Waltworks Custom Bicycles
    Park City, UT USA
    www.waltworks.com
    waltworks.blogspot.com

  10. #10
    Moderator Moderator
    Reputation:
    Join Date
    Jan 2004
    Posts
    3,833

    $1900

    $1900, custom geometry and color, including an RP23.

    More info on the website, of course.

    -Walt

    Quote Originally Posted by Rideon
    Looks like a great bike. Can't wait to hear the ride report.

    And Walt, what do you charge for one of these babies?
    Waltworks Custom Bicycles
    Park City, UT USA
    www.waltworks.com
    waltworks.blogspot.com

  11. #11
    ride more
    Reputation:
    Join Date
    Mar 2007
    Posts
    2,658
    hey! thats my dream bike...............

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •