Using asymmetry to run 142mm hubs in Boost spaced Alternator dropout bikes- Mtbr.com
Results 1 to 7 of 7
  1. #1
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    1,391

    Using asymmetry to run 142mm hubs in Boost spaced Alternator dropout bikes

    I may be acquiring a Deadwood soon, and it has me thinking about the rear wheel setup. In doing so, I came upon an idea that seems to have some merit . . .

    Salsa is supposed to be making "Boost Reduction Plates" available soon so that boost spaced frames can be configured to run normal 142x12 wheels. Basically its two 3mm plates, one for each side, that mount between the frame and the dropouts. Easy enough. But it leaves your chainline more inboard and risks tire/chain interference on some crank/tire combos.

    But there is another option with those plates, albeit not intended by Salsa. It provides an opportunity for a zero-dish 142x12 rear wheel by offsetting the rear hub in the frame. Simply place both reducer plates on the non-drive side (offsetting the rear axle 6mm to DS), and also "un-dish" your rear wheel by 6mm toward the NDS (so wheel asymmetry cancels frame asymmetry) . You'd likely need longer bolts than those that will ship with the reduce plates, but that should be manageable.

    Why do this? Its one way to make good use of sort-of-becoming-obsolete 142mm spaced hubs/wheels, while still offsetting the chain sufficiently to clear 3" tires (ie, cassette is in same place as a Boost wheel). Gets most of the benefits of Boost (chainline spaced outboard, stronger wheel) without a new wheel.

    Especially on the Deadwoods and new Fargos, which have Boost rear and non-Boost forks, it could be a useful trick to utilize old wheels. Or folks buying Woodsmoke or Timberjack frames using their "old" 100x15 spaced Fox 34's and 142x12/100x15 wheelsets.

    I realize that rear triangle / wheel offset is not a new technique, but this seems like a novel way to achieve it where it wasn't intended.

  2. #2
    mtbr member
    Reputation:
    Join Date
    Dec 2007
    Posts
    79
    That is a novel solution. Since you are talking about moving the 3mm spacer from the DS to the non-DS you would only need to remove 3mm of dish. You may also need some longer hardware. Are there typically enough threads in a spoke to do that?

  3. #3
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    1,391
    Doh! You're right about the math, 3mm of "un-dishing" not 6mm.

    Of course it depends on how the wheel was built, but assuming it wasn't at the limit of spoke lengths, 3mm rim movement should be trivial. You can quantify it on a spoke calculator by changing the flange distances by +/-3mm. With a DT 350 142 hub and 600mm ERD rim, for example, the spoke lengths change by only 0.3mm (lNDS) and 0.2mm (DS). That's about 2/3 of a turn tighter for NDS nipples and 1/3 turn looser for DS nipples.

    PS: since its only 3mm, it won't get you to a dishless wheel if you have symmetric rims. But if you have an asymmetric rim with typical ~3mm offset, it gets you to a dishless wheel.

  4. #4
    mtbr member
    Reputation:
    Join Date
    Dec 2007
    Posts
    79
    More solid info! I like this idea a lot, as I am waiting for a Timberjack frame... I also have the calc's from my current wheelset saved in DT Swiss' online tool so that should be easy for me to validate. Thanks!

  5. #5
    mtbr member
    Reputation:
    Join Date
    Oct 2015
    Posts
    450
    Would you have to put the plates on the outside of the NDS Alternator dropout so that the caliper aligns with the rotor?

    There's also this: https://www.bikerumor.com/2015/12/31...2mm-rear-hubs/

    Pretty sure they're showing a Deadwood in the pics.
    2003 Kona A
    2005 Kona A
    2012 Cannondale Hooligan
    2016 Salsa Deadwood

  6. #6
    mtbr member
    Reputation:
    Join Date
    Dec 2007
    Posts
    79
    January, good to know. Thanks.
    Last edited by sean916; 12-09-2016 at 02:53 PM.

  7. #7
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    1,391
    Quote Originally Posted by buell View Post
    Would you have to put the plates on the outside of the NDS Alternator dropout so that the caliper aligns with the rotor?

    There's also this: https://www.bikerumor.com/2015/12/31...2mm-rear-hubs/

    Pretty sure they're showing a Deadwood in the pics.
    That color looks like a Deadwood but the dropout appears to be on the outside of the frame, which isn't Deadwood-y.

    There are various sources for the simple 3mm axle spacer rings, like those linked in the post above, on eBay. One of them also has a 6mm version to mount only to one side. Example: MTB Tools Adapter Set For a 12mm x 142mm Rear Hub to 148mm Boost Application | eBay That method is functional, but not nearly as elegant or robust as the Alternator reducer plates.

    The Salsa Alternator dropouts mount to the inside of the frame. So the "reducer plates" are 3mm thick and simply insert between the dropouts and the frame. This reduces the "OLD" distance by 6mm but (importantly) keeps the derailleur hanger and brake mount (which are part of the dropouts) in proper orientation to the wheel, so no caliper spacing or rotor spacing is necessary.

    The reducer plates QBP number is FS2360. Supposedly to be available early January.

Similar Threads

  1. Replies: 5
    Last Post: 03-13-2016, 06:57 AM
  2. WTB: Salsa Alternator Dropout(s)
    By rollingout in forum Salsa
    Replies: 2
    Last Post: 11-13-2015, 11:07 AM
  3. Replies: 29
    Last Post: 12-14-2014, 02:09 PM
  4. Replies: 7
    Last Post: 06-26-2013, 12:54 PM
  5. Alternator dropout position.
    By AUSTIN672 in forum Salsa
    Replies: 2
    Last Post: 06-10-2013, 12:35 PM

Members who have read this thread: 5

Posting Permissions

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

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2019 VerticalScope Inc. All rights reserved.