power loss. need help- Mtbr.com
Results 1 to 8 of 8
  1. #1
    mtbr member
    Reputation:
    Join Date
    Jul 2017
    Posts
    833

    power loss. need help

    i have sram 746 hubs on my specialized stumpjumper

    rebuilt them over the winter as the bearings like to fail. on these hubs
    note: did not rebuild the xd driver

    is it my imagination? every once in a while the pedalling effort becomes so much easier. eg. familiar trail ride. shift into the straightest chainline on the cassette and boom the effort frees up. not every time.

    today i went out for a 30km ride and when i started, i knew it was going to suck, as you could feel that pedalling effort just in the first few yards. around the half way point, i stopped and added psi to the rear tire and even tried aligning the rear calliper. just in case there was some drag there. bike just didnt have that coast feeling.

    has anyone ever felt this and did you chase it down?

    im wondering if its a bad bearing and some wear that makes it harder under load. seems to spin okay on the stand!
    Last edited by Fuse6F; 2 Weeks Ago at 05:24 PM.

  2. #2
    Uly
    Uly is offline
    mtbr member
    Reputation:
    Join Date
    Aug 2009
    Posts
    377
    Check if your derailleur pulleys are starting to seize up

  3. #3
    mtbr member
    Reputation:
    Join Date
    Jul 2017
    Posts
    833
    jockey wheels all good

    dropped both wheels. inspected the bearings feel fine to me, coast side of the hub feels okay.

    will align brakes again, perhaps some pad wear is causing some drag.

    unless someone else has found something like this before....

  4. #4
    mtbr member
    Reputation: fredcook's Avatar
    Join Date
    Apr 2009
    Posts
    920
    It was a long time ago, on a no name hub that would feel tight and would sometimes "free up" after a few miles. That started happening after a rebuild. It was a low end hub, so I had used low end (cheap) bearings. I finally replaced them again with better bearings and didn't have that issue any more.
    You didn't quit riding because you're old, you're old because you quit riding.

  5. #5
    mtbr member
    Reputation:
    Join Date
    Jul 2017
    Posts
    833
    i suspect its something like this.

    tonight i hit a diff trail. its heavy rooted at places. shock things up alot. noiced on a couple laps the bike felt like a rocket. on the uphill. then it seemed to tighten up just a little, not as bad as the other day.

    i think its time for a new hub.

    but if im going to do all that work, might as well be on a new rim like an i45. so hence the other thread.

  6. #6
    mtbr member
    Reputation:
    Join Date
    Jul 2017
    Posts
    833
    Update

    tore down the wheel and removed cassette to inspect the hub.

    Gritty freehub bearings. would definitely affect the coast side of things. i rebuilt the freehub with some new bearings and the bike rolls much nicer now.

    my sram 746 hub, Drive side bearing, didnt feel great either after being replaced just two months ago.

    looking into having a spacer machined to fit inside the main hub body to support the bearing races. Much like that found on the freehub

    Should keep the rear end happy longer.

  7. #7
    mtbr member
    Reputation: One Pivot's Avatar
    Join Date
    Nov 2009
    Posts
    9,418
    Did you use Enduro blue bearings? 2 months is about right for those.

  8. #8
    mtbr member
    Reputation:
    Join Date
    Jul 2017
    Posts
    833
    Yeah thats what the shop used on the hub.

    I used china 61902-rs on my freehub as that was all i could get on short notice

Similar Threads

  1. Replies: 5
    Last Post: 07-19-2015, 04:42 PM
  2. Job loss = passion loss...
    By Cormac in forum Riding Passion
    Replies: 75
    Last Post: 05-18-2015, 09:49 AM
  3. 3x10 to 1x10 - weight loss to low range loss formula
    By flipsidem in forum Drivetrain - shifters, derailleurs, cranks
    Replies: 36
    Last Post: 10-15-2013, 08:57 PM
  4. Help with weight loss? And a dual weight loss stratgy.
    By hedonistic in forum Weight Weenies
    Replies: 7
    Last Post: 10-09-2013, 01:32 PM
  5. Weight loss equals power loss?
    By HelmutHerr in forum Clydesdales/Tall Riders
    Replies: 12
    Last Post: 05-16-2013, 07:12 PM

Members who have read this thread: 65

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 2020 VerticalScope Inc. All rights reserved.