Have questions or want to discuss cycling? Join Now or Sign In to participate in the BikeRide community.

New: Take Part in the May's Giveaway: Win the LIVALL PikaBoost 2 E-bike Conversion Kit


Gear changes under load
#1
trek hardtail 3900 shifts under load uphill, got this in nov 09 new, rode it a couple of times, no problems,the first day above 40 I had it out and rode it long and hard. Going uphill with weight on pedals only, it shifted and I almost had my first crash of the year. Its happened quite a few times since then, any ideas? Thnx.
  Reply
#2
First of all check out the info here, especially Alex's video. Than print the instructions and go through the tune up process. Park Tool site has a good process for setting up the dérailleur. Basically start by setting the hi/low positions so the rear dérailleur is straight down in both top and bottom position, the front so it just clears the inside and outside than start tune up on the center front sprocket using the cable barrels a 1/2 turn at a time.

Not enough info given is it the front or rear??

If you do not have a bike stand use rope to hang your bike from rafters, bike hooks or whatever you can so you can pedal by hand and see what the problem is.
Never Give Up!!!
  Reply
#3
(04-12-2010, 01:44 PM)GeorgeET Wrote:  First of all check out the info here, especially Alex's video. Than print the instructions and go through the tune up process. Park Tool site has a good process for setting up the dérailleur. Basically start by setting the hi/low positions so the rear dérailleur is straight down in both top and bottom position, the front so it just clears the inside and outside than start tune up on the center front sprocket using the cable barrels a 1/2 turn at a time.

Not enough info given is it the front or rear??

If you do not have a bike stand use rope to hang your bike from rafters, bike hooks or whatever you can so you can pedal by hand and see what the problem is.

PS you say its a fairly new bike , so its likely that the cable stretched in which case try turning the adjustment barrel at the rear derailleur counter clockwise 1/2 turn at a time and test. If its the front turn the handlebar out counterclockwise and test.
Never Give Up!!!
  Reply


Possibly Related Threads...

Forum Jump:

[-]
10 Latest Posts
First long distance ride..
Today 11:26 AM
Massive Chainring redux
Today 07:03 AM
Is anyone riding with music?
Yesterday 09:49 PM
Great Giro
Yesterday 08:32 PM
Quiet is good
Yesterday 09:38 AM
What is your favorite MTB trail/route in...
05-28-2025 06:55 AM
Wearable Fitness Trackers
05-28-2025 06:47 AM
The deadliest U.S. counties for cyclists
05-28-2025 06:28 AM
POLL: Are non-recumbent riders looking a...
05-28-2025 06:21 AM
The great thing about trikes
05-27-2025 10:39 AM

[-]
Join BikeRide on Strava
Feel free to join if you are on Strava: www.strava.com/clubs/bikeridecom

[-]
Top 5 Posters This Month
no avatar 1. Painkiller
16 posts
no avatar 2. Flowrider
16 posts
no avatar 3. GirishH
14 posts
no avatar 4. SPINMAN
13 posts
no avatar 5. rydabent
13 posts