shifting trouble
07-12-07 | 10:40 PM
#1
Thread Starter
Senior Member
Joined: Oct 2005
Posts: 386
Likes: 0
From: mississippi
shifting trouble
Anyone else have problems shifting from the the little ring up the big ring?
I recently converted from a trip to a double and i've had some problems (my lbs claimed to fix it, but definitely didn't) shifting.
Most of my problems occur when:
a. I'm in a really small cog on the rear cassette, then attempt to shift from small ring to big ring.
b. i'm in my biggest cog on the rear cassette, then attempt to shift down, from the big ring to the small ring. (my chain slipped off on a 22% grade yesterday and i literally had to walk my bike up the rest of the hill because i couldn't get any momentum after i put my chain back on! all because of this!)
anyways. does anyone have any tips on how to do this, preferably without having to bring the bike up to the lbs, i'm no mechanic, but if you point me at the right screws to tighten, i think i can manage
I recently converted from a trip to a double and i've had some problems (my lbs claimed to fix it, but definitely didn't) shifting.
Most of my problems occur when:
a. I'm in a really small cog on the rear cassette, then attempt to shift from small ring to big ring.
b. i'm in my biggest cog on the rear cassette, then attempt to shift down, from the big ring to the small ring. (my chain slipped off on a 22% grade yesterday and i literally had to walk my bike up the rest of the hill because i couldn't get any momentum after i put my chain back on! all because of this!)
anyways. does anyone have any tips on how to do this, preferably without having to bring the bike up to the lbs, i'm no mechanic, but if you point me at the right screws to tighten, i think i can manage
07-13-07 | 01:28 AM
#2
Rat Bastard
Joined: Jul 2006
Posts: 1,504
Likes: 0
From: Sammamish, WA
Bikes: Cannondale Prophet, Specialized S-Works SL2, Specialized S-Works Stumpjumper
If the LBS claimed to have fixed it take it back to them. Assuming you paid for the service, and it wasn't just a touch up they did for free, I'm sure they'll tweak it for you.
07-13-07 | 01:59 AM
#3
Take it back for adjustment. One of the mysteries of bikes is that when the cable tension is "perfect", the bike will shift quickly and smoothly on a work stand, yet still hesitate or hang-up when pedaling hard out on the road. Sometimes a tech needs to "road test" a bike to get the shifting dialed in.
Bikes shift best when you have a straight chain line. Because chain stays have gotten silly short over the past two decades, a truly "straight" chain line is limited to just a few gear combinations.
For example, when you are on the largest three cogs in the back, and the small ring in front, you have a straight chainline. But, if you are on the largest rear cog, and then shift to the big ring in front, your chain is now at an angle, making shifting more difficult.
So, if you are on the large cog and small ring, first shift over to a middle cog. Then move to the large ring. And, shifting works best when you are pedaling smoothly, but lightly. If you are half-way up a steep hill, and putting maximum pressure on the pedals, you have waited too long. Gotta shift before things get tough.
Bikes shift best when you have a straight chain line. Because chain stays have gotten silly short over the past two decades, a truly "straight" chain line is limited to just a few gear combinations.
For example, when you are on the largest three cogs in the back, and the small ring in front, you have a straight chainline. But, if you are on the largest rear cog, and then shift to the big ring in front, your chain is now at an angle, making shifting more difficult.
So, if you are on the large cog and small ring, first shift over to a middle cog. Then move to the large ring. And, shifting works best when you are pedaling smoothly, but lightly. If you are half-way up a steep hill, and putting maximum pressure on the pedals, you have waited too long. Gotta shift before things get tough.
07-13-07 | 06:49 AM
#4
Banned
Joined: Mar 2004
Posts: 5,402
Likes: 501
From: under bridge in cardboard box
Originally Posted by YATES
Most of my problems occur when:
a. I'm in a really small cog on the rear cassette, then attempt to shift from small ring to big ring.
b. i'm in my biggest cog on the rear cassette, then attempt to shift down, from the big ring to the small ring. (my chain slipped off on a 22% grade yesterday and i literally had to walk my bike up the rest of the hill because i couldn't get any momentum after i put my chain back on! all because of this!)
a. I'm in a really small cog on the rear cassette, then attempt to shift from small ring to big ring.
b. i'm in my biggest cog on the rear cassette, then attempt to shift down, from the big ring to the small ring. (my chain slipped off on a 22% grade yesterday and i literally had to walk my bike up the rest of the hill because i couldn't get any momentum after i put my chain back on! all because of this!)
big cog, big chainring is a no-no
small cog, small chainring is a no-no
many shifting systems wont even do big ring big cog without lots of chain noise and complaining, todays cassettes are wider than what the chain will allow at the extreme ranges of gear combos
