Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Questions on Shimano 100GS

Notices
Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

Questions on Shimano 100GS

Old 09-02-07, 06:08 PM
  #1  
sykerocker 
Senior Member
Thread Starter
 
sykerocker's Avatar
 
Join Date: Dec 2005
Location: Ashland, VA
Posts: 4,420

Bikes: The keepers: 1958 Raleigh Lenton Grand Prix, 1968 Ranger, 1969 Magneet Sprint, 1971 Gitane Tour de France, 1973 Raleigh Tourist, 3 - 1986 Rossins, and a '77 PX-10 frame in process.

Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 221 Post(s)
Liked 237 Times in 129 Posts
Questions on Shimano 100GS

A couple of days ago, my wife dropped by the local transfer station (aka, county dump) and comes home with a GT Passage (21 speed hybrid/city bike) complete and seemingly in good condition despite the usual rust on the fasteners, etc. It's condition was proven to me by my promptly pumping up the tyres and taking it for a mile ride. This is the first bike that I've ever gotten from the dump in (almost) ridable condition.

It's obviously their low line (although it came from a local bike shop) model as evidenced by no quick release on the rear axle and Shimano 100GS components throughout. I've never messed with this line, and they're obviously cheap although they seem to do their jobs nicely. Now, I've yet to start tearing into the bike, and it's going to get a complete work over before it replaces my Raleigh Sports at work as the lunchtime errand runner. I've got a couple of questions in the meantime:

1. The shifters are sticky. The rear one works half the time, always works on going down the cluster, hangs up half the time when I try to get the derailleur to climb the freewheel. Obviously it needs cleaned out. Anyone have any favorite method, chemicals, etc. on doing so?

2. The front shifter climbs the freewheel perfectly. Going down, it immediately snaps from third to first on one push of the button. Am I correct in assuming we're talking cleaning, or was this a cheap and dirty deliberate design on the part of Shimano?

Otherwise, this looks like one of the easiest jobs I've had in ages. Wire brush the rust off the fasteners, disassemble, grease, polish, reassemble. I'm amazed how nice the frame paint is.

Thanks for the assistance.
__________________
Syke

“No one in this world, so far as I know — and I have searched the records for years, and employed agents to help me — has ever lost money by underestimating the intelligence of the great masses of the plain people. Nor has anyone ever lost public office thereby.”

H.L. Mencken, (1926)

sykerocker is offline  
Old 09-02-07, 06:51 PM
  #2  
DMF 
Elitist Troglodyte
 
DMF's Avatar
 
Join Date: Jun 2006
Location: Dallas
Posts: 6,925

Bikes: 03 Raleigh Professional (steel)

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Shimano 100GS group (xx-M100) was made 1991-2. I know of no on-line docs for the group.

1) Wash out/soak the shifter with something like WD-40 until it works, then spray in a light lube if you have one. Exact procedures vary.

2) It's probably a matter of adjustment of the FD, but giving the left shifter the same treatment couldn't hurt.

Also check that the cables are smooth in the housings.
__________________
Stupidity got us into this mess - why can't it get us out?

- Will Rogers
DMF is offline  
Old 09-02-07, 07:01 PM
  #3  
sykerocker 
Senior Member
Thread Starter
 
sykerocker's Avatar
 
Join Date: Dec 2005
Location: Ashland, VA
Posts: 4,420

Bikes: The keepers: 1958 Raleigh Lenton Grand Prix, 1968 Ranger, 1969 Magneet Sprint, 1971 Gitane Tour de France, 1973 Raleigh Tourist, 3 - 1986 Rossins, and a '77 PX-10 frame in process.

Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 221 Post(s)
Liked 237 Times in 129 Posts
Originally Posted by DMF
Shimano 100GS group (xx-M100) was made 1991-2. I know of no on-line docs for the group.

1) Wash out/soak the shifter with something like WD-40 until it works, then spray in a light lube if you have one. Exact procedures vary.

2) It's probably a matter of adjustment of the FD, but giving the left shifter the same treatment couldn't hurt.

Also check that the cables are smooth in the housings.
Thanks. I had a feeling that WD-40 was going to be in there somewhere. My two favorite tools on cleaning up a junkyard bike: WD-40 and compressed air.

I also had a funny feeling that this 100GS line was not exactly one of Shimano's majors when I did a search on eBay and came up with NOTHING . By the way, thanks, you've also dated the bike for me. I was wondering what era they would have combined 100GS with BioPace chainwheels (which I thought had disappeared in the late 80's).
__________________
Syke

“No one in this world, so far as I know — and I have searched the records for years, and employed agents to help me — has ever lost money by underestimating the intelligence of the great masses of the plain people. Nor has anyone ever lost public office thereby.”

H.L. Mencken, (1926)

sykerocker is offline  
Old 09-02-07, 07:37 PM
  #4  
DMF 
Elitist Troglodyte
 
DMF's Avatar
 
Join Date: Jun 2006
Location: Dallas
Posts: 6,925

Bikes: 03 Raleigh Professional (steel)

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Biopace is alive and well! Check eBay. If the rings are in good shape you might consider selling them.

Looks like 100GS was a low-end mountain group. No reason to keep it intact if something needs replacing.

Be aware that WD-40 is a lousy lubricant. It's main asset is that it drys, then mostly goes away.
__________________
Stupidity got us into this mess - why can't it get us out?

- Will Rogers
DMF is offline  
Old 09-02-07, 10:00 PM
  #5  
Bill Kapaun
Really Old Senior Member
 
Bill Kapaun's Avatar
 
Join Date: Feb 2007
Location: Mid Willamette Valley, Orygun
Posts: 13,824

Bikes: 87 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds.

Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1774 Post(s)
Liked 1,231 Times in 852 Posts
"2. The front shifter climbs the freewheel perfectly. Going down, it immediately snaps from third to first on one push of the button."

I had an Altus front shifter that wouldn't "catch" the middle when going up or down. WD-40 did the trick!
After a couple "flush cycles", when SLOWLY easing the shifter down from BIG, I could start getting it to catch the MIDDLE. Progress was pretty quick from that point, with another flush.

Edit-
This link helps identify the era of some components.
https://www.fa-technik.adfc.de/Herste...o/Gruppen.html
Bill Kapaun is offline  
Old 05-07-12, 01:42 PM
  #6  
scoostraw
Newbie
 
Join Date: Aug 2011
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked 2 Times in 2 Posts
Originally Posted by Bill Kapaun
"2. The front shifter climbs the freewheel perfectly. Going down, it immediately snaps from third to first on one push of the button."
I happened upon this old thread and thought I'd add to it.

I just got a Trek 800 with Shimano 100GS shifters and the front one was doing the same thing. Yes flushing with WD40 will almsot certainly do the trick, but I prefer to take the cover off. It makes it easier to clean.

Below is the shifter with the cover removed (one phillips screw holds the cover in place)



The arrows point to the cam which is the culprit. As the factory grease thickens with age, it dampenss the cam's movement, causing it not to "catch". I find it easiest to use a solvent such as brake-kleen, and physically move the cam up and down many times to get the old grease out. Then I re-lube with WD40.

You can tell at once, with the shifter in your hand that it is working properly before re-installing. I have yet to see a shifter that has failed due to mechanical flaw or wear. They all just seem to become gummed up in the old grease.

Hope this helps!

scoostraw is offline  
Old 05-08-12, 07:40 AM
  #7  
Kimmo 
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Posts: 9,533

Bikes: https://weightweenies.starbike.com/forum/viewtopic.php?f=10&t=152015&p=1404231

Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 1520 Post(s)
Liked 716 Times in 508 Posts
That right there, as simple as you'll ever see it, is what goes wrong with STI most of the time.
Kimmo is offline  
Old 01-12-13, 02:07 PM
  #8  
jwkelton
Newbie
 
Join Date: Jan 2013
Posts: 1
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I just stumbled into this forum today looking for help with a similar bike. My 91 era GT Passage's rear derailler fell off. I am looking for a replacement or the proper nut to re attach. Any thoughts? THX in advance
jwkelton is offline  
Old 01-12-13, 02:12 PM
  #9  
Airburst
Senior Member
 
Join Date: Oct 2009
Location: England, currently dividing my time between university in Guildford and home just outside Reading
Posts: 1,921

Bikes: Too many to list here!

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 4 Times in 2 Posts
Originally Posted by jwkelton
I just stumbled into this forum today looking for help with a similar bike. My 91 era GT Passage's rear derailler fell off. I am looking for a replacement or the proper nut to re attach. Any thoughts? THX in advance
A picture would help - there are a number of potential failure points, but it's not common for a rear derailleur to simply fall off.
Airburst is offline  
Old 01-12-13, 09:22 PM
  #10  
LarDasse74
Guest
 
Join Date: Jul 2008
Location: Grid Reference, SK
Posts: 3,768

Bikes: I never learned to ride a bike. It is my deepest shame.

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 6 Times in 6 Posts
Yeah, I have never seen an entire derailleur 'fall off.' I would like to see a picture too.
LarDasse74 is offline  
Old 01-13-13, 10:44 AM
  #11  
Looigi
Senior Member
 
Looigi's Avatar
 
Join Date: Dec 2010
Posts: 8,951
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 14 Post(s)
Likes: 0
Liked 13 Times in 12 Posts
Originally Posted by scoostraw
...The arrows point to the cam which is the culprit. As the factory grease thickens with age, it dampenss the cam's movement, causing it not to "catch"....
It's a pawl, not a cam.
Looigi is offline  
Old 01-14-13, 11:30 AM
  #12  
scoostraw
Newbie
 
Join Date: Aug 2011
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked 2 Times in 2 Posts
Originally Posted by Looigi
It's a pawl, not a cam.
You're correct. It is called a pawl, not a cam. My error.
scoostraw is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
okane
Classic & Vintage
26
07-02-17 08:28 AM
IMontoya
Bicycle Mechanics
23
12-21-16 06:41 PM
spectastic
Bicycle Mechanics
15
03-04-16 09:15 PM
Donsell
Bicycle Mechanics
11
08-15-12 08:04 AM
Chrise510
Bicycle Mechanics
3
09-29-11 10:40 PM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.