Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

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.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 06-18-09, 09:59 AM   #1
jimn
Junior Mint
Thread Starter
 
jimn's Avatar
 
Join Date: Mar 2006
Location: Brooklyn, NY
Bikes: http://nachlin.com/bicycles/
Posts: 100
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
STI with Suntour cranks - front derailer adjustment

Hello!

I am attempting to use a Shimano RSX (600) front derailleur and brifter with a SunTour Cyclone double road bike crank.

I have moved the front derailer to be about 2 mm above the largest chainring, and adjusted the low stop so that shifting down to the small ring works fine.

Shifting up is more of a problem.

If I adjust the high stop and the cable tension so that I can actually shift onto the big ring (52 tooth, no ramps), it sometimes overshoots and the chain falls off.

If I adjust the high stop so it never falls off, it also won't shift into the big ring.

It NEEDS a bit of over-shoot for the chain to grab the big chainring.

There seems to be no in-between.

Would using a Shimano crankset make a difference? Do I need new chainrings? The chain is new.

Thanks!
-Jim

P.S. Sorry I used the word "brifter".

Last edited by jimn; 06-18-09 at 12:36 PM.
jimn is offline   Reply With Quote
Old 06-18-09, 11:10 AM   #2
joejack951
Senior Member
 
joejack951's Avatar
 
Join Date: May 2004
Location: Wilmington, DE
Bikes: 1984 Trek 660, 2003 Specialized Hardrock, 2004 LOOK KG386i (RIP), 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1, 2014 Islabikes CNOC 14 (son's)
Posts: 10,189
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 189 Post(s)
You do realize that there is a high stop too, right? Adjust it in far enough to prevent overshifting. There is a sweet spot where the shift will be easy, quick, and not throw the chain. What shifters are you using anyway?
joejack951 is offline   Reply With Quote
Old 06-18-09, 12:37 PM   #3
jimn
Junior Mint
Thread Starter
 
jimn's Avatar
 
Join Date: Mar 2006
Location: Brooklyn, NY
Bikes: http://nachlin.com/bicycles/
Posts: 100
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Yes, the high stop is what I meant!!

Original post edited.

ANYway, that sweet spot is what I'm saying doesn't exist. It either throws the chain or won't shift at all, because it seems to need to push the chain past the outer chainring a bit to engage.
jimn is offline   Reply With Quote
Old 06-18-09, 12:54 PM   #4
joejack951
Senior Member
 
joejack951's Avatar
 
Join Date: May 2004
Location: Wilmington, DE
Bikes: 1984 Trek 660, 2003 Specialized Hardrock, 2004 LOOK KG386i (RIP), 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1, 2014 Islabikes CNOC 14 (son's)
Posts: 10,189
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 189 Post(s)
Adjust your front derailler lower.
joejack951 is offline   Reply With Quote
Old 06-18-09, 03:40 PM   #5
jimn
Junior Mint
Thread Starter
 
jimn's Avatar
 
Join Date: Mar 2006
Location: Brooklyn, NY
Bikes: http://nachlin.com/bicycles/
Posts: 100
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I don't think it can go any lower without rubbing on the big chainring. It's about the width of a nickel off.
jimn is offline   Reply With Quote
Old 06-18-09, 06:53 PM   #6
joejack951
Senior Member
 
joejack951's Avatar
 
Join Date: May 2004
Location: Wilmington, DE
Bikes: 1984 Trek 660, 2003 Specialized Hardrock, 2004 LOOK KG386i (RIP), 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1, 2014 Islabikes CNOC 14 (son's)
Posts: 10,189
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 189 Post(s)
What chain are using? Any chance you are using a 9 or 10 speed chain? Have you verified that the derailler cage is parallel to the big chainring?
joejack951 is offline   Reply With Quote
Old 06-18-09, 07:06 PM   #7
Panthers007
Great State of Varmint
 
Panthers007's Avatar
 
Join Date: Sep 2008
Location: Dante's Third Ring
Bikes:
Posts: 7,479
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
As with any FD that misbehaves - the easiest fix is to uninstall it and start over. Seriously, this takes less time than trying to adjust the FD on the bike. Once (or if) an FD starts to screw up, each adjustment tends to cascade - knocking more and more things out of adjustment.
Panthers007 is offline   Reply With Quote
Old 06-19-09, 07:52 AM   #8
jimn
Junior Mint
Thread Starter
 
jimn's Avatar
 
Join Date: Mar 2006
Location: Brooklyn, NY
Bikes: http://nachlin.com/bicycles/
Posts: 100
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
joejack951: Pretty sure it's the right chain. I'll check that.

Panthers007: Not a bad idea.

But I'm surprised nobody's mentioned the two things I would have thought it was:

* the chainring isn't ramped

* the Cyclone cranks have the wrong spacing between the chainrings
jimn is offline   Reply With Quote
Old 06-19-09, 07:58 AM   #9
joejack951
Senior Member
 
joejack951's Avatar
 
Join Date: May 2004
Location: Wilmington, DE
Bikes: 1984 Trek 660, 2003 Specialized Hardrock, 2004 LOOK KG386i (RIP), 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1, 2014 Islabikes CNOC 14 (son's)
Posts: 10,189
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 189 Post(s)
Quote:
Originally Posted by jimn View Post
But I'm surprised nobody's mentioned the two things I would have thought it was:

* the chainring isn't ramped

* the Cyclone cranks have the wrong spacing between the chainrings
I haven't mentioned them because I've used older cranks without ramped/pinned chainrings with STI (Sora) and had no problems getting it to shift ok. With that said, upshifting does require a slight delay of the shift lever motion for the shift to complete. Whereas with ramped and pinned rings you can just quickly push the lever to shift then let go and the shift will complete, without the ramps and pins you need to hold the shift lever in for a half second then let go. Does this make sense?

For some reason, I blanked out on this until it occurred to me this morning.
joejack951 is offline   Reply With Quote
Old 06-19-09, 09:22 AM   #10
vredstein
Senior Member
 
vredstein's Avatar
 
Join Date: Aug 2008
Location: Tucson, Arizona
Bikes: '02 Lemond Buenos Aires, '98 Fuji Touring w/ Shimano Nexus premium, '06 Jamis Nova 853 cross frame set up as commuter, '03 Fuji Roubaix Pro 853 back up training bike
Posts: 704
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Is your setup (rings, cogs, chain, shifters) a 6,7,8,9, or 10-speed?
I'm running a 9-speed setup with Cyclone cranks, no-ramp Suntour ring, 9-speed SRAM chain, 9-speed downtube shifter, and Ultegra derailleur without issues.
vredstein is offline   Reply With Quote
Old 06-19-09, 01:44 PM   #11
jimn
Junior Mint
Thread Starter
 
jimn's Avatar
 
Join Date: Mar 2006
Location: Brooklyn, NY
Bikes: http://nachlin.com/bicycles/
Posts: 100
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks for all the good info.

It's a mystery why it doesn't engage. I'll have to take another look at the whole thing.

You guys have definitely saved me some money buying Shimano cranks.
jimn is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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



All times are GMT -6. The time now is 10:24 AM.