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-   -   Derailleur Issue (https://www.bikeforums.net/bicycle-mechanics/1209157-derailleur-issue.html)

chip.mcbride 08-02-20 11:31 AM

Derailleur Issue
 
I have 90s era Linear Folding Recumbent. I picked it up a few months back. I had the LBS replace the tires and tubes...before realizing I could accomplish it myself. I've since then been reading the forums and watching youtube and have successfully made some adjustments to my other bikes (repacked bearings, switched out shifters etc....) The issue with the Linear is the derailleur. It has six speed cassette and a suntour derailleur. I can not get the thing to go into the largest cog of the cassette, as the lower cog of the derailleur arm is hitting it...There is no adjustment to the B screw, it is in as far as it will go and the arm will not drop any lower. It will only move to the smallest cog, no matter how far the H screws is turned, without pedaling about half a turn in reverse...so it's shift, pedal, reverse pedal, and it will drop on. Not the most efficient way to shift. I've made sure the cable has no slack, the bottom of the derailleur doe not have an adjustment for cable tension, only at the shifter....It probably has been put down a few downs since it's creation. Should I just update the whole system, shifter, derailleur, cabling?

canopus 08-02-20 12:40 PM

Pictures would help. How is the chain length? Do you think these are the original parts or were they maybe changed out during its life? Is it a cassette or a freewheel? Maybe a larger rear tooth count than designed for the derailleur? or smaller derailleur than designed for the tooth count? I have had the b screw when screwed in actually miss the mount step that is designed to sit against so screwing it in did nothing. I can't really see a suntour derailleur not being able to handle a 6s unless something is out of alignment or bent or broken.

chip.mcbride 08-02-20 02:06 PM


Originally Posted by canopus (Post 21620015)
Pictures would help. How is the chain length? Do you think these are the original parts or were they maybe changed out during its life? Is it a cassette or a freewheel? Maybe a larger rear tooth count than designed for the derailleur? or smaller derailleur than designed for the tooth count? I have had the b screw when screwed in actually miss the mount step that is designed to sit against so screwing it in did nothing. I can't really see a suntour derailleur not being able to handle a 6s unless something is out of alignment or bent or broken.

https://cimg8.ibsrv.net/gimg/bikefor...d39969791a.jpg
https://cimg0.ibsrv.net/gimg/bikefor...5b9373dd36.jpg

andrewclaus 08-02-20 02:22 PM

There are three possible problems: shifter, cable, or derailleur. I like to disconnect the cable from the derailleur and inspect each area separately.

You can check the derailleur by itself by (carefully) moving it manually while pedaling. Adjust limit screws while doing that.

Make sure the shifter clicks six times and the cable moves freely.

Move each section of cable housing along the cable and check for friction. Clean cable and lubricate.

canopus 08-02-20 03:48 PM

Looks like a 34 large cog in the rear... and a 7s freewheel. Is it a 34t cog? Is it friction or indexed? It looks like the derailleur can't handle the cog. Looks like the wheel is shoved all the way forward also. You could try pulling the rear wheel back in the dropout (see where the previous QR marks are?) to see it that gives your large cog some clearance from the pulley. Also try what andrewclaus suggested, loosen the cable and try to manually move the derailleur through the shifts, If you can move it manually through the shifts then you can look at the cable and shifter to see if it pulls enough to move the shifter. Look at the B screw and see where it is on the mount and if it makes a difference when adjusted while the cable is loose.

chip.mcbride 08-02-20 04:57 PM


Originally Posted by canopus (Post 21620325)
Looks like a 34 large cog in the rear... and a 7s freewheel. Is it a 34t cog? Is it friction or indexed? It looks like the derailleur can't handle the cog. Looks like the wheel is shoved all the way forward also. You could try pulling the rear wheel back in the dropout (see where the previous QR marks are?) to see it that gives your large cog some clearance from the pulley. Also try what andrewclaus suggested, loosen the cable and try to manually move the derailleur through the shifts, If you can move it manually through the shifts then you can look at the cable and shifter to see if it pulls enough to move the shifter. Look at the B screw and see where it is on the mount and if it makes a difference when adjusted while the cable is loose.

Good catch on the tire being all the way forward.....I never thought about that...I had switched to a larger 26 inch wheel to see if it would fit and never gave a thought about where it was sitting before or after....I will take a look at it first thing in the morning....probably the issue...as I had not noticed it occurring before I started messing with it. As for the other questions...I haven't a clue...I could count the teeth...but I will have do a little terminology research to get up to speed on the rest. I'm pretty sure all the parts are factory....the cable shroud does have a nick in it from the previous owner moving the seat and catching it, it seems. If it is the tire too far forward, I will rectify it and then start some cleaning and maintenance on the cable systems. replace, clean and lube....it could use some love and cleaning.....Thank you for the prompt response.

**Edit. I took another look at it. The tire has to be forward, or the brake calipers engage on the tire...the shoes are slid as far down as possible. When I picked it up from the LBS after getting tires and tubes...that is what happened on my test ride...they did not check it...So, I moved the tire forward so I have rear brakes...loosened the the derailleur assembly, tilted it down, moved the B screw in...then tightened it down...I now have all but the highest of the gears working....I have adjusted and readjusted the screws till I'm leaving a puddle of sweat in the garage. The other problem with long recumbents is how to lift them for maintenance....this one involves adjustments, lift the rear, hold the steering with your thigh, spin the pedals. I have most of the gears working again and brakes. I never use the top ones anyway...I just wanted it all to work 100 percent as designed. I will be replacing the cables and doing a thorough cleaning and lubing (there very well may be some crud keeping it from moving freely)...but in the mean time...I will ride it and enjoy it. I alternate between this and the MTB to change up the ride. Thank you again for the advice.


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