Suntour Accushift doing my head in - mechanic?
Posted: Mon Oct 22, 2012 11:15 am
I have an old Genesis from 1991 or so, with 7-speed Accushift downtube shifters and Suntour SL rear derailleur.
I stopped riding it about 10 years ago after I busted my elbow and couldn't straighten my arm any more - I had to adjust my position on the bike a lot (saddle down, stem up and shorter) but still couldn't stay comfortable. However, I determined to drag it out of the garage and get it back on the road. Mission accomplished, sort of.
When I was riding it years ago, the Accushift system drove me mad. It would shift smoothly for a while but then after some kms, would jump down the cluster under load, not sit properly on a cog etc.
In the meantime, I had discovered some scans of a Suntour mechanic's troubleshooting guide and using that I worked out the problem was probably related to cable tension at the RD. I fiddled with it, backing off the tension and I got it shifting perfectly. Nice, positive clicks at the shifter and positive shifts at the RD. A short ride around my local streets and it was shifting beautifully.
I then ride for about 8kms to the park my wife and kids are at - the bike performed beautifully. Leaned it against a tree for 40 minutes or so while the kids played, but when I got back on, it was a mechanical nightmare. Back to uncommanded shifts (particularly from big/big to the next gear down) and then no positive position on big/gear 3 or 4. Off the bike trying to fix it, the cable tension now feels so tight it doesn't want to shift up from the smallest cog! By adjusting tension at the RD I was able to get it shifting well enough to get home, but I had difficulties if on the big ring. These are the exact problems that led me to stop riding the damn thing back in the dim past.
I am going to work my way through the trouble-shooting guide again but does anyone have some suggestions as to what the hell might be going on; and any recommendations for Sydney-based bike mechanics who might know their way around Suntour gear to help me solve this?
Thanks in advance for any help from the brains trust,
smith
I stopped riding it about 10 years ago after I busted my elbow and couldn't straighten my arm any more - I had to adjust my position on the bike a lot (saddle down, stem up and shorter) but still couldn't stay comfortable. However, I determined to drag it out of the garage and get it back on the road. Mission accomplished, sort of.
When I was riding it years ago, the Accushift system drove me mad. It would shift smoothly for a while but then after some kms, would jump down the cluster under load, not sit properly on a cog etc.
In the meantime, I had discovered some scans of a Suntour mechanic's troubleshooting guide and using that I worked out the problem was probably related to cable tension at the RD. I fiddled with it, backing off the tension and I got it shifting perfectly. Nice, positive clicks at the shifter and positive shifts at the RD. A short ride around my local streets and it was shifting beautifully.
I then ride for about 8kms to the park my wife and kids are at - the bike performed beautifully. Leaned it against a tree for 40 minutes or so while the kids played, but when I got back on, it was a mechanical nightmare. Back to uncommanded shifts (particularly from big/big to the next gear down) and then no positive position on big/gear 3 or 4. Off the bike trying to fix it, the cable tension now feels so tight it doesn't want to shift up from the smallest cog! By adjusting tension at the RD I was able to get it shifting well enough to get home, but I had difficulties if on the big ring. These are the exact problems that led me to stop riding the damn thing back in the dim past.
I am going to work my way through the trouble-shooting guide again but does anyone have some suggestions as to what the hell might be going on; and any recommendations for Sydney-based bike mechanics who might know their way around Suntour gear to help me solve this?
Thanks in advance for any help from the brains trust,
smith