Bicycle Mechanics - New bike and I'm having trouble adjusting the derailleur

I recently bought a Raleigh Alyeska (1985 I think). It's an excellent bike, but the some of the outer gears slip or do not shift properly. I'm used to a Shimano rear derailleur which has the tension screw to adjust slipping, but I don't know much about the derailleur on this bike. It's a Suntour XCD 6000 7 speed. I understand what the H and L screws are for, but not too sure what the A<-->B setting is for. The A<-->B setting is under the H and L screws (see attached picture). Also there is a setting on the shifter, there is a UL, P, and RE setting. I have attached pictures of the rear derailleur and the shifter. Any help would be awesome!

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That's commonly called the b-tension screw, adjusts how far forward the derailleur can pivot. If only some gears are "slipping" then it's unlikely that it's just adjustment. Very possibly the outer (smaller) cogs are worn. If so they would slip under pressure. We need more info about exactly what you mean by slipping and how/when it occurs.

That's commonly called the b-tension screw, adjusts how far forward the derailleur can pivot. If only some gears are "slipping" then it's unlikely that it's just adjustment. Very possibly the outer (smaller) cogs are worn. If so they would slip under pressure. We need more info about exactly what you mean by slipping and how/when it occurs.

By slipping I mean that the derailleur shifts quickly in and out, but stays on the same gear. It only happens when I am peddling really hard. I hope that description makes sense.

No, I don't know what you mean by in and out. It's best not to conclude what a particular part is doing but rather describe the sound or feel. If it feels like the pedals slip forward then again the likely problem is worn small cogs, although extreme pressure on some bikes may cause enough flex to affect rear derailleur alignment. Pedaling "really hard" is generally not good for your bike or you.

No, I don't know what you mean by in and out. It's best not to conclude what a particular part is doing but rather describe the sound or feel. If it feels like the pedals slip forward then again the likely problem is worn small cogs, although extreme pressure on some bikes may cause enough flex to affect rear derailleur alignment. Pedaling "really hard" is generally not good for your bike or you.

Yes! it feel like the pedals slip forward. I did some tweaking to the B-tension screw and everything shifts fine, only the middle gear is where the "slip" happens. I'll just stay away from that gear for now until I can get a replacement cog or a new cassette.

I see this often with a worn freewheel and most often, when under a heavy load (highly doubt bike has a cassette). Can be a variety of causes. New freewheel means you will want a new chain too at that time.

Positions on the Suntour shifter are related to indexing options as I recall. If so, shift lever is not original or your bike is newer (more likely), as Suntour indexing came out in 1987.

Cable and housing need replacement.


Here it is:


UL:- is for indexed shifting with an Ultra-7 (Narrow Spaced) Suntour Winner System 7-Speed freewheel.

P:- is for non-indexed power shifting with any freewheel, regardless of sprocket spacing.

RE:- is for indexed shifting with a standard spaced Suntour Winner System or a freewheel.