"Tightening" Suntour Perfect Freewheel
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"Tightening" Suntour Perfect Freewheel
Hi, I'm presently touring on a vintage mtb with a suntour "Perfect" freewheel. The action on the freewheel is loose, and getting annoying as it tends to "click clack" in lower gears. (The click clack can't be the BB, as I had it replaced, and when I pull the Freewheel from side to side it is rather loose, and it makes the identical noise as when I'm cycling in certain gear combinations.) The teeth on the freewheel aren't too terribly worn so I don't see the point in replacing the whole unit, difficult to do as I'm in Europe and would have to wait for a replacement to get shipped here. So I'd like to "tighten" it.
According to Sheldon Brown this can be accomplished by removing the cone holding the freewheel bearings in place then removing a shim washer or two:
"Use a hammer and punch (or an old flat-blade screwdriver) alternately in one hole, then the other, to drive the ring in a clockwise direction. This ring is actually a bearing cone with a left ("reverse") thread, and once you have removed it you will see a row of 1/8" bearing balls and a stack of very thin washers surrounding the threads that the cone threaded on to. These are shim washers, and you can remove one or more of them to make the bearing tighter, if the freewheel has too much play."
Has anyone tried this? Any advice?
Thanks!
According to Sheldon Brown this can be accomplished by removing the cone holding the freewheel bearings in place then removing a shim washer or two:
"Use a hammer and punch (or an old flat-blade screwdriver) alternately in one hole, then the other, to drive the ring in a clockwise direction. This ring is actually a bearing cone with a left ("reverse") thread, and once you have removed it you will see a row of 1/8" bearing balls and a stack of very thin washers surrounding the threads that the cone threaded on to. These are shim washers, and you can remove one or more of them to make the bearing tighter, if the freewheel has too much play."
Has anyone tried this? Any advice?
Thanks!
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So is your MTB indexed for 6 speed, and you can only buy 7 speed freewheels?
I've had sprockets apart, but never the internals of the freewheels. Cone adjustment would be if it is ratchetting ok, but otherwise easy to wiggle in the opposite plane.
It looks like you got it apart. What happens if you grease it up, remove a shim, and put it back together?
I've had sprockets apart, but never the internals of the freewheels. Cone adjustment would be if it is ratchetting ok, but otherwise easy to wiggle in the opposite plane.
It looks like you got it apart. What happens if you grease it up, remove a shim, and put it back together?
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The frame, a 1983 Diamond Back Ridge Runner, was designed to work with the pretty sweet but rare suntour superbe tech derraileur, the Shimano Perfect freewheel I've got has six sprockets. barcon friction shifters. I'm not trying to replace it at all, want to make it work til it's completely useless. Then I'll try to source one from the internet, I'm sort of a purist when it comes to these things.
That picture was a random one taken from google images. I just did the job, took off the two shims inside the freewheel, but it wouldn't rotate when put back together. So I put one of the shims back and now there's no play, it doesn't "rock" back and forth any longer, but also doesn't rotate smoothly, there is a little bit of resistance for about 15 degrees of a full rotation. I guess that's cause the cone is worn down a little and the "sweet spot" of being tight enough to not allow rocking & loose enough to allow for easy rotation is impossible, unless I can find a new cone or a shim which is thinner than the one which I've got there. Basically impossible.
But i'd rather have the fw a little tight than rocking back and forth as i ride, so off i go.
That picture was a random one taken from google images. I just did the job, took off the two shims inside the freewheel, but it wouldn't rotate when put back together. So I put one of the shims back and now there's no play, it doesn't "rock" back and forth any longer, but also doesn't rotate smoothly, there is a little bit of resistance for about 15 degrees of a full rotation. I guess that's cause the cone is worn down a little and the "sweet spot" of being tight enough to not allow rocking & loose enough to allow for easy rotation is impossible, unless I can find a new cone or a shim which is thinner than the one which I've got there. Basically impossible.
But i'd rather have the fw a little tight than rocking back and forth as i ride, so off i go.
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If the freewheel is tight, it won't completely freewheel when you are coasting. You won't be moving the chainwheel but the freewheel will keep moving. This results the top loop being slack and the bottom loop being tight. If you don't start to pedal soon, you will have the effects of chain suck but from a different cause. The loose chain can get in the spokes and cause havoc. The tight chain can break the derailleur or sacrificial hanger.
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With some basic tools and a bit of determination you can make your own shims. A soda can, a pair of scissors and a Stanley knife will get you started.
Try different combinations. Throw out all stock ones. Use a stack of your own. Replace one stock with one own. Or two, or whatever it takes.
Try different combinations. Throw out all stock ones. Use a stack of your own. Replace one stock with one own. Or two, or whatever it takes.
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The freewheel isn't THAT tight, it's just not perfect. If it doesn't smooth out with riding I'll throw the shim back on it and deal with the play, or get a new freewheel... And, dabac, the soda can aluminum would be way too thick for a shim, plus I want LESS shims, not more. Ideal would be I think 1.5 shims of the current thickness, 2 being too loose, none being too tight and one being a little on the tight side. But just a little.
thanks for the input!
thanks for the input!
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N.B. the freewheel will tighten with use. The freewheel bearings are used only when coasting. Their action, while coasting, will tighten the left threaded cone. So, a freewheel that's adjusted "just right" may become unacceptably tight after 50 to 75 miles.
You may try using aluminum foil for shim stock in an emergency.
You may try using aluminum foil for shim stock in an emergency.
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Okay! I'll keep that in mind.... I cycled about 5km today and noted that the clicking of the pawls was unusually low volume. But no sagging.
I'm starting a 300km cycle ride across Ireland tomorrow, so I'll see what happens. Sagging, as mentioned, and I'll give the aluminum file a shot. I've got at least 1500km cycling in Europe before I go back to the USA, so I'd best make this work... worst case scenario I order a new one over ebay and just wait for it to show up... I lost the shim I pulled out already so I'm running out of options.
thanks so much, i appreciate it!
I'm starting a 300km cycle ride across Ireland tomorrow, so I'll see what happens. Sagging, as mentioned, and I'll give the aluminum file a shot. I've got at least 1500km cycling in Europe before I go back to the USA, so I'd best make this work... worst case scenario I order a new one over ebay and just wait for it to show up... I lost the shim I pulled out already so I'm running out of options.
thanks so much, i appreciate it!
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Agreed with SNinNYC. One doesn't want a tight freewheel. There's a reason why freewheels and freehubs always have a slight slop to them (the many millions made are not wrong...) Sun Tour freewheels are known for their tendency to rock slightly twice per revolution on their pawls. This happens more in some chain/cog combos then others as the cog in use gets further away from the placement of the pawls there is a greater lever arm acting. Some freewheels were worse then others. I always attributed it to manufacturing tolerances sometimes build up the wrong way. Andy.
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Well, pride comes before a fall, so they say... after about 100km, as predicted, the freewheel came apart, the cone sheared off, ball bearings spilled, cogset body separated from the center of the freewheel, and I found myself wishing I'd followed sheldon's red print advice to NOT attempt freewheel surgery. Couldn't put it back together for the life of me, just took off the cogset and trudged. So I got myself stranded in the Irish countryside. Not a bad place to be stuck, really... some things you learn the hard way. Didn't expect something that dramatic!
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