How to understand a Worn Freewheel or Cassette
#1
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How to understand a Worn Freewheel or Cassette
Hello all,
I have a vintage MTB with Suntour groupset from 1992. I really like this bike but the chain skips at the 6th cog. I replaced the chain and still the same issue. This happens under heavy load. Given that the freewheel is 30+ years old, I am assuming that is the culprit. Now, I found the same freewheel on sale for $30. This is manufactured in late 1990. Do you think this is in good condition and has many more miles left? I am having difficulty understanding the wear condition. Any help would be appreciated. Please see the photos of the freewheel which I am considering buying.
I have a vintage MTB with Suntour groupset from 1992. I really like this bike but the chain skips at the 6th cog. I replaced the chain and still the same issue. This happens under heavy load. Given that the freewheel is 30+ years old, I am assuming that is the culprit. Now, I found the same freewheel on sale for $30. This is manufactured in late 1990. Do you think this is in good condition and has many more miles left? I am having difficulty understanding the wear condition. Any help would be appreciated. Please see the photos of the freewheel which I am considering buying.
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You can buy a brand new 7 speed freewheel for the price of that old one. If I could get it for $5 with free shipping I might buy it to try out. You can't assess how worn a freewheel is from a picture. You don't have to buy a Suntour freewheel for your bike
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#3
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Doesn't look particularly worn to me. When you refer to the 6th cog, do you mean the second smallest, which looks somewhat more worn than the rest? And when you indicate 'skips' do you mean that the chain jumps clear over this cog under high load, or the chain clatters away as if it is in-between gears?
Finally, 'replaced the chain'... did you replace your old chain with another old chain? Or did you replace the chain with a 11-speed chain a local shop carelessly shoved you out the door with?
Sorry to sound fussy, but I volunteer at a bike Co-op, and every statement made our clientele regarding their bikes has to be very carefully considered. For example, when someone says that they "broke their rim", without seeing it in person, it could mean:
Finally, 'replaced the chain'... did you replace your old chain with another old chain? Or did you replace the chain with a 11-speed chain a local shop carelessly shoved you out the door with?
Sorry to sound fussy, but I volunteer at a bike Co-op, and every statement made our clientele regarding their bikes has to be very carefully considered. For example, when someone says that they "broke their rim", without seeing it in person, it could mean:
- Flat tire
- Busted spokes
- Dented rim
- Bad hub (multiple reasons)
- Bad freewheel/cassette
- Etc.
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#4
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Thank you for your feedback. I agree with you and I have another vintage bike with all changed-out parts. But this one has only original parts and I try not to start replacing.
#5
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Doesn't look particularly worn to me. When you refer to the 6th cog, do you mean the second smallest, which looks somewhat more worn than the rest? And when you indicate 'skips' do you mean that the chain jumps clear over this cog under high load, or the chain clatters away as if it is in-between gears?
Finally, 'replaced the chain'... did you replace your old chain with another old chain? Or did you replace the chain with a 11-speed chain a local shop carelessly shoved you out the door with?
Sorry to sound fussy, but I volunteer at a bike Co-op, and every statement made our clientele regarding their bikes has to be very carefully considered. For example, when someone says that they "broke their rim", without seeing it in person, it could mean:
Finally, 'replaced the chain'... did you replace your old chain with another old chain? Or did you replace the chain with a 11-speed chain a local shop carelessly shoved you out the door with?
Sorry to sound fussy, but I volunteer at a bike Co-op, and every statement made our clientele regarding their bikes has to be very carefully considered. For example, when someone says that they "broke their rim", without seeing it in person, it could mean:
- Flat tire
- Busted spokes
- Dented rim
- Bad hub (multiple reasons)
- Bad freewheel/cassette
- Etc.
Chain skips in gear 20th under heavy load in high speed. Hard to describe, but it feels like it moves to the adjacent cog (5th one, or gear 19th). When I use the bike in Gear 19 or 21, I don't have any skipping regardless how hard I push the bike. This made me think that the 6th cog (which has been my favorite and used a lot) is to blame.
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Hello all,
I have a vintage MTB with Suntour groupset from 1992. I really like this bike but the chain skips at the 6th cog. I replaced the chain and still the same issue. This happens under heavy load. Given that the freewheel is 30+ years old, I am assuming that is the culprit. Now, I found the same freewheel on sale for $30. This is manufactured in late 1990. Do you think this is in good condition and has many more miles left? I am having difficulty understanding the wear condition. Any help would be appreciated. Please see the photos of the freewheel which I am considering buying.
I have a vintage MTB with Suntour groupset from 1992. I really like this bike but the chain skips at the 6th cog. I replaced the chain and still the same issue. This happens under heavy load. Given that the freewheel is 30+ years old, I am assuming that is the culprit. Now, I found the same freewheel on sale for $30. This is manufactured in late 1990. Do you think this is in good condition and has many more miles left? I am having difficulty understanding the wear condition. Any help would be appreciated. Please see the photos of the freewheel which I am considering buying.
Pastor Bob is a forum member here, And he fractures, fixes and fine tunes freewheels.
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Skips only in #6? It's been ridden by someone with one favorite gear. Very common. Now SunTour made lots of spare cogs and unscrewing them and screwing on a new wasn't hard (before 30 years of sitting there) but you had to have the new cogs. They are still around but not common and maybe not cheap.
Edit: To the new freewheel - as others said above, try it. Visuals tell you nothing unless it's way beyond worn.
SunTour is good stuff and I applaud trying to stay original and proper, but ... freewheels are consumables like sneakers for basketball players. If you gotta go out on that court and play, good sneakers are worth far more than trying to keep your favorite Nikes going. Shimano, SunRace and others make good freewheels that work. (And once its dirty, they all look the same.)
Now, an older chain might run fine over that #6 and will in time wear down its sisters to match. I have two newish freewheels with the same (my preferred) gearing. Better one had one worn cog that rode OK if I didn't push it and skipped every time I did on my best 7-speed. I took the other off my city bike, put it on the good one and ran the older city bike chain over the freewheel with the skipping cog. Runs like a dream. They both do.
Edit: To the new freewheel - as others said above, try it. Visuals tell you nothing unless it's way beyond worn.
SunTour is good stuff and I applaud trying to stay original and proper, but ... freewheels are consumables like sneakers for basketball players. If you gotta go out on that court and play, good sneakers are worth far more than trying to keep your favorite Nikes going. Shimano, SunRace and others make good freewheels that work. (And once its dirty, they all look the same.)
Now, an older chain might run fine over that #6 and will in time wear down its sisters to match. I have two newish freewheels with the same (my preferred) gearing. Better one had one worn cog that rode OK if I didn't push it and skipped every time I did on my best 7-speed. I took the other off my city bike, put it on the good one and ran the older city bike chain over the freewheel with the skipping cog. Runs like a dream. They both do.
Last edited by 79pmooney; 12-22-22 at 06:13 PM.
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Two points
1- the pictured freewheel is close to new condition as far as wear goes.
2- it's rare, but not unheard of, for wear to cause skipping on any of the larger freewheel sprockets. So, I'd do dome more diagnostics before replacing the freewheel.
1- the pictured freewheel is close to new condition as far as wear goes.
2- it's rare, but not unheard of, for wear to cause skipping on any of the larger freewheel sprockets. So, I'd do dome more diagnostics before replacing the freewheel.
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FB
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An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
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As the years have gone by after the non SR SunTour ended I find it less and less worthwhile to invest much in an indexed SunTour system. The cog to cog spacing and lever cable pull amounts were different across the range of travel. I was told that it was based on cable tension goals. Whatever it clearly lost in the real world market place.
This from someone who first had SunTour on his first sew upped bike, a 1972 Fuji Finest. Ran BarCons and then ST's indexed ones till mid 1990s. I have disliked the Shimano 500 lb. gorilla for years. But at some point one must get with the future if they want to continue to wear out parts by using them. That and the preference to not bend axles on FW hubs that handle 7 cogs. Andy
This from someone who first had SunTour on his first sew upped bike, a 1972 Fuji Finest. Ran BarCons and then ST's indexed ones till mid 1990s. I have disliked the Shimano 500 lb. gorilla for years. But at some point one must get with the future if they want to continue to wear out parts by using them. That and the preference to not bend axles on FW hubs that handle 7 cogs. Andy
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#10
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Spot on Andrew R. Stewart! Suntour is/was a somewhat sad case: perhaps David and Goliath with Goliath winning. Time to move on at this point.
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Depends on friction or index
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Check your derailleur alignment before you start replacing parts.
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Shimano MF-TZ30Tourney Freewheel (14-34T 6 Speed)
Three of this particular Freewheel I have used emitted a Cluck/Click after moderate wear. All the teeth looked like they were still usable but the Cluck would intermittently start in the 3rd gear. Man I had more than a bugger of a time chasing those dam Clucks checking everything and then I switched out a wheel set that had a different Freewheel and the Cluck disappeared. I have not figured out why this happens but these Freewheels are very economical so I just replace them when they Cluck...Image From:https://www.redringtones.com/chicken-clucking/
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Wear on a cog doesn't start with the teeth, but the transition between the teeth. the teeth will look fine but when the chain pulls further into the transition it wears the chain into that cog wearing the roller pivot in the chain, then the wear on the cog teeth begins. The chain skips in other gears before the teeth wear is evident because the chain and that one cog are mated. Worn in. if the gears had been changed more and the wear spread across the cogs more, there might not be a problem now.
So I'm saying the cog wears first in the transition and that wears the chain next.
Anyway, my theory.
Last edited by Schweinhund; 12-25-22 at 01:33 PM.
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I'd replace it with the all-chromed Sunrace 7-speed. (Under $25 shipped.) The all-chromed models are their best quality product. The cogs are ramped, so shifting will improve.
https://www.ebay.com/itm/17524944499...Bk9SR_D92sCqYQ
https://www.ebay.com/itm/17524944499...Bk9SR_D92sCqYQ
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I'd replace it with the all-chromed Sunrace 7-speed. (Under $25 shipped.) The all-chromed models are their best quality product. The cogs are ramped, so shifting will improve.
https://www.ebay.com/itm/175249444991?
https://www.ebay.com/itm/175249444991?
You're aware that zinc isn't chrome, right? it's more of a rust preventative than anything else.
Plus it's shiny