1984 Suntour freewheel interchangeability
#1
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1984 Suntour freewheel interchangeability
I just got a 1984 Team Fuji with an ultra 6 freewheel and I'm wondering if the 7 spd freewheel I took off my 1989 Ironman
Expert will work on the fuji. I believe it is a Suntour Ultra 7?
Expert will work on the fuji. I believe it is a Suntour Ultra 7?
#2
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Should work as long as it fits with the hub spacing. You will have to adjust the rear der. and some may not drop low enough to reach the lowest cog, you just have to try it. Your going to run as friction correct?
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#3
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If you can measure the clearance between the teeth of the smallest cog and the inside face of the dropout, a determination can be made as to whether or not the 7s freewheel will fit and still allow chain clearance.
If you're seeing 7mm or better clearance, I'd bet that the 7s freewheel will have plenty of operating room for the chain.
If the existing freewheel is perhaps an Ultra-6 spaced freewheel, then add a couple of millimeters, you might need 9mm of existing clearance.
Since this is a high-quality frame, there should be no issue of derailer claw bolt (or axle-stop screw/nut) protruding into the chain/freewheel's operating space.
I often up-fit older bikes with N+1-speed freewheels!
If you're seeing 7mm or better clearance, I'd bet that the 7s freewheel will have plenty of operating room for the chain.
If the existing freewheel is perhaps an Ultra-6 spaced freewheel, then add a couple of millimeters, you might need 9mm of existing clearance.
Since this is a high-quality frame, there should be no issue of derailer claw bolt (or axle-stop screw/nut) protruding into the chain/freewheel's operating space.
I often up-fit older bikes with N+1-speed freewheels!
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If you can measure the clearance between the teeth of the smallest cog and the inside face of the dropout, a determination can be made as to whether or not the 7s freewheel will fit and still allow chain clearance.
If you're seeing 7mm or better clearance, I'd bet that the 7s freewheel will have plenty of operating room for the chain.
If the existing freewheel is perhaps an Ultra-6 spaced freewheel, then add a couple of millimeters, you might need 9mm of existing clearance.
Since this is a high-quality frame, there should be no issue of derailer claw bolt (or axle-stop screw/nut) protruding into the chain/freewheel's operating space.
I often up-fit older bikes with N+1-speed freewheels!
If you're seeing 7mm or better clearance, I'd bet that the 7s freewheel will have plenty of operating room for the chain.
If the existing freewheel is perhaps an Ultra-6 spaced freewheel, then add a couple of millimeters, you might need 9mm of existing clearance.
Since this is a high-quality frame, there should be no issue of derailer claw bolt (or axle-stop screw/nut) protruding into the chain/freewheel's operating space.
I often up-fit older bikes with N+1-speed freewheels!
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When they came out, the Ultra-6 was touted as a 6-speed that could fit in the space of a standard 5-speed (i.e. 120 mm OLD). The Ultra-7 was similarly touted as the 7-speed that could fit in the space of a standard 6-speed (i.e. 126 mm OLD). I believe that you will need to spread and realign the dropouts and add washers to the rear axle to make it work. You might also need a longer axle. That said, are you sure you have an Ultra-6? Perhaps it's a standard 6-speed, which was not uncommon in 1984. Check the OLD and see if it's around 126 mm.
Last edited by davester; 08-10-20 at 10:34 AM.
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^^^^^ +1; I'd START by measuring the rear triangle spacing and OLD of the axle.
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Since you have both the wheel and the freewheel, it's best just to try it and see. Your wheel may be dished for the 6 and may or may not work with the 7. I have a wheelset with a 6, and when I tried a 7 that was a bit wider, the face of the small cog went past the locknut face, so no go. Options were to use the 6, find a thinner 7, or move a hub spacer from one side to the other and redish the wheel. I opted to keep the 6.
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If the OP is willing to tinker with axle spacing and dish, a 7s should work with frame spacing at 124mm or even a little smaller than that.
For example, a Shimano 7s freehub can have a 1mm washer removed from both ends of the axle and boom you have a 124mm freehub with stock/intended wheel dish and still with generous clearance for the chain (unless axle-stop or claw hanger hardware is present or unless the seatstay is poorly shaped).
The 124mm hub spacing can then be slipped into slightly narrower frame spacing like Peugeot's typical 121mm.
I often do as noobinsf suggested and start by screwing on the wider freewheel to see exactly how far out that the locknut extends out from the face of the smallest cog, since I only need about 3.3mm there or even slightly less if I use 9s chain.
For example, a Shimano 7s freehub can have a 1mm washer removed from both ends of the axle and boom you have a 124mm freehub with stock/intended wheel dish and still with generous clearance for the chain (unless axle-stop or claw hanger hardware is present or unless the seatstay is poorly shaped).
The 124mm hub spacing can then be slipped into slightly narrower frame spacing like Peugeot's typical 121mm.
I often do as noobinsf suggested and start by screwing on the wider freewheel to see exactly how far out that the locknut extends out from the face of the smallest cog, since I only need about 3.3mm there or even slightly less if I use 9s chain.
#10
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Everybody's pretty much covered the bases. If you're shifting friction, the primary issues are whether your axle is:
1. Spaced wide enough to allow the 7spd freewheel to fit in the frame
2. Spaced wide enough for the chain to be able to shift on/off the smallest cog without contacting the inside of the dropout/seatstay
If the 6spd freewheel is an Ultra-6, the outer face of the outer cog will be flush with the outer face of the freewheel body. If the outer cog overhangs the outer face of the body, you have a standard-spaced 6spd.
Standard-5/Ultra-6 is supposed to fit/work with 120mm rear axle spacing. Std-6/U-7 are supposed to work with 126mm spacing. Especially with Std-6/U-7, if you're retrofitting, you sometimes need a couple mm more. Mostly depends on how "fat" the chainstay and seatstay ends are at the dropout. Most frames designed for more cogs will have those ends profiled/thinned for more clearance, but an earlier frame may not.
I checked an '84 catalog, and the '84 Team did come with an Ultra-6 freewheel. Don't know if that means the rear is spaced 120mm. I'd a thunk they'd have gone wider in the rear by then, and the higher-end Fujis were Ultra-7, so they were 126mm. They likely went U6 instead of U7 to help hit the lower price-point, but that doesn't tell me whether they spaced the rear at 120 or 126. We didn't sell a lot of Teams, and my memory's flown.
You _could_ cram a 126mm-spaced axle into a 120mm frame, but it's not recommended. Better to widen the stays, and align the rear end and dropouts.
1. Spaced wide enough to allow the 7spd freewheel to fit in the frame
2. Spaced wide enough for the chain to be able to shift on/off the smallest cog without contacting the inside of the dropout/seatstay
If the 6spd freewheel is an Ultra-6, the outer face of the outer cog will be flush with the outer face of the freewheel body. If the outer cog overhangs the outer face of the body, you have a standard-spaced 6spd.
Standard-5/Ultra-6 is supposed to fit/work with 120mm rear axle spacing. Std-6/U-7 are supposed to work with 126mm spacing. Especially with Std-6/U-7, if you're retrofitting, you sometimes need a couple mm more. Mostly depends on how "fat" the chainstay and seatstay ends are at the dropout. Most frames designed for more cogs will have those ends profiled/thinned for more clearance, but an earlier frame may not.
I checked an '84 catalog, and the '84 Team did come with an Ultra-6 freewheel. Don't know if that means the rear is spaced 120mm. I'd a thunk they'd have gone wider in the rear by then, and the higher-end Fujis were Ultra-7, so they were 126mm. They likely went U6 instead of U7 to help hit the lower price-point, but that doesn't tell me whether they spaced the rear at 120 or 126. We didn't sell a lot of Teams, and my memory's flown.
You _could_ cram a 126mm-spaced axle into a 120mm frame, but it's not recommended. Better to widen the stays, and align the rear end and dropouts.
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