does a 120mm spaced cassette hub exist for multiple cogs?
Im strapped to a 120mm spacing
I would love to build a wheel with those nice tight UG IG cogs. Im running a 5 speed freewheel, and the ultra 6 just wont work because of dated cog profiles, I have tried all kinds of chains the only solution to get 6 or maybe even 7 is casette or try to find a shimano sis 5 speed-which most likely also dos not exist. mike |
SunRace makes a 5 speed 14-28 freewheel with Hyperglide cogs. Done.
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Since the difference between "regular" and "ultra" spacing is in the spacers, would it be possible to cram 6 cogs onto a 5-speed freewheel with narrower spacers? Or would that plan fall apart with the outer cogs?
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I'm fairly certain there was a 120mm UG hub back in the day. You could always respace a 126 down to 120. A trick setup would be to start with a 126mm HG hub, remove spacing from the gear side untill the chain hits the stay/dropout then add 1mm. From there go to the non-gear side and space down to 120mm.
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The Colonel beat me to it. I just took off a rusted Sunrace 5 speed HG freewheel from a 24" wheeled kids' mtb that I picked up for parts. So, at least these exist.
Other option, find an old/used Uniglide 6 speed freehub, respace it and cut off the excess axle length. I think a 7 speed freehub would yield too severe a dish at 120mm OLD. |
I've put modern 6-speed freewheels on bikes with 120mm spacing, and in some cases the standard-spaced 6s freewheel fit on the bike's stock rear hub with no modification to the axle spacing.
Going from there, there is a lot of minor tweaking that can be done to the axle spacers and wheel dish that will let you put even a 7s hG freewheel into a 120mm frame with still no difficulty slifing the wheel in. I re-did the axle spacing and dish on this wheel for my early PX10, and still used the stock 5sp axle! It's nice and strong and the 7sp freewheel plays nice with a pair of 8s Ergo Shifters. http://farm8.staticflickr.com/7076/7...a4baae22_c.jpg |
I showed this pic before but here it is again
I got the ultra 6 in there but due the distance between the BB and the rear axle the chain is far more angled then on a 700 wheeled bike the falcon7 and shimano body are just too wide to fit in there. this is what i got: http://i51.photobucket.com/albums/f3...s/IMG_6721.jpg here is some comparison regina 5 ultra 6 falcon 7 shimano 7 http://i51.photobucket.com/albums/f3...s/IMG_6772.jpg |
2, the hybrid hub that Brompton has used for many years , uses 2 external cogs on a 3 speed IGH. for 6 speeds
They had Sachs as a supplier , AW , 3 spline cogs, [I use the 15t on my AW3. every 5th tooth is short for shifting.) now Sturmey makes their hubs, half steps the 3 internal gears Shimano BMX spline same as S3X uses.. stock is a 13, 15, new 2 speed hubs without IGH are sold as 12, 16t pair 28 hole.. fine for the 16" wheel.. |
Originally Posted by ThermionicScott
(Post 14614611)
Since the difference between "regular" and "ultra" spacing is in the spacers, would it be possible to cram 6 cogs onto a 5-speed freewheel with narrower spacers? Or would that plan fall apart with the outer cogs?
You only have to remove the smallest, externally-threaded cog and fond a rubber o-ring to snap into the exposed gap. Any 126mm 7-speed Shimano freehub is instantly made into a 124mm freehub just by removing the 1mm washer from each end of the axle assembly, so no re-dishing required and the wheel fits easily into a narrower frame. A bit of additional spacing can be removed from the left end as well, further narrowing the hub with almost-negligible effect on dish, and that's still with 7 speeds on there. Using a 6-speed cassette could easily allow further symmetrical narrowing of the axle assembly, enough to slip right into a 120mm frame with perhaps a 122mm axle assembly. A couple of millimeters of chainstay splay doesn't have a meaningful effect on anything. |
Originally Posted by puchfinnland
(Post 14614217)
the ultra 6 just wont work because of dated cog profiles,
I have tried all kinds of chains |
I never cease to be amazed by how much the shifting on an Ultra-6 freewheel is improved by using a 9sp chain.
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Originally Posted by puchfinnland
(Post 14614695)
I showed this pic before but here it is again
I got the ultra 6 in there but due the distance between the BB and the rear axle the chain is far more angled then on a 700 wheeled bike |
the shimano body is too wide to fit-look at pic above
-sombody please prove me wrong and show me a narrow body! thanks for the offer on the chain but I cant even get a 10spd chain to work on my arrangement. the only way is to build a UG-ultra 6 if the narrow body exists. |
Originally Posted by cyclotoine
(Post 14614807)
That looks like a 700c wheel, did I miss something? What size of wheel are you putting this on?
its a 24" junior roadbike. |
Originally Posted by puchfinnland
(Post 14614812)
thanks for the offer on the chain but I cant even get a 10spd chain to work on my arrangement.
. |
Originally Posted by dddd
(Post 14614739)
Any 7-speed Dura-Ace or Sante 7sp freewheel can be run as a narrower 6-speed "Ultra" freewheel, no need to change any spacers.
You only have to remove the smallest, externally-threaded cog and fond a rubber o-ring to snap into the exposed gap. Any 126mm 7-speed Shimano freehub is instantly made into a 124mm freehub just by removing the 1mm washer from each end of the axle assembly, so no re-dishing required and the wheel fits easily into a narrower frame. A bit of additional spacing can be removed from the left end as well, further narrowing the hub with almost-negligible effect on dish, and that's still with 7 speeds on there. Using a 6-speed cassette could easily allow further symmetrical narrowing of the axle assembly, enough to slip right into a 120mm frame with perhaps a 122mm axle assembly. A couple of millimeters of chainstay splay doesn't have a meaningful effect on anything. |
Originally Posted by old's'cool
(Post 14615440)
dddd, I like the way you think. I have a fantasy rear wheel build that is completely at the conceptual stage since I don't know much about cassettes and freehubs yet. The goal is to have a rear wheel that is at least as strong as the front wheel, with the same rim design, optionally more spokes. The key to this is minimized dish and axle overhang, which I would like to achieve by using a 130mm frame and axle, and the narrowest cassette available, which I assume is a 6-sp, along with the widest possible hub, e.g. a tandem hub or perhaps other freehub, e.g. SS, if compatible with cassette somehow. Do you have any recommendations? If this is too much of a tangent to the OP, we can start a new thread. :)
Another similar strategey is to coldset the rear end so that the dropouts are offset approx 8mm toward the DS and then re-dish the rim for equal spoke tension so that it is back inline with the frames front triangle (but rim is not centered between dropouts). I dont think there is much need to try to gain extra strength for the axel if you are using casette hub, bending/breaking axels isn simply not the problem that exist with freewheel hubs. |
+1 on the above.
Too bad that the invention of the derailer bicycle didn't immediately decree that rear wheel mounting points would forever be positioned with a 5 or 10mm offset toward the right. The way things could have been done! |
Originally Posted by dddd
(Post 14616248)
+1 on the above.
Too bad that the invention of the derailer bicycle didn't immediately decree that rear wheel mounting points would forever be positioned with a 5 or 10mm offset toward the right. The way things could have been done! |
Good points; thanks for the feedback! I will now go and try to digest this new information...
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I suspect that the freehub AND the offset rear wheel mounting may have been invented by the time of the derailer, but that such ideas didn't catch on due to existing tooling, parts compatibility or whatever.
Pushed to the limits, as for cyclocross racing, the rear spacing finally came up to 135 and of course the freehub already took over, the better for stronger wheels and axles, not to mention less stress on the DS dropout. |
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