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Dustine
Joined: 17 Jul 2006
Posts: 159
Location: United Kingdom
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 Posted Sun Aug 9, 2009 9:07 pm |
I have an older bike with a 5 speed freewheel, and was wondering if I can fit a 7 or even 8 speed freewheel in its place?? The rear end spacing is 120mm.
Thanks for any help!
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redvee
Joined: 09 Oct 2007
Posts: 4197
Location: Bristol
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mattsccm
Joined: 22 Nov 2006
Posts: 130
Location:
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Posted Mon Aug 10, 2009 9:52 pm |
6 and 7 speeds free wheels are normally spaced at 126 mm whereas 8 speed cassettes are 130 or 135 if a mtb.
Some Ultra 6 set ups were 120 although this is not going top be common. Assuming you have 5 speed threaded wheel you are probably going to need the wheel redished to allow for the wider set of sprockets. ie as the axles has to be moved more ot the right the rim needs moving. not a big job for any shop.
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Dustine
Joined: 17 Jul 2006
Posts: 159
Location: United Kingdom
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Posted Mon Aug 10, 2009 11:24 pm |
Ah, thanks folks!! I should be ok to redish the wheel myself (i built it in the first place) i gather i move some of the spacers from the non-drive side to the drive side. VeloSolo actually sell axle spacers of a variety of thicknesses which might make life a little easier too. I will have a good look and see how much space i have on the non-drive side first though. Thanks for the help!
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Tom753
Joined: 24 Jun 2003
Posts: 737
Location: United Kingdom
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Posted Tue Aug 11, 2009 9:54 am |
I would doubt if there are any washers/spacers on the left hand side you could move to the RH side. On my hubs, the LH side only has the cone, a thin washer and the locknut.
You need to increase the OLN of the hub to 126mm or 130mm by adding more washers/spacers to the RH side. If going to 126 you can probably still use the same hollow axle, but for 130 you probably need a longer one.
Then there's the issue of your frame rear end width. If you don't make it wider by bending the stays permanently (cold setting). you'll need to spring open the frame every time you refit the wheel, plus the fact that the dropouts will no longer be parallel.
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Dustine
Joined: 17 Jul 2006
Posts: 159
Location: United Kingdom
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Posted Tue Aug 11, 2009 8:23 pm |
No, youre right, there are no washers on the left. Damn. There is space for 6mm worth of spacers on the axle, easily, but as you say i will need to be springing the drop outs every time i change the wheel. Thats do-able, but the drop outs not being parallel is more of a pain. Although theyre forward facing, and its geared, so a bit less of an issue i guess.
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crankycrank
Joined: 12 Jan 2009
Posts: 401
Location: San Diego, USA
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Posted Wed Aug 12, 2009 1:04 am |
If you are going to widen the dropouts to 130mm there are a couple of things to note. First I recommend you get the dropouts parallel. Most shops have a tool to do this properly. The reason being that uneven dropouts put extra stress on the axle causing it to break prematurely. Second, almost all old freewheel hubs have the drive side bearing placed fairly close to the center of a properly dished wheel and even more stress will be put on the axle when you put a longer one on for 130mm spacing. Just make sure you use the highest quality-strongest axle you can find and it should work OK. That's one of the benefits of the newer cassette hubs is that the hub drive bearing is moved closer to the outside of the hub for more strength.
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Dustine
Joined: 17 Jul 2006
Posts: 159
Location: United Kingdom
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Posted Wed Aug 12, 2009 8:25 pm |
Blimey, its a minefield!!! Ive never bent an axle (though i have bent cranks and forks on various bikes!!) but i do recall that its one of the advantages of modern hubs... Hmmmm. Does anyone know how much wider a 6 or 7 speed freewheel is than a 5 speed?? If its only a couple of mm then i could get away with a couple of mm spacer, which would hardly move the drop-outs at all. If its much bigger, then it is going to be adding quite a bit of stress to the axle, and im not so sure i want that.
In some ways, the main problem is the slipping of the chain, which is new and an 8 speed, and it means i cant get out of the saddle at the moment for fear of it chucking me against the bars!!! But also, its not so easy finding 5 speed freewheels new, 6 is easy. Maybe i just need to splash the cash and then bodge it; but i have wasted quite a bit of money on those types of failed bodges in the past!!!!
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mattsccm
Joined: 22 Nov 2006
Posts: 130
Location:
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Posted Thu Aug 13, 2009 5:46 pm |
Search for sheldon Brown. Its all there.
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NervexProf
Joined: 30 Sep 2005
Posts: 2600
Location: United Kingdom
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Tom753
Joined: 24 Jun 2003
Posts: 737
Location: United Kingdom
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Posted Thu Aug 13, 2009 10:10 pm |
I've seen those Shimano 5 speed freewheels before, but I didn't buy any, I don't think they wouldn't fit in my 120mm bike. The freewheel body is wider than necessary, you can see it protrudes out past the smallest sprocket. I suspect Shimano have used a body designed for 6 sprockets and just left off the smallest to make it into a 5 speed.
But they would be good to use on a 126mm wheel to lessen the dish by moving the washers/spacers from the RH side of the hub to the left.
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Dustine
Joined: 17 Jul 2006
Posts: 159
Location: United Kingdom
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Posted Sun Sep 6, 2009 9:23 pm |
Did those cheap ones off ebay fit the wheel ok?? Whats the overall width of the sprocket part??
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IO
Joined: 08 Nov 2009
Posts: 1
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Posted Sun Nov 8, 2009 10:57 pm |
Have you worked something out yet?
I have a 120mm dropout spacing and I fitted a 6 speed, standard spaced not Ultra, Suntour freewheel (around the mid 80's ! ) without changing the wheel or spacing, I guess it just depends on the clearance on your frame.
I'm now looking to upgrade to 7 speed as the overall freewheel size is only a couple of mm bigger and I reckon it will still fit.
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