Bicycle Mechanics - 5 spd freewheel to 7 -- issues?
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06-20-08, 07:50 AM
I've got an old Univega gran turismo that I'd like to replace the 5 spd freewheel w/ a 7 spd freewheel from a 700C wheel that I have on hand. Assuming the 7 spd freewheel will fit into the 120mm spacing once I remove the spacer that is on the axle, what other issues do I need to deal with? Will the spacing on the left side of the freewheel be messed up w/o the spacer there and can I readjust by moving everything a bit to the left side? thanks!
Sounds like good questions for the Classic and Vintage thread. Here are some comments from Sheldon Brown on those issues:
<<5-Speed to 6- or 7-Speed
Hubs originally intended for 5-speed freewheels can be converted to use 6- or 7-speed freewheels. You will generally need to add a few spacer washers to the right side of the axle, building it up far enought that the cone locknut can reach the frame dropout through the wider freewheel body. You will need to re-center the axle but probably won't need to replace it with a longer one. You'll also need to re-dish your wheel (http://sheldonbrown.com/gloss_da-o.html#dish) , and probably re-space your frame (http://sheldonbrown.com/frame-spacing.html). If you're fairly handy, this is not an unreasonable thing to do.>>
I in no way disagree with the above. However, I just wanted to point out that 7 speed freewheels were designed for a 126mm rear hub and 5 speed freewheels were designed for a 120mm rear hub (to the best of my knowledge). Someone please correct me if I am wrong.
yes, that is my understanding. With the exception that Suntour made the Ultra, which was a 6 speed freewheel designed to fit in the 120mm (5 speed) spacing. I believe "normal" 6 and 7 speed freewheels were designed for frames with the 126mm spacing.
06-20-08, 10:43 AM
As long as the axle is long enough (you can change if needed) you might get by with adding a 5-10mm of spacers under the axle lock nut to space it out a little you may also need to cold set the frame drop out a little.
I did this upgrade on an old tandem but I went from 6-7 but it needed a little spacing as well.
I have a few photos of this on my Tandem Project page if you want to look no details but just some photos of the changes I made which all worked fine.
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