new member question about freewheels

[phil007]

hi, thank yo for letting me join this group.

I am updating an old dawes 27inch wheel 531 frame. I have put sora levers and derailluers on it. these work fine, though there are gaps in the rear changer as i have 5 speed freewheel. i have located an8 speed freewheel :

Tranzmission Freewheel Cassette

on a site called dotbike.

this should correspond to the changes on the sora lever. however, i am worried whether my rear wheel and drop outs will be compatible. i have read elsewhere about " dishing" the rear wheel but i dont know what this is.

any advice welcome

thank you

PS i currently ride a giant scr3 aluminum frame. the reason for doing upp the old bike is to see how diferent, if atall, a steel framed bike with crossed spokes and box rims feels to ride. apparently it should be more comfortable and responsive but a little slower. when i have done this i can consider whther to ever buy a carbon bike . PLANET X ????

 

[RecordAceFromNew]

Welcome to the forum!

A tough question to answer quickly, but I shall try...

First off 8 speed freewheels (as opposed to cassettes) are very rarely used. This explains why.

If your 5 speed freewheel is original for the frame, then your frame is likely to have a OLN distance of 120mm. Now since 8 speed freewheels are designed for frames with 130mm OLN distance, you are likely to encounter problems (chain clashing with frame, inadequate axle length etc.) if you simply install it on your hub. Even if the axle length is adequate and clash can be avoided by packing the axle with washers on the right hand side, you will end up with the rear wheel/tyre not centered at the back, hence the need to redish the wheel also.

If your frame is steel (which is likely), the conventional upgrade path is not to use an 8 speed freewheel, but to upgrade the wheel to one with a modern road bike rear hub of 130mm OLN distance, and spreading the frame to accommodate (per second attachment above). Most people would also opt for modern 700c rims as opposed to 27" rims to go with the modern hubs since there is a much wider/better tyre/hub choice, but with the possibility of having to address the problem of brake caliper reach (since a 700c rim's braking surface is about 4mm lower than that of a 27" rim). You can see whether you have this problem by checking whether your brake pads can readily go lower by this amount front and back. If they can't, you will also have to change the brake calipers to long drop ones if you use 700c rims.

You will see that the late great Sheldon Brown had covered the above much better than I.

Good luck!

 

[Cheule]

My bike had an 8-speed freewheel fitted and I had nothing but problems with it, the axle started to buckle on it. Just replaced it with a Shimano hub and cassette and very happy with it. I recommend you do the same.