7 speed freehub cassette on 5 speed gear system

[Stodgy]

Hi,
Not sure if this will work so thought I'd see if anyone had tried. I have an old sixties bike with a 5 speed suntour vx derailleur. Could I put some modern 700c wheels on it with a cassette style freehub and a 7 speed block? Would the mech be able to move far enough?

Cheers,
Sam

 

[Hillwalker]

In theory this is possible. But you will need to consider:

The brake drop. 700C wheels are slightly smaller in diameter than 27 wheels so choose your brake calipers carefully. It can be done though.

Your rear mech will need to be 7 speed capable. If using a compact 7 speed block you might be able to cheat with a 6 speed mech.

A better solution might be to use a screw on 7 speed freewheel with your original wheels. :shock:

Have your cake and eat it. No need to change wheels. Some 7 speed mechs will fit into a 126 OLD dropout so might be usable with your original 5 speed mech.

Or, if you only have the frame, then check out the specs of your Suntour RD at Velobase.com to see what cogs/teeth you have to work with.

HW

 

[Stodgy]

Hi,
Thank for the reply. I thought it might be tricky.

I currently have 700C rims on the bike and have callipers that fit. However, they are built onto Miche track hubs so I am very limited with options on those - Miche track sprocket or nothing.

I do have the wheels that were on the bike when I got it second hand which are Sunshine (?!) hubs on Mavic 700c rims. It has a threaded freewheel so I could use my 5 speed block. I'm just not sure how good they are, and I'm not expecting great braking performance from the rims.

Might try them and see how it goes.

Cheers,
Sam.

 

[Hillwalker]

My understanding is that Sunshine hubs (no matter how improbable the name :shock: ) are of good quality and possibly a forerunner of Dura Ace. Others may know more. Personally I would be very happy with a Sunshine/Mavic wheel setup in this case. I have 2 pairs of these hubs on various wheels and they look pretty good to me. I would say go for it!

HW

 

[GasPipeWarrior]

Velobase on Sunshine/Sansin

Unless the Mavic rims are in some manner knackered I'd be surprised if you experienced any braking issues - chromed steel issues aside. However if swapping a five speed block for a seven speed block would the wheel need to be redished/respaced to ensure the rim is centred between the stays/brake?

 

[Stodgy]

Re:

They are alloy rims on the sunshine set. I would only run the 5 speed screw on freewheel on these. I have another, much more contemporary, set of wheels - shimano 105 cassette body hubs with mavic 321 rims. I have loads of 7 speed cassettes so was going to try bunging these wheels in the old frame to see if it would change gear. I suspect there will be a number of issues, but it's all good fun.