6 speed Campag freewheel/hub to Shimano?

Hi, I've just picked up a 1989 'Abilita' built by Paul Wilkins in Dorset, and have a quick question regarding Campag freewheel/hub/Shimano freewheel compatibility.

The guy I bought it from used to race it and it has a really small block on the back, something like 14-20, and I'm really struggling on steep climbs.

Can I fit a 14-28 Shimano 6 speed freewheel, or change the inner ring to a 32?

Thanks!

No way will you get a smaller chainring on that - any more and the bolts would be outside the teeth! 39T is smallest on Shimano.
The cog spacing is the same (5.5mm) on 6 speed, so provided the freewheel doesn't have a strange threading you should be able simply to fit a larger size. Beware however that you may need a longer chain to get the big-big combo to engage (but you should fit a new chian with a new freewheel anyway). ALSO, the rear mech might not like the larger size, the jockey teeth may rumble along the sprocket. This depends on how long the mech hanger is below the axle. If that's the case use a mech dropper to lower the mech (£2 on ebay).

hamster":3mf1o98j said:

No way will you get a smaller chainring on that - any more and the bolts would be outside the teeth! 39T is smallest on Shimano.

Click to expand...

Doh! :facepalm: I see that now, thanks!

hamster":3mf1o98j said:

The cog spacing is the same (5.5mm) on 6 speed, so provided the freewheel doesn't have a strange threading you should be able simply to fit a larger size. Beware however that you may need a longer chain to get the big-big combo to engage (but you should fit a new chian with a new freewheel anyway). ALSO, the rear mech might not like the larger size, the jockey teeth may rumble along the sprocket. This depends on how long the mech hanger is below the axle. If that's the case use a mech dropper to lower the mech (£2 on ebay).

Click to expand...

Hmm...it's not clear from what I can see on Sheldon Brown's site re Campag vs Shimano freewheels (https://www.sheldonbrown.com/freewheels.html)

I'm assuming the Campag hub is Italian threaded and a Shimano freewheel would be ISO threaded? not a lot of difference:

Type Inch Metric
Italian 1.378" x 24 tpi 35 x 1.058 mm
ISO 1.375" x 24 tpi 34.92 x 1.058 mm

I think I'd definitely need something to lower the mech, as it looks really close on the middle cog at the moment.

hamster":f7jc1v4q said:

No way will you get a smaller chainring on that - any more and the bolts would be outside the teeth! 39T is smallest on Shimano.

Click to expand...

shimano is 38 smallest. (I'm running 38/49 on my training bike) Campag is 135mm BCD so it'll be 39T smallest.

Looks like this is the mech
http://velobase.com/ViewComponent.aspx? ... &AbsPos=32

So *should* be ok up to 30 tooth sprocket, if the data is correct. Just need to make sure your wrap is ok.

mattr":2rap1lo4 said:

hamster":2rap1lo4 said:

No way will you get a smaller chainring on that - any more and the bolts would be outside the teeth! 39T is smallest on Shimano.

Click to expand...

shimano is 38 smallest. (I'm running 38/49 on my training bike) Campag is 135mm BCD so it'll be 39T smallest.

Click to expand...

Indeed 38T with 130mm and 39T for Campag, my brain freeze and wrote Shimano instead of Campag.

Thanks for the replies, that makes life easier for me

So, I shouldn't have any issue using a Shimano freewheel on the Campag hub?

*Shouldn't* have any issues. If tolerances are out and it is an IT threaded freehub it *might* not play nice. (or it might be fine.)

Personally, i'd be popping it off and checking which thread it is (or confirming hub model/year and going from that.)

hamster":3c3crk9b said:

my brain freeze

Click to expand...

Wednesday is a swine for that.

If that chainset is a 144PCD then minimum is 41T that you can fit