30 teeth sprocket for 8 speed Campag cassettes

[fausto99]

I think I'm correct in saying that there are some cassettes with the big cogs are alu.

Yes indeed. Probably the ones where the bigger sprockets are riveted onto a carrier thereby not contacting the freehub directly.

[mig]

i'm still running two bikes with campagnolo 8 set ups.

the commuter one uses DT levers so if the hub or rear mech dies then i'll be okay using a shimano wheel or similar.

the other runs '96 ergos and has a frame with no bosses for DT levers. going to be expensive methinks when the rear hub or ergo or rear mech fails on that beast. luckily it just goes on summer runs and sees no undue duress. i don't really want to fit a whole new groupset and the prices of campagnolo 8 kit are potty - plus you never know how much wear any item really has had.

not sure that either rear mech of mine has the capacity to run a 30T sprocket though.

[Brucey]

i'm still running two bikes with campagnolo 8 set ups.

the commuter one uses DT levers so if the hub or rear mech dies then i'll be okay using a shimano wheel or similar.

the other runs '96 ergos and has a frame with no bosses for DT levers. going to be expensive methinks when the rear hub or ergo or rear mech fails on that beast. luckily it just goes on summer runs and sees no undue duress. i don't really want to fit a whole new groupset and the prices of campagnolo 8 kit are potty - plus you never know how much wear any item really has had..

the shift ratio of current shimano 11s is not identical but it is within a gnat's wotsit of campag 8s. If the campag 8s RD failed and I didn't have another, I'd try a shimano 11s mech and see how that went. If necessary I'd respace the sprockets to suit that combination more exactly.

If the hub failed and I wanted to use a 8s shimano cassette, all that is required is to respace the middle six sprockets +0.2mm. This means adding 5 x 0.2mm = 1mm to the cassette width, which ought to be possible in most cases. If the lockring runs out of thread, then using a (dished) 10s bottom sprocket will 'buy back' ~1.0mm of spline length on the freehub body.

If the ergos failed and you had no replacements I'd suggest that you could engineer a bracket on the stem nosebolt which would accept a set of band-on DT levers. This is fairly easy provided the levers have integral cable stops. If anyone is interested I have made such things and I can post a photo.

cheers

[fausto99]

I will investigate if splines could be laser or water jet cut economically.

I have drawn up a 28T and 32T sprocket with an inner hole to fit a Campagnolo 8 speed (8 spline) freehub. My local waterjet cutter did not laugh me out of court, so I intend to send them CAD files to get a quote and some idea of any quantity price breaks.

Anyone else interested in having some in 1.8mm thick steel ? If so, what would be your upper price limit/sprocket?

[drossall]

Oh interesting. But would want it to fit a 9-speed cassette - don't have any 8-speed cassettes or, more importantly, wheels, so my plan is to build 8 sprockets onto a 9-speed cassette. I believe the splines are deeper on 9.

What do you reckon, 3 quid a sprocket would be a big saving.

[fausto99]

I managed to get a price from my local water jet cutter. Looks like custom sprockets will be about £10 each; going down to about £7 for larger quantities. Standard material thickness is 2.0 mm.

I will probably end up getting two of each (28 and 32 teeth). Does any one else want any?

[mattsccm]

I have a mate who might be. I'll ask later.

[Dickyboy]

@fausto99 - did you get anywhere with the larger sprockets, I'm looking at respacing my campag 8sp to suit shimano 9sp shifter and mech, so would need an extra sprocket and a 28t wouldn't go amiss.