Convert 10sp to 8sp

Stelvio1925 said:

I have a spare Powertap 2.4 wheel w/ Campy hub I'd like to convert to 8-speed for use on 2 older bikes with 8-spd campy Chorus drivetrains from the mid 90s. My LBS told me they couldn't convert the Ergo levers to 9 or 10 spd as parts were unavailable anymore. But I wondered if anyone's found cassette spacers that would allow me to use the wheel with just 8 cogs from current year Campy 10-spd cassettes. I've tried the spacers from 8-sp cassettes but the cogs are still loose. I haven't gotten hold of spacers from a 7-sp or 9sp group yet, so I don't know if that's an option.

A search of the forums have revealed no threads addressing this specific issue. Thanks in advance for any information that may help. I'm just looking for the simplest solution to allow me to use the Powertap wheel in these 2 bikes, without having to upgrade to 10sp.

Why bother, you may ask. I guess I hate discarding things that are still working well. Plus I like the aesthetics of the early Ergopower Campy groups from the 90s, before carbon came into vogue.

If you have 8s levers, I have the disc to convert to 9s..Cannot convert a pointy top ERGO from 8s or 9s to 10s.

To keep the levers 8s->

Use a Veloce loose cog 9s cogset and then use either black Campagnolo 8s spacers or Wheels manufacturing RED spacers and use 8 of the 9 cogs.
Adjust rear derailleur, go ride.

Stelvio1925 said:

I have a spare Powertap 2.4 wheel w/ Campy hub I'd like to convert to 8-speed for use on 2 older bikes with 8-spd campy Chorus drivetrains from the mid 90s. My LBS told me they couldn't convert the Ergo levers to 9 or 10 spd as parts were unavailable anymore. But I wondered if anyone's found cassette spacers that would allow me to use the wheel with just 8 cogs from current year Campy 10-spd cassettes. I've tried the spacers from 8-sp cassettes but the cogs are still loose. I haven't gotten hold of spacers from a 7-sp or 9sp group yet, so I don't know if that's an option.

A search of the forums have revealed no threads addressing this specific issue. Thanks in advance for any information that may help. I'm just looking for the simplest solution to allow me to use the Powertap wheel in these 2 bikes, without having to upgrade to 10sp.

Why bother, you may ask. I guess I hate discarding things that are still working well. Plus I like the aesthetics of the early Ergopower Campy groups from the 90s, before carbon came into vogue.

You can CUT supplemental shims for your spacers from soda/beer cans ...

Use a pair of scissors to remove the top-and-bottom of the can + a vertical slice to make small "sheets" aluminum which you will want to "flatten" slightly so you can work with them more easily. Trace the INNER & OUTER diameter of one of the spacers on the can with a SHARPIE marker ... cut out, and then use some emery cloth to "round" the edges, slightly.

Some care probably needs to be taken so you don't cut yourself before you round the edges!

Aluminum cans are THIN (I think someone measured it at only 0.2mm), so it could be tedious OR the perfect solution.

You MIGHT be able to cut some "supplemental shims" from the plastic container that is used for talc, liquid laundry detergent, etc. -- different containers undoubtedly are molded with different thicknesses.

WHEELS MANUFACTURING used to provide "conversion" spacers ... I don't know if they have any for using 10-speed Campagnolo cogs respaced for 8-speed indexing.

The spacers that come with those convert-your-freehub-to-Single-Speed may be the right thickness out-of-the-box, but may only be the same thickness as an 8-speed spacer.

If none of those options is viable, you can get some PCB pipe (1 3/8" ID?) & cut some custom spacers ...

BTW. "Bottom Bracket" spacers will sleeve onto a freehub body ... some LBSes may still carry them ... they are/were available in different thicknesses ... but, that is possibly the most expensive option.

BTW. You CAN simply cut/file the indexing notch into the 8-speed cogs using a FLAT [censored] file (or, a triangular file) to get an 8-speed cog to fit on a 9-/10-speed Campagnolo freehub ... the fit may (seem to) be tight, so you may want to relieve the inner "diameter" of the cogs with a very light pass of a half-round file, but I don't think it is a necessary step to get an 8-speed cog to fit onto a 9-/10-speed freehub body.

I don't remember the difference in the length of an 8-speed freehub, but you will undoubtedly need at least ONE "spacer" to take up the slack ...

I think you will want to "borrow"/(i.e., buy) a 12t from an 11-to-whatever cassette so you can put the spacer on the dropout end of the freehub so that you won't have to fiddle with the indexing when you swap wheels. You may still need a shim for the flange side of the cassette.

alfeng said:

... some PCB pipe (1 3/8" ID?) & cut some custom spacers ...

OOPS! That should be "PVC pipe" unless some corporation in the future wants to create a printed circuit on a cylinder!

Thanks for the ideas guys. Didn't realize spacers were available for for converting freehubs for single speed use. But my previous dry fitting of the 8-speed spacers with 8 of the Centaur loose cogs revealed I only needed a few mm to get the lockring to engage.

Most of the conversion spacers were too thick. But everyone's suggestions prompted me to think out of the box and voila: the solution was literally sitting under my nose. I used the loose 16t cog as the "spacer" placing it hub-side of the 23t cog, used the 8sp spacers as I originally intended, and the lockring engaged fine. The drivetrain shifts properly for all the gear combinations I normally use with the bike on the workstand. There's enough clearance on the dropout-side and no chain rub after some minor rear & front derailleur adjustment.

I have yet to test it on the road under load as there's too much snow on the ground. Seems to work on the trainer so far. Thanks everyone.