Rear cog for a Campy cassette - Single Speed build

Hi all,

Looking for some help. I am building a little single speed roadie for my son, but my knowledge is limited so please excuse any stupid questions or component fopars.

I have a slick looking wheelset, Mavic cp 30’s (I think) on a set of campy hubs. The rear hub previously had a full cassette on it so I have bought a Wheels Mfg. SSK-CA Single-Speed Conveversion Spacer Kit.

Crankset was going to be a Campy Pista, but it just doesn’t have the clearance for the frame, probably about 0.25mm on the non drive side with a Campy Veloce 111mm BB. So I am changing to a Stronglight Track 2000 which has a much greater Q factor and should give the clearance to the frame I need.

I am runnng a KMC 1/8 (track / BMX) chain.

I am looking for a suitable rear cog, that will suit the Campy free hub. I have googled the cr@p out fo this but cannot find anything anywhere. I presently have a cog from the cassette on the bike, but it is very narrow and does not suit the chain.

My son is only 11, so the torque produced is only small and his frequency of riding is once a month at best, so it wont see a lot of use. But I would prefer to get it as “right” as I can.

Any advice on the:

  • BB Crankset combo?
  • Is there a rear (track) cog which will suit the campy free hub?

Cheers
Stu

Please to be using the search function.

Your answer is for the SS Sprocket is here. Ditch the 1/8 chain and chainring, use a road ring & 3/32" chain (8speed would be good) (Stronglight make a nice selection of 3/32 rings btw):
http://www.fixed.org.au/forums/thread15432.html

Also, greater Q factor will only spread the little ones legs further apart (bad thing), if the chainring at a 42mm chainline (Normal track chainline) hits the stays, so will any track crankset with a 42mm chainline. Solutions are 1) wider chainline (easy if you’re doing a cassette SS setup, use a road crankset and put the ring on the outside), 2) smaller chainring, 3) dent the stays.

The 111mm Veloce is the wrong BB for the cranks anyway, and would put the ring out further than normal.

Finally, he’s 11, the smallest ring you can put on your cranks is a 42 (41 theoretically), sounds like he’s going to be overgeared.

I did try the search function but was overwhelmed with info and gave up trying to skim through it for the relevant info. So thanks for the link to the other thread it was really informative. I will go on the hunt for a Gusset sprocket. I guess the ease of procurement will determine whether I go for your suggested total revamp or stick with the 1/8 set up. Any suggested suppliers of the Gusset sprockets?

In the interim I’ll stick with the cassette cog, (brand new) as he has never ridden a roadie, so it will be very easy going.

The issue with the clearance of the cranks is the crank arms, not the chainring. The Stronglights spread about an extra 2-3mm either side, as I took the pair off my bike and they worked a treat.

Your concern about over gearing has me thinking. What should I resonably expect he should be able to have fun on without having issues with slippping of the cog or struggling to turn. I will start with a TA 44t on the front and a 23t on the back with 165’s doing the work. Equates to about 52 inches.

I can always try a larger cog on the rear to bring it further down for him. I am just iching to get him onto this bike but don’t want to ruin the experience for him.

Ok, arm-stay clearance can only be fixed by either denting the stays (see old aluminium Cannondale track frames) or a different frame. Otherwise you have to go to a wider Q-factor, as you have done.

Gearing wise, perhaps look at the gearing on kids BMXs and gear restrictions for jnr trackies and compare. But 52 does sound ok to begin with.

Using a sprocket from a cassette, and with a 1/8" chain to boot, be careful about dropping the chain. I used an 18T campy cassette sprocket for a while and the ramps/low cut teeth caused it to throw the chain quite often.

Nice Stronglight 3/32" rings are pretty cheap on Ribble Cycles btw.

The frame I have is a pearla. An old Atom, Aussie I think, steel frame. I’ve powder coated it Teal, as requested by youngest son. So bending the stays is not really an option. I was a bit bummed when the Pistas didn’t have the clearance, but hey.

It never takes too much to convince me I need another Ribble order, but purhaps I should at least wait til after the current one arrives! I’ll hunt for the Gusset first.

Thanks for the help Blakey.