chefmac

I've been commuting to work for 7 years on a Marin San Marino (Campy Veloce) road bike. The hubs have gotten to point where they need to be replaced so I've decided to convert it to a fixie. I am currently in London and it is difficult to find a decent selection of fixed gear parts. Currently I have the Formula/Mavic wheelset combo from the Wheel & Sprocket shop and a pair of Sugino XD cranks I bought locally. I plan on using the bottom bracket that came with the bike if possible.

My questions:
1. Can I use a MTB outer chainring (T.A. brand or similiar) for a fixed gear?
2. Can I use my ringbolts that are currently on my bike?
3. Can I use one of my Campy sprockets in this setup?
4. 48x18 or 46x16? (i am sure there are posts regarding this debate, but thought I would ask anyway)

Any other advice is greatly appreciated. Cheers.

Aeroplane

1. Yes, but it will probably drop your chain a lot unless your chainline is perfect (experience talking here)
2. Yes, but it will probably take some work. Just dropping the $5-$10 for some single-stack/BMX bolts will save a lot of time and filing (filing being the method of shortening them, unless you have a bench grinder)
3. No. You'll need to buy a new ISO threaded cog and lockring. Surly and On-One make good cogs (On-One is even in the UK, so that's a plus for you)
4. 46x16 - more skid patches.

Why not just use your current cranks? If they are campys, odds are you will need a new BB too to go with the Sugino's (though that is constantly up to debate).

lvleph

Or you could do 47x17 and have plenty of ski patches.

crushkilldstroy

Isn't the Marin San Marino like a $2000 road bike with vertical dropouts? If I were in your position, I'd sell that little buddy and pick up something that's a little bit easier to convert.

chefmac

When I bought the bike 7 years ago I paid around half that much. Letīs just say the bike has sentimental value. Iīve put a lot of road/street miles on it plus a few spills. Itīs a solid Italian steel frame which is nice for soaking up some of the bumps. Yes, it does have vertical drops but according to the frame specs I can use a 48x18, 46x16 or 44x14 gear ratio (fingers crossed).

I thought about keeping the Campy cranks but they are a bit long (175mm). But then again... does 10mm make that much of difference? I guess I should have posted my questions before I started buying stuff.

chefmac

btw.... thanks for the help.

bbattle

10mm makes a big difference. For fixed, I'd go with something shorter, 165mm is good unless the frame is really big, then 170mm.

Aeroplane

1. No Marins are Italian, no matter how much Campy they have on them. Doesn't stop it from still being a good ride of course, but I just thought I'd be a pedant.
2. Expect to do a little filing on the dropouts if you want to have the chain last more than a few weeks. Chain-stretch will occur, and you'll need to retighten it sooner or later.

chefmac

If my memory serves me correctly (it doesn't quite often!), when Marin introduced road bikes to their lineup the Columbus frames were designed and manufactured in Italy. Marin imported them to California and kitted them out.

Regarding the chain... if I use my current stainless steel chain (about 1 year old) would there be much stretch?

Aeroplane

Holy crap, I knew as soon as I put that out there that you would come back with actual history...

Old chain probably won't stretch much, but you'll have to replace it eventually. You're going to need some adjustability in there sooner or later; not a ton, but a little.

chefmac

True.