Bicycle Mechanics - New rims

A pair of rims arrived today. They are called Mavic Open 4CD. What makes them strange is that they don't have the nice wide machined braking surface most rims have. In fact the braking surface isn't any more than about 10-12 mm wide. The rims themselves are hard anodized. What do I have? Track rims, perhaps?

Track rims have no need for any breaking surface. You have a road rim. Perhaps you will need to be careful setting up your brakes.

Do unknown rims just arrive at your house unexpectedly?

Google.

A pair of rims arrived today. They are called Mavic Open 4CD.

I just traded off some NOS Open 4CDs I had laying around here. Nice rims. I used to train on them a lot. I used RGC400 brakes with them, and regular pads, and never had a problem stopping.

Do unknown rims just arrive at your house unexpectedly?

Yes, I'm still waiting for a set of Campy Bora wheels to show up. So far so bad. So I guess I'll have to build these into something instead.

I guess these rims will work OK. Thanks for the input.

I just traded off some NOS Open 4CDs I had laying around here. Nice rims. I used to train on them a lot. I used RGC400 brakes with them, and regular pads, and never had a problem stopping.

Thanks. That gives me a boost in confidence for my first wheel build. Take care.

A pair of rims arrived today. They are called Mavic Open 4CD. What makes them strange is that they don't have the nice wide machined braking surface most rims have. In fact the braking surface isn't any more than about 10-12 mm wide. The rims themselves are hard anodized. What do I have? Track rims, perhaps?

Early '90s road rims. Machined brake surfaces weren't common until the late '90s. I'd bet the seam is pinned instead of welded.

Early '90s road rims. Machined brake surfaces weren't common until the late '90s. I'd bet the seam is pinned instead of welded.

You would win that bet. They seem to be nicely made. They are clinchers and drilled for presta valve. The 28 spoke holes are nicely ferruled in stainless steel. The overall rim has a gray hard anodized finish. They were new old stock and I bought the pair for $50 so I think it makes a good quality but affordable foundation for my first build. After some reading, I've decided to lace them 2 cross front and rear. I'll use my 28 spoke Garcia wheels as a template. I've settled on double butted 1.8-1.6-1.8 spokes as the way to go with them. The hubs haven't arrived yet so I haven't been able to calculate spoke lengths. I'm getting there.

The Open 4CD was a predecessor to the current Open Pro rim and didn't have the welded seam or machined brake tracks that came on later Mavic rims.

I had a set of these rims built on 32 hole Ultegra hubs I bought in 1995. They were reasonably light and held their trueness just fine (more the result of a good build). They weren't particularly durable as the rear rim cracked through the brake track from abraison at about 12,000 miles but the front one lasted over 30,000.

You should get good service from them and at $25 each, they were a bargain.