I bought them from someone on ebay for $375. The front spins nice and easy and both wheels are true but the rear doesn't seem to spin as easy as the front. There is zero play in either axle.

Unfortunately, they did not come with tools, skewers or the wheel magnet. How difficult is it to adjust them? Should I just take them to my LBS?

The guy said they were like new but they have a few scuffs and scratches...I can live with that though. He also said they have about 750 miles on them. I have no way to verify that but the braking surface looks pretty good, not much wear if any.

These are 2005 wheels.

I can't really remember for sure, but I *think* the bearings on Ksyrium are essentially non-adjustable, hopefully someone else knows for sure. I remember replacing bearings on them but I can't ever remember adjusting a hub.

I'm not sure if someone would have put the hub back together incorrectly or what... does it feel like there is a grinding/vibration/gritty feeling when it spins? Thats what a "too tight" hub will feel like. If its just smooth even resistance, the wheel may still have some stiff grease in it as new hubs are usually a bit overpacked and stiff from the factory.

No, they are very smooth. No gritty feeling at all. It just doesn't spin quite as easily as the front. Probably just me being skeptical... :D

In my limited experience, the front wheel will spin longer/smoother. I have always figured it is b/c it lacks a freehub, which must create a bit of resistance. Am I wrong about that?

In the olden days when I was a kid, the method for adjusting wheel bearings was to put the valve at the 3 o'clock postion and let the weight of it carry it to the 6 o'clock position with a couple of swings to and fro before coming to rest. Provided there is no play in the bearings, this is a good way to set up for minimum resistance. The back wheel was done tha same way.

Special tool needed. You might just as well bring them to your LBS, they'll tell you if problem or not and save you from buying a tool you'll seldom use.
Had to get the front one play adjusted a month ago, took them two minutes to do the adjustment.

You hold one side with a 5mm allen wrench and adjust the bearing using the Mavic spanner tool. Have your shop adjust it and show you the tool then get them to order one for you. You can also use the red handled Park pin spanner. But the mavic tool is easier. it is a rare to need to mes with one but handy to have the tool because the adjustment is so simple.

This is one of the best features of these wheels; you do the adjusting with the wheel mounted to the bike, giving a perfect setting with the QRs clamped down.

As the good Rev. says, it's an easy adjustment (although you don't use a 5mm wrench) and as Cycliste says, it rarely needs doing once it's done.

Most better bike shops have lots of these tools (they're made of plastic); one comes with each wheelset and the shops rarely pass them onto the customer. If you ask nice they might give one to you as well as show you how to use it.

Thanks everyone. I drove by my LBS and they checked it out and said it was fine. They were drooling over the price I paid for them and I picked up a pair of Continental tires to mount on them while I was there.

I'm looking forward to riding them this weekend. :D

Ah, but you do if it is not on the bike. Makes it easier to hold the axle still.

Check out the Mavic web site. It tells you how to lube the cassette body. My axle uses 5mm allen wrenches on both sides. I lubed it with 80w gear oil. It seems to run quieter now. Be careful not to break anything, Mavic sells a rebuild kit for $50.00. I have 13k on my original seals. Good Luck!