the front rotors on my 2000 A6 2.8Q, are going really bad (just one side actually), I was looking at prices online, and I'm not sure what the difference is, basically there are
front rotors (288mm diameter), ranging from $35-85, and
(312mm diameter) $75-$100

naturally I want to get the cheaper one, so is there any disadvantage to getting the $35, or $45 288mm diameter front rotors.

also, is it ok to change just one side, at least for a couple of month? and finally

how hard is it, if I want to change it myself?

 

Hi, b0b0

To help with your question about the different rotor sizes, the 288 mm rotor will depend on the wheel size on your car and whether or not its a quattro. The 288 and 312 mm were primarily insalled on the cars equipped with 15" and 16" wheels. The 321 mm are usually reserved for the cars with the larger wheels...17" and above. If you're not sure what size yours are, take off one of the wheels and measure the rotor. Make sure this is done accross its diameter (centered accross the widest point).
On the question about only replacing one rotor??? It won't hurt anything...brakes are usually changed either both fronts at once or both rears at once, but you will notice a dfference in how the car drives and brakes, simply because the axle with the new rotor and pads will "bite" better and stop more efficiently.
On the last question, brakes are not hard to change. If you're mechanically inclined and have basic hand tools this is something you should be able to tackle yourself. If you take your time and do a good job of cleaning and prepping everything for the job, it takes 45 minutes to 1 hour per axle.
If you've never done anything like this yourself, you should maybe check with any friends or family that have and ask them to help you with it. You'll save wads of money on labor doing this or any other repair or maintenance job yourself. Hope this was helpful

 

If your grinding now on one side, you'll prolly be grinding the other real soon. Brakes rarely go out on one side only unless something is wrong.

And yes, if your marginal, changing only one side can set you for an accident by pulling to on side when braking. Especially under hard braking.

 

thanks for your answers, and thank you TwinTurboC5. I have 16" wheels, so I guess I'll go ahead and get the 288mms, and since it's pretty cheap I'll just get both fronts.

I don't think I'll replace the pads though, because I have enough padding on them. One of the rotors is causing a rotational noise (as I was informed by the dealer), which is why I just wanted to replace that one.

There is a step by step instruction online on replacing the rotors for an A6, and it doesn't seem to bad, maybe I'll give it a try.

 

if you have never done brakes befor you may want to have a set of pads on stand by. When you pry the calipers apart to free the pads from the rotor you could damage the pads if you dont know what you are doing. Make sure you get the right pads. (pads with sensor lines to the brake monitor. Not Autozone specials.)