99 *new**hub bearing and rotors=cast -vs- composite

I did a search, which was inconclusive or only talked if one is retaining the old bearing and or rotors. I am in the middle of replacing both hub bearings and rotors on my 99. Apparently I have to pick either cast or composite. I want to go with cast. I'm not sure what I currently have. Question-Since I am replacing both hub and rotor on each side, couldn't I just get the desired cast from the get go and get the hub bearing asseblies made for cast? ...as opposed to needing to stick with whatever my xj came with, regardless that I am replacing them?

Thanks all! :sunshine:

I'm confused, the rotors don't have any bearings in a 4wd, thats a different assembly, basically all you do is pull the tires off, remove the caliper, pull the rotor off, put new one on and put calipers back. No bearings involved.
Unless you have a 2wd....then it might be different but then I've not seen many 2wd XJ's...

I'm replacing the rotors AND the hub bearing assemblies. The problem is when you go to order your hub assemblies, it wants to know if cast or composite. Since I'm getting NEW rotors, could I just order cast ones from the get go, even if the old ones may have been composite.
thanks!

I'm still confused, I have my stock OEM ones with composite rotors from the factory, I also have wagner rotors that are solid steel and both the composite and steel fit the same hub...
I'd just order the ones for composite which are what the OEM's are and put on a good set of rotors..
Is there some kind of price difference ?

In my limited research, it seems the cast may be less prone to warpage. Mine aren't bad now, but I know that they have never been replaced after 84k and I'd like to start new with it since I got it last spring.

IndyXJ --

I believe you can do what you suggest. They key is that the cast rotors have a thicker "hate" (center" section, which offsets the rotor differently from the composite ones. The change was made in mid-1999, so you'll need to use your VIN number to determine what you have.

What you also need to check is whether the composite-equipped vehicles and the cast-equipped vehicles use the same steering knuckle and caliper, because both can also affect offset. Easiest way to check is to get the part numbers for a 98 (composite) and for a 2000 (cast), and see which of those matches up with yours. If the knuckles and the calipers are the same part number regardless of rotor, then you are good to go as you suggest, replacing rotors and hubs with the correct, corresponding units.

You can mix and match hubs, and rotors....AS LONG as you match hub years to rotor years. I.E. Same year hub, as rotor. AFAIK the D30 never changed knuckle design...just hub design.

Cast rotors are stronger than composite, both kinda suck(10 inch brakes do not work with bigger tires)

Eagle said:

They key is that the cast rotors have a thicker "hate" (center" section, ...

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That's "HAT" section, not "hate"

Storydude said:

AFAIK the D30 never changed knuckle design...just hub design.

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Sure did. Not sure when it was, but my buddies' 87s had different hole patterns for mounting the calipers than my 95. On one of those 87s we tried to put on a non-disco D30 from another XJ (unsure the year) and the 87's calipers would not bolt on. Holes didn't even line up on the outer knuckles.

LEarn something new..