rotor size question

hi guys, i have to order some new rotors and i was just wondering if you could help me out with what ones to choose. firstly, its a 1990 chevy silverado Z71, k1500 (4wd), 6 bolt, standard cab, stepside. from what i see there are 2 different size rotors, a normal and an HD. is there anyway to differentiate without taking the wheels off and measuring? thanks in advance.

Best to have a look and see.

I have the same truck except that mine is a GMC. You will have a F44 RPO code on the SPID sticker in the glove box if you have the Heavy Duty Chassis.

//2000CAYukon

thanks a ton dudes!

OK heres a real head scratcher. 295 mm Diameter, 25 mm thickness (wear? I'm told its supposed to be 33 mm). Also, the previous brake pads were replaced with a non-HD type. The 295 diameter rotor would tell me that its HD, but there's no f44 RPO code. could the rotors have been replaced with the larger hd type? Here's another curve ball, the brake caliper is really expanded (6 mm of wear on rotor and brake pad wear?).

HEEEELLLLPPPPPP

Both rotors (HD and non-HD) are 295 MM in diameter.

If the rotor says min thickness 25 MM then it is a non-HD rotor. The HD rotor has a min thickness or 31 MM.

//2000CAYukon

my supplier says otherwise. so a 295mm diameter by 25 mm rotor is normal for a 6 bolt?

This one's fairly easy. The standard rotors are 1" thick and the HD's are 1.25"; same diameter. The HD's are the ones I use since I have an extended cab. SSB uses the standard rotors with their rear disk conversion kit.

well, i was sent the HD's. i just went out and checked ... theres a 1" gap between pads from the rotor, and the calipers are expanded about 15mm! are the HD calipers different from the normal ones?

Calipers, pad and rotors are different between HD and non-HD.

//2000CAYukon

so now I'm S.O.L. if i don't get the HD calipers pretty much, eh? they (calipers) should bolt on?

heres the next question, which of the old parts will swap to the back with a rear disk kit?

You may/ might be able to re-use your non-HD rotors with a TSM rear disk conversion. SSB doesn't part out their kits. Baer actually uses an Impala rear rotor that's redrilled and you have to have the hub machined slightly smaller. I was turned off on the Baer kit when I found that out. Wilwood might have a good rear disk conversion. Don't skimp on brakes! That's why I went with the Stillen kit. It has the internal expanding emergency hub brake like some of the late model vehicles.

so the calipers will swap?

well, thanks to your guys eagerness to give incomplete information (guess what, HD spindles / hubs are different too) and lack of responses i now have about 200 bucks worth of useless brake parts in my garage.

i know this is probably a lost cause but does anyone want to lead me to somewhere i can get wheel spacers?