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Rotor conversion

6K views 11 replies 7 participants last post by  offroad safari 
#1 ·
I have a 90 astro.
Can i use s10 rotors on the front to convert to 4.75 bolt pattern?
Thanks for any input.
 
#2 ·
Hi hangmans8

I doubt that it would work HM, but I'm not sure here. The rule of thumb for me is the bolt pattern sizes. The smaller the bolt pattern "Usually" means smaller spindle and bearings.

The best place to check and make certain would be an auto-wrecker that sells both s10s and astro/safaris. They have a cataloged cross reference guide that tells them if it will fit or not. Just to be sure.

Hope this helps.:)
 
#4 ·
Hey hangmans did you find anything out?? I just did a quick check at the autozone web site and the front bearings and inner races are the same between a 1990 astro and an S10 so theortically the front rotors would bolt on to the spindle...now as to the size diff that might be in issue and I have no idea if the rears would be a straight bolt on....either way I'd be curious to know what your findings were.
 
#6 ·
yep astro vans use full size truck rotors

s10 are G body front end IE car small rotors and calipers and spindles

tiny

the smallest GM used on the RWD cars

so...

ppl seem to have a hard time with this simple concept dunno why,..,
 
#7 ·
hangmans8 said:
S10'S ARE 10.50" and astro's are 11.5" almost but not right.
I'm going to sell my iroc rims and find something else!
yep, let em go. they would be cool. but not being able to stop isn't cool...lol. there are lots of wheels you could choose from. being a 1/2 ton, there are lots of options.
 
#9 ·
offroad safari said:
I looked into this there was a camaro in the 80s that had 11.5" rotors
what was the bolt patern on that wheel?
 
#11 ·
astroracer aka Mark posted this on the old board

"I couldn't get a match on the rear drum part numbers between the Caprice and the Astro so I don't know what the differences are. The "G" body drums would be what you would want to swap to get the small bolt pattern but I know some of the "B" bodies had the 4 3/4 also (I've got the front corners off an 84 Olds 88 that have the 4 3/4 Bolt pattern). Comparing the drums at a parts store would be the only way to verify what will work.
The rotors from the Astro to the Caprice carry the same part number for the 12" dia. rotors. The 11" diameter rotor from the Caprice is a different number and I don't know if this would be the smaller bolt pattern.
12" part number Bendix-141216 for Astro and Caprice
11" part number Bendix-141201 for Caprice only. If this is the small bolt pattern it will bolt on the Astro spindles because the wheel bearings are all the same.
Another (better) option would be to use the Camaro 1LE front rotors. !2" diameter, 4 3/4 bolt circle and it will work with the Astro caliper. The Camaro guys use the "B" body front knuckle with new upper control arms to improve their suspension geometry and they bolt the big Camaro rotor to the "B" body spindle... This is how I am going to go when I rebuild the front of my van with the 5" drop.
Any other info along these lines would be greatly appreciated...

The front rotors have the lug studs pressed into them. [highlight=]If you swap over to the '88-'92 F body 1LE 12" rotors you will get the 5 on 4 3/4 bolt circle and nothing else has to change.[/highlight]The rears are a little more difficult just remember these housings were used in F, G, A and B body cars AND the S10 trucks so I am sure there is a small bolt circle rear drum that will swap over and then all that would need to be done is redrilling the axle flange for the new B.C."

My research:

Autosone lists 1990 Chevrolet Camaro IROC-Z 5.7L FI 8cyl front rotors that are 11.86" in diameter with a 5x4.75 bolt pattern. - cost $90.99 and use the same inner and outer wheel bearings as a 2wd astro
 
#12 ·
i also just looked and the diameter of the astro is .0002" larger so its basically the same size and the astros rotor thickness is 117.8mm and the IROCs is 117.9. Now all we need is someone to test is out.
 
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