brake differences between extended cab/reg cab

[dusterbd13]

so ive got a deal on some 2 inch drop spindles for my 89 extended cab 1/2 ton. comes with rotors and calipers included.

i know my truck had the larger 1.25 rotors and heavy duty brakes due to it being an extended cab/long bed.


seller told me the spindles are currently on a regular cab 89 1500, which to me says they are probably the 1 inch thick rotors.

quick research on rockauto says that the reg cab calipers use 2 1/2 pistons, extended use 2 15/16 pistons.

what am i looking at here as far as brake performance with going down in piston size like this? my thinking is a bit higher and firmer pedal, but no loss of braking performance except insofar as less ability to dissipate heat due to the thinner rotors.

am i right in my thinking?
also, can i swap the larger calipers onto the smaller rotors without issues? anything i should be worried about?

thanks
Michael

 

[DRAGGIN95]

The light duty 88-91 brake's weren't on all of the RCSB's, my 90 model had the same 1.25 rotor's and part's as an ext. cab and all 92 up 1/2 ton 2wd's. So I would check his to see what they are for sure, and I am sorry to say if they are the light duty brake's I wouldn't do it, with the weight of an ext. cab truck trying to stop you would warp your rotor's all the time from the extra heat and the thinner rotor.

 

[Sully]

rotor to caliper to pad.... its all ratios that get engineered like crazy. The weight of the vehicle vs the amount of pressure over the size of the area and then heat and wear. Its not something you can just play with. If you are going to upgrade one element, upgrade them all.

 

[1badgmc]

The light duty 88-91 brake's weren't on all of the RCSB's, my 90 model had the same 1.25 rotor's and part's as an ext. cab and all 92 up 1/2 ton 2wd's. So I would check his to see what they are for sure...

True, but the odds are in favor of the smaller rotors. My '91 has the smaller rotors. It pissed me off when Stylin' sent me the wrong spindles after I made sure I ordered the correct ones.

Anyhow, I agree with DRAGGIN. Find out for sure what that '89 has. If it has the smaller rotors, pass on the deal.