1" vs. 1-1/4" rotors

[kevinr1970]

Alright, I have seen this brought up in conversation before when talking about buying drop spindles.

I am real close to getting my crew swb project jump-started but have some questions in regards to this.
My crew and swb donor are both 1987 model year.
The swb donor is an ex-USFS Custom Deluxe, v6, manual stripped down model; I assume that this truck has the 1" lighter duty rotors. (are they really a "lighter duty" rotor?)
The crew is going to be swapped over to 1/2 ton suspension and will be completely rebuilt including brakes at this time.

If the donor has 1" rotors, can I buy new spindles for the 1-1/4" rotors, new 1-1/4" rotors and the the accompanying(sp?) parts?
Are the 1-1/4" rotors that different in braking performance to even bother considering this?
If I end up switching over the 1-1/4" rotors, what other parts am I looking at having to buy to accomodate this?

I already have 3" drop springs and am thinking that I might end up with drop spindles too later, after I see how much clearance I have trying to get up my driveway. For now, I would like to avoid having to buy spindles if I don't have to.

Thanks in advance!

[nlped]

I did this on my '87 SWB. It originally came with the 1" rotors, but when I put the drop spindles on it, I went with the 1.25" rotor set up. It went without a hitch. I only chose to do it because I sometimes would pull my boat or a car trailer, and I figured the more braking power the better .

I replaced the rotors (duh), the bearings (the outer is actually the same, but I chose to replace it anyway) and seal, brake caliper (I used loaded ones...the pads are actually the same, but the caliper has a "wider mouth" to accomodate the thicker rotor). I also replaced the hoses since I was doing all of this and one of the old ones had a few cracks in it...seemed like the perfect time to do it.

Good Luck!!!

[love my 72]

Since you would like to postpone the spindle purchase i would use the "LD" brake system you have now with the stock spindles. Once you are ready to buy drop spindles get the 1-1/4" spindles, you will need 1-1/4" calipers & 1-1/4" rotors, the "HD" version, i guess the 1/4" difference in the rotor thickness decreases the chance of the rotor warping under severe braking conditions.

As other board members have mentioned, the "LD" brakes work well, but if you will be towing or hauling loads often, get the "HD" brakes.

Me personally, if i am replacing spindles i would get the 1-1/4" while you are at it i don't think there is a price difference if any.

Best wishes on you project!!!

[kevinr1970]

But I am going to be redoing the brakes at this time also (neccessity). I don't want to have to go back later and redo the brakes?

My concern is that the crew cab is going to weigh signifigantly more than the swb. Don't want to be going down a grade and have the brakes disappear on me!?!

Originally Posted by love my 72

Since you would like to postpone the spindle purchase i would use the "LD" brake system you have now with the stock spindles. Once you are ready to buy drop spindles get the 1-1/4" spindles, you will need 1-1/4" calipers & 1-1/4" rotors, the "HD" version, i guess the 1/4" difference in the rotor thickness decreases the chance of the rotor warping under severe braking conditions.

As other board members have mentioned, the "LD" brakes work well, but if you will be towing or hauling loads often, get the "HD" brakes.

Me personally, if i am replacing spindles i would get the 1-1/4" while you are at it i don't think there is a price difference if any.

Best wishes on you project!!!

[love my 72]

In that case i would try and get a spindle from a wrecking yard or something like that, if you can afford the extra $$ and/or down time i would buy the drop spindle. It is a better way to achieve a 3" drop Vs. a drop spring.

FWIW: I found that the "LD" or 1" brake rotor for a 1/2 ton 2WD came in to production in 1982, so anything prir to that would have been 1-1/4" thickness.

I'm in the process to go from a 1-1/4" rotor, stock height spindle on my 73 2WD K5 to a 1" rotor on a 3" drop spindle i purchased at a swap meet.

[spinem]

are the 1.25 (evil looks from die hard members) brakes that much better /w/ stopping power?

[cableguy0]

The thicker rotor isnt a matter of stopping power. The thinner rotors will heat up faster and be more prone to warping. The 1 1/4 rotors are the way to go. You will be way less likely to warp up the rotors. I doubt either one is going to stop better than the other but in the long term the 1 1/4 rotor will last over the 1 inch rotor just due to being able to deal with the heat better.

[love my 72]

Originally Posted by cableguy0

The thicker rotor isnt a matter of stopping power. The thinner rotors will heat up faster and be more prone to warping. The 1 1/4 rotors are the way to go. You will be way less likely to warp up the rotors. I doubt either one is going to stop better than the other but in the long term the 1 1/4 rotor will last over the 1 inch rotor just due to being able to deal with the heat better.

Makes sense!

[nlped]

Originally Posted by cableguy0

The thicker rotor isnt a matter of stopping power. The thinner rotors will heat up faster and be more prone to warping. The 1 1/4 rotors are the way to go. You will be way less likely to warp up the rotors. I doubt either one is going to stop better than the other but in the long term the 1 1/4 rotor will last over the 1 inch rotor just due to being able to deal with the heat better.

Because I knew that I was going to be towing the extra weight was the reason I went ahead and put the thicker rotor on the front with the drop spindle. After all the new stuff, it had a much firmer brake feel, but it could have been any of the new parts. With the additional weight of your project, you should really consider just going ahead and upgrading. And spindles make for a much smoother riding method of lowering vs. just a 3" spring in my opinion.

[Tx Firefighter]

A brake assembly turns kinetic energy into heat energy. It's as simple as that.

Your 4 door truck will have more kinetic energy to be dissipated as heat by the brake rotors than a 2 door truck would. The thicker rotors can dissipate more heat due to their larger mass. This makes them much less prone to fade and warping.

[spinem]

anyone removed the dust shield for cooling power?

[dan76]

The dust shield serves as a barrier for dirt, mud and water which otherwise would hit the rotor and reduce braking efficiency.

[lolife99]

Whichever size you decide to use,... just remember that the spindle, rotor and caliper all have to match.
The 1" and 1-1/4" stuff won't interchange.

[kevinr1970]

As it turned out, after talking with the guy doing the work (boardmember), he just happened to be sitting on a pair of Bell drop spindles. So I went ahead and ordered all new parts for the 1-1/4" rotors, including 1-1/4" rotors.

Hopefully in the next 10 days or so, my truck won't have to be parked in the street due to being too low get get up my driveway.
I am sitting on three fiberglass rollpans, so I will start with the worst one just incase there are issues...