Undersized Rotors

[mark]

I just picked up a set of Bronco/F150 hubs and rotors, I was hoping to use them as-is but I just measured them, the "discard" is 1.22, they measure out at 1.21 and could probably use a clean up so they will get a little thinner.

The "correct" way is to replace them, but I'm being a cheap ass and have other fixes I would rather spend money on this round (I'll replace them later). So, for a pure wheeling rig, what is the potential catastrophic failure running rotors that are under the discard thickness?

I'll be using Chevy 1/2 ton calipers, and the pads are pretty much new. I'll have to check the discard thickness of a set of Chevy rotors and see if there is any difference. I'm really wondering if the discard is more for safety factor and liability. I've seen pictures of people that have run rotors to the cooling ribs, and if this was a street rig i wouldn't even ask since you need the mass for heat dispersion. Is there even a concern about the calipers running out of travel? But I wouldn't think so as the amount of slop built in with the thickness of the pads.


Its only about $80 for a new set of rotors, so I might bite the bullet anyway, but as I was looking at them, and the amount of meat left on them, I got thinking of what tolerance there actually is in them.



Thoughts?

 

[dvdswan]

if its just a wheeling rig then the only concern would be warping them from riding the brakes.

I know chevy rotors are around 19.95 ea so I would think the same for ford. do you really want to put it all together and then take it back apart 2 wks later.

its your call though.

 

[Boonie Buster]

I say new pads, get new rotors.

Is $100 worth an injury?

You will destroy the new pads and then you'll have to replace both. they should make good wheel chocks!:redneck:

 

[CHOP SHOP]

I finally put brakes on the ol ladies 4runner after it wore completely through one side of the rotor and was on the fins.


Seemed to work fine until it hit the fins.



Dont tow a camper downhill and you will be fine.

 

[WA-Wheeler]

Rotors are cheap...... buying all the make up beer for a buddy after rolling back and smashing his brand new super sweet lights and super expensive warn winch is not....

That being said, if you don't want to do it just yet, i would just throw some shoes on there and run it :awesomework:

 

[Binder]

They won't fail from being too thin. The only thing that could possibly fail would be the calliper and it's nowhere close to that happening.
I would clean them up and run them.

 

[zukkev]

If you can see the factory chamfer on the outside edge of the braking surface, I'd clean 'em up and run 'em....specially on a wheeler.
What yr Bronco wheel hub/rotors? Reason I ask is most 1/2T ford rotors were discard thickness of 1.12" ish...not 1.22".....I can check for sure when I get home...

 

[nowires]

I finally put brakes on the ol ladies 4runner after it wore completely through one side of the rotor and was on the fins.


Seemed to work fine until it hit the fins.



Dont tow a camper downhill and you will be fine.

They won't fail from being too thin. The only thing that could possibly fail would be the calliper and it's nowhere close to that happening.
I would clean them up and run them.

If you can see the factory chamfer on the outside edge of the braking surface, I'd clean 'em up and run 'em....specially on a wheeler.
What yr Bronco wheel hub/rotors? Reason I ask is most 1/2T ford rotors were discard thickness of 1.12" ish...not 1.22".....I can check for sure when I get home...

What they say.
check them for cracks, small dents like they have been dropped on something harder than them

 

[Jay W]

Thoughts?

Been there, doing that on my Jeep, going on 10 years now with under spec rotors. No problems.

 

[Hip]

Mark i probably have some you could have....:redneck:

but id run em if they are smooth. if you take them to smucks they wont turn em....

if you do take a cut on em they will be about another .030 to .060 thinner.

 

[zukkev]

Actually if you measured from the thinnest point, the thickness loss will only be .001"-.002" from the original measurement...anyone taking .030" or more off beyond the thinnest point of a rotor needs to change professions...IMHO of course...:redneck:

 

[mark]

id run em if they are smooth. if you take them to smucks they wont turn em....

if you do take a cut on em they will be about another .030 to .060 thinner.

I got a friend at the local Napa. Assuming they still have their brake lathe, I'm sure I could get a skim coat for a couple beers.


Sweet, this is the info I needed. Thanks guys. The Scout owners reputation of being cheap-asses will remain intact :redneck:

 

[Dogboy]

I've found that new rotors don't cost much more than having them turned.