What if you start with a "thicker" rotor?

[PandaBear]

Just an educated guess. Let's say the car I have uses a thinner version of the same rotor another car uses. It has the same diameter, same 5 bolts holes (ok 14.6 vs 16.75 mm is not going to change much), same center hole, same vane, same vent type. The only difference would be 28mm starting thickness vs 25mm, and discard thickness being 25mm vs 22mm. The height is 49mm vs 46.3mm. So, it almost seems like they are the same rotor except the extra thickness for another car instead of my car, and that is 3mm. I think the caliper pins should be able to handle the 3mm height difference.

If I want to "upgrade" and use a thicker rotor to start with, in theory I can turn it and use it within spec for 1 more time, or if I don't mind the grooves I can pad slap it one more time afterward, is that a correct assumption?

 

[The_Jeff]

I went through this (accidentally) with a 4th gen Prius and Prius Prime. They take different rotors for some reason and Rockauto thought they could just cut and paste the catalog.

The thicker rotor didn't fit in the bracket.

Additionally, I don't think you'll be able to push the caliper back all the way with new pads.

 

[Rand]

Will the caliper and pads fit over it? They get pretty close.

 

[PandaBear]

I went through this (accidentally) with a 4th gen Prius and Prius Prime. They take different rotors for some reason and Rockauto thought they could just cut and paste the catalog.

The thicker rotor didn't fit in the bracket.

Additionally, I don't think you'll be able to push the caliper back all the way with new pads.

I was exactly thinking about the Prius V rotor vs the Camry one.

 

[slacktide_bitog]

Just get better pads and rotors for the correct size. EBC Ultimax2 Blackstuff pads and the EBC rotors or other brand name rotors with a Geomet type coating.

 

[The_Jeff]

They do make rotors with thinner air gaps in the vanes, so "more metal." I doubt they could advertise it as being "more turnable" as the liability for going past the manufacturer minimum thickness is huge. But they supposedly "warp less" because of the bigger heat sink.

I can't name names-- this is from a display at an auto parts store that claimed a rotor was "better" for this reason.

 

[Gyro Gearloose]

Most of my rotors are still adequate thickness for resurfacing but the local parts stores are 50/50 whether they improve the rotor or create new defects. A cynical person might be highly suspicious of that outcome. I've determined that in the long run I'm financially ahead to just plan to buy new rotors from RA.

 

[DCDG]

How many more times are you looking to cut the rotors? I wouldn't want to cut a rotor more than once. I would go with one that's known to fit the vehicle and a high carbon steel. Bosch, AC Delco and Beck Arnley are a few examples that use a higher carbon content.

 

[The Critic]

Just an educated guess. Let's say the car I have uses a thinner version of the same rotor another car uses. It has the same diameter, same 5 bolts holes (ok 14.6 vs 16.75 mm is not going to change much), same center hole, same vane, same vent type. The only difference would be 28mm starting thickness vs 25mm, and discard thickness being 25mm vs 22mm. The height is 49mm vs 46.3mm. So, it almost seems like they are the same rotor except the extra thickness for another car instead of my car, and that is 3mm. I think the caliper pins should be able to handle the 3mm height difference.

If I want to "upgrade" and use a thicker rotor to start with, in theory I can turn it and use it within spec for 1 more time, or if I don't mind the grooves I can pad slap it one more time afterward, is that a correct assumption?

No, the caliper will not fit over the pads.

 

[mk378]

No, the caliper will not fit over the pads.

Yes exactly. It's set up so there is only a mm or so clearance with a new (correct size) rotor and new pads.

 

[4wd]

had aftermarket where the plates were thicker - but the rotor width was the same (more iron)

 

[PandaBear]

How many more times are you looking to cut the rotors? I wouldn't want to cut a rotor more than once. I would go with one that's known to fit the vehicle and a high carbon steel. Bosch, AC Delco and Beck Arnley are a few examples that use a higher carbon content.

I highly doubt I would cut more than once but then again, more meat means more flexibility in theory if it works. Was thinking if it would fit why not (obviously it didn't).

I have typically done pad slap till the rotor got a "lip" that is 1mm on each side sometimes 2mm before replacing. I also had a car that the rotor lasted 180k miles before replacing. Based on my calculation it is easier to just get new rotors and buy them when they go on sale ahead of time instead of cutting even once.

 

[RaymondP]

Three millimeters of an increase to OEM thickness seems like a lot for a rotor. As an alternative strategy, depending on the condition. first consider resurfacing the originals. If not possible, I would pay extra for a new cryo-treated rotor that will last the remaining lifetime of the vehicle under normal driving conditions. Biggest challenge one has is availability. TireRack was my most recent resource, but I see they too now have a very limited selection.

 

[bladecutter]

Just an educated guess. Let's say the car I have uses a thinner version of the same rotor another car uses. It has the same diameter, same 5 bolts holes (ok 14.6 vs 16.75 mm is not going to change much), same center hole, same vane, same vent type. The only difference would be 28mm starting thickness vs 25mm, and discard thickness being 25mm vs 22mm. The height is 49mm vs 46.3mm. So, it almost seems like they are the same rotor except the extra thickness for another car instead of my car, and that is 3mm. I think the caliper pins should be able to handle the 3mm height difference.

If I want to "upgrade" and use a thicker rotor to start with, in theory I can turn it and use it within spec for 1 more time, or if I don't mind the grooves I can pad slap it one more time afterward, is that a correct assumption?

Every measurement you provided shows that the two rotors you are comparing aren't even close, and there's no way its going to work with the original brake caliper and caliper mounting bracket.
You would need to order the caliper and mounting bracket from the vehicle who's rotor you are trying to use, and hope that the mounting bracket can mount to the knuckle on your car, which it probably can't.