Orkboyz

I had one of the rear wheels on my IS500 off today, and the rear rotor thickness caught me by surprise. It looked way too thin for a 2-ton car. The car only has 8K miles and stock pads, so I discounted rotor/pad wear. A quick check with some vernier calipers had both rear rotors at 20mm. Fronts are 30mm. Pads are good, about 10mm all around.


I know the IS 500 in its stock form is not intended for the repeated heavy braking you do on track, and that the front brakes do most of the work, but this seems unusually thin to me even for occasional spirited driving along back roads or canyons.

LeX2K

Many cars don't even have vented rear rotors be happy you have that lol. Very disappointing to see that level or rust already.

SlowlaneAZ

My 2016 tacoma had rear drum breaks.....

604GSE21

the newest Audi Q4 E-tron have rear drum brakes too lol

Orkboyz

I've looked for rotor specs regarding thickness but cannot find anything definitive for the IS500. For an IS350 F Sport the discard width on the rears is supposedly 17mm. That seems reasonable given that I am measuring 20mm, but it still bugs me. I am probably hung up on it because I am accustomed to the beefier rotors on the Z06. The discard width on those is 30mm front and 25mm rear.

Also, I have to keep reminding myself that I got this car as a daily driver, not to be a backup weekend track car that I drive daily.

mavisky

Nose heavy car so not a ton of need for massive rear rotors.

Avi8orco

I had one too…and those fkn things worked. That thing could hold a bulldozer from rolling down a hill strapped to the tow hitch.

SlowlaneAZ

In all fairness, it really did. I never had any issues with it. It was just odd to see drum brakes on a 40k+ vehicle.

snowyblue

for the 12.7 inch diameter rear rotors, the standard thickness is 20mm. min thickness is 18.5mm

Orkboyz

Yeah, I've become so accustomed to thicker rotors that seeing the.rears were only 20mm caught me of guard. So far I have resisted the urge to flush the brake fluid with some high temp fluid and throw on some more aggressive pads just to see what it is like at a place like VIR. I know if I do, that other changes will eventually follow, and I'll end up going down a rabbit hole of suspension and brake mods along with an extra set of wheels/tires.