348 Rear Axle temp vs Front

Terminology and pointing fingers::

Wheels are hotter implies heat is being added from somewhere {bearing going out, heat transfer from sticking caliper through rotor, outer CV joint is going out, ...} If both wheels are doing this it is probably normal.

Tires are hotter overall implies too much toe-in,
Tires are hotter inner edge implies too much camber,
Tires are hotter outer edge implies too little camber.

Rear axles are close to exhaust and get radiative heat transfer when you run the car hard (like you are supposed to).

But before you read too much into the above--you need to remember:: tires are supposed to run close to 200ºF when you are thrashing the car within an inch of its life. 100º is (as they say) nothing.

In all my years of running the snot out of my F355, I never bothered at all with wheel temperatures--tire temperatures are critical--wheels are just along for the ride.

 

Rear axles get heat from the transmission and the heat generated in the CV
Also radiation from the exhaust
Wheels get heat from brakes and tires
Tires warm up from rolling resistance and during braking
The rear ones also from the engine power
Rear tires and wheels are normally a bit warmer in my experience
20F is normal in my opinion

 

The rear axles are inches from the catalytic converters that are well over three hundred degrees Just for them to start working that is, they get double that.

The front wheels are inches from well.... nothing but cool air.

 

The rear tyres also get some heat from the radiator fans. It all adds-up.