Kuz

Hey all,

Just got my new wheels. Put them on and synced the TPMS sensors. After a mile or so this alert comes on. If I turn of the car it goes away, until I drive another mile.

I got 20" wheels with 225-30-20 and 255-30-20. I see others with AWD on the forum running that setup.

Anyone have any ideas?

Thanks in advance!
Kuz

CJW

iTrader: (1)

Your tires are likely too far off from being the same diameter.

I'm not sure on the tolerance, but yours are almost 3% difference in diameter. The system likely senses this and throws a warning. I'd be curious to know if Lexus has a spec.

Kuz

Yeah I wouldn't know how to get them any closer. Maybe the front tires are a little more stretched? Wheels are the same height and so are the tires.

???

timmy0tool

iTrader: (7)

tires are not the same size. using this: http://www.miata.net/garage/tirecalc.html

225/30/20 = 25.3in diameter
255/30/20 = 26.0in diameter

there is a 2.8% difference between the front to rear sizing. i usually would only allow <2%, plus you are AWD so running staggered is generally not a good idea.

mrkjsn

I was just about to post the link and information above. As a reference, the stock F sport wheels are 225/40-18 (front) and 255/35-18 (rear), which has a 0.1" difference. Yours is at 2.8% - far too big of a difference.

Better tire size would have been
225/40-20 and 255/35-20 (.1" difference) or 225/35-20 and 255/30-20 (.2" difference).

zarraz

I have an awd with 225/35/20 front and 255/30/20 rear with no warning, but my tire diameter is very close front to rear

IS350S2K

You could see if adding an extra or two more psi in the front tires or dropping a little in the rears help equalize the diameters but not extreme to where it adversely affects your handling.

mrkjsn

Which might trip the TPMS. Best solution is to replace the front tires with 225/35-20.

Kuz

Thanks for the insight fellas. I think that is what I will do. Go with the 35 profile tire on the front.

F me.

sydtoosic

that's a good idea... It will work. I have an AWD LS460 245/40 and 275/35... Check 1010 tires and play with the set up calculator, do you know your offsets? Never had a code nor a problem with my set up.

DoomBuggy

iTrader: (1)

F me, too.

Ive got the exact same set of staggered tires awaiting wheels for my AWD. Is this seriously going to be an issue to run? What happens if you ignore the alert?

mrkjsn

With that setup the front will rotate 797 revolutions per mile while the back will rotate 775 revolutions per mile. It will be out of sync and destroy your differentials. They could literally shatter or explode.

DoomBuggy

iTrader: (1)

What a drag. How are RWD members able to run this set? A revolution is a revolution, no?

Thankfully, I havent taken mine out of the wrapping from TireRack yet. Might swap out my Hankooks for some Sumitomos or Yokohamas that offer the 225/35/20. Grrrr.

mrkjsn

The front is not connected to the transmission in a RWD setup so there's nothing to go out of sync.

forum429

You are running wrong size of tires.
You need to keep the front and rear at the same or very close overall diameter.
To keep your speedo and odometer correct you need:
F225/30R20
R255/25/20