mfdif

I picked up a 07 IS250 AWD a few months ago and have been slowly catching up on maintenance here and there. Looking at the tires, the fronts are worn down more noticeable than the rear. But they are also a different brand than the backs tires, so no telling if it was just not rotated or if the back tires were replaced and not the fronts.

I'm was going to rotate them but wanted to double check if the fronts indeed do wear down faster than the rear. My understanding is that this car has a heavier torque split bias to the rear.

On my old WRX AWD had a locked 50/50 awd torque split. The fronts would always wear down faster because it had to deal with braking and turning. My GTO RWD of course ate the back tires a lot faster than the front.

What about this car? Wears the front or the back faster? Anyone know what the default torque split is on these cars and how much it can transfer either way?

MikeFig82

iTrader: (13)

Are you on stock 17's? If so the previous owner probably never rotated the tires front to back. The IS250 is 30/70, and goes 50/50 if you get into trouble. I tend to rotate them out every 10k. I'm getting good tire life that way, and also checking tire pressure once a week.

Check your alignment too depending how they are wearing.

Lexus news room reference:

The all-wheel-drive system available for the IS 250 and IS 350 provides extra traction in diverse driving conditions. A planetary-gear center differential and a wet-type multi-disc clutch control front-to-rear power distribution. The system normally sends 70 percent of available power to the rear wheels to provide the performance advantages of a rear-drive car and will vary the torque-split ratio from 30:70 to 50:50 in response to driving conditions and driver input. The AWD system's electronic-control strategy takes inputs such as steering and throttle angle from driver activity combined with vehicle signals from wheel speed and yaw rate sensors.
Aiding the IS models’ traction and control is Vehicle Dynamics Integrated Management (VDIM). More advanced than other traction and stability systems, VDIM is designed to anticipate the onset of a vehicle skid or slide and help correct the situation with a combination of braking and throttle control. VDIM integration provides precise management for Electric Power Steering (EPS), Vehicle Stability Control (VSC), the Anti-lock Braking System (ABS), Brake Assist (BA), Electronic Brake force Distribution (EBD), and engine torque (via the electronically controlled throttle). The driver can disengage VSC via the "TRAC off" switch, which can be useful in certain situations.

mfdif

Yup I'm on the stock 17s. That's helpful info! So you recommend putting the more worn fronts in the the back even with the 30/70 split? Since the fronts are a different brand than the rears I can't tell if he just didn't rotate or replaced the rear before the front.

MikeFig82

iTrader: (13)

Either way depending on how worn they're. It's a hazard as any sharp object you run over. Could easily blowout the tire at high speeds. That's a call you're going to have to make.

olsen_karl

I think it depends on how much more worn those front tires are -- it's generally recommended to keep the newer (deeper tread) tires on the rear, because it's safer. More traction on the rear tires than the front = understeer is more likely than oversteer, and more controllable.

If you're talking about just slight differences in wear, then rotate, and hope to even out the wear. My AWD IS wears the inner corners of the front tires first, which is a common thing on these cars.

Aspect

Front typically wears down faster in my experience. Given the inherent 2IS toe wear issue wearing out the inner tire faster than the outer, I'd have a perfectly usable tire until I looked under the car and the threads are showing through on the inside. Most 2IS owners remedy this with stiffer LCA bushings from FIGS or RR Racing USRS. As for the wear rates after the fact, I still think the fronts get worn more, so I rotate them every so often

mfdif

They are not down to the wear bars yet and have some meat left. Thanks guys for the details. I'll swap them around and see if I can get a little more life outta the set before upgrading.

MikeFig82

iTrader: (13)

If you want better tire wear for your inner tires. Upgrade to some RR, or Figs LCA Bushings. It's the first mod I did went with the RR though. The breaking inprovement is a big plus for me. As they will pretty much eliminate nose dive when hard breaking. If you are sensitive to NVH you could just upgrade to the stock ISF LCA Bushings.

olsen_karl

I changed out that front control arm bushing for the factory RC-F bushing, which was quite a bit stiffer than the original IS bushing. That improved the front inner tire wear, but did not eliminate it. I didn't really want to go to a poly bushing because of past squeak issues with polyurethane bushings on suspension parts.

2013FSport

iTrader: (2)

^^ WIN!!
What everyone needs to know is tires and driver habits, plus how the car is used d1cktate what tire pressure and toe in work best for THEIR CAR!!!

Running IS-F LCAB... Go with the RCF and start with a zero toe and watch how and where they wear.

If you squirrel through the parking lot more than you use the open road, toe and tire pressure adjustments are needed. These cars turn sharp and the toe-in on turns scrubs the cr@p off the edges. Now if turned sharp and excessive power applied you have more wear. Period!

Tire wears evenly across = good toe and pressure.
Wears edges (both) = pressure too low.
Wears middle = pressure too high
Wears outside = too much toe in.
Wears inside = too much toe out.
Repeat above mixing pressures and toe for added fun! lol

Tiny adjustments matter over 40,000 miles.