Does Anyone else's Gen 4 eat tires?

[Shadow351]

So I was doing my 245k mi oil change and I noticed some cords showing through on the inside edge of my front passenger tire. The out side edge sill looks ok, and the 'Replacement tire monitor' is just starting to fade to 'Replace Tire'. I've noticed it wearing the inner edges before, and I've rotated the tires and have had the alignment checked/done a few times over the last couple years, and it continues to eat the inner edge of the tires. Is this common for these cars? Is the alignment shop botching the alignment? I have lifetime alignments there so I've always taken it to the same place. I'm gonna try to get new tires put on it tomorrow, and I'll see if I can get the alignment checked there (different shop).

 

[76FoMoCo]

Time to have toe links and all the front suspension bushings look at.

 

[Shadow351]

I've replaced:
Front Lower Control Arms (including the bushings) 9/2020
All Struts/shock & Springs 9/2020
Rear Toe Links 9/2020
Inner & Outer Tie Rods (not sure of the time but the steering is still tight) & Stab links

Maybe the tires were too far gone to notice a change in the wear pattern after the parts had been replaced?

 

[Ta2dResqr]

Is your car lowered? I would look at Camber and Toe. If you can find a place willing to do 1/2 spec on their alignment, that is the best (it is a setting in some machines that will only allow half the tolerance. This will put you closer to optimum.)

 

[Shadow351]

Suspension is stock, no lowering. according to the alignment document from 9/2020 the final settings were:
Camber is pretty negative, and front right Toe looks like it would just barely be in 1/2 spec.

(This was after replacing toe links and lower control arms so the 'before' being out of range is expected)

 

[Ta2dResqr]

Item​	LH​	RH​	Total/Split​
Front ​
Camber (all except vehicles with 2.0L Gasoline Turbocharged Direct Injection (GTDI) engine)	-0.55° ± 0.75°	-0.75° ± 0.75°	0.20° ± 0.75° a
Caster (all except vehicles with 2.0L GTDI engine and Police vehicles)	3.10° ± 0.75°	3.30° ± 0.75°	-0.20° ± 0.75° b
Caster (Police vehicles)	2.90° ± 0.75°	3.10° ± 0.75°	-0.20° ± 0.75° b
Toe (positive value is toe in, negative value is toe out)	—	—	0.20° ± 0.20°
Rear ​
Camber (all except vehicles with 2.0L GTDI engine and Police vehicles)	-1.00° ± 0.75°	-1.00° ± 0.75°	0.0° ± 0.75° a
Toe (positive value is toe in, negative value is toe out), All Vehicles	0.12° ± 0.20°	0.12° ± 0.20°	0.24° ± 0.20°
Thrust Angle	—	—	0.0° ± 0.30°

Front (SHO vehicles)

52 mm (2.05 in) ± 10 mm (0.39 in) Rear (SHO vehicles) 14 mm (0.55 in) ± 10 mm (0.39 in)

Inner edge (or shoulder) wear occurs on the inside edge of the tire and is usually caused by excessive toe out and/or excessive negative camber. If the tread depth of the outer shoulder is at least 50% greater than the tread depth of the inner shoulder, the tire is experiencing inner edge/shoulder wear. To determine whether tires have this type of wear, visually inspect the tires. In some instances, it may be necessary to measure the tread depth of each rib and compare it to that of the shoulder.

Inner edge/shoulder wear	Excessive toe out and/or negative camber
	Incorrect wheel and tire assembly rotation intervals
	High-speed cornering

Is the tread depth greater than 2/32 inch?

Yes	ROTATE the wheel and tire assemblies. CHECK and ADJUST the toe to nominal +0.15 degrees (toe in). CHECK and ADJUST caster and camber to nominal.​
No	INSTALL a new tire(s). CHECK and ADJUST the toe to nominal. CHECK and ADJUST caster and camber to nominal.​

These are the specs I have available from my repair service. They look slightly different but, all your numbers look like they are within normal tolerance. Ride Height is height of the Center of control arm mounting bolt minus the height of the bottom of the ball joint on the front and center of the inner control arm mounting bolt minus center of the outer mounting bolt on the rear.

 

[Shadow351]

So I got new tires on it today, the tire place doesn't have an alignment rack, so I might take it by the dealer and see what they say (as long as they don't charge an exorbitant amount for an alignment). The troubleshooting section says adjust to "Nominal +0.15 degrees" do they mean to adjust it to 0.36 (0.21 + 0.15) total toe?

 

[Ta2dResqr]

So I got new tires on it today, the tire place doesn't have an alignment rack, so I might take it by the dealer and see what they say (as long as they don't charge an exorbitant amount for an alignment). The troubleshooting section says adjust to "Nominal +0.15 degrees" do they mean to adjust it to 0.36 (0.21 + 0.15) total toe?

That is how I read it. My guess is given that everything else is perfect, toe out causes inner edge wear so they are toeing it in to alleviate that wear. I cannot seem to find a toe spec, just cross toe. cross toe seems to be 0-.4. So if you assume the ideal of .2, split that in half, .1 is nominal. Add.15 and .25 becomes the new desired setting.

 

[DouglasB_SHO]

Had the same problem on mine 2011 SHO some years ago. Inner shoulder on both fronts worn down to the belts. We caught it when I had it in the shop to have the brakes looked at. Whew! Replace tires and did an alignment. Haven't seen the problem since and on my third set of tires since then, with alignments after each tire change. At 105K now and about to have front quick struts, inner and outer tie rod ends, control arms, stabilizer links, and stabilizer bushings done, with new alignment, of course.

 

[6500rpm]

Take it to the dealer where they have the proper spec for your car, or at a min don't take it to the place you've been using. Excessive toe will cause a saw tooth wear pattern that you can feel as you drag your hand across the tire. Wearing the inner edge is excessive negative camber. Wear in the center of the tire is over inflation. Wear on both outside edges is under inflation. I rotate front to rear and cross rotate the rears to the front every 5k miles. I also stick the tread depth L-C-R on each tire when I rotate and adjust air pressures as needed. It's a bit of a game, but it works, it all starts with the initial alignment being correct. Too much negative camber and not enough air will show much more quickly as you have 2 factors working against you. Toe angle will cause the fastest tire wear, but results in a choppy saw wear pattern. Capiche

 

[Kevin81]

Based on the pic, that's negative camber. That it's happening on only 1 corners means that either, you've got something worn in the suspension (bushing), OR, at some point, you hammered a pothole or something, and knocked the alignment out ever so slightly. Especially if you hit the same spot, doing the same rout. Repeated hits will progressively knocked your alignment out.

Add to that how heavy these cars are, and how aggressively we tend to drive them (at least, I do), and the wear can get excessive very quickly.