how to replace a flat tire (1 Viewer)

[185]

Well finally acquired my first sidewall puncture, half inch to an inch away from the tread. I dont think anyone will patch it.

The set of 4 on axle have exactly 10k miles on it, while the spare has zero. Should i just replace the flat tire with the spare or will the new tire not play nice with the powertrain?

 

[Bang Bang]

Personally, I would put the current spare and a new tire on the axle that has the flat and move the good 10k mile tire from that axle to the spare. Then, around 5k-7k miles from now, I would begin a 5 tire rotation regimen so that this issue is not repeated.

 

[185]

Thanks. I am debating whether i can measure the tread depth of the existing tire on axle and then having the spare shaved down to minimize tread depth variance between the axle tires.

@Acrad is there a specific tread depth variance Lexus has indicated as a a requirement in the FSM? And is that variance between all tires on axle or just between two tires on a specific axle?

 

[r2m]

10,000 mile isn't all that much on current tires, I'd just swap out the flat with your spare and get a new spare.

 

[Rednexus]

You can get a tread depth gauge on Amazon or at your local auto parts store. They are a few dollars.

Using the tread depth, calculate the different in circumference of both the ruined tire and the new tire. For example if the stock tire diameter/height is 32.8" but the old tire has 11/32" of tread remaining instead of the new tread depth of say 13/32" (which you can find on the website for the tire maker), the diameter/height of the old tire is 32.74". The circumference (pi*D) would only be 0.2" difference between tires (0.2% difference in travel over one tire rotation), which I would personally not worry about.

 

[ericm979]

Either Bang Bang or r2m's suggestions will work fine, depending on if you want to go with a five tire rotation or four tire.

I'm doing five tire rotation on the GX for the first time in my life. It's kind of a pain (I do my own rotations) compared to four tire, but I wanted to have a spare that's always matched to the other wheels and tires. At least it makes me take the spare down periodically, making sure the spare tire mechanism isn't frozen (not likely in my part of California) and the spare is aired up.

 

[Jstawgn]

There is a guy in GXOR that run 7000 miles with three 265/70R17 and one 285/70R17 unknowingly. No damage at all. He finally got free upgrade to 285/70R17 when he brought it back to Discount Tires and shows them the problem.

The myth about AWD have to have matching size tires is overblown for GX. We do not have viscous coupling diff. The diff would see 1/2 the difference and center diff 1/4 of the difference.

 

[re_guderian]

There is a guy in GXOR that run 7000 miles with three 265/70R17 and one 285/70R17 unknowingly. No damage at all. He finally got free upgrade to 285/70R17 when he brought it back to Discount Tires and shows them the problem.

The myth about AWD have to have matching size tires is overblown for GX. We do not have viscous coupling diff. The diff would see 1/2 the difference and center diff 1/4 of the difference.

This x a million. Torsen specs like a 3% difference for the center diff, and you know that's conservative. That's like a 12% for the same axle. Like running a 29" and a 32" tire and still being okay.

 

[185]

Thanks for the guidance folks. Im going to pick up a tread depth gauge tonight and report back.

Lexus owners manual has this to say, which screams grey area

Do not mix tires of different makes, models or tread patterns.
Also, do not mix tires of remarkably different treadwear.
● Do not use tire sizes other than those recommended by Lexus.
● Do not mix differently constructed tires (radial, bias-belted or bias-ply tires).
● Do not mix summer, all season and snow tires.
● Do not use tires that have been used on another vehicle.
Do not use tires if you do not know how they were used previously

Did some reading on SAE, graciously the author has made it available to everyone, found that on awd systems (different from 4wd systems like ours)

In this study, the rolling radius of tires is measured on vehicle to understand the impact of tread depth, tire brand and model, and inflation pressure on the rolling radius. It was found that the rolling radius is not as sensitive to tread depth as it is to tire brand and model or even inflation pressure. Therefore, matching tread depths is not the most relevant criteria when replacing a single tire or tires in pairs. It is more important to match tire brand and model and maintain proper inflation pressure to ensure equal rolling radii across all tires

Tire Rolling Radius Evolution with Tread Depth and the Implications for Tire Replacement on All-Wheel Drive Vehicles

All-wheel drive (AWD) and four-wheel drive (4WD) vehicles are becoming more prevalent in the market today. However, it is not well understood what the correct practice is when only one tire on the vehicle needs to be replaced. There are var

www.sae.org

 

[jdam]

Also from what I understand, our trucks are overdriven front to rear anyway. Something like 40/60. And if you don't rotate them (like I did), I ended up with a 4/32nds difference between the front and rear just leaving it alone for 25,000 miles. Swapped them front to back and the truck didn't care.

 

[ericm979]

All 4wd vehicles turn the front tires a little faster than the rears. Otherwise you can get some funny handling. Typically something like 3-5% faster. But that is enough to make the tires wear more if you leave it in 4wd on dry pavement.

With AWD, which GXes are in most of the time, the center differential will ensure that the front and rear tires are turning the same speed at all times. The front tire wear that you saw from not rotating the tires was due to the vehicle being front heavy and understeering in turns. That wears fronts out faster than rears.

 

[185]

Update

Front Axle:
Driver: 8/32
Passenger : 8/32

Rear Axle
Driver: 10/32 (this is the spare)
Passenger: 9/32

13-25% I assume difference in tread depth

According to the FSM, thanks @Acrad

Question regarding type of front and rear diffrential - ClubLexus - Lexus Forum Discussion

GX - 2nd Gen (2010-2023) - Question regarding type of front and rear diffrential - I want to understand a bit more about mechanical stuffs on my gx. Per lexus website for 2016 model below and Wikipedia about torsen lsd, gx has a type c torsen CENTER diff. So what type of differentials are for...

www.clublexus.com

 

[Bang Bang]

So, I will stick to what I recommended above. Spare and new tire on one axle, the 2 even tires on the other axle, the 9/32 tire to the spare and start a 5 tire rotation. You never worry about this issue again.

 

[185]

So, I will stick to what I recommended above. Spare and new tire on one axle, the 2 even tires on the other axle, the 9/32 tire to the spare and start a 5 tire rotation. You never worry about this issue again.

That depends on whether the new tire will come with a tread depth of 10/32. If not, I am back in the same conundrum.

 

[Bang Bang]

If the spare has never been on the ground and you buy the same tire then you will be fine. It would be no different than buying a new set of tires. You don't measure the tread depth on new tires to make sure they are the same. You are really overthinking this.

 

[Rednexus]

It is good to routinely measure tread depth. I use mine yearly to check up on tire wear, make verify how much rotation I do or don't need, and forecast how much tread life the tires have left. Pretty nice little tool for $6.

Amazon.com

 

[185]

If the spare has never been on the ground and you buy the same tire then you will be fine. It would be no different than buying a new set of tires. You don't measure the tread depth on new tires to make sure they are the same. You are really overthinking this.

I might be. I got off the phone with tirerack, and i asked them if they could confirm the tread depth on the new tire, and for some reason they said it would be better to just pay for shaving the new tire to 10/32 just incase their stock was for some reason thicker then the spare.

 

[185]

i think the big part of me overthinking besides what i have stated.

a) would a 2/32 difference between axles and 1/32 difference between tires on the same axle damage the powertrain/fluids?
b) really dont want to purchase another bridgestone, since i planned to upgrade to defenders ltxs when these would wear out.

 

[Rednexus]

i think the big part of me overthinking besides what i have stated.

a) would a 2/32 difference between axles and 1/32 difference between tires on the same axle damage the powertrain/fluids?
b) really dont want to purchase another bridgestone, since i planned to upgrade to defenders ltxs when these would wear out.

You need to run the calculations per my post above . I'm betting you are well under 1% which I would personally not worry about at all.

 

[re_guderian]

All 4wd vehicles turn the front tires a little faster than the rears. Otherwise you can get some funny handling. Typically something like 3-5% faster. But that is enough to make the tires wear more if you leave it in 4wd on dry pavement...

Is this true? First time I've heard this in 40 years of owning 4wd vehicles. Not sure how a transfer case could do this on a 4wd vehicle.