Fixing your own flat tires

[RL Lemke]

Re: Re: Fixing your own flat tires

Do the chalk test to see where your tires touch the road; this will help you determine proper psi.

Excellent advice as how the tire meets the road is the key to proper inflation. I do this often by looking at the dust on the tread of the tire. BTW: My experience with the BFG ATs is that the pressure on the door jam provides for very even wear. That only with the proper balancing machine attachment (lug centric) can the tires be balanced. And lastly, I add a couple pounds of air to the rear tires when I carry a load, or pull a trailer.

 

[greasefingers]

The links provided where very useful. And I thank those that suggested the Safety Seal Kit. It was what I was looking for. Something that is better than the typical auto parts store junk.

I would think that the tire manufacturer specification would supercede the vehicle door jam spec. I have been running my Dunlop’s at 48psi for 17 months. Got 32k miles on them. No sign of wear at the center. I bought the Toy new and it came with 50psi in them. Anyone with factory Dunlop Grantrek AT20 (P265/65 R17) out there with any comments? I may re-read those articles and re-evaluate the pressure if needed.

I got the day off from work today, so I am trying to get a coat of wax on her before the snow comes.

Thanks for everyone’s input

 

[HuntRunner]

.....I would think that the tire manufacturer specification would supercede the vehicle door jam spec.....

From the Dunlop ("the tire manufacturer") web page:

"Always maintain inflation pressure at the level recommended by the vehicle manufacturer as shown on the vehicle placard or in the Owner's Manual. Higher inflation pressure increases stiffness which may deteriorate ride and generate unwanted vibration."

"Tire footprint and traction are reduced when van, pickup or RV tires are over inflated for the loads carried. In particular, tires with aggressive tread patterns may contribute to oversteer or "roadwalk" if inflated beyond the inflation pressure specified in the Owner's Manual and vehicle placard for standard or customary loads. Over inflation also increases the chances of bruise damage."

 

[greasefingers]

So like why then did the dealer supply me with the tires at 50psi? Not that I doubt their confidence or anything J

 

[dcampen]

So like why then did the dealer supply me with the tires at 50psi?

Because these were not stock, OEM tires and they don't have a clue what to do with non stock tires so they just inflated them to the max pressure shown on the sidewall.

And, as ToyotaDoodz says, with non OEM tires, especially when the OEM tires were passenger rated tires and your tires are LT rated, neither the doorjamb nor sidewall pressure recommendation are necessarily correct.

Still, when going from passenger OEM to LT rated tires but maintaining the same tire width as the OEM tire then the doorjamb pressure should be a pretty good guess; much closer than the max pressure shown on the tire sidewall.

 

[dcampen]

Anyone with factory Dunlop Grantrek AT20 (P265/65 R17) out there with any comments?

So those were OEM tires! I can't find any info about them at the Dunlop web site.

What is the doorjamb pressure recommendation. If it is not 50 psi you should write to Toyota and ask them if the dealer was correct in inflating your tires to 50 psi.

 

[SteveM]

Yeah, Safety Seal claims that their plugs make permanent repairs and I have a Safety Seal kit in case I need to use it offroad. Still, I would feel much better with a patch placed inside the tire, it doesn't cost that much to have it done. I wonder if a tire shop will apply an internal patch on top of a Safety Seal plug?

I used to work at a tire shop (20 yrs ago so things may have changed a bit). When we got a tire with a slow leaking plug, we used to remove the plug and patch over the hole from the inside. Occasionally, we would cut the wicking flush with the inside of the tire surface and then patch over that.

No tire shop in SoCal will do a plug anymore; they all claim it to be illegal. I asked further and some of them claim that the act of forcing the wick through the hole risked damaging the steel belts by separation.

If you're stuck somewhere and can't patch, then plug to get home. Otherwise a patch is the best repair.

Someone in thisthread was asking about stem replacement without breaking the bead. Replacement cannot be achieved without breaking the bead since the new stem is inserted from the inside portion of the rim. The valve stem insert can be replaced very easily without breaking the bead. If you're fast enough, it can be replaced without losing all of the air!

 

[dcampen]

Tirerack:
http://www.tirerack.com/tires/Spec.jsp?make=Dunlop&model=Grandtrek+AT20

gives the following specs for the 265/65-17

max load = 2337 lb at 51 psi max pressure.

Assuming your 4Runner weighs 6000 lbs then these tires should be inflated to:

(1500/2377)*51 psi = 33 psi

 

[HuntRunner]

My 4Runner came with the Dunlop Grandtrek AT20 (P265/65 R17) as well, but the air pressure was 32 psi from the dealership.

 

[Hank]

My dunflops came from the stealers @32psi. I tend to put a little more air in all my tires on all my vehicles, close to, but never at the max cold pressure rating unless the tire's max press is 35psi. I ran mine @ about 37psi last summer (cold temp, but SoCal doesn't really get very cold overnight during the summer). I recently brought the front tires up to 40psi front & 37psi rear (cold; but we recently had much colder weather than usual, then we had some pretty warm days just this week). I noticed my ride was noticeably harsher now than before. Yesterday I checked the "warm" pressure in my tires & they were @ 44-45psi. I allowed the tires to cool down overnite to about 40psi when I checked this morning. I aired it down to 35psi before leaving for work & I noticed that the ride wasn't as harsh as it was the prior day. I'll be leaving it at the lower pressure now since I know how different the ride is when the pressure is too high. I can't imagine how the ride will be @ 51psi and besides, at the highway speed that I drive, 51psi will cause it to have a pretty jouncy ride, if not unstable control when hitting non-smooth road surfaces on the freeways/highways. Just my 2cents

btw: can't wait for the dunflops to wear out so i can get some Revos!

 

[greasefingers]

Yea I’m with you on the Revo’s. I too can’t wait for my Dunlop’s to wear out. I am thinking that the Sport comes standard with these Dunlop Grandtech AT20s?

 

[Kmvreter]

patch...

A plug only fixes the immediate leak. If you want to keep your tire for the long term then get it patched by a professional on the inside to avoid corrosion in the carcass (rust in steel belts) that is the leading reason for tire seperation (not caused by underinflation or a manufacturing defect.)
Also, greasefingers, is the Dunlop a P or LT? All "P" (passenger) tires are rated at 35 psi max unless they are "XL" which are 41 psi max. This is industry standard. Inflation psi for LT is load and speed based, not a simple straight line calculation like dcampen suggests. Go with the vehicle placard as long as you haven't overloaded the vehicle (then you have other concerns, like braking distances.)

 

[greasefingers]

From the Dunlop Website:
Grandtrek AT20
Original Equipment All-Season SUV and Light-Truck Radial
P265/65R17

I thought the “P” in front of the tire size indicates passenger, but their description states” Light-Truck Radial”

So I am confused.

 

[Kmvreter]

look at the tire...

to clear it up. What does it say on the tire? The website might have it wrong. Then follow the recommended pressure on the door-jam placard and you can't go wrong. There is no reason to run an LT tire at max psi on a 4Runner because you are nowhere near the max. tire rated load.

 

[02SE]

So like why then did the dealer supply me with the tires at 50psi? Not that I doubt their confidence or anything J

Because whoever has the job of prepping vehicles at that dealership is incompetent. :

 

[dcampen]

Inflation psi for LT is load and speed based, not a simple straight line calculation like dcampen suggests.

Yes, for LT tires the manufacturer should supply a table showing inflation vs load. This is nowhere to be found on the Dunlop web site. The straight line is a good approximation.