Chalking

[Ozbronco]

I had some 315/70/17 KO2s put on last week (on a 4 dr Badlands). The shop put 39 psi in the tires. I'm trying to dial in the correct pressure by chalking. I'm down to 33 psi all around. The attached pic shows the test this morning when the tires were as cool as they were gonna be (outside temp was around 75 deg).

If you've done this before, how does this look? It looks like it could go a bit more, but I don't want to go too low. I like the way it drives right now. Thanks for any advice.

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[ScLeCo]

Still slightly over inflated but pretty close.

 

[SuperDave150]

I had some 315/70/17 KO2s put on last week (on a 4 dr Badlands). The shop put 39 psi in the tires. I'm trying to dial in the correct pressure by chalking. I'm down to 33 psi all around. The attached pic shows the test this morning when the tires were as cool as they were gonna be (outside temp was around 75 deg).

If you've done this before, how does this look? It looks like it could go a bit more, but I don't want to go too low. I like the way it drives right now. Thanks for any advice.

I applaud you for chalking! I learned this decades ago and can attest to its effectiveness.

In regards to wear & traction I agree with @ScLeCo

Yet if I were taking a road trip in summer I’d go with what you have or even add a couple of PSI. This is especially true for BFG all terrain or mud tires because of their thick sidewalls; great for off road durability but on-road the thick sidewalls are heat sinks that build up heat and won’t give it up. Heat kills tires, and blowouts kill people.

 

[Silver-Bolt]

Still a couple of PSI high. Where you are at is probably good for long highway trips.

 

[Skott]

Can someone elaborate on what "chalking" is, and perhaps how it's done?

Never heard this term before.

Thanks.

 

[Rspayde]

Can someone elaborate on what "chalking" is, and perhaps how it's done?

Never heard this term before.

Thanks.

Basically just putting chalk on the tire and driving. Lets you see where the tire is contacting the ground. Where the chalk is left is where the is no contact with the ground.

 

[Ozbronco]

I applaud you for chalking! I learned this decades ago and can attest to its effectiveness.

In regards to wear & traction I agree with @ScLeCo

Yet if I were taking a road trip in summer I’d go with what you have or even add a couple of PSI. This is especially true for BFG all terrain or mud tires because of their thick sidewalls; great for off road durability but on-road the thick sidewalls are heat sinks that build up heat and won’t give it up. Heat kills tires, and blowouts kill people.

Thanks for the reply. I had never heard of chalking till someone mentioned it in a post here. Went and watched a couple vids on it and it seemed to make perfect sense.

I dropped another pound of pressure and checked again this morning. It looks real close in front, pretty close in rear. I'm gonna go with it for now. (see pic)

How do you tell if your tires are getting too hot? I just took a 600 mile trip with the tires started at 34 and they seemed fine.

 

[Dad life]

Yet if I were taking a road trip in summer I’d go with what youThis is especially true for BFG all terrain or mud tires because of their thick sidewalls; great for off road durability but on-road the thick sidewalls are heat sinks that build up heat and won’t give it up. Heat kills tires, and blowouts kill people.

No Bronco is going to blow out a new BFG due to heat at anywhere close to these pressures, no need to scare people.

 

[TX-Dennis]

Mid 20s (psi) is where you start to worry about overheating tires at highway speeds.

Some of us (me) are old enough to remember the Explorer Firestone tire fiasco with the blowouts and rollovers caused by under inflated tires. Ford was recommending people run then at 26. Firestone took the blame, but it was mostly Ford's fault.

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