Tire Pressure for street use...

[lobobronco]

Did a search, but didn't come up with much...

Thought I would throw the question out there for those that drive their bronco on the streets daily or regularly.

Mine are 33X12.50 Goodyear MTRs and have been running 30 psi (tire says 35 cold). Not sure if am in the right spot, but no bad tire wear issues. Have a buddy running 25 psi. Any thoughts...

Don't want to keep this thread at the 33's...let see what others are running on all sizes and the luck they have had. Yeah...dreaming of larger and smaller for when I get a trailrig and LUBER later in life ;D!

Thanks,

Matt

 

[lobobronco]

Just realized I was in the "chat" area and this probably belongs in the "tech" area...feel free to move.

Many apologies....

Matt

 

[Broncobowsher]

I did a good amount of playing around, high 20's is a good starting point. That did well for me when running 33 12.50s on 10" rims.

When lower (under about 26) it squirmed around a lot, floating side to side. Tires also barked a lot harder when the trans hit 2nd under throttle in a turn pulling away from a stop sign.
Getting up into the 30s the tire would start bowing and riding on the crown.
That left me with about 28 as a happy street pressure. Often I would fill to 30 or so and when it started feeling floaty I knew it was back down to about 26, time to top off again. As long as they all creep about the same rate I didn't worry. When one tire would bleed down faster then I would look for a leak (usually valve stem).

Back in the mid 90's I knew some factory tire pressure specs that were as low as 26. After that firestone/Explorer low pressure overheating tires blowout deal the pressures creeped up to the mid 30's with improvments to fuel economy, tire life and handling and a slight loss in ride quality.

For the most part, I like them high on the highway. Just not so high that they crown and ride on the center of the tread. Weight of the vehicle, specifics to the tire (even the same size, different brands/patterns), and a huge one is rim width will all factor what a good street pressure will be.

Hint, the sidewall pressure is what the tire is rated at when running at it rated capacity. I forget the exact weight rating of the tire I ran, 3,000 Lb? If you weighed in at 12,000 then the max pressure on the sidewall would be a good choice to run. Sorry, no simple math equasion to get a proper pressure of known weight. Not that easy either.

 

[74 Bronco Boy]

30 psi is fine for street. 25 to 30 with 33" so your in the right zone.

 

[garberz]

I run 26 PSI. 35" KM2's on 15x8" wheels.

 

[HGM]

An old procedure to get you in the ballpark was to use a chalk line.. Basicly, in a long driveway or parking lot, you would keep your tires straight ahead and draw a line accross the treads. Drive straight forward for a short distance and see how the chalk wore. Your goal is to use the maximum air that will wear the whole line off evenly. As mentioned above, no good math equation, just trial and error since all tires are not the same and no tire is made for a particular vehicle..

 

[tasker]

i run 20 on mine with 15x8 and 33x12.50 Destination M/Ts....was wearing the center at 25

 

[Broncobowsher]

i run 20 on mine with 15x8 and 33x12.50 Destination M/Ts....was wearing the center at 25

20 would scare me. How hot do the sidewalls get after a long (50+ mile) highway drive?

 

[tasker]

never had a problem and i drive mine....alot. Long trips at highway speeds (don't like slow for some reason) and never had any problems....If i'm going long highway trip i'll push them to 25 but not very often

 

[lobobronco]

Lot's of great info....might have to try the chalk trick to see what is really happening. Other than that, looks like I'm in the ballpark.

Thanks for the info!

Matt

 

[deltarat]

I used to run 17 in Q16 bias 6 ply buckshots for 20 years with no problems. They didn't squat and stood up well and drove fine. My Maxis mudders squat really low at that pressure. I run 26 in them.

 

[73stallion]

i run in the low 30's in mine on 10" rims.

 

[NYLES]

Go get your tires dirty! then drive down the road and read the tread! clean in the center not the edges too much air. air em down till the whole tread surface is touching the road!

Simple as that