Tire test question?

[Oldfart]

I was reading a tire test on the Tire Rack site and they had some info I've never seen before and was wondering if it made any sense to you guys.

Here's a quote from the test, "It may come as a shock, but when comparing LT-Metric and Standard Load tires of the same dimensions, the LT-Metric tires require more air pressure to reach the same load carrying capacity. As such, the BFGoodrich tires in our test were inflated to 48¹ psi, as opposed to the 35 psi for the rest of the group. Between the additional inflation pressure and the robust construction of the BFGoodrich, the ride was quite stiff to the point that it seemed to induce additional movement due to the flexing of the vehicle structure."

I've never run across the bolded sentence and it really doesn't make sense to me. I've never seen tire ratings quoted per tire pressure anywhere. Am I missing something? I do know my tires at 48 psi would be stiff as hell!

 

[FDHog]

I'm running my "E" rated KO2's at 38 psi and they're wearing fine.
Have about 5K on them and can't see any unusual wear.

 

[smurfslayer]

I've never seen tire ratings quoted per tire pressure anywhere. Am I missing something? I do know my tires at 48 psi would be stiff as hell!

so when you put your old lady on the back of the bike, the bike rides a little lower, right?

DON’T. You know I mean the living, breathing old lady, blow up / HOV doll does not count.

Anyway, you need more preload, more compression, more rebound, and more psi in the back to get back some of the handling characteristics.

ZX14 has some crazy, Raptor like ratings - 41/41 IIRC, which even with the stock rubber made it ride like cr@p. I ended up around 34/33 solo, 36/38 2 up

I can see some of the tires taking more psi for load making perfect sense.

 

[Oldfart]

But they were talking about specific load rating capacities according to different tire pressures. That I've never seen before.

 

[GCATX]

I believe they mis-spoke. LT tires usually have a higher weight load rating than passenger tires, but they require more PSI to meet the higher weight rating. That is to say you can run both at 38 psi, but the load carrying capacity may be the similar at that PSI. LT's are usually rated at higher capacity and would take more psi to achieve the capacity.

Instead of this:

the LT-Metric tires require more air pressure to reach the same load carrying capacity

They should have written this:

the LT-Metric tires require more air pressure to reach it's HIGHER MAX load carrying capacity

Think dually, or 3/4 truck tires, some you have to run 80 psi to get to 3500 lbs of capacity, whereas a similar sized passenger tire may only be rated at max 2400 lbs of capacity at max 35 psi. Most tires do have a load/psi chart available, you may have to poke around to find it.

Conversely, you could just put helium in your inflatable 3-way roadshow and ride in comfort.

 

[jzweedyk]

What he said. ^^^

 

[Oldfart]

I believe they mis-spoke. LT tires usually have a higher weight load rating than passenger tires, but they require more PSI to meet the higher weight rating. That is to say you can run both at 38 psi, but the load carrying capacity may be the similar at that PSI. LT's are usually rated at higher capacity and would take more psi to achieve the capacity.

Instead of this:

the LT-Metric tires require more air pressure to reach the same load carrying capacity

They should have written this:

the LT-Metric tires require more air pressure to reach it's HIGHER MAX load carrying capacity

Think dually, or 3/4 truck tires, some you have to run 80 psi to get to 3500 lbs of capacity, whereas a similar sized passenger tire may only be rated at max 2400 lbs of capacity at max 35 psi. Most tires do have a load/psi chart available, you may have to poke around to find it.

Conversely, you could just put helium in your inflatable 3-way roadshow and ride in comfort.

Thanks, that makes more sense than what they wrote. I have never seen a load/psi chart. I know 48 psi in my truck tires would definitely ride like crap.

 

[snt505]

This is funny because I have never heard that either. I went back to the Toyo pressure tables and saw this. I guess I want to research that mechanism now.

WARNING! Please note that size-for-size, LT-metric tires require higher air pressures to
carry equivalent loads of P-metric tires and that any failure to adjust air pressure to achieve the
vehicle’s load requirements will result in tire fatigue and eventual tire failure due to excessive
heat build-up. Due to the higher PSI requirements of LT-metric tires they may not be suitable for
replacing O.E. P-metric tires because of the ride harshness that results from higher PSI requirements.

https://www.toyotires.com/media/212...FjAMegQIBBAB&usg=AOvVaw0zaHumL9xB01d0CRYFLPCS

 

[richnot]

That's still confusing in a way especially if your trying to compare one manufactures tire like a BFG (KO2) LT315/70R/17C it is 2535 lbs @ 45 psi, and standard on the raptor, and the next is
a LT315/70R/17E it is 3195 lbs @ 65PSI BUT it is an E rated tire. If you go to a standard 35X12.50X17E that is also an E rated tire it is 3195 lbs @ 65 psi

At one time BFG did offer another 315/70R/17 Tire but it has been discontinued. The KM3 has 37x12.50x17D and they have a 39x13.50x17C

Unless your maxing tour trucks carrying capacity out why would you inflate the tires to the max.Inflate them down to what other members are running and see how it works for you, you can always do a simple tire chalk test to see just how much of the tire is making contact with the pavement. I ran BFG 35`s that were E rated on my Jeep and had them down to 6 plus for rock crawling and 26 psi to 30 psi on the street depending if the Jeep was loaded up or not