China Tire Manufacturing

I think that exceeding the max wheel pressure would be a bozo-nono. That was one of the things that the Goodyear stressed.
The fact that you heard it on the Internet doesn't hold up well in the real world.

CapriRacer wrote:
Just to clear up a point on ST tires.

Part of the tire standard published by the Tire and Rim Association is a note that the max speed for ST tires can be increased to 75 mph if 10 more psi is used - and to 85 mph if a reduction in load of 10% is also used.

Note: This is part of the STANDARD. This applies to ALL ST tires (unless they have a speed symbol that supersedes the speed restriction).

So even if the particular chart you are looking at doesn't have the note, it still applies. I note with interest that Goodyear seems to have a bulletin that makes this exact point - and it doesn't seem to appear with the chart in the manual. I suspect that this is just a matter of waiting for an update to the manual. It is not unusual for these updates to take a decade or more (Low priority vs the amount of revision work needed) As an example, the Rubber Manufacturers Association recently updated their passenger car tire manual after about 20 years - and it took them 2 1/2 years to complete.

It would be really helpful to all if a link to the standard itself could be put up.

This subject gets a LOT of discussion at this site, and there's a lot of disagreement as to whether the Goodyear Bulletin is "legitimate", whether it would apply to other tires, and/or whether any such standard exists at all.

A link or other such reference would/MIGHT help to lay the question to rest once and for all.

CapriRacer
Thanks for the update on that. I was wondering what the TRA's stance was.
As for GY and Maxxis updating their charts, there is the rub. It used to be printed in the load inflation charts and product briefs. It is only in the last year or 2 that it seems to have been removed.

So I guess it is settled ;)

Just to clear up a point on ST tires.

Part of the tire standard published by the Tire and Rim Association is a note that the max speed for ST tires can be increased to 75 mph if 10 more psi is used - and to 85 mph if a reduction in load of 10% is also used.

Note: This is part of the STANDARD. This applies to ALL ST tires (unless they have a speed symbol that supersedes the speed restriction).

So even if the particular chart you are looking at doesn't have the note, it still applies. I note with interest that Goodyear seems to have a bulletin that makes this exact point - and it doesn't seem to appear with the chart in the manual. I suspect that this is just a matter of waiting for an update to the manual. It is not unusual for these updates to take a decade or more (Low priority vs the amount of revision work needed) As an example, the Rubber Manufacturers Association recently updated their passenger car tire manual after about 20 years - and it took them 2 1/2 years to complete.

dougrainer wrote:

RVUSA wrote:

BeerCan wrote:
The mere fact that all ST tires are limited to 65mph should be the first indicator.

Nope. you can go on Goodyear's site and they list instructions for over airing the tires to allow for 75 mph on their Marathon ST's.

Goodyears site shows NO inflation over 65psi and NO SPEED OVER 65mph for ST tires which ARE the tires for Towable trailers. LT tires are NOT for trailers. That said, I do not believe there are ANY tires (ST) out there designed for trailers that will allow driving OVER 65 mph. The China tires have a max speed of 62 mph. On my last long distance trip a few weeks ago on my Motorcycle, (98 to 102 degree heat), I averaged 70 mph and I was passed by numerous Boats and RV trailers going a LOT faster than me. I am IN the RV business and I truly believe that the majority of blow outs and tire failures are caused by
1. driving on tires older than 5 years old
2. driving TOO FAST on tires that are not designed to go faster than 65 mph.
Sorry, but driving faster than 65 mph towing ANYTHING is IDIOTIC and a hazard to all around you. Doug

"Goodyear's site shows NO inflation over 65psi and NO SPEED OVER 65mph
for ST tires which ARE the tires for Towable trailers".

Hate to bust your bubble, Doug....:W

(Agreed) It would be idiotic to run GY ST balloons, in the first place, and *really* idiotic to follow these GY recommendations which you aren't aware of...


GY - Increase Marathon psi - Increase Speed

BTW -
would you like a link to Michelin's LT tire trailer usage info also?..:S

~

John wrote:
What is not clear is what psi is needed, wanted, or best; max or per load tables.

IMO this is where experience comes in.
CapriRacer makes a good point on taking advantage of a tires reserve capacity you IMO erroneously are calling a safety margin. There is no advantage of the D tire over a C tire at those severally reduced pressures.

This advice from Nitto tire I believe CapriRacer has brought to the forums attention previously. The tire types/pressures are different but the same scenario applies so pay close attention to the last sentence :

Load Comparison Example, P vs. LT:
"P265/75R16 114 Max Load = 2,601 lbs @ 35 PSI
In order to carry the equivalent load, a LT265/75R16 Load Range C must be inflated to 50 PSI. Using this
example, even LT265/75R16 Load Range D, or E must be inflated to 50 PSI to carry the P-metric load at
35 PSI.
LT tires do not offer any benefits of being "heavy duty" when under-inflated."

I have a single axle 3400 lb bass boat and a light weight 14" tandem axle lawn service type trailer with 2700 lb axles. I keep P tires on both of them. Speed limit on I-44 near me is 75 mph which I sometimes take advantage of when pulling either trailer.

John, thanks for hunting down these tires. I think I'll switch to these on my horse trailer once the present one's wear out.

CapriRacer wrote:


John,

If you are going to match the load carrying characteristics of the 13" tire, why move to the 14"? Why not take advantage of that increased capacity - by using a higher pressure, which improves the reserve capacity?

My issue is the 65mph limit. I prefer to travel 65-75mph. The only tire I can find w/o the 65mph limit and that will fit the wheel well is the 185R14 trailer tire. This tire is Q=99mph rated which would give a good safety margin.

I have load safety out the wazoo!

My axle weighs 2040lbs, or ~1020lbs per wheel. The separate weights are L(street) 980 and R(curb) 1060lbs. The tires are rated at 1360lbs. I already have 300+lbs per wheel safety margin. Per the tire load tables, I could use anything between 35 and 50psi. I keep them between 45-50psi.

What is not clear is what psi is needed, wanted, or best; max or per load tables. K-Z, the mfgr, says 50psi for the orig ST175/80R13.

I believe they simply quoted the max psi because they can't, for obvious legal issues, get involved with anyone's particular situation. The load capacity of the tires exceeds the GVWR of the TT. Even if the TT were loaded to the GVWR, there would only be 1200lbs per tire, leaving 160lbs excess. K-Z, no doubt, choose that tire because it is the next tire just above their TT specs. K-Z has clean hands on tire capacity.

Now, back to the proposed 185R14. It has a 65psi and 1764lb rating. I propose that I will use whatever psi give at least 1360lb capacity. It is certain to be less than 65psi.

HTH;
John

full_mosey wrote:

FastEagle wrote:

When using replacement tires with a different size and design it must first be determined that the replacement tire has the basic qualities to satisfactorily replace the Original Equipment (OE) tires.

The recommended tire pressure (s) for such replacement tires will be derived from the load capacity and air pressure of the OE tires. For instance, if the tire placard depicts a recommended tire pressure of 65 psi and that pressure provides 2540# of load capacity the replacement tires recommended tire pressure would be whatever it takes to get 2540# of load capacity from the replacement tires.

FE

Thank you.

K-Z specifies 50psi, the max, and the current tires are rated for 1360lbs each, also the max. By moving to the 1764lb max rated trailer tire, I should be able to use the tire loading tables to find the pressure that yields at least 1360lbs load.

HTH;
John

John,

If you are going to match the load carrying characteristics of the 13" tire, why move to the 14"? Why not take advantage of that increased capacity - by using a higher pressure, which improves the reserve capacity?

Trailer houses have come a long ways, 2X6 floors, 2X4 walls & sheetrock, but still 2X2 truss roof system & stupid 8 to 10 year shingles.
Common sense should tell the MFG, if I'm getting a trailer house I want tin on the roof for when it rains. Crazy bunch, why put something wont last no longer than that when tin is good for 50~75 years long as you keep it coated.
Neil