# Trailer tire inflation



## lemaymiami (Feb 9, 2007)

Smaller diameter trailer tires are working a lot harder than the tires on your vehicle at any given speed... make a point of inflating them to exactly what the manufacturer recommends.... This is from a guy who tows a skiff more than 20,000 miles per year (and has for some years....).


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## Sublime (Oct 9, 2015)

Remember those small tires don't have a lot of volume, so don't let the high PSI freak you out. There are a lot less square inches involved. Now try putting 90 psi in a big tractor tire for example and you better have your will updated. Lots of 90 PSIs in those.


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## WhiteDog70810 (May 6, 2008)

The tire max PSI and the recommended PSI for the trailer are usually different. The tire max is the max safe pressure the tire can operate at (don't go above this). The recommended PSI for the trailer takes the anticipated load into account (for best performance, inflate to X). Inflate to the PSI the trailer recommends. If the trailer loadplate says to inflate to 90 PSI, do it.

Nate


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## firecat1981 (Nov 27, 2007)

I'm with you, I don't like filling them to the max, especially since it gets so hot here. I typically run mine at 80-85psi.


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## jfboothe (Dec 19, 2012)

Thanks guys and I do understand. Having worked in aircraft maintenance all my life we have tires that we inflate to well over 120 psi. But those are some beefy tires carrying a lot of load! I do understand inflating high load tires on trucks and trailers to much higher psi but 90 psi in this little trailer tire seems excessive but I am going to follow the recommendations. The worst part is that with that amount of pressure, there is absolutely zero flex in the tire so every bump is transmitted directly into the trailer and boat.

Getting ready to make another long 600 mile trip so I am doing all my preventative maintenance (bearing repack, tire pressure, torquing lug nuts, etc). I have towed this trailer on some 13+ hour trips several times now and it does pretty good (knock on wood...).


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## TheAdamsProject (Oct 29, 2007)

I inflate my trailer tires to the max when trailering as those tires are under load. If my Carlisle says 50lb I run 50 always and sometimes 55lb on long haul highway trips. The new HDs go to 80psi. A few years ago Goodyear came out with a service release when running its marathons on highways speeds over 65mph to inflate 10psi above stated sidewall rating.

We have also seen guys who have larger boats like a 20 Shearwater on a single axel trailer blowing tires constantly and found the Kuhmo 857 205/R14 which have a higher D load rating and 65psi and the blowouts stopped. I can assure you that blown tires occur more due to under inflation than over inflation, by a long shot.

Not a Marathon guy, I run Kuhmos or the new Carlisle HDs

Here is the Goodyear Service that was issued back in 2011-ish. I dont run them but think they have even upped the speed rating and load on newer Marathons.
"Special Trailer (“ST”) Tires
Goodyear Marathon trailer tires are widely used in a variety of towable trailer applications and are designed and branded as “ST” (Special Trailer) tires.
•Industry standards dictate that tires with the ST designation are speed rated at 65 MPH (104 km/h) under normal inflation and load conditions.
•Based on these industry standards, if tires with the ST designation are used at speeds between 66 and 75 mph (106 km/h and 121 km/h), it is necessary to increase the cold inflation pressure by 10 psi (69 kPa) above the recommended pressure for the rated maximum load. o Increasing the inflation pressure by 10 psi (69 kPa) does not provide any additional load carrying capacity. o Do not exceed the maximum pressure for the wheel. o If the maximum pressure for the wheel prohibits the increase of air pressure, then the
maximum speed must be restricted to 65 mph (104 km/h). o The cold inflation pressure must not exceed 10 psi (69 kPa) beyond the inflation specified
for the maximum load of the tire."


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