Question on inflating trailer tyres

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Joyous70

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Quick question, Am i o.k. to inflate my trailer tyres to the recommended PSI, prior to loading and travelling my horse. I only ask as someone said I should only inflate them once the trailer is loaded up.
 
Someone is talking complete rubbish!
You need to ensure that your trailer has trailer tyres fitted to it and not normal car tyres. Trailer tyres require a tyre pressure of about 80 p.s.i. (Pounds per square inch).
Unfortunately some people replace their trailer tyres with car tyres to save expense but this is potentially very dangerous.
 
Main thing is to ensure you know how to attach trailer to vehicle, its on youtube, and that tyres are the correct type, ie NOT car tyres. Take trailer out for a few practices and get them up to pressure when cold/cool. Make sure brakes are good etc etc.
 
Not all trailer tyres need that much pressure! Check what they should be (trailer dealer or tyre place should be able to advise), always try to check them when they're cold and it's a good idea to get yourself a decent gauge, as the ones in petrol stations etc. are notoriously unreliable.

The rating is on the sidewall, something like 106J or 70T for example. Also check that you have n't got mixed tyre types. Unlikely, but not impossible and it is illegal as well as unsafe to have crossplies and radials on the same axle.
 
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If the tyres on your trailer require a pressures of less than 60 p.s.i then they are car tyres and not suitable for trailers.
 
Tyre pressures (car or trailer) don't change according to the weight of the vehicle (although they should be higher if you are carrying a greater weight, e.g. you should increase the pressure of your rear car tyres for towing, according to your manual) but they will change according to the temperature of the tyre (which heat up with use) so you should always pump them up cold, so either before moving the trailer or after only a short journey to the garage. Ifor Williams trailers have an orange sticker on the inside of the jockey door which give the pressures (my 510 requires 65 p.s.i). Equitrek tyre pressure are much higher - up in the 80s due to the greater weight. I've had to sort the tyres on my friend's Equitrek and couldn't do it at a normal garage machine as it didn't go up high enough. I went to a local tyre place and they did it for me - they didn't charge me but I put a few quid in their tip box.
 
OWLIE185 said:
If the tyres on your trailer require a pressures of less than 60 p.s.i then they are car tyres and not suitable for trailers.
Click to expand...

Not true! As long as its maximum loaded weight is higher than 1/4 of the MAM of the trailer they are perfectly safe to use
 
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Be careful with local "tyre and battery type place" they tried to quote me for car tyres which would have invalidated insurance, also unable to "test" battery ......... which cost me a new alternator and belts.
I use a proper garage which knows all the rules. Run by a mechanic, employing mechanics.

Don' t uses a national franchise OP, they' re on sales bonuses" and know very little.
 
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OWLIE185 said:
If the tyres on your trailer require a pressures of less than 60 p.s.i then they are car tyres and not suitable for trailers.
Click to expand...

Not true. Depends on maximum load of tyre, which is dictated by trailer weight. My Rice eventer only inflates to 44psi, because it's only a 1600kg trailer. The old beaufort has 75psi tyres because it weighs closer to 3 tonnes, fully laden.
 
Joyous70 said:
Quick question, Am i o.k. to inflate my trailer tyres to the recommended PSI, prior to loading and travelling my horse. I only ask as someone said I should only inflate them once the trailer is loaded up.
Click to expand...

You can fill the adviced cold pressure even when the tyre is off the ground, then after loading the cold pressure will be the same.
Or at least , that small difference that your device wont give a different pressure.
Example : filled cold spare wheel before mounting to the trailer at 50 psi, then when mounted and loaded with horses the pressure will measure still 50 psi.

Normal car tyres or XL/reinforced/Extraload tyres are ok under a trailer if the maximum load is enaugh.
Problem is that mostly they dont have enaugh maximum load in the sise that fits under the trailer.

Can also calculate an advice pressure for your trailer, if you give GVWR/MPVW ( max permissable vehicle weight).
And of tyres maximum load and kind of tire to determine the pressure needed for maximum load/AT-pressure/maxloadpressure/reference-pressure, wich is not the maximum pressure of the tyre.
Also would be nice to have the speedcode of tyre ( letter J to R mostly).
 
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Thank you for all of your replies, I did think the comment about not pumping tyres until trailer was loaded was odd, but thought i would check with you guys.

My tyres are most definately trailer tyres, theyre the original tyres that came out of the factory when the trailer was built, they are in good working order they have been checked, however, they are a very low PSI compared to most only 35 PSI, this is what is stamped on the tyre itself and also on the sticker inside my jockey door.
 
That your Trailer tyres have 35 psi written on them , makes me suspect they are of the american system. Europe uses for standard load 36 psi/2.5 bar, but for 80% H/W also 35 psi is used. Then if they are ST tires , wich american system uses , the maximum load is given for 65m/104km/h.
European "for trailer use only" tyres mostly have speedcode N so for up to 140km/86m/h and have mostly 2 loadindex steps higher then same sise and AT-pressure ( 35 here) normal car tire for wich maximum load is calculated for 160km/99m/h.
So look again at the sidewall and search for speedcode ( that N probably) or ST written on them.
Then when your busy , give sises to see if I am right about the H/W division ( called Aspect ratio ).

This more maximum load is purely because of the more deflection of tyre allowed at lower speed.
trailer tires though have mostly less profile then normal tires , because wear is less because of the lesser miles they mostly make.
This thinner treath gives lesser isolation of the areas that produce the most heat.
I suspect a trailer tyre to be , apart from the lesser profile, a normal car tyre design, and only calculated more maximum load because of the more deflection allowed.

This makes it better to calculate the needed pressure for 99m/160km/h to give the tire same deflection a normal car tyre would have, wich is better for live time and savety . Then still no terrible bumping.
I once concluded by reactions about bumping, that if you have more then 85% of the weight , the pressure is calculated for , on tyre, that comfort for people and animal is acceptable.
But this is for calculated for 160km/99m/h.

Made a topic on American RV forum about this subject.
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/27477930.cfm

Also there the Loadindex system research.
 
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