Tire pressure

[Martinjmpr]

So what tire pressure are most of you running? Curious to know.

I checked the pressure on Bubbles, which uses old car tires I got from Coker Tire (seems you can't buy super skinny tires with wide whitewalls at Discount Tire!) Pressure was around 25 which seems low to me.

OTOH, Bubbles only weighs ~1000 lbs. So maybe 25 is OK? One of the drawbacks to a home built trailer running car tires is I don't really have a "manufacturers recommended" tire pressure.

So what pressure are most of you running?

[jstrubberg]

Manufacturers recommended tire pressure is usually bunk, too. I highly recommend chalk-testing your tires with your intended load to determine tire pressure.

Get a stick of kids sidewalk chalk and head out to your nearest large parking lot (Wal-Mart, etc). Run a heavy band of chalk horizontally across both trailer tires, then roll your rig forward 100 feet or so. Get out and check the chalk. If it's worn off the center of the tire, you are overinflated. If the chalk is gone off the edges of the tire and the center hasn't been worn off, you are underinflated. You are trying to get a nice, even wear pattern across the tire.

Bad alignment will also show, but you will see wear on one side or another rather than center/edges.

The problem with even a manufacturer recommended tire pressure is that they assume a given load. If you are substantially lighter or heavier than their standard, your tire pressure will not be optimal. BTW, the number on the sidewall is not recommended tire pressure, it's recommended MAX tire pressure.

[aggie79]

I run our wide whites at 25 psi. I haven't weighed our teardrop but I'm guessing it's around 1500#.

[mustangcats]

I inflate my trailer tires to about 45 psi. The trailer weighs approximately 2800 lbs.

[pchast]

At 560 lbs I run 30 lbs in the original harbor freight tires.
The chalk test is good. I found my alignment is 1/8" toe out.

I was advised it was good not to worry and check wear at
5000 miles?

[Dale M.]

Over time the tread wear will tell you what tire pressure is correct (long term version of chalk test) .... If tires are wearing on outside edges you are under inflated, if wearing in center you are over inflated..... This has been true since the day of the pneumatic tire....

A give tire and a given load (manufacturers recommendation on door frame of most cars now a days) is probably good place to be IF you are still diligent and watch the wear... ON unspecified loads ( subject of this discussion), the "inflate to" pressure on tire side wall is a MAXIMUM pressure not to be exceed, for the maximum LOAD RANGE of tire, but not always correct pressure for your application/weight....

A tire wear gauge can tell you exactly how tire is wearing...



Tires wear will also indicate alignment issues, but that is not topic for discussion here....

Dale

[asianflava]

I run about 25psi on mine, it weighs around 1200lbs. I've tried 30psi but got too much bouncing. My trailer has crossed the country probably 4 or 5 times now and I've never had a problem.

[desertrat9]

Never heard of the chalk test. Thanks for posting it.

[Franco Novo]

What about a basic answer for a harbor freight trailer
I have the folding trailer 1195 lbs. max load....trailer is loaded and all weighs in at around 980 lbs.

Tires indicate: inflate to 60 PSI ?
too much.??
I haven't towed before....

best regards
Franco

[capnTelescope]

Thanks for the chalk test, jstrubberg. I will do that next.

I started with as-inflated tires hard as a rock. Northern Tool cheap Chinee chit. Waaay too much shaking. Lowered to 20 psi and wore the outer edges something awful. Went back up to 30 psi which seemed about right, and wore the tires out on the last trip. Only got about 10K miles out of them at the most. I just bought new tires and will definitely do a chalk test and report in.

The trailer weighed 1320# half built, and I estimate 1600-1800# now.

[angib]

A safe rule of thumb is that a tire can carry the same proportion of its maximum load when inflated to only part of the maximum pressure on its sidewall.

So half maximum inflation pressure is safe to carry at least half the maximum load. Don't forget to multiply by two for the two tires on a trailer!

[Franco Novo]

Towing newbie seeking simple answers
yeah, well, I have one of the cheapo chine trailers from HF and it's already built, I'm a newbie, and a bit nervous about towing.
you all had it once...Fear of towing....
there is a bit of a story or formula or haughtiness in many responses, when some of us are just trying to find out an answer to questions you all had at one time
or, maybe it's just my nature of over researching...could be that. who knows

OK..I 'm thinking like...".OH....990 lbs loaded. small cargo trailer, pulled with ford focus....how about 45 PSI."

Now, moving on: Bucking: Surging: Push Pull" ....???? I am about to redo the sloppy hitch again...Perhaps reading here is making me overthink everything
But, there are new guys, and gals out here who don't really know what towing feels like. a small trailer like that I have...and I can feel it...pushing and pulling on the car...I know the back end of the focus wagon is soft.. I'm playing with loading weights and tongue weights now

Last night I read on some other forum, dig this.... that the bucking or push pull could be. " loose trailer coupler" , loose hitch bar in receiver, loose ball, bearing that is stuck, could just be the type of road I'm on, could be the tongue weight is too much, could be the tongue weight is too little. could be a harbor freight trailer...I need a trailer with 16" tires and a Dodge hemi to pull it

You see why it's dangerous to read forums....I did find another forum, you can write me if you want, i'll give you newbies the name, there is a section on people helping people...that is not full of code and formula's and overbuilders who spend four months joining a sheet of f*ckn plywood with a cnc router, when it can be done in half an hour with a scarf joint or a block and some glue and screws.

Franco

[Socal Tom]

Check out this thread I started a while back. Its got some links to charts that help with the pressure /weight.
viewtopic.php?f=2&t=49677
Tom

[capnTelescope]

Check out this thread I started a while back. Its got some links to charts that help with the pressure /weight.

Tom, thanks for the links to some hard info. I'd looked before and couldn't find anything nearly this good.

The Toyo Tire link has moved to:
https://toyotires2-1524598101.netdna-ssl.com/assets/lib:toyo%20content/Application_of_Load_Inflation_Tables_20150623_Final.pdf
The must-have PDF this links to is full of info by tire size, type, etc. I'd say everyone should download and save it in case it goes away.

Thanks again!

P.S. Just returned from an excursion on my new radial passenger tires. Much better ride in back.

[felixx]

I did the chalk test on my car tyres too..