14" Tires ST 205/75 R14

[Vich]

Ok, So it finally happened to me. I had a 3 year old Tow-Master St 205/75R14 literally disintegrate yesterday. I was truly blessed that it did not cause any real damage. I can not afford to buy 5 hole 15" rims and tires. So I guess the question becomes - Is there any really good reason that I should not try ST 215/75R14 vs. the ST205/75R14's it came with? The rims are 14X6 J. The 215's are .6 inch taller (.3 inch closer to the wheel wells) It will give about 110 lbs. more head room. 1870 vs. 1760# still at 50 PSI. The revolution per mile go from 798 for the 205's to 781 for the 215"s. I would think that the reduced RPM would help it run a little cooler.

1999 safari 25SS

Any thoughts would be appreciated

VicH

[SpletKay06]

Id look into the new Carlisle radial trail hd tire and stepping up one size would help a little.

[Action]

If it fits greater load capacity is a good thing ... well to a point. And that switch will not exceed that point.

Keep the sun off of the tires
Always check and fill tires in the am to the correct pressure.
Avoid road hazards as best as possible
Know the loaded weight of your trailer
And know that speed kills

>>>>>>>Action

[Vich]

I just had 5 new Carlisle 205/75r14 Load range D 105M installed today with metal valve stems. They are Discount Tire #27208. The old tow-master tire were Load range C - 1760# at 50 PSI. The new Carlisle RADIAL TRAIL HD product number 6H04561 is rated at 2040# at 65 PSI. I will also be installing TST 507 TPS w/ FTS. I will be taking at trip to Duncans Mill, CA (near Bodega Bay) soon and I will update when I get back

VicH

[Ray Eklund]

I am sure you are speaking about 15" tires, not 14" that are only used on the 23 foot Airstreams.

Was the tire failure on the right side of the trailer?

I had excellent luck with Greenball Tow Master 14"... and would expect the 15" just as reliable. If you find the tire weight between Marathons and Tow Masters, it would be a good comparison.

The Carlisle's are probably a good choice as well for 15".

The biggest disappointment are the 14" Marathons on 23 foot Airstreams. Same with Airstream using them and not beefing up the 23 foot with Dexter Axles and 15" wheels and tires. But then again, I must be dreaming if that would ever happen.

[Ray Eklund]

Just another question. Although if you have a 25 foot Airstream, you would have 15" tires, NOT 14".

Greenball makes ST205/75R15 Load Range C, ST225/75R15 Load Range D, ST225/75R15 Load Range E and ST225/75R15 Load Range F trailer tires.

Tires weigh from 22.9# to 28.9#. Big differences.

You are better off getting a higher Load Range.

You most likely were using the Load Range C option. Cheaper, of course.

Available Options: Load Range C at 1850# at 50psi, Load Range D is rated at 2150# at 65psi, Load Range E is rated at 2830# at 80psi., Load Range F is rated at 3137# at 95psi.

I am looking at www.greenball.com Among the Special-Trailer-Radial.pdf

For some reason when I use the full web site address it gets garbled on the post...

[Vich]

I wish that the 1999 safari 25SS came with 15's but it did not, they are in fact 14's. Yes it blew the curb side front tire. I was doing 60 MPH at the time and had checked the temperature with my heat gun about 30 minutes prior at the rest stop and it, and the others were 106F to 108F. The outside temp was 92F. The CAT scale weight was 5100#. As you can see I was well within the load range C weights (1760 X 4) of 7040#.

[Vich]

Hi - all I Here are the results and data from my trip to Duncans Mills, CA from Sparks, NV. When I left at 7am It was 51F, the tire pressures were exactly at 65PSI. When at got to Vacaville, CA it was 105F outside and the tire temps were 108 - 110F, the pressures were from 81 - 83 PSI. Everything seems to have been ok so kept on going to Petaluma, CA for the night. Next morning it was 71F air temp and tire temp, the pressure was 67PSI. Traveled to my destination at Duncans Mills, CA. arrived about 11AM. outside temp was 65F, tire temp 73-75, PSI 68-69F.


The one thing I would like to determine is - What is the maximum allowable pressure increase from a "cold" state?????? The question is should I have stopped at some point and reduced tire pressure????

It is not uncommon for it to be 40-45F when I leave home and 100-110F when I get where I am going.

[Action]

Never remove air out of a hot tire if you are going to travel on same tire later that day. There is not an air pressure spec for a hot tire so removing air just takes you to some place of unknown and less tire load capacity.

If the increase of tire pressure from cold to hot is greater than I think 10% then the tire is overloaded or under filled. Removing air would take the tire in the wrong direction and the tire would generate greater heat until it fails.

Based on the data you provided :
On the first day the tire pressure changed from 65psi cold to 83psi hot or a greater than 20% change.
On one day the tire pressure changed from 67psi cold to 69psi hot. That is normal.

>>>>>>>>>>>Action.

[Vich]

Thanks for the input - However what if anything do I do about day one's 20% increase? Cat scale weight was 5100#, each tire is rated at 2040# at 65 PSI cold for a total of 8160#. Starting altitude was 5000', ending altitude was about 150'. I am using straight 5000' air (not nitrogen) from my home compressor. Would using nitrogen make any difference? I have noticed that my wife's new GMC Acadia that came with nitrogen does not change pressure by more that 4# from cold (60F) to hot (105F). Of course that is not apples to apples - but interesting .

Thanks VicH

[Action]

I could ask you a bunch of questions and you would give a bunch of data ...... or you can go here http://www.airforums.com/forums/f438...es-148198.html

And get knowledge from guys that are actually in the tire industry. (I am not nor have I ever played that part on TV)

There is some drama in that thread and you can skip that if you start at post 25. This will give you some good answer to the questions you have.

And as far as I know there isn't a tire fill pressure given for a hot tire. So adding or filling a hot tire it is an unknown. I would want to know before I make changes to a part on my trailer that has the kind of impact a tire does.

>>>>>>>>>Action

[CapriRacer]

So you started one day with 65 psi @ 51 degrees. The peak was 83 psi @ 105 degrees.

If we take the change in themperature: 105 - 51 = 54 degrees (whew!) and say that for every 10 degrees the pressure rises 3%, then the the pressure would be +16.2 psi = 81 psi. So you got 2 psi (~rise from operating the tires. That's 3% and well within the 10% limits.

Should you have reduced the inflation pressure to account for the increase in ambient temperature? No! While yours is probably the worst case I have ever seen, the tire was going to cool overnight back to where you started. Plus the bursting pressure of tires is very much larger than the max pressure listed on the sidewall. You were in no danger of the tire exploding from temperature alone. Better to leave it alone rather than keep taking air out and putting air in.