Opinions on PSI

[Barkoff]

So I decided to go with to go with the Vision 7.5 Heavy Hauler and the Hercules 19.5 265's all around, so what would you advise running them at?

They are rated to 123 psi max, but I'm pretty sure I don't need that much in the tires.

After having them mounted I took them up to the truck stop about 12 miles away, they sure felt a lot better than the 16" 265 E rated rubber I had on there before. The same railroad tracks I used to bounce up and down three times on, I now just bounced one time, they felt firm with 100 psi in the rear, and 90 in the front. Took them up to 70mph (rarely go faster than that) and they were balanced well, no vibration at all.

When I arrived at the truck stop, I took some weights, the front axle of the Dodge Ram weighed in at 4440 lbs, the rear axle 6220 lbs, and the overall weight of the Ram and Lance 950 was 10,660 lbs, with empty water tanks and no groceries or luggage in the camper.

The 6260 lbs in the rear, with a dry, empty camper, the possibilities of towing a boat, confirmed I was up against the limits of my old 16" 265's E rated. Being a single axle 2500, the camper still gets some slow speed rocking, but feels a lot more firm.

Does 100 in the rear, 90 in the front, pretty much match what others are running at?

Thank you.

[ISBRAM]

Barkoff wrote:


Thank you again, I'm going to give it a try. I'm surprised the longer one blew off with the two screws holding them in, any chance one of the screws might have vibrated out, were they still screwed into the wheel when you found your cap missing?

Both screws were still in the wheel as was a little piece of plastic on each one. I guess that cap could have had a defect in it. I already had an extra set of the short ones so I gave it a try.

[Barkoff]

ISBRAM wrote:

Barkoff wrote:

So you concentrated the heat towards the outer portion of the cap away from the wheel, correct? Did you apply the head while the cap was in place, and then apply pressure, or did you heat it up without it being mounted? I'm wondering how quick you have to be once you get it heated up.
Am I seeing burns in the chrome finish or just reflection?

Thanks again

I slowly heated to cap with the heat gun on low from the inside. I test fitted it several times as I heated it until it was soft enough to slip on. Once the caps flange bottomed out on the wheel I just let it cool there. The chrome did not discolor but you can see some minor imperfections from the stretching.

Thank you again, I'm going to give it a try. I'm surprised the longer one blew off with the two screws holding them in, any chance one of the screws might have vibrated out, were they still screwed into the wheel when you found your cap missing?

[ISBRAM]

Barkoff wrote:

So you concentrated the heat towards the outer portion of the cap away from the wheel, correct? Did you apply the head while the cap was in place, and then apply pressure, or did you heat it up without it being mounted? I'm wondering how quick you have to be once you get it heated up.
Am I seeing burns in the chrome finish or just reflection?

Thanks again

I slowly heated to cap with the heat gun on low from the inside. I test fitted it several times as I heated it until it was soft enough to slip on. Once the caps flange bottomed out on the wheel I just let it cool there. The chrome did not discolor but you can see some minor imperfections from the stretching.

[Barkoff]

ISBRAM wrote:

Barkoff wrote:
The one down side was that the rear hub covers were not deep enough to fit on. I could live with it, but I'll call the manufacture next week and ask them about an exchange.

The cap that fits over our rear hub is much longer than the front one. I bought a pair and I didn't really like the look. On the first high speed highway trip I made one of the caps went mia, they stick out so far I suspect the wind at 75mph was too much. The depth on the shorter one was ok but it tapered at the tip and was not contacting the wheel by almost 7/16 of an inch.
I carefully used a heat gun to soften the chromed plastic cap and pushed it over the rear hub. It worked out fine and looks much better than the long caps in my opinion.
This photo shows the longer cap on my Ram.

Great, thanks for that tip!

So you concentrated the heat towards the outer portion of the cap away from the wheel, correct? Did you apply the head while the cap was in place, and then apply pressure, or did you heat it up without it being mounted? I'm wondering how quick you have to be once you get it heated up.
Am I seeing burns in the chrome finish or just reflection?

Thanks again

[ISBRAM]

Barkoff wrote:
The one down side was that the rear hub covers were not deep enough to fit on. I could live with it, but I'll call the manufacture next week and ask them about an exchange.

The cap that fits over our rear hub is much longer than the front one. I bought a pair and I didn't really like the look. On the first high speed highway trip I made one of the caps went mia, they stick out so far I suspect the wind at 75mph was too much. The depth on the shorter one was ok but it tapered at the tip and was not contacting the wheel by almost 7/16 of an inch.
I carefully used a heat gun to soften the chromed plastic cap and pushed it over the rear hub. It worked out fine and looks much better than the long caps in my opinion.
This photo shows the longer cap on my Ram.


Here is one of the heat stretched cap.

[skipbee]

With a very heavy rig we have used 85 psi front, 105 psi rear, for many miles and years. We are on our second set of tires. We replaced the first set after 7 years although the tred was still good. Rickson the 19.5" wheel manufacturer suggested the tire pressure.

[mbloof]

I think the minimum PSI for my Toyo 265/70 608Z's is 80PSI. I've been running that in the front and 90-95 in the rear.

Each tire manufacturer and model is different. Please don't assume that the load charts are in any way "universal".

Both the front and rear axles on my F250HD stuck out to much for the 'standard' covers so they had to order the deeper set for my truck.

[CapriRacer]

Barkoff wrote:
Anyone understand this table?



Table

Yes, it is a conversion table between Load Index and the maximum load carrying capacity (also known as the rated load) Every tire will have a load index on it - and if you look up the Load Index on that table, it will correspond to the maximum load (more or less).

[Barkoff]

The one down side was that the rear hub covers were not deep enough to fit on. I could live with it, but I'll call the manufacture next week and ask them about an exchange.

[Reddog1]

I'm thinking the minimum is more important than the maximum. As I understand, 70 PSI is the minimum for 245x19.5s. I typically run 80 frt and 80 to 90 rear. It has been working for about 7 years. My weight is 4200 frt, 6200 rear (about). My truck is a '97 2WD, Dodge 2500 DSL.

[Bigfootchevy]

I run my 225's at 75 front and 90 or 95 rear. My rig is a little over 12000 lbs wet. I find all my weight is on the rear tires with the crew cab.

Paul

[dadwolf2]

I run 85 front 95 rear...but haven't done a lot of trial and error.

[Barkoff]

Mich F wrote:
Try Michelin's Load and Inflation Table They probably make your size tire, should be the same specs for weight,

Thanks, that helped.

Looks like I could run them down a bit, but of course Hercules is no Michelin, so I think I'll add about 10psi to those figures, so 85-90 on the front, 95-100 on the rears sounds right with the camper on.

[jimh406]

On my SRW with 19.5s, I ran 80-90 front and 95-105 rear. The front tended to wander more with higher pressure. I could have had more air in the rear, but at 100 I was 20 lbs over the stock tires which seemed plenty.

Fwiw, my F450 which is a DRW has air pressure ratings of 80 front and 75 rear for the 19.5s to reach the 14,500 GVWR.