Another Tire Pressure Thread

[robbecky]

I know this has been discussed before but I want to ask again. I just bought a new set of four Towmax tires for my Vibe TT. They are marked as maximum cold pressure of 80PSI.

At 80PSI the ride of the TT is extremely rough. I had a copy of the tire pressure chart for those tires sent to me. Based on the chart and weight of my TT (6200lbs) I could have the pressure at like 30 PSI.

Now of course I would not put my tires to 30 PSI due to the fear of terrible tire wear.

But if I keep the pressure consistent with the chart, taking into account a margin of safety for bumps, etc, is it o.k. to put the tires to maybe somewhere between 50 and 65 PSI? Will it cause me to wear out the tires badly and too soon?

Thanks everyone,
Rob

[larry2c]

I don't really have an answer for you but I'm really surprised that with a relatively light TT, you ended up with such high load rated tires. It seems like most manufacturers put the minimally compliant tire for the max weight of the TT. What model Vibe do you have? Are the tires you have on it what the manufacturer recommends?

[robbecky]

Originally Posted by larry2c

I don't really have an answer for you but I'm really surprised that with a relatively light TT, you ended up with such high load rated tires. It seems like most manufacturers put the minimally compliant tire for the max weight of the TT. What model Vibe do you have? Are the tires you have on it what the manufacturer recommends?

My tires are not the tires that came on the TT. I had them replaced recently and stepped up from Load Range D to Load Range E.

[jadatis]

In the Netherlands , where I live, a reserve 30% or more to GVWR is seen as exageration and not adviced by officiall institutes.
So swiching from D- to E-load, I also think is a useless step.

Can you give that list here, so I can check wich formula was used. American lists give higher loadcapacity's for the pressure then European .

If you give tirespecifications, toghether with the already given GVWR , I can put it in my made calculator for TT, and it will come to a bit higher pressure, but still low.
Need 3 things read from sidewall, but sises would be nice too.
1. Maximum load or loadindex
2. Pressure behind AT , is called reference-pressure, and nowadays als maximum cold pressure most tiremakers allow for ST and LT tires.
3. Speedcode ( N =max 140kmph/87mph, Q and higher maxload is calculated for 160kmph/99mph). But also give if ST ( speciall trailer)

Additional info to 2.
Continental group , and mayby others too, give 2 pressures on sidewall, so search for that on sidewall too.
They give the 65psi for D- load right after the service-descriptions ( fi 112N 65psi) without AT in front of it.
But furter on tire after maxload info " maximum inflation pressure" wich is also cold, and 10 psi higher then AT ( fi 75 psi if 65psi)
So also search for D- or E-load or LRD or LRE.
Alao in your list , in case of D-load, max given pressure then is 65 psi, so you can also see it at the list.

[Larry-NC]

Originally Posted by robbecky

I know this has been discussed before but I want to ask again. I just bought a new set of four Towmax tires for my Vibe TT. They are marked as maximum cold pressure of 80PSI.

At 80PSI the ride of the TT is extremely rough. I had a copy of the tire pressure chart for those tires sent to me. Based on the chart and weight of my TT (6200lbs) I could have the pressure at like 30 PSI.

Now of course I would not put my tires to 30 PSI due to the fear of terrible tire wear.

But if I keep the pressure consistent with the chart, taking into account a margin of safety for bumps, etc, is it o.k. to put the tires to maybe somewhere between 50 and 65 PSI? Will it cause me to wear out the tires badly and too soon?

Thanks everyone,
Rob

The experts on this site have observed that radial tires don't have nearly the wear-sensitivity to inflation of the bias-ply tires we grew up with. If they did, running lightly loaded tires at maximum pressure would wear out only the very center of the tread.

Larry

[MR.M]

Originally Posted by robbecky

My tires are not the tires that came on the TT. I had them replaced recently and stepped up from Load Range D to Load Range E.

You should be fine at 65 to 70 psi . no way 30

[Walholler]

Your reading something into the tire pressure that is not there. Maximum tire pressure, not to exceed 80 PSI. That doesn't mean to inflate your tires to 80 PSI, it means not to exceed 80 PSI when your inflating them. The tires on my Chevrolet 2500HD says the same, not to exceed 80 PSI, I run 60 PSI in front and 70 PSI in rear in order for the ride to not feel like a horse drawn wagon.

[Comanchecreek]

You're running a heavier duty tire on a lighter axle so it stands to reason you should lighten up the air pressure. I run 80 psi on my fifth wheel because that is what is called for given the weight etc. I agree with others, drop the pressure to 65 psi or so and you should be good. Glad to see you went to load range E's, just find the Tow Maxes a little suspect. Keep an eye on them. Watch for tread separation.

[Wolverine 1945]

Is 10 psi below Max a good rule ???

[JohnD10]

I'm surprised that someone actually purchased a set of the BlowMax tires.

These are well documented 'China Bombs'.

[kfergiez]

Originally Posted by Wolverine 1945

Is 10 psi below Max a good rule ???

No.

Using the correct pressure is a good rule. Even if the correct pressure IS the max pressure.

[kfergiez]

Originally Posted by JohnD10

I'm surprised that someone actually purchased a set of the BlowMax tires.

These are well documented 'China Bombs'.

Well it stands to reason that since they upgraded to a higher load range, they may be less susceptible to blowing out.... Here's hoping.