rear bump stops

[RickOKC]

Hi 89Vette, long time, no talk. (And, BTW, thank you for all the questions you asked when we were both VX shopping at the same time. Your questions were so much better than mine and the responses you got helped me decide to buy a VX.)

So, what tires do you have?

I think there's a good probability that my ride quality has been reduced 'cuz I went with non-OEM tires and they are about 3" taller than stock. Funny, they actually improved and rode smoother in everyday driving once I boosted them up from OEM to about 40psi. To me it doesn't seem right that the higher pressure makes for a better ride. But.... I'm not a tire expert so there is obviously something I'm missing! s

[89Vette]

Hi 89Vette, long time, no talk. (And, BTW, thank you for all the questions you asked when we were both VX shopping at the same time. Your questions were so much better than mine and the responses you got helped me decide to buy a VX.)

How much sidewall do you have compared to before? By ride, are you referring to handling or cushy-ness.

[tom4bren]

I don't care what the techies say. I always have & I always will inflate my tires to the TIRE mfr recommended pressure rather than what is on the doorjam of the vehicle. Think about it. The VX is 10+ years old. Do you really think that Isuzu had a crystal ball back then to KNOW what innovations/improvements would be made to tire technology over the course of the next decade??? Look at all of the variety of tires out there: MT/AT/street, 6/8/10 ply, directional versus not, speed ratings, life ratings, temperature ratings. How can one recommended tire pressure work for all???

That said: it's just a starting point for me. I adjust the tire pressure to maximize life of the tire. Our MPG sux anyway so tire pressure really isn't gonna make that much of a difference. Maybe I'm a numb butt, but I really don't notice any difference in ride quality based on tire pressure anyway (especially with the VX ride quality - or lack thereof). With a 100 mile commute daily, it's all about making the expendables on a vehicle last as long as possible.

IMHO

That's my $.02 ... & I want change.

[pbkid]

Should we be using 29lbs inflation with over-sized tires?

You definitely want to run yours high pressure unless offroad Jon. You have so much sidewall, it would be dangerous to run yours low pressure at highway speeds.

Im with tom on this one, (wow thats hard to say) the tire pressure on the door jam is designed for the factory tires and doesn't compensate for mods or new tire technologies. I know it sounds nuts, but i run my tires at 55psi, and get 3-4 more mpgs out of em and ride quality is all in the shocks and springs. If your VX rides that bad I'd look into the heavy duty torsion bars.

I don't care what the techies say. I alwmodsays have & I always will inflate my tires to the TIRE mfr recommended pressure rather than what is on the doorjam of the vehicle. Think about it. The VX is 10+ years old. Do you really think that Isuzu had a crystal ball back then to KNOW what innovations/improvements would be made to tire technology over the course of the next decade??? Look at all of the variety of tires out there: MT/AT/street, 6/8/10 ply, directional versus not, speed ratings, life ratings, temperature ratings. How can one recommended tire pressure work for all???

That said: it's just a starting point for me. I adjust the tire pressure to maximize life of the tire. Our MPG sux anyway so tire pressure really isn't gonna make that much of a difference. Maybe I'm a numb butt, but I really don't notice any difference in ride quality based on tire pressure anyway (especially with the VX ride quality - or lack thereof). With a 100 mile commute daily, it's all about making the expendables on a vehicle last as long as possible.

IMHO

That's my $.02 ... & I want change.

[Ldub]

I don't care what the techies say. I always have & I always will inflate my tires to the TIRE mfr recommended pressure rather than what is on the doorjam of the vehicle.

I'm gonna have to disagree witcha Bro, & here's my take on it...yeh, I know...

The pressure on the sidewall is not recommended pressure, it's the MAX that the tire is designed to handle, also, if you go read your sidewall, there is a max load associated with the max psi. Keep in mind that max load rating is per tire, so that #, x 4 is the total that all 4 tires are capable of carrying.

Tires with a higher volume (more width & sidewall height) require less pressure to achieve the same contact patch (correct inflation pressure for the load carried) than a tire with less volume.

Think of this comparison...

A racing bicycle tire, with very little volume, may require around 100 psi to carry a load that's 200 lbs or less...a 44x66 tire on an average monster truck, carries a total load (divided by four) of 10-12,000 lbs, & is typically inflated to 15 psi.

I'm not say'n that high psi is bad or dangerous, as long as you are satisfied with the wear etc, go for it.
It's the misconception of the max press on the sidewall being mistaken for a recommendation that I disagree with...

[tom4bren]

Im with tom on this one, (wow thats hard to say) ...

OUCH!!!

I'm gonna have to disagree witcha Bro, & here's my take on it...yeh, I know...

The pressure on the sidewall is not recommended pressure, it's the MAX that the tire is designed to handle, also, if you go read your sidewall, there is a max load associated with the max psi. Keep in mind that max load rating is per tire, so that #, x 4 is the total that all 4 tires are capable of carrying.

Tires with a higher volume (more width & sidewall height) require less pressure to achieve the same contact patch (correct inflation pressure for the load carried) than a tire with less volume.

Think of this comparison...

A racing bicycle tire, with very little volume, may require around 100 psi to carry a load that's 200 lbs or less...a 44x66 tire on an average monster truck, carries a total load (divided by four) of 10-12,000 lbs, & is typically inflated to 15 psi.

I'm not say'n that high psi is bad or dangerous, as long as you are satisfied with the wear etc, go for it.
It's the misconception of the max press on the sidewall being mistaken for a recommendation that I disagree with...

I DO have a response to that ... actually 2.

1. PV=mRT

2. Watcha gonna do when the recommended pressure on the door jam is higher than the max pressure listed stamped on the tire???

[pbkid]

Aww cmon tom, like my dad always says, 'if im not razzin ya, that probably means i dont like you anymore'

[tom4bren]

Aww cmon tom, like my dad always says, 'if im not razzin ya, that probably means i dont like you anymore'

I think I told you once that you strike a disturbing resemblance to my nephew. If'n we're in fact fambly then ... GAME ON Peanut Butter!!!

[Ldub]

I DO have a response to that ... actually 2.

1. PV=eRT

2. Watcha gonna do when the recommended pressure on the door jam is higher than the max pressure listed stamped on the tire???

In response to:

1. . ...P-vert?

2. . When that happens, lemme know, we'll talk...

[tom4bren]

Mt Dew tru da nose on dat 1 Mr. Dub

[SlowPro48]

I'm not say'n that high psi is bad or dangerous, as long as you are satisfied with the wear etc, go for it.
It's the misconception of the max press on the sidewall being mistaken for a recommendation that I disagree with...

Well I'll say it then. It's dangerous!

Example: max recommended pressure on my TerraGrapplers is 50psi. At that pressure there would be about 42% less rubber in contact with the road than what Isuzu intended, which will significantly increase stopping distance - and reduce lateral grip as well. Unless you're hauling a lot of weight, for safety's sake you might want to air down a little! Who knows - it might keep you from rear-ending somebody on the freeway someday. And BTW, 29psi is specified as cold - so pressure increase according to the Ideal Gas Law is already accounted for.

[pbkid]

Well I'll say it then. It's dangerous!

Example: max recommended pressure on my TerraGrapplers is 50psi. At that pressure there would be about 42% less rubber in contact with the road than what Isuzu intended, which will significantly increase stopping distance - and reduce lateral grip as well. Unless you're hauling a lot of weight, for safety's sake you might want to air down a little! Who knows - it might keep you from rear-ending somebody on the freeway someday. And BTW, 29psi is specified as cold - so pressure increase according to the Ideal Gas Law is already accounted for.

I'm gonna agree to disagree with this statement. sure at rolling speed, you lose an amount of rubber contact with the road as the tires expand in the middle of the tread, but what happens when you press those brakes hard and the weight of the vehicle is thrown onto the front tires? you then have 100% contact and have regular tire grip.
Lets see if i can word this to make sense as it does in my head
As well, if we are talking safety, which is my point for inflating my tires so high; if you have your tires at lower pressure, say 29 psi as your door jam suggests, how is your vehicle supposed to handle in a panic skid or quick swerve? My reasoning is, as your sidewall gives, it causes body roll, increasing chance of a rollover. I personally would rather skid a little (key word little), than have the tires grab hard and roll me over.
Now, this also supports my thought behind hard straight line braking, if you swerve and put the weight of the vehicle on 2 tires, you now are operating at optimal traction levels (enough to skid but also handle). Rather, at low tire pressure you increase your traction to a level of rollover or poor handling (low tire pressure proves to make for sloppy handling).

Let the bashing and arguments begin

[RickOKC]

How much sidewall do you have compared to before? By ride, are you referring to handling or cushy-ness.

I went with a tire that was 3" taller overall so there was a bit of growth. I'm talking strictly about ride comfort quality - I really haven't seen any noticible difference in handling except for when I had them aired down super low (15-20psi) for off-road. Some of the streets around here are in extremely poor condition!