rear bump stops

[workmeistr]

So...should I cut down my rear bump stops?

[PK]

So...should I cut down my rear bump stops?

Apparently you only do this modification -


















if you think it will help keep your nuts cool.

PK

[SlowPro48]

So...should I cut down my rear bump stops?

They're not bump stops until you chop them in half. Until then they're spring helpers.

[workmeistr]

I now, then, have bump stops. Cut mine yesterday. I removed and cut on the bench. I really haven't noticed much of a difference, MTF.

[RickOKC]

Hey Bren, I haven't said "hi" for a long time so... "HI!" Do you still have the original shocks? Or replacement original shocks?

I met a local VXer recently and he let me crawl all over/under his VX and then he took me for a ride around the block. His VX rides quite a bit smoother than mine on the factory original shocks (and I have the softer Rancho XL9000s!) Our unmodified spring-helper-bump-stops-whatever seem to sit at the exact same position so.... I'm pondering on why they ride so differently.

Now I'm curious if brands of tires, inflation pressures & various minor differences between hand assembled vehicles may make a difference ranging from small to big.

(BTW, I think his local '99 Astral may be up for sale soon... I'll add more input if he posts it.)

[89Vette]

Hey Bren, I haven't said "hi" for a long time so... "HI!" Do you still have the original shocks? Or replacement original shocks?

I met a local VXer recently and he let me crawl all over/under his VX and then he took me for a ride around the block. His VX rides quite a bit smoother than mine on the factory original shocks (and I have the softer Rancho XL9000s!) Our unmodified spring-helper-bump-stops-whatever seem to sit at the exact same position so.... I'm pondering on why they ride so differently.

Now I'm curious if brands of tires, inflation pressures & various minor differences between hand assembled vehicles may make a difference ranging from small to big.

(BTW, I think his local '99 Astral may be up for sale soon... I'll add more input if he posts it.)

tire weight? oem inflation is 29lbs according to my local NTB.

use: city/hwy/off-road = less suspension wear

[VXorado]

tire weight? oem inflation is 29lbs according to my local NTB.

use: city/hwy/off-road = less suspension wear

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

[89Vette]

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

Good question. You MIGHT even want to use less.

More seems to improve MPGs -- like you'd expect. Less probably gives the better ride. I've also run less with the vette. Figure it's better to enjoy the car and ride (loosing some tire life) than getting best mpg's possible.

I'm running 285/60-20's. Maybe a hair less sidewall height that OEM. They made the ride a bit harsher than the fluffy 285/70-16's that I bought it with.

With the former, 35psi felt about right and I got better mpg. 35psi is a bit too stiff now that I have shorter sidewalls. So really, that's probably the biggest indicator vs the overall size.

[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???

[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.