Help! I want bigger tires for my VX

[sloop]

My Question being some what of a Tire expert my self is ( not trying to cause a arguement just need to understand as tires I know, Mechanics not so much) in theory all you are doing is adding weight! and not a whole lot compared to if you had 250 lb passanger that rode to work with you everyday,if that was the case would it not be suggested to upgrade your brakes then? I think the bigger issue would be with rolling resistance and the stress on the CV and other components more so then brakes that are used infrequntly. Like I said Just wondering myself I Am Not a Mechanic.

[mdwyer]

My Question being some what of a Tire expert my self is ( not trying to cause a arguement just need to understand as tires I know, Mechanics not so much) in theory all you are doing is adding weight! and not a whole lot compared to if you had 250 lb passanger that rode to work with you everyday....

I'm not an engineer, either. Not a mechanical one, at least. But I believe the problem is not so much the added weight added so much as where it is and what you're doing with it. Weight on the wheels is 'unsprung weight', which impacts handling.

[Riff Raff]

'unsprung weight'

Excellent "link". Unsprung weight (aka unsprung mass) has nothing to do with tire diameter, only pure mass of weight that is "suspended" in rotating motion.

For example-- take two identical size/brand tires like the Grabber AT2, but which have different individual weight.

TIRE A: Grabber AT2 in P275/65R18, C-Load Range (6-Ply) (32" O.D./44 lbs).
TIRE B: Grabber AT2 in LT275/65R18, E-Load Range (10-Ply) (32" O.D./54 lbs).

Now, using equal pushing force-- shove each tire down the street and let it freely roll on its own merit until it finally peter's-out, wobbles, and falls over. Measure the distance traveled by each tire. You will discover, the heavier TIRE B rolled further due to its combined "suspended" (unsprung) momentum, centrifical force and perpetual motion that kept the tire rolling further. Simply put, it takes more braking effort to stop a heavier tire than a lightweight tire.

When auto manufacturer's design and engineer their vehicles, the OEM brakes are perfectly adequate to stop the OEM tires (and vehicle) within a recommended safe stopping distance set by the automotive industry. There is a window of allowable variance that aftermarket tires may be heavier than the OEM tires and still allow braking distance to be within safe margins.

The tire industry and US-DOT has determined this safe allowable variance of additional aftermarket tire weight to be 10 lbs over OEM tire weight on any given vehicle. This will still allow the vehicle to safely stop within the prescribed stopping distance for that type of vehicle.

Thus; for us VX'ers, since our OEM tires weighed only 34 lbs each, the maximum allowable variance for a heavier aftermarket tire is 44 lbs (10 lbs over OEM). I like to think of excess tire weight as "tire fat", in which case the tire industry & US-DOT allows us to have 40 lbs (10 lbs x 4 tires) of extra "tire fat" per vehicle and still be able to safely stop within a prescribed safe stopping distance.

Of note, most VX's are wrecked/totaled because they rear-ended the car in front of them because they simply couldn't stop in time using the unmodified OEM factory brakes in a safe distance due to very excessive "tire fat" (extremely heavy tires). During an emergency panic stop in conjested traffic, the small OEM factory VX brakes will say (if they could talk)-- "You want me to stop these big humungous meats??? Sorry; not today, ain't happening!!!" That's why I always harp on people to please, please, please allow an extra cushion of space between the car in front of you when running extremely heavy tires greater than the recommended 44 lbs maximum per tire weight on the VX!!! That's why I like www.TireRack.com as they list individual tire weight on their "spec" chart and is the very first place I check when people ask me about various tires. Riff

[sloop]

Excellent "link". Unsprung weight (aka unsprung mass) has nothing to do with tire diameter, only pure mass of weight that is "suspended" in rotating motion.

For example-- take two identical size/brand tires like the Grabber AT2, but which have different individual weight.

TIRE A: Grabber AT2 in P275/65R18, C-Load Range (6-Ply) (32" O.D./44 lbs).
TIRE B: Grabber AT2 in LT275/65R18, E-Load Range (10-Ply) (32" O.D./54 lbs).

Now, using equal pushing force-- shove each tire down the street and let it freely roll on its own merit until it finally peter's-out, wobbles, and falls over. Measure the distance traveled by each tire. You will discover, the heavier TIRE B rolled further due to its combined "suspended" (unsprung) momentum, centrifical force and perpetual motion that kept the tire rolling further. Simply put, it takes more braking effort to stop a heavier tire than a lightweight tire.

When auto manufacturer's design and engineer their vehicles, the OEM brakes are perfectly adequate to stop the OEM tires (and vehicle) within a recommended safe stopping distance set by the automotive industry. There is a window of allowable variance that aftermarket tires may be heavier than the OEM tires and still allow braking distance to be within safe margins.

The tire industry and US-DOT has determined this safe allowable variance of additional aftermarket tire weight to be 10 lbs over OEM tire weight on any given vehicle. This will still allow the vehicle to safely stop within the prescribed stopping distance for that type of vehicle.

Thus; for us VX'ers, since our OEM tires weighed only 34 lbs each, the maximum allowable variance for a heavier aftermarket tire is 44 lbs (10 lbs over OEM). I like to think of excess tire weight as "tire fat", in which case the tire industry & US-DOT allows us to have 40 lbs (10 lbs x 4 tires) of extra "tire fat" per vehicle and still be able to safely stop within a prescribed safe stopping distance.

Of note, most VX's are wrecked/totaled because they rear-ended the car in front of them because they simply couldn't stop in time using the unmodified OEM factory brakes in a safe distance due to very excessive "tire fat" (extremely heavy tires). During an emergency panic stop in conjested traffic, the small OEM factory VX brakes will say (if they could talk)-- "You want me to stop these big humungous meats??? Sorry; not today, ain't happening!!!" That's why I always harp on people to please, please, please allow an extra cushion of space between the car in front of you when running extremely heavy tires greater than the recommended 44 lbs maximum per tire weight on the VX!!! That's why I like www.TireRack.com as they list individual tire weight on their "spec" chart and is the very first place I check when people ask me about various tires. Riff

Well put on my next tire test I will do a little experiment to test this, we have a skid path at the Texas proving grounds. I will try to use 4 sets with different weights and use the exact same wheels for all

[pbkid]

Of note, most VX's are wrecked/totaled because they rear-ended the car in front of them because they simply couldn't stop in time using the unmodified OEM factory brakes in a safe distance due to very excessive "tire fat" (extremely heavy tires).

ok buddy... im gonna have to play devils advocate on this one...
2 things-

1. where did you get the information that most wrecked VX's have oversized tires on them, and how do you know that the tires were the cause of the accident?
2. there are MANY more influences on the road that are far more important than tire size. if everyone drove exactly the same and perfectly safe (ie: never looked away from the road, never drove drowsy, etc) then yes, theoretically tire size would effect car accidents. but in that case, personally i would take my integra over the VX any day. its stopping distance is significantly less than the VX.
so, what im trying to say is that stupid drivers who dont pay attention, or dont drive correctly is what causes accidents, not tires. (i guess its a similar argument to that of gun control eh? )

in fact, i consider myself a MUCH safer driver with my huge tires than 90% of the drivers on the road. because of 2 things- i DO pay attention to the road all the time, and consistently try to not be distracted. and second, but MUCH more importantly, i have NO quams with diving my VX into the median doing 90mph because i know that my huge tires are gonna be able to handle the ruts and dips.

[pbkid]

sorry to pick on you riff. nothing personal, i just had a long day.

and i view it a little differently than you.

and, yes, i have driven my car through the median more than 5 times to make sure i dont get rear ended by the idiot behind me that isnt watching where he is going.
yup, and he has definately rear ended the guy i was following, which should of been my rear end instead of his...

[Riff Raff]

Jack--- No harm, no foul. I hope you have a better day tomorrow my friend.

[Triathlete]

I would have to say EXCESSIVE SPEED has probably been responsible for the biggest amount of VX accidents where the VXer was at fault.

[tomdietrying]

Of note, most VX's are wrecked/totaled because they rear-ended the car in front of them because they simply couldn't stop in time using the unmodified OEM factory brakes in a safe distance due to very excessive "tire fat" (extremely heavy tires). Riff

I like your facts. Could you please give me your source?

Peace.
Tom

[Ldub]

You will discover, the heavier TIRE B rolled further due to its combined "suspended" (unsprung) momentum, centrifical force and perpetual motion that kept the tire rolling further.

The tire industry and US-DOT has determined this safe allowable variance of additional aftermarket tire weight to be 10 lbs over OEM tire weight on any given vehicle. This will still allow the vehicle to safely stop within the prescribed stopping distance for that type of vehicle.
Riff

I wanna know when they finally got around to perfecting "perpetual motion"...

I come from a long line of tinkerers/inventors who've been chasing that elusive goal for decades...

Perhaps you were referring to inertia?

I'd also like to see where you got this "fact"...please post a link if possible.

Also , You'll find that if you refrain from posting as a self proclaimed "absolute authority on all topics", & learn to leave yourself a bit of wiggle room, by throwing in a "possibly", "theoretically", "sometimes" or even "it's possible", you'll find you get called out a lot less often...

Jack, I've never seen a reason to apologize for calling "made up BS" for what it is...ESPECIALLY when it's been presented as fact.

[Ldub]

This is the type of "fact" I'm referring to:

Of note, most VX's are wrecked/totaled because they rear-ended the car in front of them because they simply couldn't stop in time using the unmodified OEM factory brakes in a safe distance due to very excessive "tire fat" (extremely heavy tires).

Where do you get those stats?... Got a link?

All the other info regarding unsprung weight & rolling inertia is true AFAIK.

Having some experience with MX racing bikes, I agree with riff, unsprung weight is bad with regard to how quickly suspension can react to sudden changes in terrain etc.
It's also harder on the equipment controlling suspension components, shocks in particular.
And yes, I agree that larger tires & wheels will generally create more inertia, hence longer stopping distance.

That having been said, IIRC the VX has one of the shortest, if not THE shortest stopping distance of any SUV ever tested in the years that were being reported in various magazines of the time.

IMO, once you've installed heavier wheels & tires, you quickly re-learn the diminished braking & acceleration capabilities of your vehicle, & drive accordingly.

And all that is just my opinion, worth exactly whatcha paid for it, maybe even less...

[psychos2]

Of note, most VX's are wrecked/totaled because they rear-ended the car in front of them because they simply couldn't stop in time using the unmodified OEM factory brakes in a safe distance due to very excessive "tire fat" (extremely heavy tires). During an emergency panic stop in conjested traffic, the small OEM factory VX brakes will say (if they could talk)-- "You want me to stop these big humungous meats??? Sorry; not today, ain't happening!!!" That's why I always harp on people to please, please, please allow an extra cushion of space between the car in front of you when running extremely heavy tires greater than the recommended 44 lbs maximum per tire weight on the VX!!! That's why I like www.TireRack.com as they list individual tire weight on their "spec" chart and is the very first place I check when people ask me about various tires. Riff

I am wondering where you got your info from? I have seen many pics of vx's with stock tires totaled. And as far as that goes isn't it following too close that causes this to happen? I have larger and alot heavier tires than stock and have not rearended anyone . I think that the rubber lines on the vx brakes suck and that would be all I would change if there was a concern. And the stock pad thing,they are ceramic pads. If you go with a good ceramic pad then you do not need to by stock pads. shawn

[Jolly Roger VX'er]

My R1 Concepts slotted/drilled rotors I bought a few years back were equipped with PB/Axxis Ultimate Pads from Australia (kangaroo insignia) as per Joe Black's advice (recommended amongst rally racing crowd), and they were awesome but the only drawback for me was the brake dust that would stain the chrome wheels. These pads are a mix of ceramic/metallic.

I wore the pads down to bare minimum recently and just went to the "hot setup" LDub mentioned utilizing stock pads. My opinion is the stopping power seems as good and the pedal feels a bit harder and hopefully the dust issue is no more.

I couldn't help but notice the "mitsubishi" emblems on my new pads from Isuzu...anybody else notice this?

I feel that the R1 Concepts rotors with Independent 4X4 S.S. lines and quality pads more than address any issues with me going from stock to 32" tires.

I am so much more concerned with being the "hittee" rather than the "hitter" that for Christmas I asked my parents for the Rhino tubular (with step built in) plug-in for the receiver hitch (that Joe uses & got rear-ended with). I plan on removing it for any off-roading (using clevis instead). It sounds like good protection against people who text & drive...ugh.

[Ldub]

I couldn't help but notice the "mitsubishi" emblems on my new pads from Isuzu...anybody else notice this?

It's almost Mitsu...If you look at it again, you'll see that it's three triangles, Mitsu uses three diamonds as their logo.
I thought the same thing when I saw that, it's also cast into the caliper.

I am so much more concerned with being the "hittee" rather than the "hitter" that for Christmas I asked my parents for the Rhino tubular (with step built in) plug-in for the receiver hitch (that Joe uses & got rear-ended with). I plan on removing it for any off-roading (using clevis instead). It sounds like good protection against people who text & drive...ugh.

Couldn't agree more, I had a VERY close call last summer when I heard brakes lock up & rubber squealing from the car behind me. (woman person in a Mercedes, yakking on her phone...)
Since I always leave a 15-20' "cusion" in front of me when in city traffic, I was able to move forward, out of harms way.
She didn't seem very interested in getting too close to my rear bumper after the light turned green...:_

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