What's the SHORTEST tire GM fitted to 4-door Grand Blazers / Tahoes between '91 & '07?

[Marky Dissod]

Specifically, what are smallest diameters GM ever OE fitted for 4-door Tahoes between 1991 & 2007 (GMT400 & GMT800)?
(Please ignore 2-door Blazers.)

My Z71 presently wears 255/70R18 (32.05") - thank previous owner for 18" wheels.
Want to lower it a wee lil bit, but not with shorter springs at this time.
Must keep 18" wheels - planning on upgrading front brakes to either GMT930 or GMTK2Y.

Wondering if 255/55R18 (29.04") or 235/60R18 (29.10") would be safely workable?
What passes for 'roads' in the 5boros of NYC can become 'off-road' at a moment's notice.
I can live with the pointing fingers and the laughing behind my back - it's mine, no one else's.

 

[Marky Dissod]

Managed to find some stuff y'all may find interesting - unless it's already common knowledge.

GMT900 Police Pursuit Tahoes used 265/60R17, 29.51" tall. Is this correct?
GMT900 Special Service Tahoes used 255/70R17, 31.05" tall. Is this correct?

Wayback Machine

web.archive.org

GMT800 Special Service Tahoes (5W4?) used 245/75R16, 30.46" tall.
But what tire size did GMT800 Police Pursuit Tahoes use? I prefer not to guess.

Wayback Machine

web.archive.org

GMT400 Police Pursuit Tahoes (Z56?) used the same tires as '90s Caprice 9C1s:
235/70VR15, which are 27.95" tall. Had I not seen this in writing, I'd not believe it.

I do not yet know the tire size of the 2000 (GMT400) Tahoe Limited.

 

[iamdub]

Managed to find some stuff y'all may find interesting - unless it's already common knowledge.

GMT900 Police Pursuit Tahoes used 265/60R17, 29.51" tall. Is this correct?
GMT900 Special Service Tahoes used 255/70R17, 31.05" tall. Is this correct?

Wayback Machine

web.archive.org

GMT800 Special Service Tahoes (5W4?) used 245/75R16, 30.46" tall.
But what tire size did GMT800 Police Pursuit Tahoes use? I prefer not to guess.

Wayback Machine

web.archive.org

GMT400 Police Pursuit Tahoes (Z56?) used the same tires as '90s Caprice 9C1s:
235/70VR15, which are 27.95" tall. Had I not seen this in writing, I'd not believe it.

I do not yet know the tire size of the 2000 (GMT400) Tahoe Limited.

You beat me to it. I was gonna mention the PPV as having the shortest factory-spec'ed tire size. It's common knowledge that they're smaller, but all the specific sizes probably aren't memorized.

I did a little digging and ran across something saying the 2003 Tahoe PPV tire size was a 255/70R16. This calculates a 30.1" height. Most of the relevant tires you've listed are right in the 30" range. I wouldn't count that 28" tire on the GMT400 since that platform is much smaller in most every aspect than the GMT800+.

 

[Marky Dissod]

I wouldn't count that 28" tire on the GMT400 since that platform is much smaller in most every aspect than the GMT800+.

How much does a GMT420 - Tahoe weigh?
How much does a GMT820 - Tahoe weigh?

 

[iamdub]

How much does a GMT420 - Tahoe weigh?
How much does a GMT820 - Tahoe weigh?

According to info my ten seconds of Googling returned:

GMT420: 2,312kg = 5,097lbs.
GMT820: 2,250kg = 4,960lbs.

 

[MassHoe04]

From my experience the ride with PPV tires sucks!
In case Y'all might be wondering... It was driver's seat experience, not back in the cage.

The low sidewall profile, very stiff sidewalls (for speed and cornering) and high speed-rated belts make for a kidney-busting, tooth-breaking ride!

I understand you are looking to go lower in height, but PPV tires would not be my recommendation. Especially, in NYC! As you say, the roads go to hell in the matter of several feet. You might have more options if you had 17" or even 16" rims. But I would definitely not recommend PPV tires. Because the PPV tires have to really perform and hold up at high speed, they come with a hefty price tag too.

Someone here will have some good suggestions for you, but stay away from PPV tires. IMHO

 

[Marky Dissod]

T- is PLENTY of speed rating for me. No plans to EVER exceed 90MpH.
Although making my Z71 handle somewhat more like a PPV would be appreciated - keeping the 18" wheels for room to fit larger brakes - I'm not willing to sacrifice much of its Z71-ness.

If I wanted a vehicle that handled THAT much like a PPV, either a mid-'90s Caprice 9C1, or a Holden Caprice 9C1.
I got a Tahoe Z71 instead. How much better can a Z71 dance on the highway without ruining its Z71ness anyway?

Will I ruin the vast majority of its Z71ness by going from 255/70R18 to 255/55R18, regardless of which tire I choose?
Most important thing is to be able to press 4Hi in wintry road conditions and keep going anyway (may never press 4Lo).

 

[Alex_M]

From my experience the ride with PPV tires sucks!
In case Y'all might be wondering... It was driver's seat experience, not back in the cage.

Probably sucks from back in the cage, too

OP, is it looks that is leading you to wanting smaller tires? Generally larger tires are more appropriate for more rugged terrain.

To answer your question, shorter sidewall and smaller tire will always lead to a harsher ride. Some tires and load ratings will be worse than others depending on compound and construction, but smaller will always be harsher than larger.

For winter traction, narrower is better than wider. More point pressure so your tires sink down thru the snow to the hard pack or asphalt below better.

Tread also, obviously, makes a big difference. If this is for looks you won't want an off road or winter tire, but I would look at all season tires. Look for something with lots of siping (pronounced sipe-ing) and grooves perpendicular to the direction of rotation.

 

[Marky Dissod]

Not sure what you mean by 'looks'. I care about aesthetics far less than most people.
Maybe I'm crazy, but I cannot presently afford to lower my Z71 using more conventionally acceptable means.
Was thinking, if GMT400 Tahoes weigh roughly about as much as my GMT821 Tahoe, then tires of similar diameter / height are also safe.
Am I right or wrong?

My thinking so far:
235/75R15 (28.87") was OE on many if not most GMT430 bubbas, right?
Not willing to go under 255/55R18 (29.04") or 235/60R18 (29.10").
No such tire size as 275/50R18 (28.82"), but the extra width would likely cost more than 255/55R18 or 235/60R18.
Basically an tire between 29" & 32" tall, between 235mm & 265mm.
235/65R18 (30.03") would also be under consideration of course.

Year-round grip in rain, and to a lesser extent snow & ice, are paramount crucial tire characteristics.
True winter-snow&ice tires that are only useful 14 days or less a year are not worth it though.
I'm not opposed to offroad-ish tires if they also handle rain/snow/ice better than other options.
Snow is a higher priority than hardcore offroading.
Example:
If I still had a Caprice today, I'd choose between Falken WildPeak A/T Trail or A/T3W, Cooper Discoverer AT3 4S, and Vredestein Pinza AT - they all are superior in rain and snow to Michelin Defender LTX M/S, they also have offroad ability, and they're all cheaper too.

 

[Alex_M]

Sure, size has little effect on safety as long as you are keeping within safe load/speed ranges. It's just a bit unconventional to look at smaller tires when also trying to increase ride quality on rougher terrain. Only attempting to understand your desire so I can offer a better recommendation.

Since you specifically brought it up, and since you are not going specifically for a "street truck" look, the Falken AT3W is a great choice. I've had 3 sets and love em. Price has gone up a bit in the last few years, but what hasn't.

Lots of folks also give the Coopers rave reviews. I have limited experience with them. Only a couple half used sets. Under half tread, I was unimpressed with their rain handling.