2WD '99 OBS - Wheels?

[Ironhorse]

Looking at possibly buying a 2 WD '99 Tahoe OBS for a daily driver. Has 225K on the clock which is just under 10K a year. Not bad mileage for a 23 year old vehicle. Tahoe is pretty well loaded the way I want and plans are to just maintain and drive it as a daily. Not sure about the wheels on it tho. Don't care for the present wheels it has, not my thing. Has 235/75/15s on it so..... will either the 15 x 7 five lug or 15 x 8 five lug square body rally wheels fit the 2wd five lug hubs on the '99 OBS? Like the old school rally wheels for looks with nice caps and rings. I know the 15 x 7 rallies are van wheels and harder to find but that is the thrill of the hunt as they say.

Posted this question here as it is the 99-06 message forum but I thought the 99 OBS was still the GMT 400 series not the GMT800 series? Mods feel free to move this post if it needs to be in the GMT400 sectionl

[S10Fan]

I had rally wheels on my 97 Yukon 2dr 2wd. I bought mine aftermarket from Summit, 15X7 front with 15X8 (5"BS) on the rear. I'm speaking of what many folks call Corvette Rally wheels. I liked the look, especially with a drop. Of course the 97 was 5 on 5, but the same rally wheels are available in 6 lug for your 99.

I'll have to dig around my computer for pictures.

[Ironhorse]

My '99 2wd Tahoe is a 5 on 5 pattern, just not sure about the back space and disc brake situation. Will have to wait until it gets here, just did purchase and it being shipped in from North Carolina. Could not find what I wanted locally after looking over year and a half. Will post up some pics when it gets here.

Would like to run the square body 15 x 7 rallies with caps and rings if they will fit. The disc brake calipers and the back spacing may be an issue? Will know more when it gets here and then will have to find 5 on 5 15'' x 7'' rally to borrow locally hopefully.

[1976gmc20]

Squarebody wheels have a drastically different backspace and will stick out farther than GMT400 wheels.

I was dealing with 6 hole but I know from sad experience that they will NOT fit the other way as the GMT400 wheels will hit the brakes on a squarebody. When I say "hit" I mean they will not even go on all the way. Actually you have to cut the centers out to get them on at all (which incidentally means you can't return them).

So the squarebody wheels on a GMT400 will be supported only by the lug bolts.

[Ironhorse]

Originally Posted by 1976gmc20

Squarebody wheels have a drastically different backspace and will stick out farther than GMT400 wheels.

So the squarebody wheels on a GMT400 will be supported only by the lug bolts.

Not surprised but not what I wanted to read, LOL. Don't think riding on the lug bolts would be the thing to do.

[1976gmc20]

Originally Posted by Ironhorse

Not surprised but not what I wanted to read, LOL. Don't think riding on the lug bolts would be the thing to do.

Yeah, that's why those five junkyard wheels I bought are now junk! One of them is now a tire chain basket and I used the others full of rocks to support fence posts in solid rock ground.

It should have been obvious but I got so fixated on the bolt pattern being the same. When you look at them, the old wheels' center portion is about the middle of the width of the wheel, but the newer ones are basically at the outside edge of the wheel. All "modern" wheels seem to be like this anymore.

My experience is strictly with the GMT400 4wd six hole wheels but I don't expect there is much difference with the 2wd five hole wheels.

[hatzie]

The Nissan Titan wheels spec out with 77.8mm center bore and 2mm smaller lug studs. They supposedly will fit tho.

Nissan Titan 2004-2015
- Bolt Pattern 6 x 5.5" (6 x 139.7mm)
- Offset 25mm
- Center Bore: 77.8 mm
- Stud_Size: 12mm x 1.5mm

1988-2014 Chevrolet Tahoe, & 6 lug pickups
- Bolt Pattern 6 x 5.5" (6 x 139.7mm)
- Offset 25mm
- Center Bore: 78.1 mm
- Stud_Size: 14mm x 1.5mm

The 1981-1987 squarebody trucks had a 15mm offset rather than the 25mm offset of the T400 T800 & T900 trucks. A little over 3/8" difference.

[1976gmc20]

Originally Posted by hatzie

...

The 1981-1987 squarebody trucks had a 15mm offset rather than the 25mm offset of the T400 T800 & T900 trucks. A little over 3/8" difference.

Sure seemed like a lot more difference than that?

10 mm would jam hard against the disc brakes?

I can't measure "offset" (from center?) but I could measure from the back of the wheel to the part that mates against the hub face. The steel rally wheels went with the 'burban but I still have the crappy alloy wheels that were replaced, plus the T400 wheels that I had the centers cut out of.

[1976gmc20]

Originally Posted by hatzie

The Nissan Titan wheels spec out with 77.8mm center bore and 2mm smaller lug studs. They supposedly will fit tho.

Nissan Titan 2004-2015
- Bolt Pattern 6 x 5.5" (6 x 139.7mm)
- Offset 25mm
- Center Bore: 78.1 mm
- Stud_Size: 12mm x 1.5mm

1988-2014 Chevrolet Tahoe, & 6 lug pickups
- Bolt Pattern 6 x 5.5" (6 x 139.7mm)
- Offset 25mm
- Center Bore: 78.1 mm
- Stud_Size: 14mm x 1.5mm

The 1981-1987 squarebody trucks had a 15mm offset rather than the 25mm offset of the T400 T800 & T900 trucks. A little over 3/8" difference.

Sorry - I don't know where those specifications come from but I just went out in the snow and measured the following:

1991 (squarebody) Suburban 6 hole 15" alloy wheel: ~3.75" from back of rim

GMT400 6 hole 16" steel wheel: ~5.75" from back of rim


About two inches difference!

[Ironhorse]

hatzie, you may have missed it but my incoming '99 OBS Tahoe is a 2 wheel drive with the 15' wheels and 5 on 5 lugs. Have seen several wheels I'd like to run on it but they ALL have too many wheel lugs. Seems 15'' wheels were the standard base line offerings on all 2 wd Tahoes at the time but guess GM was pushing the 4x4s for a bigger return in profit, LOL.

[hatzie]

Originally Posted by Ironhorse

hatzie, you may have missed it but my incoming '99 OBS Tahoe is a 2 wheel drive with the 15' wheels and 5 on 5 lugs. Have seen several wheels I'd like to run on it but they ALL have too many wheel lugs. Seems 15'' wheels were the standard base line offerings on all 2 wd Tahoes at the time but guess GM was pushing the 4x4s for a bigger return in profit, LOL.

15' wheels are some bigguns. LOL.

In all seriousness.
DOT pares down the allowable OEM offerings to weight rated wheels on the 6 & 8 lug trucks since those vehicles are likely towing. The 4x4 trucks likely also got at least 6 lug wheels with uplevel brakes.

The T400 5 x 5" and 15" wheels are the wild west. 6" to 9" wide and 38mm to 51mm offset depending on what wheel you got.

If you have 16" wheels originally I would not be surprised to have 15" wheels hit the brakes. I've had brake caliper rub when I mounted 8-lug 16.5" steel wagon spoke wheels for an F250 on a K20 that came with 16" wheels. They fit just fine on my 3/4 ton 1978 Power Wagon. Not noticeably different stick out from the fender wells of all three trucks but the front brakes on the Chevy didn't like em.
The offset will also affect your wheel well rub.

[Ironhorse]

Yup, 15 ' wheels are pretty good size, pretty sure they are more like 15 '' wheels to be exact.

The originally offered 5 on 5 fifteen inch wheels () aren't my first pick by no means. They would work but the style not much to my liking. Do like the 16 inch 4x4 six lug wheels but GM never offered those in the five lug style.

Will have a better idea what I will have to work with when the Tahoe gets here via transport shipper. Will post up some pics then.

[1976gmc20]

I guess I have no idea what 5 hole wheels the GMT400 2wd models came with. Somehow I thought they were 16" five holers?

Suburbans are awfully heavy and the half ton squarebodies with only 15" wheels (5 or 6 hole) were in my experience hard to keep tires on because you could only get up to C range (unless maybe you special ordered?). So what I was trying to do was economically convert a 6 hole squarebody to 16" wheels and bigger E range tires to withstand gravel roads. I used to go through LT235/75r15C tires like they were kid's balloons - pop, pop, pop!

The expensive discovery was that 6-hole GMT400 wheels will NOT fit on the squarebody 4wds even if you cut out the center hole to fit over the hubs. I suppose the reverse is possible although the wheel & tire would sit 2" farther out and the center hole would be too big so all the weight would be on the lug bolts.

[Just call me Sean]

4wd rims have 2" more backspacing than the 2wd rims. 2wd and 4wd use different rear ends, the 4wd being 4 inches wider. There are no 5 lug 4wd rims. I use a van rim as a spare on my 93 and 99. There is nothing wrong with the rim being supported by the lugs, it's called lug centric. My 93 has lug centric wheels as does my van, factory installed.

[hatzie]

It's likely possible to swap the 6 lug 4x4 knuckles onto the 2wd chassis.
You'll want the shell of a knackered outer CV joint to bolt through the hub bearing to hold it together.
The rear axle is a cakewalk to swap in.

[Just call me Sean]

You only need to swap on 2500 light duty rotors to get six lugs on the front. I did the opposite, I made mine 5 lug. You'll need a 2wd 14 bolt rear to do the back, or custom drilled axle shafts.

[special-K]

The 2wd Tahoe came standard with 15 x 7 styled steel wheels. Can't you run truck rallyes? I think you can run anything the earlier trucks ran on GMT400 C-models. The 454SS trucks ran nice 15" wheels. They were an option on all 2wds. 8" rallyes shown on lowered truck

[Ironhorse]

Tim, l do like the looks of the SS454 wheels, have that "old school'' look about them that appeals to me. Just don't see them a lot, the SS454/Sport Truck I believe was a lower production amount number of vehicles?

Can't find it now but seems I read here on the board at one point that the older square body rally wheels fit the earlier GMT400s but GM changed the front rotors and calipers in '99?

Just trying to get in some early sifting and sorting of info before the Tahoe actually gets here via shipper. That is so I have an idea of what will and will not fit and is a wheel style I like. Narrow the playing field some what. Wheels are always either a like or dis-like individual decision.

[Palf70Step]

I would not worry on whether the wheels are hub or lug centric. all my OBS models and my 02 for 10 years without issue. I regularly check my wheels for torque and all anyways. Not sure in 99 if Tahoe was still the OBS or classified new style, but I know my 02 brakes would NOT clear 15" wheels. It 99 Tahoe's had 15" wheels standard on 2WD models, than to me 15x8 truck ralleys are the way to go. The SS slots are only 15x7. They look good, but I liked the way the 15x8s made the trucks handle better. BTW, most aftermarket wheels are lug centric, so using the ralleys not a big deal.

Also, the Nissan alloy wheels do fit on the 99 up, but it is a super tight fit on the wheel hubs. They work well, but they are a very snug fit.

[Just call me Sean]

My 99 has factory 15" wheels. The calipers are the same as my 93, the only difference in the rotors is the 99 ones have the ABS tone ring.

[Ironhorse]

Bill, those square body rallies do look good on the GMC. What size tires are you running on there? The new style caps look good also.

Sean, thanks for the info there also. Looking more and more like will run the square body rallies, new style caps. Just need to locate a set of 15'' 5 on 5 wheels.

Just did get off phone with my shipper, Tahoe was picked up for shipment just over an hour ago. Will post up some pics when I get it. My new (to me, that is, ) daily driver. Thinking the '99s were all considered OBS and that stopped in 2000.

[Palf70Step]

31x10.50x15 were the tires. I really liked how they filled up the wheel wells. Just so you'll know, if you run them you will be going around 5to8 mph faster than the speedo says.

[1976gmc20]

Originally Posted by Just call me Sean

4wd rims have 2" more backspacing than the 2wd rims. 2wd and 4wd use different rear ends, the 4wd being 4 inches wider. There are no 5 lug 4wd rims. I use a van rim as a spare on my 93 and 99. There is nothing wrong with the rim being supported by the lugs, it's called lug centric. My 93 has lug centric wheels as does my van, factory installed.

Okay - that really surprises me since GM tends to standardize parts as much as possible. So nothing I said applies to 5 hole rims. Sorry!

I've been scared to run the rims that I had the centers cut out of on my 89 K1500 that I bought later. One of them is a basket for tire chains, one is sitting out in my junkpile, and the others I hauled up on the hill and filled the back side with rocks and used them to support fence posts where the ground is too hard to dig or drive in a post.

So I suppose that I could mount an old tire on one of them and use it for an extra spare since we live way out of town...?

[Just call me Sean]

I did a bit of research on all this before I converted my 2500 to 5 lug. The 4wd 6 lug wheels from these trucks have 6 inches of backspacing so no they don't work on a squarebody. I have one on a K5 in my yard so it's not sitting on a block but it won't roll with it. You can use the 2wd 6 lug wheels because they have 4 inches of backspacing, the same as a squarebody.

[special-K]

Here is a view of the rallye wheel and GMT400 center cap combo. Also narrow trim rings. I prefer this look. The set is 7" / 8". I also included a set of the standard GMT400 C1500 wheel they called styled steel, 15 x 7. I looked a long time to find that set. Rallyes are far easier to find