O.K. , I'm looking at buying a 1976 GMC 2500 long bed and the guy swapped out the stock 8.25 X 16.5" wheels & tires for some Suburban 16" chrome wheels & tires and I feel it runs out a little fast (RPM wise) on the freeway ~ I need to drive this lump to Canada and back without scattering the good running 292 Long Stroke InLine 6 Banger . Yes , I know this is the AD forums but I looked over in the '76 forums and no one appears to know anything so here I am . TIA ,
Looking at a brochure for the 1976 GMC pickups, it shows 2 tire sizes for the 3/4 ton pu. 8.75x16 and 9.50x16.5. I could not find any data for the 8.75x16, however I did find some good data on the 9.50x16.5 tire. Tread width for the 9.50x16.5 is 9.8", diameter is 30.6". With that said, you could substitute a modern day 16" radial LT245/75R16 and achieve almost the same dimensions. The radials measure 9.5" on tread width and 30.5" in diameter. If you don't want to spring for new tires (we know how you like baldies), I keep thinking of the great tech tip that Coilover posted some time back. Hook up your tach/dwell meter so that you can see it in the cab and see what RPM's you're running while you take it thru its paces. Here's a link to the brochure that I was looking at. Pretty cool! www.oldcarbrochures.com/main.php?g2_itemId=49207 Hope this helps. Ken
Tire Circumferance/Diameters Well ; I do kinda - sorta and you're wrong ~ if 30" Dia. tires are not made for the wheel in question or if they're like $85.99 Ea. , I'll have a serious problem on my hands as this is supposed to be a cheap work truck . Ken , THANX for the brochure link ! I got the OE tire size off the build sheet sticker in the glovebox , I was thinking it was an odd size but I remember the 1970's well , all the truck sellers and tire salesmen assured me that 16.5" was not only the new thing but it was also the end-all , BE all tire size and I should scrap my old 6 lug 16" wheels as soon they'd stop production on 16" tires of any kind , completely . Jerks and liars all of them . I'm still waiting to hear back from this guy , I bet he's waiting for _me_ to call him and offer more $$ . I'm hoping to find someone who'll swap me the stock wheels for these chrome Barrio things , I hate 'em already and I've not yet purchased it . Just what I need ~ more junk in my back yard ~ at least this isn't a FUGLY AD GMC . (runs & hides)
30" tire is a 30" tire, whether made for a 15", 16", 16.5", 17,18 19 or 20" rim. A 30" tall tire for a 16" rim will not fit on a 16 1/2" rim. Outer Circumference doesn't enter into the equasion. We're talking about Inner Circumference here. 16.5" rims were an experiment in the 70s or so that, like most 70s stuff, is better off forgotten. They may still be used on heavy duty stuff also.
I Can See That : No one os bothering to actually read my posts about the availability of tires in the desired circumferance . I guess it makes no nvermind now as I bought the darned thing , even my son the Racer , said it was " a nice old truck " (amazing) . He likes the chromie 16" wheels it has and it came with four nearly new Bridgstone E rated 16" tires so that's a good thing . He says I was doing well over 60 MPH on the freeway home , I drove it by ear and the speedo said 60 MPH .
I ~did~ catch this, however... Ya know, I think this is JUST what you need! Now about trying stuff in the 70's... .........um...... what were we talking about?.....
if your concern is tire availability then stick with the 16" rim. I had an 81 chevy that had 16.5 rims on it and when i blew out a tire on a road trip, it took the better part of a day to track down a tire.
Thanx ! You hit the nail on the head . It had two near new Bridgestone E rated LT tires on it and the seller gave me two more so I'll have a matched set now .
