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Topic: Tire pressure for 86 GV.  (Read 393 times) previous topic - next topic

Tire pressure for 86 GV.

I know this topic has been covered in many ways on this forum. But I think our question is different enough to ask ..


The factory plate ( attached) shows the tire pressure for our coach.  FEG. 33 tag axle GV..  65 psi...  but the rating on the tires are 110...  that's a lot of difference is required/suggested tire pressures.... 

Is there a technology difference to our new tires ( 12-1-2019) and the " vintage" manufacture plate from 1986 using the mid 80's technology and science. ?

1986 Grand Villa, 454 Chevrolet, 33 SBI tag axle
Build # 2658
2nd owner, original owner was Newman/Freeman Racing, racer Bill Freeman and actor/racer Paul Newman

Re: Tire pressure for 86 GV.

Reply #1 –
Correct MINIMUM PSI is still based on actual weight, with heavier wheel position on each axle determining correct minimum PSI for all tires on that axle. With actual weights, you can go to your tire manufacturer's Inflation Chart.

So, said another way, we have no idea if 50 or 100 PSI is correct for YOUR coach.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Tire pressure for 86 GV.

Reply #2 –
Quote from: wolfe10 –
Correct MINIMUM PSI is still based on actual weight, with heavier wheel position on each axle determining correct minimum PSI for all tires on that axle. With actual weights, you can go to your tire manufacturer's Inflation Chart.

So, said another way, we have no idea if 50 or 100 PSI is correct for YOUR coach.

Ok.  But where does the calculation for the 65 on the mfg plate come from....  we will review the tire mfg tire pressure chart if available.  But if we get this coach weighed on Monday before we head to MN from CO and it is the 6000 front and 9000 rear as plate reads.  Than the 65 psi is correct ?   
1986 Grand Villa, 454 Chevrolet, 33 SBI tag axle
Build # 2658
2nd owner, original owner was Newman/Freeman Racing, racer Bill Freeman and actor/racer Paul Newman

Re: Tire pressure for 86 GV.

Reply #3 –
The recommended PSI on the GVWR plaque is ONLY accurate for:

Original tires
Each axle loaded to GAWR

Said another way, probably irrelevant as tire specs have changed quite a bit in the last 30+ years.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Tire pressure for 86 GV.

Reply #4 –
Quote from: Subsilked –
Ok.  But where does the calculation for the 65 on the mfg plate come from....  we will review the tire mfg tire pressure chart if available.  But if we get this coach weighed on Monday before we head to MN from CO and it is the 6000 front and 9000 rear as plate reads.  Than the 65 psi is correct ?
With new modern tires on your coach, ignore the mfg plate.

Get the coach weighed.  Take the current axle weights and look in the current manufacturer chart for your current tires, and read the recommended pressure.  (Some say add 5 psi to chart pressure for safety pad)  That is the cold pressure you want to run.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Tire pressure for 86 GV.

Reply #5 –
And, cold= current ambient temperature before driving, NOT a particular temperature.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Tire pressure for 86 GV.

Reply #6 –
Quote from: Chuck & Jeannie –
With new modern tires on your coach, ignore the mfg plate. Get the coach weighed.  Take the current axle weights and look in the current manufacturer chart for your current tires, and read the recommended pressure.  (Some say add 5 psi to chart pressure for safety pad)  That is the cold pressure you want to run.
X2......Ours had new Michelin XRV 255/80R 22.5 tires when we bought her, rode like hell. Had it 'four cornered' and found someone had inflated the tires 25 lbs MORE than needed. Rides perfect, now.  ^.^d
1993 U-240 "La Villa Grande"..CAT 3116 w/ Pacbrake PRXB...Allison 3060 6-speed..
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