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ViperDriver · 05-23-2008, 07:09 AM

I weighed our 2003 KS3905 yesterday for the first time. With full fuel, LP, and fresh water and everything and everybody loaded aboard, it was 28,010 pounds, well below the 29,500 GVWR, with the front axle at 10,930 and the rear at 17,080.

My question is about tire pressure. I have Goodyear G670 275/70R22.5's on the front and Michelin XZA2's on the rear. Using the weights above and Goodyear's and Michelin's tables, I'm coming up with 95# in the front and 85# in the rear. This seems low. The previous owner said he always used 115# all around and the shop I got the Goodyears from advised me to use about 105#. Can one of you experts advise me on my 95/85 numbers? Thanks.

ViperDriver · 05-23-2008, 07:09 AM

I weighed our 2003 KS3905 yesterday for the first time. With full fuel, LP, and fresh water and everything and everybody loaded aboard, it was 28,010 pounds, well below the 29,500 GVWR, with the front axle at 10,930 and the rear at 17,080.

My question is about tire pressure. I have Goodyear G670 275/70R22.5's on the front and Michelin XZA2's on the rear. Using the weights above and Goodyear's and Michelin's tables, I'm coming up with 95# in the front and 85# in the rear. This seems low. The previous owner said he always used 115# all around and the shop I got the Goodyears from advised me to use about 105#. Can one of you experts advise me on my 95/85 numbers? Thanks.

GaryKD · 05-23-2008, 07:45 AM

My signature coach weighs more than you do and per Michelin PSI talbles I carry 95 in the front and 85 in the rear. After 35K miles, the tires are wearing:
1. very little
2. very even across the tire
The ride is also very smooth. I have XZE on the front and XZA on the rear.

Route 66 · 05-23-2008, 08:15 AM

I agree with your reading of the tables if the XZA2s are the same size as the G670s.

However, it's quite common for the side to side weights to be different, so it's possible one corner could be overloaded at those pressures.

That's why the individual wheel weights are so important.

racer0624 · 05-23-2008, 10:41 AM

I sure agree with Dirk. Until you can get the individual corner weights I'd add 10-15#'s to what the charts show. It would be a real fluke if your coach was perfectly balanced side-to-side.

ViperDriver · 05-23-2008, 11:11 AM

Thanks for your responses. Good points. I think I'll go with 100 front and 90 rear, at least until I can get individual corner weights. If I read the tables right, the extra 5# will handle quite a bit of side to side imbalance.

MCDDY · 05-27-2008, 07:23 AM

Viper Driver
You did it right
Reading weight issues over the years on different forums, it's amazing how many people don't weigh with a worst case scenario. +-3/4 fuel, +-1/2 water, +-etc, +-etc. Do the worst case from the get-go and you're done other than individual wheel weights under the same conditions.
Our coach is a lot heavier than yours but the recommended pressures by axle are about the same but with 295/80/22.5 tires.
Dave