Goodyear G647RSS are on the front.

quote:

Nobody says 6".

regardless of brand; compare 750X16 w/235/85R16 all this talk re. tires has caught my attention.

Gonna need 19.5"

You might get away with 245 on the front but not in the rear. If you wheels are 6 inch, then the tire spacing for duals (rear) would not be enough and the tires would touch.

I have Alcoa wheels and as far as I know, the only Alcoa 19.5 wheels are 6 inch wide.

You are correct, all manufacturers of 245 tires recommend a minimum of 6.75 at a minimum with the preferred width of 7.5 inch. You would be compromising the side wall strength to run 245 on 6 inch wheels by changing the running angle vs tread width.

I run 225/70R19.5 all the way around with no problem.

OK, will stick to 225x70x19.5 for 6" rims. Will now search for prices. I know that FMCA has the program on Michelin but not on Goodyear or Bridgestone. Guess you get what you pay for.
Jim

Jim,
If the coach is in Pa. and you are getting tires there, try Service Tire. They service that area and have good pricing on RV tires. I bought my Michelins from them and are happy with the brand. Service Tire said they had issues with Michelin, but that was a while ago. And they will mount and balance them at their shop in a 1/2 day. Just need to make an appointment.
Another thing to take into consideration is the usage of the coach. When I bought tires for Barth 1, I put Sumitomo's on it. The local tire dealer said that there was no sense in putting high dollar tires on the coach if we were not going to be putting 7-8K+ miles on a year, as the age would require replacing before the wear. They were great tires and are still on and being used by the present owner and were half the price of Goodyears and Michelins.

The original tires were 8R19.5. Keep in mind the metric sizes are smaller in diameter so you speed at a given RPM will be slower. With the 542 allison you will be turning close to 2500 rpm at 65 even with 8R19.65. 8R19.5 tires will rotate 628 times in a mile, and 225/70R19.5 tires rotate 644 times.

Read more: The Effects of Changing From 8R19.5 to 225/70 19.5 Tires | eHow.com http://www.ehow.com/list_74404...s.html#ixzz1yGb9SkHO

Based on what Gary says, I will put Bridgestone 8R19.5 R187s on the rear. Don't want to loose those RPMs. And others have had good experience with Bridgestone R187. That does leave an option for the front. With the 6" rims, I could go to a 225 70/R 19.5. Some think that with a little more meat on the road the handling would be better. But I've seen posts that stated good handling on 28' Breakaways with 8Rs on the front. One of the tire shops said that if you use anything other than what the manufacturer of the motor home stated, you might be sol if anything went wrong with the tires. Any opinions/experiences would be appreciated. Need to make the decision in the next couple of days.