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Topic: Aspect Ratio of a 8R19.5 Tire and Gear Ratio of a P30 Southwind 37Y?

Posted By: AWK on 07/19/04 11:09am

I need to know the Aspect Ratio of the 8R19.5 tire, or what is the tire that measures the same as the 8R19.5 in the 225/70R19.5 size configuration.

Also I was wondering if anyone knows the axle ratio of a 1993 Fleetwood Southwind 37Y. It is a P30 Chassis and uses the Dana 11inch ring gear.

I need this information to help diagnose a vibration it has.

Thank you,


I had a 1993 37' Fleetwood Southwind P30
2004 GMC Sierra Z71
Great wife and
2 Dogs (Elmo and Ellie)

Posted By: Rachel's dad on 07/19/04 09:23pm

Don't know about the tire issue, but my guess for the rear-end is probably a 4:56.

Pete-Colleen-Rachel ">

2004 Pace Arrow 35G
Banks Stinger System
Jeep toad

Posted By: George The Jeep on 07/20/04 01:48am

Most gear ratios in Motorhomes with Dana 70 HD rearends are 4.56 The height on my Cooper 8R19.5 rear tires are 34" I went with Toyo 265/70R19.5 on the front axle to get 34" to match the rear. When I was looking for new tires last year I found the 225 at 32" & the 245 at 33" My rear tires have 6" of tread width, the front are 8 1/2" wide. As my motorhome is 4 wheel drive I had to match front & rear height.

1991 36' Monaco Crown Royale
8.3 Cummins, 643 4 speed
1985 31' 4X4 Itasca Sunflyer
Wa. State License 4X4HOME
454, Banks, gearvenders, 205 transfercase, Warn winch
1962 Jeep CJ3B
24' enclosed trailer
Seattle Jeep Club
FMCA F334228
FMCA 4-Wheelers

Posted By: AWK on 07/20/04 05:49am

Thanks for the information. The only information I could find stated 4:56 ratio on the Dana 70 gear, but I could not find anything labeled on the motorhome.


Posted By: Sully2 on 07/20/04 07:02am

In 1993 they ran a 4.63 : 1 rear end....but I THINK..?? 1993 they used Spicer rear ends under the P30's...

2002 Jeep Liberty
2016 Ford Escape

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