tire size

AA Ford Discussion Group relating to the repair and restoration of your AA Ford.
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smilebigtt
Posts: 267
Joined: December 27th, 2008, 9:30 pm
Body Type: flatbed
Model Year: 1930

tire size

Post by smilebigtt »

what tire size and # ply are you guys running? I have one old tire on mine and it reads 33x6 12ply
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fordman88
Posts: 207
Joined: February 7th, 2009, 8:44 pm
Model Year: 1929
Location: Salina, Kansas

Re: tire size

Post by fordman88 »

hi there! im new to this site and this is my first time on..yeay! my AA came with 650x20s but i found a pair of 750x20s to replace the rotted ones in the back. they fit and will work till i can afford the right ones.
Trevor O Davis
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rollingsculpture
Posts: 553
Joined: December 9th, 2008, 7:30 am
Body Type: platform
Model Year: 1931
Location: Takoma Park maryland

Re: tire size

Post by rollingsculpture »

well mine came with 4 rotted 600-20 6ply heavy duty firestone tires but firestone doesnt make the 600's anymore just 650's are the sizes interchangable? how does that work?
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Neil Wilson
Posts: 3062
Joined: February 5th, 2003, 9:42 pm
Body Type: 82-A/89-A
Model Year: 1930
Location: Boulder, CO
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Re: tire size

Post by Neil Wilson »

You can look at http://www.cokertire.com/ to find 6:00x20 tires. The Firestone 6:00x20 tires have a passenger car style tread. I would not used them on an AA truck given the look!

650x20 tires should not be used on the front of a '30/'31 AA since the tire will hit the brake rod. Using a 6:00x20 on a '28/'29 AA will also result in the tire hitting the brake rod. Original tire informaiton is as follows:

AA Tire Information

Tire Sizes:

For 1928 and 1929 Ford provided 30x5 tires on the front and 32x6 high pressure tires on the rear.

The 30x5 size translates to 5:00x20. The five is the tire height (inside dimension). So, 5x2=10 and 30-10=20 (the rim size).

The AA came with AA wheel stops (i.e. the spindle bolt locking pins) designed for the 30x5 tire size. Using oversize tires on the front results in the tires hitting the brake rods. So, wheel stops need to be lengthen to resolve the problem. Longer wheel stops result in a shorter turning radius.

The 32x6 size translates to 6:00x20. The six is the tire height (inside dimension). So, 6x2=12 and 32-12=20 (the rim size). These 32x6 tires had more plies than the 6:00x20 tires supplied for dual wheel trucks. Consequently, the outside height is close to a 6:50x20 tire.

For 1930 and 1931 Ford provided 6:00x20 tires (front and rear) for dual wheel trucks. Trucks with single rear wheels were provided with 6:00x20 front tires and 32x6 high pressure rear tires.

Using oversized tires on the front results in the tires hitting the brake rods! The 1930 and 1931 AA’s do not have wheel stops which can be adjusted since the turning radius is controlled by the spindle design. Using oversized tires on the rear might cause clearance problems between side walls.

Most parts vendors (including the companies which just sell tires) incorrectly list 6:00x20 as equal to 30x5 and 6:50x20 as equal to 32x6.

Tire Manufactures:

Information from Ford archive photographs:

Goodyear – ’27 picture (rear = 32x6; front = 30x5)
Firestone – ’27 picture (rear = can’t read – tread design same as front; front = 32x6)
Goodrich – 6/12/28 picture (rear = 32x6; front = 30x5)
United States Royal – 3/22/28 picture (rear = 32x6; front = 30x5)
United States Royal – 4/10/28 picture (rear = 32x6; front = can’t read – tread design same as rear)
United States Royal – 4/10/28 picture (rear = can’t read – tread design same as front; front = 30x5)
US Royal – 2/18/29 picture (rear and front = can’t read – tread design same)
US Royal – 2/18/29 picture (rear = 32x6; front = can’t read – tread design same as rear)
US Royal – 1/28/29 picture (rear = 32x6; front = can’t read – tread design same as rear)
US Royal – 2/18/29 picture (rear = 32x6; front = can’t read – tread design same as rear)
Firestone – 12/15/30 picture (rear = 6:00x20; front = 6:00x20)
US Royal – 12/15/30 picture (rear = 6:00x20; front = can’t read – tread design same as rear)
US Royal – mid/30 pictures (rear = 6:00x20; front = 6:00x20)
US Royal – 10/2/31 picture (rear = 32x6; front = 6:00x20)
US Royal – 1/3/31 picture (rear = 6:00x20; front = 6:00x20)
Goodyear – 12/3/31 picture (rear = can’t rear – tread design same a front; front = 6:00x20)
Firestone – 4/30/31 picture (rear and front = can’t read – tread design same)
Firestone – 2/4/31 picture (rear and front = can’t read – tread design same)
Firestone – 8/6/31 picture (rear and front = can’t read)
US Royal – 2/25/30 picture (rear and front = can’t read)
Regards, Neil Wilson
______________________________________
aafords.com@gmail.com - use this email for contact
https://aafords.com/
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akstraw
Posts: 34
Joined: December 11th, 2008, 10:34 am
Body Type: Huckster
Model Year: 1929
Location: Hickory, North Carolina

Re: tire size

Post by akstraw »

When I originally acquired my truck, it had 32 x 6 US Royal tires on it, that were 4-ply, and you could see no tread and three of the ply exposed -- probably a result of WW2 rationing. Back when I replaced the tires about 8 years ago, I read somewhere that the 29 AA with 131" wb and single rear wheels was supposed to have 6.00 x 20 on the rear and 5.50 x 20 on the front. I had a pair of 6.00x 20 Generals that I had bought new 20 years earlier, and I used them on the rear. The only ones I could find for the front were listed as 5.25/5.50 x 20, and made by Lester. So, that's what I am running today.
Andy
1929 AA Huckster - body by York
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Neil Wilson
Posts: 3062
Joined: February 5th, 2003, 9:42 pm
Body Type: 82-A/89-A
Model Year: 1930
Location: Boulder, CO
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Re: tire size

Post by Neil Wilson »

The 6:00x20 modern day tires would have been the 32x6 tires. However, the plies on the 32x6 were considerable more that what I have found available today. Not much of a concern unless your truck is for work.

I have not found a 5:00x20 (which would be the 30x5 tire). Anyone know of a source.
Regards, Neil Wilson
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https://aafords.com/
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Boomer
Posts: 191
Joined: July 15th, 2006, 7:26 pm
Body Type: 82-A Closed Cab
Model Year: 1929
Location: Mankato, MN

Re: tire size

Post by Boomer »

Would the 475-500-20 Firestones listed on the Coker site be adequate/work for the front of the 28-29 AA?
Drew N.

1929 AA Closed Cab

Skol Vikings!
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Neil Wilson
Posts: 3062
Joined: February 5th, 2003, 9:42 pm
Body Type: 82-A/89-A
Model Year: 1930
Location: Boulder, CO
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Re: tire size

Post by Neil Wilson »

Yes, that would be basically the same 30x5 original size. For my taste, I don't like the tread design (looks like highway tread). And, I don't think you will find 600x20's for the rear with the same tread.
Regards, Neil Wilson
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https://aafords.com/
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TruckMan
Posts: 132
Joined: March 10th, 2009, 10:36 am
Body Type: Garwood Dump
Model Year: 1928
Location: Wisconsin

Re: tire size

Post by TruckMan »

I put 6.00 x 20 front, 6.50 x 20 rear, singles. I wanted to be authentic but still be able to haul heavy loads.
TruckMan
Hayslip
Posts: 235
Joined: February 26th, 2007, 6:20 am
Model Year: 1930

Re: tire size

Post by Hayslip »

I have 6.00x20 tires on the front of my 1928AA. The only time the tire hits the brake rods is when I'm backing up with the wheels cut at the sharpest angle. You couldn't drive forward with the wheels cut at that angle and i can't see what damage the tire could do to the brake rods while backing up. Ford made some special AA nuts that go on the back of the axle on the king pin wedges to prevent tire/brake rod contact. I have the shorter incorrect car ones on my truck. When you buy the car king pin set which is used on the 1928/1929 AA you get these shorter nuts. Sincerely, Ed Hayslip
Hayslip
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Neil Wilson
Posts: 3062
Joined: February 5th, 2003, 9:42 pm
Body Type: 82-A/89-A
Model Year: 1930
Location: Boulder, CO
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Re: tire size

Post by Neil Wilson »

Yes, the A stop nuts can be welded up to increase the length for the '28/'29 AA. Also, an extra lock washer can be used to make up the extra length. Attached is a picture showing the two styles of spindle bolt pin setups - A and AA.
Attachments
xA-AA Spindle bolt locking pins 1c.jpg
xA-AA Spindle bolt locking pins 1c.jpg (52.63 KiB) Viewed 8996 times
Regards, Neil Wilson
______________________________________
aafords.com@gmail.com - use this email for contact
https://aafords.com/
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