When I bought my 1929 AA, it had two new 6.50x20 tires on the back but the front tires were bad. I ordered two new 6.50x20 Firestones from Coker and have now installed them on the front. The only problem is that I have only about a half inch or less clearance between the tires and the outside fender edge. Actually when making a sharp turn, I can hear the tires rub. From what I read, 6.00x20 would have been better....but that is hindsight. Now that I already have the new tires installed, is there any way to raise the front end of the truck a little to give better clearance? My truck has shocks on the front but the Pittman arms and connecting links are missing so there is no shock action there. I don't know if hooking up the shocks would raise the front any or not. Any advice to this problem would be greatly appreciated by a total novice to this hobby!
Gerald
Front Tire Clearance
AA Tires
Gerald,
Im glad I noticed your misfortune before I ordered new tires. So I reckon 6.50 20s in the rear and 6.00 20s in the front.
The only way I can figure to get more clearence is by jacking up the front end same way we did a '57 Chevy. Put bigger shackles there! Might ought to work but Ive not known anybody to do it.
Mark
Im glad I noticed your misfortune before I ordered new tires. So I reckon 6.50 20s in the rear and 6.00 20s in the front.
The only way I can figure to get more clearence is by jacking up the front end same way we did a '57 Chevy. Put bigger shackles there! Might ought to work but Ive not known anybody to do it.
Mark
- mikeg
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Re: Front Tire Clearance
Hello Gerald, another thing you may want to check is the spring sag, if the spring has little left in it the entire front end will ride lower.Gerald wrote:When I bought my 1929 AA, it had two new 6.50x20 tires on the back but the front tires were bad. I ordered two new 6.50x20 Firestones from Coker and have now installed them on the front. The only problem is that I have only about a half inch or less clearance between the tires and the outside fender edge. Actually when making a sharp turn, I can hear the tires rub. From what I read, 6.00x20 would have been better....but that is hindsight. Now that I already have the new tires installed, is there any way to raise the front end of the truck a little to give better clearance? My truck has shocks on the front but the Pittman arms and connecting links are missing so there is no shock action there. I don't know if hooking up the shocks would raise the front any or not. Any advice to this problem would be greatly appreciated by a total novice to this hobby!
Gerald
I have read some where that if you can easily slip the spring into the spring shackles without spreading the spring it may need to be re-arched. I would imagine it wouldn't take too much for you to loose 1 to 2 inches of clearance this way.
The proper tire for the 30/31 trucks is the 6:00/20, even the rear tires, the 28/29 trucks I don't know for sure but it probably is the same.
- tiredtruckrestorer
- Posts: 338
- Joined: April 20th, 2003, 7:09 pm
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- Location: Orwigsburg, PA
AA front tires
Hello Gerald,
The original tire size on the 1928-29 AA's were 30X5 on the front and 32X6 on the rear. These were the high pressure type tire sizes. In about July 1929 the balloon type tires were introduced for the fronts in the 6.00X20 size. This is an interchange for the 30X5 high pressure size. With the introduction of dual rear wheels on the new bevel gear rears in late 1929-early 1930 the 6.00X20 were also used on the back. Single wheel trucks continued to use the 32X6 size tires. The interchange for this size is 6.50X20 in the ballon type tires. Since the 30X5 and 32X6 sizes are no longer available today, the correct tires sizes for your truck would be 6.00X20 on the front and 6.50X20 on the rear.
One other thing you may want to check is the kingpin lock bolt nut part number AA-3124. Many aftermarket kingpin sets came with a regular nut. This would allow the tires to turn too far and contact the fender and/or the brake rods. The correct nut sort of looks like a long acorn nut and is 1 9/32" long. It is longer than the Model A nut which is 1 5/32" long. A lock washer is also used under the nut and must be used to get the correct setting for the spindle stops. I do stock these special AA nuts.
Hope this helps you out. Keith Ernst
The original tire size on the 1928-29 AA's were 30X5 on the front and 32X6 on the rear. These were the high pressure type tire sizes. In about July 1929 the balloon type tires were introduced for the fronts in the 6.00X20 size. This is an interchange for the 30X5 high pressure size. With the introduction of dual rear wheels on the new bevel gear rears in late 1929-early 1930 the 6.00X20 were also used on the back. Single wheel trucks continued to use the 32X6 size tires. The interchange for this size is 6.50X20 in the ballon type tires. Since the 30X5 and 32X6 sizes are no longer available today, the correct tires sizes for your truck would be 6.00X20 on the front and 6.50X20 on the rear.
One other thing you may want to check is the kingpin lock bolt nut part number AA-3124. Many aftermarket kingpin sets came with a regular nut. This would allow the tires to turn too far and contact the fender and/or the brake rods. The correct nut sort of looks like a long acorn nut and is 1 9/32" long. It is longer than the Model A nut which is 1 5/32" long. A lock washer is also used under the nut and must be used to get the correct setting for the spindle stops. I do stock these special AA nuts.
Hope this helps you out. Keith Ernst
Thanks to both Mike and Keith. I never thought about spring sag but that is definitely a possiblity. I have a very good spring service shop about 50 miles from where I live so I plan to remove the front spring and have it re-arched. I will also check the nut Keith mentioned and see if that might be allowing the rub. I also appreciate the education about which tires and wheels came on the truck.
I drove the truck to its first showing this weekend at our church Heritage Day. It was very well received...but then again, I am slightly prejudice.
Thanks again.
Gerald
I drove the truck to its first showing this weekend at our church Heritage Day. It was very well received...but then again, I am slightly prejudice.
Thanks again.
Gerald
- Neil Wilson
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Hello to all involved in this discussion,
The spindle stop nut needs to be long enough to handle the front tire size. I have a couple of original 30x5 tires. This front tire is actually smaller than 6.00x20 tires. A 6.50x20 tire will be much larger than the 30x5 originals.
If I could get 5:50x20 tires with the same tread design as 6:00x20 tread design, then I would used 5:50x20 on the front and 6:00x20 on the rear. However, I used all 6:00x20 tires since the 5:50x20 tires don't seem to be available.
Washers can be added to the stop nut until it prevents the tire from hitting the brake rod. If it requires too many washers for the pin threads, then the end of the nut can be welded to make it longer or a longer nut can be machined.
Note that the original '28/'29 AA pins would not prevent the 6:00x20 tire from hitting the brake rod. So some change is needed for either 6:00x20 or 6:50x20 tires. This will also affect the turning radius.
The spindle stop nut needs to be long enough to handle the front tire size. I have a couple of original 30x5 tires. This front tire is actually smaller than 6.00x20 tires. A 6.50x20 tire will be much larger than the 30x5 originals.
If I could get 5:50x20 tires with the same tread design as 6:00x20 tread design, then I would used 5:50x20 on the front and 6:00x20 on the rear. However, I used all 6:00x20 tires since the 5:50x20 tires don't seem to be available.
Washers can be added to the stop nut until it prevents the tire from hitting the brake rod. If it requires too many washers for the pin threads, then the end of the nut can be welded to make it longer or a longer nut can be machined.
Note that the original '28/'29 AA pins would not prevent the 6:00x20 tire from hitting the brake rod. So some change is needed for either 6:00x20 or 6:50x20 tires. This will also affect the turning radius.
Regards, Neil Wilson
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aafords.com@gmail.com - use this email for contact
https://aafords.com/