VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Tire sizing and safety

Hi all. I have always had 6.00X16 bias tires with tubes on my 1940 sedan. I am thinking about radials, but I am getting some conflicting information. One vendor tells me I can safely put radials on my stock rims, and a tube is not necessary. Another vendor tells me I must use a tube. So my questions: 1. Can I put radials on my rims without using a tube? 2. There used to be some discussion about rim cracking with radials. Was that question ever settled? 3. Is 6.5X16 the biggest tire that I can safely use on the car? I know some of these questions have been asked before, please bear with me. I can't remember the answers! Thanks in advance for the help.

My opinion only. You can use radial tires on your stock rims as long as the rims are not bent
in any way or they will leak air , If they leak a tube in each tire will correct that.
As for radial tires cracking the rims I think not . If the rims are weak from the start they
might crack under normal conditions . As far as size someone else will have to answer
that because I'm not sure.
Good Luck with your car

Increasing tire size can be tricky. One big variable is the actual dimensions of the tire. For example, I bought 6.00 - 16 Firestone branded whitewall tires from Coker for my ”˜37 Master coupe. I was replacing black wall 6.00 - 16”˜s of various brands. The new tires were about 3/8” wider at the widest point of the sidewall. The actual tread was about the same.

My suggestion is that you need to measure the dimensions of your current tires as well as the clearances. The front is especially critical because you need to allow clearance when the wheels are in a full turn and the suspension travels.

Then you can compare that to whatever tire you plan to buy. For example, a “skinny” 6.50 - 16 might be the same width as a “fat” 6.00 - 16.

The slight difference in diameter is typically not an issue.

Thank you to both responders. Very helpful. Mike

On going to a larger tire than original may cause some concern owing to "foot print' i.e. weight to surface area covered by the tread.

Best,

Charlie

I've had two sets of radial tires (both Diamond Back) on a '37 Sports Coupe with original wheels for16-years. My car gets driven an average of 2-3k miles per year with no problems to the wheels. The only reason I bought the 2nd set was due to tire age. I did change the wheel alignment a tad as was reccomended, but I don't recall offhand what the change was. I also increased tire pressure to 32#, front & rear.

Ok, thanks everyone for the input. Much appreciated.