Width of radial tires that will fit in wheel wells 37 Roadmaster model 81

[Mutt's37Buick]

Since I'm planning on driving my car almost daily, I would like to use radial tires.

Has anyone else done this on their '37 or '38 Roadmaster and what width tires would fit in the side mount wheel wells?

Thanks

[Guest Grant Magrath]

Since they're only for spares, why bother with radials? Just keep crossplys as your spares, and get the radials sorted at your leisure!

Cheers

Grant

[Mutt's37Buick]

Radials are same price if not cheaper so think I may as well do radials on all six tires so I can rotate them.

Mutt

[Seldenguy]

I agree with Grant. But why not only buy 4 radials and put them on the road and rotate them. They are going to rot out long before you will wear them out. My '36 Roadie had worn tread tires under the cover(you can't see them on a '36) and I never opened them. I drove the car for fifteen years with a spare in the trunk. My investment was considerably less than purchasing six tires. In my opinion your goal is very difficult to reach mainly because the radials on the road and in the trunk will not access your wheelwells. But then these are only my cheap thoughts, good luck in your quest. ---Bob

[frank burns]

If you have an idea of sizes,I can get you tread and section widths (widest part of tire )

[Mutt's37Buick]

Hi Frank,

That would be great if you have that information.

Tires I'm considering are 195/80R15, 205/75R15, and 205/70R16.

Thanks

[egor]

Those sizes would all be smaller diameter than stock, raising your engine rpm's. Most of the vintage tire sites give cross section widths on the tires they sell, but even some of the new stock-size (7.00-16) bias ply tires are too wide for the sidemount covers. It'll be difficult (if not impossible) to find radials narrow enough, and still close to stock diameter, to meet your purpose.

Hi Frank' date='

That would be great if you have that information.

Tires I'm considering are 195/80R15, 205/75R15, and 205/70R16.

Thanks[/quote']

[frank burns]

The section width on a typical 205/75x15 tire is 8.6 in when fitted on a wheel that is 5.5 in wide where the bead of the tire sits. the outside diameter is 27.5 in,

If you use a narrower rim, it does affect the section width about 1/3 as much as the change in rim width.

What brand of tires were the other two sizes ?

[frank burns]

For 185/80r15 readily available outside dia 26.55 section width 7.4 at a rim width of 5.5 in

[Dwight Romberger]

If you want a matched set of six, try deflating one after it is mounted. You may be able to cram it into the well. If so, buy two more.

The other option is to install a wider well.

[Barney Eaton]

Interesting that I could not find a conversion for the 7.00 x 16 tire used on the 1937 Roadmaster. I did find that 6.50 x 16 is 29.3 in dia and 6.8 wide, the 7.50 x 16 is 31.45 dia and 8.2 wide.

If a 7.00 x 16 is exactly between the other two in dimensions, the the diameter = 30.37 and the width = 7.5

If you stay with 16" wheels, your choices may be limited to truck or SUV tires. Below is a comparison of some 16" sizes.

The 225/80r16 is very close to the diameter you need but the 225 width = 8.85 inches and that could be a problem.

size results[TABLE]

<TBODY>[TR]

[TH]Specification[/TH]

[TH]Sidewall[/TH]

[TH]Radius[/TH]

[TH]Diameter[/TH]

[TH]Circumference[/TH]

[TH]Revolutions[/TH]

[TH]Speedometer[/TH]

[TH]Odometer[/TH]

[TH]Difference[/TH]

[/TR]

[TR]

[TD]225/70-16[/TD]

[TD]6.2"[/TD]

[TD]14.2"[/TD]

[TD]28.4"[/TD]

[TD]89.2"[/TD]

[TD]710/mi[/TD]

[TD]60MPH[/TD]

[TD]10000mi[/TD]

[TD]N/A[/TD]

[/TR]

[TR]

[TD]225/80-16[/TD]

[TD]7.1"[/TD]

[TD]15.1"[/TD]

[TD]30.2"[/TD]

[TD]94.8"[/TD]

[TD]668/mi[/TD]

[TD]56MPH[/TD]

[TD]9413mi[/TD]

[TD]6.2%[/TD]

[/TR]

[TR]

[TD]215/70-16[/TD]

[TD]5.9"[/TD]

[TD]13.9"[/TD]

[TD]27.9"[/TD]

[TD]87.5"[/TD]

[TD]724/mi[/TD]

[TD]61MPH[/TD]

[TD]10198mi[/TD]

[TD]-1.9%[/TD]

[/TR]

[TR]

[TD]215/80-16[/TD]

[TD]6.8"[/TD]

[TD]14.8"[/TD]

[TD]29.5"[/TD]

[TD]92.8"[/TD]

[TD]683/mi[/TD]

[TD]58MPH[/TD]

[TD]9614mi[/TD]

[TD]4.0%[/TD]

[/TR]

[TR]

[TD]205/70-16[/TD]

[TD]5.6"[/TD]

[TD]13.6"[/TD]

[TD]27.3"[/TD]

[TD]85.8"[/TD]

[TD]739/mi[/TD]

[TD]62MPH[/TD]

[TD]10404mi[/TD]

[TD]-3.9%[/TD]

[/TR]

[TR]

[TD]205/80-16[/TD]

[TD]6.5"[/TD]

[TD]14.5"[/TD]

[TD]28.9"[/TD]

[TD]90.8"[/TD]

[TD]698/mi[/TD]

[TD]59MPH[/TD]

[TD]9823mi[/TD]

[TD]1.8%[/TD]

[/TR]

</TBODY>[/TABLE]

<FORM method=post action=tiresize.cgi><INPUT value="Perform another calculation" type=submit>

</FORM>

[Guest CAFoster]

23580R16 is available(Goodyear Marathon and others) used as trailer tires, they are 30.8" diam and 9.5" wide so they would be close in diam but wider.

[Guest Grant Magrath]

So how do you radial guys cope with the more flexible sidewall of the radials on your cars? Stiffer springs? Shocks?CheersGrantPS Remember Radial Tuned Suspension?!

[1939_Buick]

Remember Radial Tuned Suspension?!

Doubt if many folk living in the USofA would know about HQ's :eek:

Barney

What web site is that table from ? Have seen it before

[egor]

No coping required. They work great. Anyone driving aggressively enough to actually expose the flexibility of the sidewalls is crazy.

So how do you radial guys cope with the more flexible sidewall of the radials on your cars? Stiffer springs? Shocks?CheersGrantPS Remember Radial Tuned Suspension?!

[Barney Eaton]

To get the information on the chart (post#11) go to Powerdog Industries click on the "tire size caluclator"

You must enter the tire size(s) you want and it then list them with the info posted. It is handy if you are doing Plus 1, Plus 2 wheel changes and want to keep the speedometer the same. One hint, if looking for a substitute tire/wheel start by putting your present tire size in first.

Each tire you enter after that will show the + or - percent change over the original.