Radial Tires on a 60 Hawk

[Burke]

Some questions about putting radial tires on my 1960 Hawk. Is it a good idea? Does it improve the ride? Do I need different (wider) rims? and what size tire would I use? The original tire is 670-15

Right now it rides pretty stiff.

Mike Burke

[Sam Roberts]

I use 205R15s on my 1955 Commander coupe, on stock Studebaker 4.5" rims with absolutely no problems at all. Also on the front of my 1966 Cruiser, again standard Studebaker rims, and no problems. I would not have anything but radials on any car I own! Handling, ride, and piece of mind are all better with them.

quote:Originally posted by Burke

Some questions about putting radial tires on my 1960 Hawk. Is it a good idea? Does it improve the ride? Do I need different (wider) rims? and what size tire would I use? The original tire is 670-15

Right now it rides pretty stiff.

Mike Burke

Sam Roberts

[MarkC]

What Mr. Roberts has done is common practice and in casual service should pose no problem.

However, if your car will be operated routinely (as a "driver") under modern road conditions and speeds, I strongly recommend that you consider a modern radial-tire rated wheel over the 40+ year old stock wheels. Modern wheels are many times stronger than your old stockers, and there have been numerous discussions of stock wheel failure under even moderate use with radial tires. (There have been some write-ups in TW also.) If you retrofit, you also get the benefit of wider rims which will contribute significantly to the overall improvement. I bought five stock steel wheels from a mid 80's Chrysler New Yorker with six inch rims for $10 each at a wrecking yard. New replacement wheels with these specs are regularly advertised in TW and are affordable. I'm also running 205/70-15 radials and they're a great overall combination.

Good luck and take care.

MarkC

MarkC, 64 Y8
Working in Spokane, WA

[Sam Roberts]

Mark,

You make a good point on the rims, and largely I agree with it. The 1955 has standard Stude rims all the way around, and is driven maybe 1,500 miles a year. The 1966 has standard Stude rims on the front, and has been driven nearly 40,000 miles since August 1998, but had radials on it when I bought the car. Those tires are 205R75X15s by the way. The rears on the Cruiser are 235R75X15s on 5 1/2" wide Chrysler rims from the era you mentioned. I did that to effectively reduce the 3.31 axle to about 3.00 or so.

BTW, Mr. Roberts died in 1976, so you can call me Sam.

quote:Originally posted by MarkC

What Mr. Roberts has done is common practice and in casual service should pose no problem.

However, if your car will be operated routinely (as a "driver") under modern road conditions and speeds, I strongly recommend that you consider a modern radial-tire rated wheel over the 40+ year old stock wheels. Modern wheels are many times stronger than your old stockers, and there have been numerous discussions of stock wheel failure under even moderate use with radial tires. (There have been some write-ups in TW also.) If you retrofit, you also get the benefit of wider rims which will contribute significantly to the overall improvement. I bought five stock steel wheels from a mid 80's Chrysler New Yorker with six inch rims for $10 each at a wrecking yard. New replacement wheels with these specs are regularly advertised in TW and are affordable. I'm also running 205/70-15 radials and they're a great overall combination.

Good luck and take care.

MarkC

MarkC, 64 Y8
Working in Spokane, WA

Sam Roberts

[N8N]

IIRC in a '55 the rims were 5" wide not 4.5" so it would actually be safer to run radials on those than the later rims. My 56J uses the same wheels I believe and there is noticeably less "pinch" on the tires than when looking at similar sized tires on later wheels.

The concerns about lighter gauge metal are still valid however. Apparently belted and later radial tires are more flexible than the regular bias ply tires in common use when our cars were new, and they do apparently put more stress on the wheels.

nate

[Sam Roberts]

Yes Nate, you are right about 5" rims on the '55, but the real issue might well be tire pressures involved. All radial tire manufacturers I know of recommend carrying 35 PSI in the tires, not just in some cases, but about all cases, to help prevent heat build up, and excessive flexing. I know Studebaker recommended 28-32 PSI, but I am sure on the Mobilgas economy runs they were much higher than that, probably up to 50 PSI. My point is that the flex on the rims are probably due to under pressured tires more than the rims themselves. The Cruiser's front rims are still the 4.5s that came on it, and I have never lost a wheel cover yet, but they have been inflated to 35 PSI all the time.

quote:Originally posted by N8N

IIRC in a '55 the rims were 5" wide not 4.5" so it would actually be safer to run radials on those than the later rims. My 56J uses the same wheels I believe and there is noticeably less "pinch" on the tires than when looking at similar sized tires on later wheels.

The concerns about lighter gauge metal are still valid however. Apparently belted and later radial tires are more flexible than the regular bias ply tires in common use when our cars were new, and they do apparently put more stress on the wheels.

nate

Sam Roberts