Wandering 1953's

[rustytractor]

Maybe this site will be of aid?

http://www.tirerack.com/tires/tiretech/45_conversionchart.jsp

Thanks Art, maybe that explains why the L78's rub the inner wing (but only when turning right for some reason).

[Roger Zimmermann]

  So if the original 8.20x15 equates to 235/75 R15 technically that size should clear the rear wheel shields so why did you opt for the 225/75 R15 which are both shorter and narrower - do you think that the 235's would have fouled ?

Bias-ply tires are narrower than radials. Without fender skirts at the rear, I would use the 235/75R15. However, due to that styling element, wide tires are difficult to install or remove from the rear axle unless the rear of the car is lifted one side at the time. This is the reason why I choose the smaller size.

[Philippe M. Ruel]

8.00/15 (225/75) is standard for '53 coupe. Now, Fleetwood and limo, etc. may be a different story.

8.00-15 with black walls, 8.20-15 with white walls on all Series 62 and 60.
8.20-15 on Series 75 (factory limos).
8.90-15 on Series 86 (special limos, hearses, etc.)

if the original 8.20x15 equates to 235/75 R15 technically that size should clear the rear wheel shields so why did you opt for the 225/75 R15 which are both shorter and narrower - do you think that the 235's would have fouled ?
/.../ on both my cars the L78's rub the front righthand inner wheel arch when on full lock. If the L78 equates to 235 I'd prefer to go for 225's, even if the overall height is lower.

As Roger wrote, "equivalent" means "equal diameter/height", so that speedometer and odometer reading is accurate. Radials are wider for a given diameter - 235mm is 9.25", much more than 8.20".

My '52, identical in dimensions to all 50-53s, has 235/75 R 15 radials (Cooper Lifeliners). Removing or installing a rear wheel is a pain. Even with frame fully lifted and rear axle hanging on spring leaves, it takes a lot of ingenuity - and sweat and swearwords - to get it (in or out) between brake drum and rear fender - fender skirt removed, of course. Front tires rub when cornering, too.
I will definitely switch to 225s or to "bias-ply-looking" radials upon next tire change.

I brought these radials to 100+ mph (170 kph) on straight highway with no noticeable wandering. Don't think of emergency braking, though.

[rustytractor]

8.00-15 with black walls, 8.20-15 with white walls on all Series 62 and 60.
8.20-15 on Series 75 (factory limos).
8.90-15 on Series 86 (special limos, hearses, etc.)
As Roger wrote, "equivalent" means "equal diameter/height", so that speedometer and odometer reading is accurate. Radials are wider for a given diameter - 235mm is 9.25", much more than 8.20".

My '52, identical in dimensions to all 50-53s, has 235/75 R 15 radials (Cooper Lifeliners). Removing or installing a rear wheel is a pain. Even with frame fully lifted and rear axle hanging on spring leaves, it takes a lot of ingenuity - and sweat and swearwords - to get it (in or out) between brake drum and rear fender - fender skirt removed, of course. Front tires rub when cornering, too.
I will definitely switch to 225s or to "bias-ply-looking" radials upon next tire change.

I brought these radials to 100+ mph (170 kph) on straight highway with no noticeable wandering. Don't think of emergency braking, though.

Thanks Phillipe, that's really helpful

You mention series 86 - I have both a 1960 Eureka hearse and a 1962 Miller meteor hearse - any idea what size these would have originally taken or would take now in bias belted lookalikes or radial ?

[Philippe M. Ruel]

You mention series 86 - I have both a 1960 Eureka hearse and a 1962 Miller meteor hearse - any idea what size these would have originally taken or would take now in bias belted lookalikes or radial ?

I found this information in the factory 1952-53 shop manual.
The "Standard Catalog of Cadillacs" mentions that most Cadillacs up to the mid-60s use 8.00-15 (standard Series) or 8.20-15 (Series 75) tires. Nothing about commercial chassis, but you may guess they used larger tires, like 8.90-15 or 9.00-15.

A "radial equivalent" of 8.90-15 would be 255/75R15. Same height, much wider, you should check before purchasing a complete set.

A narrower but lower dimension would make the engine rev higher at a given speed. It may be a critical drawback on a commercial chassis, that has a "short" rear axle ratio, compared to standard cars. Partly to compensate for higher tires, partly because hearses essentially ride dead slow (no pun intended).

[kav]

Rusty , I run 235/75/15 , mastercraft cased , diamondback whitewall radials . They don't scrub anywhere .
I notice you are in the UK. If so have you had the castor angle of the front end readjusted to suit the camber of the roads that we in AUS and the UK drive on ?
I have just had my steering box rebuilt and it hasn't made that much difference . What I did notice today while testing was that when I drove on the freeway in the lane that was cambered the wrong way , as it would be in the US , the car was much more pleasant to steer and seemed to track very nicely . In the left lane that we usually drive in , the car always wants to pull or wander to the left and needs constant correction . It's not as prominent on smaller roads as they don't usually have as much camber and you are travelling slower .
My car is having this corrected tomorrow, I can't wait to see if it fixes the problem .
Well  , castor correction may not be the correct terminology , anyone feel free to correct me . But I hope you get what I mean .

[rustytractor]

Rusty , I run 235/75/15 , mastercraft cased , diamondback whitewall radials . They don't scrub anywhere .
I notice you are in the UK. If so have you had the castor angle of the front end readjusted to suit the camber of the roads that we in AUS and the UK drive on ?
I have just had my steering box rebuilt and it hasn't made that much difference . What I did notice today while testing was that when I drove on the freeway in the lane that was cambered the wrong way , as it would be in the US , the car was much more pleasant to steer and seemed to track very nicely . In the left lane that we usually drive in , the car always wants to pull or wander to the left and needs constant correction . It's not as prominent on smaller roads as they don't usually have as much camber and you are travelling slower .
My car is having this corrected tomorrow, I can't wait to see if it fixes the problem .
Well  , castor correction may not be the correct terminology , anyone feel free to correct me . But I hope you get what I mean .

I completely understand where you're coming from with this. I've owned the convertible for over 25 years so this has been done a couple of times in that period but not for a few years now. Tyre wear and ruts in the road can change this so I get your drift here. It'll be interesting to hear what improvements you find when done so please keep us posted.

[kav]

Well my car has been corrected for driving on the left side of the road , and all I can say is WOW ! This is how this car is supposed to drive . It's gone from a two fisted , white knuckle drive , to a one hand , bottom of the wheel cruiser . Bloody amazing . This car was one week away from me attending its first car show with a for sale sign on it .
I have replaced the shocks , sway bar links and bushes , gone to radial tyres , reconditioned the power steering box , but this has made the biggest difference . I took it to a local guy who is a specialist suspension tuner . He does high end stuff . Yesterday he was retuning an AMG c63 black edition . He couldn't use his regular alignment gear on my car because of the guard overhangs and he didn't want to damage my white walls, so he had to go old school and measure everything . He adjusted the toe in ,the camber and castor .
If you take yours somewhere for a wheel alignment and they pretend to put their regular laser equipment on it and tell you it's done 15 minutes later , tell them to go away . I've had mine done twice now by people that I trust and both times they couldn't do it with modern equipment .
The only thing left to do now is to rebuild the drag link , there is a slight notch in it , but it can wait , I can't wait to drive it again . Next weekend I have about a 600 km round trip to a car show , and now I'm looking forward to it . Whoo  hoo .

[rustytractor]

Well my car has been corrected for driving on the left side of the road , and all I can say is WOW ! This is how this car is supposed to drive . It's gone from a two fisted , white knuckle drive , to a one hand , bottom of the wheel cruiser . Bloody amazing . This car was one week away from me attending its first car show with a for sale sign on it .
I have replaced the shocks , sway bar links and bushes , gone to radial tyres , reconditioned the power steering box , but this has made the biggest difference . I took it to a local guy who is a specialist suspension tuner . He does high end stuff . Yesterday he was retuning an AMG c63 black edition . He couldn't use his regular alignment gear on my car because of the guard overhangs and he didn't want to damage my white walls, so he had to go old school and measure everything . He adjusted the toe in ,the camber and castor .
If you take yours somewhere for a wheel alignment and they pretend to put their regular laser equipment on it and tell you it's done 15 minutes later , tell them to go away . I've had mine done twice now by people that I trust and both times they couldn't do it with modern equipment .
The only thing left to do now is to rebuild the drag link , there is a slight notch in it , but it can wait , I can't wait to drive it again . Next weekend I have about a 600 km round trip to a car show , and now I'm looking forward to it . Whoo  hoo .

That's good news - Sounds like that would be the best things for me to try and if it gave me the same improvement I'd be over the moon as well   

Do you have the settings that were applied to the car ? With modern cars there'd usually be a computer print out but if your people used "old school" techniques maybe this isn't available.

[kav]

I'll ask him if I can borrow the markers , he will have them , as he told me what he had done and exactly where he had set everything . He  also asked me to report back as to how it was . I did , nothing but praise . Can't wait to drive it again tomorrow .

[rustytractor]

I'll ask him if I can borrow the markers , he will have them , as he told me what he had done and exactly where he had set everything . He  also asked me to report back as to how it was . I did , nothing but praise . Can't wait to drive it again tomorrow .

Thanks Kav, seeing as you've had such positive results with your car that would really help. Both of these cars drive, if i can get rid of the wandering it would be fantastic.

I can't recall what model your '53 was - coupe/sedan etc.

You may have said it somewhere in the thread but I'm so tired I really can't be bothered to check (sorry) - I'm not normally this lazy but I've been doing Jury service in court for the past two weeks and I'm absolutely exhaused by it. Totally draining.

[Jon S]

My 1958 came with 8.20 x 15's. I have the 235 75 15's and can tell you they are a lower profile and a bit wider. The 820's fit in the spare tire cutout in the trunk and rolled out easily; the 235's fit extremely tight, so they are wider.

[dplotkin]

There is a new tire style which combines the radial behavior with the look of a bias tire. This may be a solution.

Yes, these are by Coker & I have a set on my 56 Fleetwood. They ride beautifully but want to "fall" off the crown of the road with abandon. Certain roads with little crown the car tracks straight, others require inordinate steering input to keep things straight. She didn't behave this way with her previous standard wide white radials, and I did an alignment before the new ones went on. But boy they ride smooth, especially if you run them at say 29 pounds and look good too. This photo doesn't really do them justice, but aside from crown sensitivity & cost, these look great.

Dan

[chstitans42]

Coker Tire makes a set of radial tires that look like bias -ply tires. Modern guts with classic looks on the outside. Maybe this is the solution to your issue? I haven't heard much about them, but it for sure sounds really awesome.

[Raymond919]

These bias-ply look-alikes are also made by Diamondback Tires where I got mine. Basically same price. You tell them the WW configuration you want and they'll do them like a custom order. Quick delivery also. During certain months, they have special deals. Ask them, they like to chat on the phone.
Ray Schuman

[dplotkin]

Coker Tire makes a set of radial tires that look like bias -ply tires. Modern guts with classic looks on the outside. Maybe this is the solution to your issue? I haven't heard much about them, but it for sure sounds really awesome.

If you had read the post above yours that I made on October 31 you would have heard about them.

Dan

[rustytractor]

After doing some tests with a spare set of wheels and some old (but good) 235/75-15 radials I decided to buy a set of American Classic radials. They're stamped both "8.20x15" and "radial" and look exactly like an original whitewall tyre and are the correct right height. 

Only one word springs to mind and that's "WOW!"

I anticipated an improvement but not the driving transformation these tyres have provided. No wandering, no following the camber or sudden unexpected deviations, just perfectly neutral driving in a straight line on any road surface. Unbelievable!

Prior to fitting these, the convertible was bad but driving the coupe was a nightmare (imagine driving on ice which was covered with ball bearings and you'll get the idea) but now it's a joy. I took the coupe to a show last weekend and enjoyed every second of the journey both there and back. In fact it was the first time I've ever enjoyed driving the car. I've now bought a set for the convertible.

These weren't cheap (around £1000 / $1400) but boy are they worth it as they look right and drive right but have a question about pressure.

I'm currently running them at 32psi and the sidewall still bulges at the bottom making them appear a bit under inflated. I used to run the L78's at 28-30psi and they looked fine - opinions on correct pressure welcome.

[Tye_Cowan]

So glad to hear your issue is resolved.  When I upgrade my Series 75, I'll consider your tire selection.  I'm currently running on 235/75R15s and am happy with the ride and control.  She does rub the left fender well in hard left turns, especially when entering a driveway.

Just to talk some technicals, tires of the day had a 90% sidewall factor, so the old 8.00 - 15 would equate to a 203/90R15, and the 8.20 - 15 = 208/90R15.  The narrower tread could explain the fender well rub, but I doubt such a tire is made today.

Ref: http://www.automobile-catalog.com/tire/1953/325805/cadillac_series_sixty-two_club_coupe_hydra-matic.html

[rustytractor]

After doing some tests with a spare set of wheels and some old (but good) 235/75-15 radials I decided to buy a set of American Classic radials. They're stamped both "8.20x15" and "radial" and look exactly like an original whitewall tyre and are the correct right height. 

Only one word springs to mind and that's "WOW!"

I anticipated an improvement but not the driving transformation these tyres have provided. No wandering, no following the camber or sudden unexpected deviations, just perfectly neutral driving in a straight line on any road surface. Unbelievable!

Prior to fitting these, the convertible was bad but driving the coupe was a nightmare (imagine driving on ice which was covered with ball bearings and you'll get the idea) but now it's a joy. I took the coupe to a show last weekend and enjoyed every second of the journey both there and back. In fact it was the first time I've ever enjoyed driving the car. I've now bought a set for the convertible.

These weren't cheap (around £1000 / $1400) but boy are they worth it as they look right and drive right but have a question about pressure.

I'm currently running them at 32psi and the sidewall still bulges at the bottom making them appear a bit under inflated. I used to run the L78's at 28-30psi and they looked fine - opinions on correct pressure welcome.

Thanks Tye, the difference is nothing more than staggering.

In my opinion these are the perfect alternative to using modern radials as they look right and match the original 8.20 X 15. I had a question about what pressure to run then at as the sidewall seemed a bit "bulgey". I spoke to the supplier who recommended 36psi as a start point but said anything between 36 and 42 would be OK depending on the weight of the car. Currently I'm running them at 42 and they seem fine.