Can I put radial tires on 59 rims?

[R Jones]

I have bias ply tires on my 59 series 62.  Can I put radial tires on 59 rims or will that cause stress on the rims that could result in failure?
Thanks

[Bruce Reynolds # 18992]

Gday R,

Yes, putting Radial Tyres on your 59 will make that much of a difference, you will wish you had done it years ago.

But, there are a couple of things that you will need to do.

Firstly, have a wheel alignment done to bring the Toe-in to  minus 1/16",

And Secondly, increase the tyre pressures to 30 psi, or if on highway speeds for a long distance, go up to 34 psi.

And, lastly, dont forget to change the spare tyre to a radial as well.

The only difference between the old rims and the new ones it the inner safety bead to stop the tyre coming away from the outer edge in the event of a puncture.

And, as a last thing, go with the Tubeless type, as it isnt necessary to put in a tube, unless you have punctured one of the tyres.

The tyres on my car have been put through hell and high water, well, not much of the high water, but hard cornering, high speed, and the only whimper has been the squeeling, just before the loss of traction which under normal driving, will never happen.

Bruce,
The Tassie Devil(le),
60 CDV, with Radial Tyres.

[David #19063]

Hi Bruce,

Can you explain to me why Toe-in to minus 1/16" is necessary.

I have neard this before, but never got a good answer.

Thanks,

David

[Bruce Reynolds # 18992]

David,

I must have been asleep at the time - yes, it was around midnight, and I should have been in bed.

The toe-in specification should have been 1/16" and not the other erroneous figure I mentioned.

You see, I had a dash before the 1/16", and when I re-read the message before posting it, the dash was on the end of the line, and the 1/16" was on the next line, so I said to myself, "that looks wrong" so I fixed it or so I thought.   Yes, silly me.

Bruce,
The appologetic Tassie Devil(le),
60 CDV

[Dave]

Im not sure about your 1959 but i had radials on my 1950 coupe on 1950 rims.They were on it when i brougth it but i had to let the air out of them to get the back tires off, they were to big to fit between the fender and the hub.Something you might want to check on.

[Frank Wurpel]

Hi guys,

Good to finally see true car topics on this site rather than having to waid through loads of uninteresting whos got the most cars kind of stuff.

Anyway, some of you may know that I have been restoring my 1965 Cadillac DeVille convertible for the last three years, and am now in the home stretch, which includes wheel alignment.
I have asked this Forum several times what the implications would be if you are to change cross ply tyres to radial tyres. It seems to me that apart from the required Toe-in adjustment to 1/16 (thanks Bruce), there is little more to be done.

Wrong!

I have been searching the internet for months on this topic (I always want to be fully prepared and informed when I start a new job) and found out that actually Toe-in, and Camber are not that important. Now before everyone starts writing e-mails let me explain my point:

1. Camber should be equal left and right, (although some compensation may be made to counter the effect of the road surface not being perfectly horizontal for water drainage.
The Camber angle will generally only be around 1°.

2. Toe-in compensates in principle for front suspension rubber bushing deformation as the rear wheels are pushing the car forward, and the front wheels initially want to stay were they are. Imagine what would happen if you were to start driving off with both front wheels locked. (they would try to go outward) The amount of Toe-in therefore is depending on your bushings, and will be very small. As Bruce mentioned, a 1/16 Toe-in will be a good figure to start of with, but I would personally keep an eye on front tyre wear to see if you need to adjust.
Too much or too little Toe-in will show on your tyre thread as a very recogniseble patern.

Right, back to the start of this message:
I discovered that Caster is the important wheel alignment variable nobody talks about:
Apparently, in the old days when cars drove around on Cross Ply tyres the specification was for negative Caster since Cross ply tyres had the tendency to deform under speed, resulting in a possitive Caster.
Therefore: when you put Radial tyres on a car that was originally equipped with Cross Ply tyres, you should re-adjust your Caster from negative to possitive. Again, the angle does not really matter as long as both sides are equal, and the angle is not too great (1° to 2° should be OK)

For more reading on this topic, refer to :
http://www.familycar.com/alignment
 

Hope this sheds some light on a difficult topic.

By the way, I am trying to engineer a device (using lasers) which I will be able to use to do the complete wheel alignment myself. Has anybody out there done a wheel alignment before (especially Caster). I am interested to see how you guys have done this. (no point re-inventing the wheel (LOL)

Thanks,

Cheers,

Frank Wurpel
Lumphanan, Scotland (UK)