1950 Buick Special 41D Daily Driver: TIRES

[Sonomatic]

Hello out there!  I'm hoping for a response from aka First born, mainly because he is already doing what I want to do with the same car that I have, a '50 Buick Special 41D.  I'm looking into new tires for my Special and I'm looking to address 3 issues:

 

1. I presently have H78 X 15's on the car of unknown vintage.  Good tread, look okay, feel hard as a brick.

 

2. Speedometer presently read high with present tires on.  In the picture, you can see the H78 leaning on the spare, a 7.60 X 15 behind it. At 60 mph indicated, GPS says I'm doing 51 mph.  I know the older cars had optimistic speedometers, but that's a bit much.  

 

3. I intend to tag and insure this car as a normal car and drive it around on dry days.  Right now, driving the car is "exciting", follows road imperfections.  Steering gear is in excellent condition.  I learned to drive in a '65 LeSabre with bias ply tires, had a 66 Mustang, 69 and 68 Torino, 71 Mach 1, and I don't recall the tires follow road imperfections this much.

 

I'd like to have tires as tall as the 7.60 X 15 for speed and rpm purposes.  From what I can tell, P235/75R15 is the size I would have to use to get that height.  I wonder if section width would cause rubbing, and, the steering gear on my Buick doesn't appear as robust as modern day cars, and then there is low speed steering effort.

 

I'd like to put wide whites on, cheapest bias ply from Coker is right at a $1000 and will probably go up Jan 2023.

 

All of this blathering is so that I can set the backround for my question to aka First Born.  I researched previous posts and saw that you were using off the rack tires.  I'd like to ask what size you are using and what are the pros and cons of your decistion?

 

For everyone else, I know this is a hot topic, the research I did gave excellent arguments for both sides  The bias camp, looks correct, drives as originally designed, radial camp, drives and rides better, wears better, less expensive.  Please feel free to add any opinions, I'm information gathering.

 

Thanks

[46 woodie]

To begin with, I would try to find a date code on those original tires. If they are "hard as a rock" as you describe you might want to avoid driving over 60 mph. As to purchasing Coker tires for you car, you might want to do some research on Coker quality on this and other site's. There are major brands that can provide wide white tires for your car. I have B. F. Goodrich, radial, wide white's on my 1946 Ford Station Wagon and highly recommend them over Coker's.

[Bloo]

@Ben Bruce aka First Born

 

[60FlatTop]

Third set of Cokers installed last Spring. First set of four went from 2002-2012. Second set 2012-2022. Up until this year I averaged 1500 miles per year. This year only 500 miles due to my wife's health.

 

My cost has been about $25 per wheel per year. My speed buzzer is set at 86 and I have no problem taking a 5 hour run up the NYS Thruway to Albany.

[61polara]

The steering effort and ride will be much better with correct size 7.60-15 bias ply tires.  This should correct your major speedometer error as well.

[Ben Bruce aka First Born]

Sonomatic,  I will TRY to help.

 I do use off the rack radials.   Yes, 235/75R are close to original height.  And I am so sorry I do not remember how close the speedometer was originally.  Early on I changed to 3.36 to 1 differential gears. Speedometer was WAY slow.  Like 20mph slow.     I went to an aftermarket GPS speedometer. 

 

  On tight turns, wheel locked left or right, steer tires rubbed slightly.   One problem is in installing an aired up tire on driver side rear.   No matter how the car is jacked up the panhard bar pulls the rear-end towards the driver side slightly.  The tire resists going between the fender and brake drum.  I went to a 225/75 and still no joy.  I have never needed to change it beside the road, but would probably not accomplish much.

 

  I am now running 225/75 all around.  With the higher gears I can get away with that.  Your experience might vary.  At just short of 20,000 miles on the 235's , I replaced them due to [10 year ]age. They probably had 70-80 percent tread.    I replaced with a  Chinese brand Shurtrac, BECAUSE OF THE WW.  About 1 5/8th inch. Widest I found at a reasonable price. Under $400 out the door.

 

  FWIW, the WW in 1950 were 3 in or less,  not the WWW many now use.  I know since I mounted scads of them in the '50s'.

 

  Hope this helps.

 

Message me if you want.

 

  Ben

[avgwarhawk]

Sonomatic, I looked at those tires when I took the picture of the Buick.  They appear to be from the 60's or 70's.  Very very old, hard and will track the road like crazy.  A set of Cokers I run on my 60 to not track much at all.  I have Universals on my 54 that track a bit but are much better than a set of old hard Densin or some odd ball bias ply on it when I purchased the Buick. 

 

    

[Sonomatic]

Thanks 46 woodie. I think the letter series tire have been gone since the 80’s, certainly by the 90’s, so at least 30 years old. They preceded the date code requirement. 

60 Flat Top, 3 time return customer for Coker says a lot for them!

61 Polara, I agree that the bias original would do the most for my speedometer error. Also heard of quality issues with Coker in the recent past, my source seemed to think that was corrected. 
Ben, exactly the information I was hoping for from you. Didn’t consider the left rear clearance problem, but did notice things are already tight back there when I was removing/installing for brakes. 235s would give me the diameter I need. Coker states minimum of 6” rim, do you know what is on our Specials?  I thought I saw 5 1/2 somewhere but can’t find it now. I’m guessing the radials ride and drive acceptable. Wondering about low speed steering effort. By the way, just finished reading about the 263 swap. Really enjoyed it. Was really hoping to see that FI intake. Hoping you did a thread for that. I tried to message you for this info and the forum says I need more posts before I can do messages. Thanks all for your help

[Sonomatic]

Hey avgwarhawk!  Thanks again for hooking me up with this car.  I'm about 1/2 way to being ready to go through inspection and tag this old gal so I can drive around.  Wiper motor is up at Fenick's, front shoes enroute from Kanter.  Gotta patch the muffler and we're on our way.  I guess you saw all this.  You know how it is here in Delaware, lots of flat, secondary roads to cruise around on, maybe RT 1 once in a while, but, I fear that with those 3.91 gears, not sure how it will do out there.  Ben Bruce has those optional 3.61's that you could get in  the Supers with the Dynaflow.  I'm sure that his Special has no problems with high speed traffic.  In regard to the tires, you hit the nail on the head.  Hard as a rock and follows everything.  I hate to spend the money, put for my Special, it will be most driveable, drivetrain wise, with the bias ply originals, but, I really hate to spend the money.  If I had Ben Bruce's set up, no brainer, I'd be going with off the rack radials, at least for a while.  Thanks for your input and thanks for hooking me up.  This car has brought nothing but joy.

 

Herb

[Bloo]

Off the rack tires often don't fit well on these old cars because of the aspect ratio. The tallest aspect ratio you can get in many cases is 75%, and old pre-1965 tires were either 100% or 90%. I believe that changed in 1948, but cant find documentation of it. 1965 was another major change. In all cases, if the exact size existed before the change, it remained the same as it was after the change. was 7.60 your original size?

 

No matter what you do, an off the rack 75 series tire will either be too wide or too short. That's just the way it is. It boils down to "what can you live with?". One problem is gearing. 40 series Buicks in of the 1930s are geared slow enough that people in 2022 generally don't like it, and shorter tires will make it worse. I doubt that is as big of a deal by 1950, and if it is, you could always change rear axle gears like @Ben Bruce aka First Born did. There are taller gears in other Buicks that will fit in a 1950.

 

Regarding the speedometer, if I am not mistaken Buick used interchangeable speedometer pinions in some cases after about 1941, and some critical reading of a Buick parts manual might find you a speedometer pinion that would work without tearing the transmission apart to change the worm. I think there is a good chance of that. It is also possible to buy a little gearbox from a speedometer shop to fix the speedometer error. It screws on at the transmission end of the cable. They cost about $100 as I recall. Just do any rearend gearing changes you might need and find some tire size you are happy with first.

 

 

[Ben Bruce aka First Born]

Sonomatic,  my gears are 3.36, from a 1955 with auto.  They will change out from 1940 through 1955.  I had them in while the 248 was still in there.

 Steering is TOUGH at complete stop. No problem as soon as rolling.

 

  I just cannot make myself pay $1000+ for a set of tires .  That is semi-truck trailer area.

 

  Ben

Edited December 13, 2022 by Ben Bruce aka First Born (see edit history)

[Bloo]

Coker isn't the only game in town for some taller tires. Almost, but not quite. There is also Diamondback  https://dbtires.com/ who have "Diamondback Auburn Deluxe" bias-look tires of their own manufacture in some of the old tall sizes. They also have modern tires with whitewalls added. All Diamondbacks are radials. Auburn Deluxe prices are comparable to Coker bias-look radials. No great opportunity to save money, but nice tires nonetheless.

 

Edited December 13, 2022 by Bloo (see edit history)

[Sonomatic]

Holy cow Ben Bruce!  3.36?  That's a monsterous change.  How did your 248 perform with those?  Or was the the whole idea behind going with the 263?  

[Ben Bruce aka First Born]

LOL

  The 248 did well!  A little more 2nd gear in town but no problem on the open road.  Dropped 3rd gear RPM by about 650 as I recall.  Car is a standard transmission and had a 4.1 gear.

 

  The warmed up 263 was a young mans dream come back to haunt an old man.  Not a bit sorry for following the dream. 

 

  Ben

[Sonomatic]

Bloo, I read you post thoroghly this morning and see that you have made a lot of good points.  What you said about off the rack, too wide or too short is exactly what I have found to be the case.  Ben Bruce has already found the best compromise in the P225/75R15.  His switch to the later 3.36 gears are also another improvement for highway use. I've heard of those speedometer calibration boxes and that would certainly take care of the speedometer.  Two things are haunting me about this car.  1st, it is such a fantastic start for a full restoration, bodywise and mechanically.  It still has the original exhaust hangers, just hasn't been altered in any way that I have found, and I hesitate to mess with it.  2nd, while researching the tire situation, in the one thread I came across on this site, someone made a comment about people buying old cars for the old car experience and then trying to alter those characteristics.  That was a major reset for me.  That was my goal a few months ago, to get my hands on a straight 8 Buick and see what they were like.  So, at this point, I'm thinking, get the bias ply 7.60 X 15s that were originally on it, keep it like it was built, and continue that journey to see what it's like. All the stuff I read about the Dynaflow has turned out not to be the case.  I say that without having been in any sort of stop and go traffic yet, but, so far, it doesn't feel lethargic, probably because of the 3.91 gears.  On the otherhand, Ben Bruce's Special is one of the coolest cars I've run across on here.  Certainly not a trailer queen.  And it continues......

[Ben Bruce aka First Born]

 While I agree with the "old car" experience to some degree, I don't all the way.   When they came out , radial tires were installed as soon as tires were needed.  By me anyway. And I don't believe I am unique.  I have never considered myself poor, but I never had enough to throw away. So the difference between my $400 worth of off the rack radials  and the $1000 or so for "correct" bias sure does buy a LOT of gas.  Others may, and do, crave different experiences. Good.  We are not clones, Thank God.

 

 Enjoy the Buick.  If we were closer , we could share.   

 Pay attention to Bloo!  He "ain't always right"  but is never wrong.🙂

 

  Ben