Studebaker Tire Sizes

[Cajun Kid]

To all Studebaker owners,

What tire sizes are you using front and rear ?

What rim as well ?

Thanks

Charles

[GH]

Charles, I run the camaro space saver wheels with the rim welded to the center. The tires are the Good Year land speed tires 26" size  on the rear and 25" size on the front. When I ran the car on the salt the first year I ran 28" size on the rear and could not pull that large a tire with the gear I was using. My new front tires I bought last spring cost $455 each.

[Bob Drury]

Charles, you need to start with the speed you want to reach.  If you are after the record then add at least 2% to that speed, and factor in the rear end ratio you are going to run, the tire size, and the rpm you think the motor will pull.  You have three choices, 26, 28, and the M/T 30 inch tire.  I have run both the 28 and 30 inch tires in stock Stude wheel wells with no problem.  By the way, the Ford 9" 2.47 is about the highest ratio you will find, unless you add a quick change rear end, which will take up to a 2.19 with the 4.10 ring gear, but you would need about 1500 h.p. minimum to pull it............Bob

[wolcottjl]

Here is my question.   With all things being equal, ignoring any aerodynamics.  I hope this makes sense.  Is it better to run a taller tire with a lower gear ratio or a shorter tire with a steeper gear?  Or is a wash? 

[Cajun Kid]

wolcottjl,

I would thiink the final ratio would be the factor. 

[Cajun Kid]

With 28" tires Sumner's program shows if I go to a 3.08 rear gear at current redline speed would be 230mph on a 212.xxx record... That assumes the motor will pull that rpm in high gear. at 500 Roms below redline the speed drops to 219 mph

Currently the motor is in my 33 Vicky with 28" tires and had a 325 rear gear using a 350 turbo auto trans.

I am going to put this motor in the 53 Stud using a 4 speed and 28" tires with a 3.08 gear

I know there are a lot more variables than just RPM, Tire Height and Rear Gear..but I have to start somewhere.

Just needed to make sure the Stude when lowered can fit 28's in the rear wheel wells.

Thanks for the input.

Charles

[Stainless1]

Make your max power power rpm that 2% above the record and that is probably the right tire size

[1212FBGS]

wolcott
the answer to your question is the taller tire! the taller tire has a bigger contact patch than the smaller tire = more traction! 
kent

[wolcottjl]

OK I get the tire patch advantage.  Since I was not the smartest kid in class.  What if traction is not the issue.  Which scenario requires more horsepower to achieve a speed?  Or are both the same?  I can see the torque increase with a stronger gear but you have to spin more weight with the larger tire. 
Joel

[Seldom Seen Slim]

I've got this nagging thought about the size of the contact patch - maybe someone will tell me if it's right or wrong.

That is, the contact patch -- the number of square inches of tire that's contacting the ground -- would be a function of tire pressure and the weight that's on those square inches.  As an example:  40 psi and 1000 pounds would need 25 square inches of contact patch.  A five inch wide tire would need to have five inches on the surface -- a ten inch wide tire would need 2 1/2 inches.  The weight/pressure would dictate the amount of rubber in contact with the ground, not the width of the tire.  Want more contact patch?  Run lower tire pressures, not different tire sizes.

Okay -- that's the math.  If it's not the way it really works -- why not?

[Stainless1]

Hey SSS, don't let air out of your Bike tire to get more traction, it will cause handling problems... 
Same with your race car unless your suspension is set up for soft tires.

[Seldom Seen Slim]

Yeah, Stainless -- I learned that one a while back.  Still -- got an answer to the quandary I've posed? 

[Stainless1]

Yeah, Stainless -- I learned that one a while back.  Still -- got an answer to the quandary I've posed? 

Thought I did....  but I'm sure some of the smart guys out there can communicate the traction math better than don't let the air out of the tires to get more contact patch... 

[GH]

Charles, I could fit 28" tires in the rear wheel wells before I narrowed the rear end housing, now I can't, they hit the frame rails. The 28" tires cross section is wider than the 26" tire. I also run the 9" ford 2.47 gear with a Jeraco 4 speed and GV overdrive for a final drive ratio of approx 1.93 to 1.

[jimmy six]

Many years ago and old time (who will remain nameless) LSR competitor told me the phrase " it's easier to pull a gear than it is a tire".

I stayed with that until I ran out of gear availability and went all the way to a 32" tire. One of the fastest, I believe fastest, Studebakers ran near 300 with 32" Firestone Indys of the 50's.. Good Luck