Technical Ok, This is a Weird Question...

Not aware of any speedometer that reads from "A" tire, or even from the rear end itself, most are driven from the tailshaft of the trans. So we know the differential can deal with two tires of different size, there is still only one driveshaft turning at x speed.

So as Jim said in first post

so 2 tires turning at different speeds and one driveline turning creates the speedo reading.

As is, 1 tall and 1 short tire, speedo reads lets pretend 30 mph
2 short tires and speedo reads 35 mph
2 tall tires and speedo reads 25 mph
As it is, it's simply broken, and needs repaired with 2 tires of the same size. Then op can figure out what height tires he needs to get correct speedo reading.
Maybe he can borrow some from another car, before they spend hundreds of dollars on new tires?

 

If you have a late 60s Olds, or an old VW, it will read whatever the front tire size is that's on the side the cable connects to.

With any car that gets it's speedometer drive from the driveshaft or transmission, and has a gear type differential, it will read the average speed of both drive tires. Maybe I'm missing something that makes things slip, but it's been my experience that splines and gears are pretty good about always staying fully engaged, unless they're really wore out. Then you won't be moving very fast, anyways.

 

I'm sure the engineer who analyzed a bumblebee and concluded it can't fly could answer that for you.

Did I ever tell you about my cousin who had a cattle ranch on a mountain? He developed a breed of cattle with legs shorter on one side than the other. At night, when the cows came home, if any of them missed the barn door, they had to go all the way around the mountain because if they tried to turn around and go back they would tip over.

 

@Johnny Gee

A person with unequal length legs walks a straight line by taking different length strides...the distance the foot is moved forward with each leg thrust.

Same principle for a person with equal length legs walking in a radius...longer and shorter step distance (stride) side to side.

 

Put a car with an open diff on a hoist or quality jack stands.
Start it, put it in gear, let it idle.
Watch the speedo reading.
Now stop one of the tires. The opposite tire will speed up.
Look at the speedo reading.
It will be the same, but one tire is stopped, and the other is spinning at 2x speed in rpm. Yet the speedo has not changed....

 

Good they are called spider gears and not crab gears. Otherwise things would get totally side way's.

 

I think all the hot rodded ones are yellow. There is a yellow coupe around my parts (Iowa) that’s been around for 30+ years.
As for the dif. Put the correct tires on it and you don’t have to worry about it. I get it’s a temp fix. But man 4 pages of theory for a temp repair. lol


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I bet that was a great feeling to get a chance to take it for a spin again.
Vic

 

All I know about differentials is that when you do a smokey burnout with a one wheel wonder, and the speedo reads 100+ mph, the spider gears in the rear end don't last very long. It tends to really make a mess out of stuff inside of the cover (and sometimes even the cover itself). I also know that if you have a posi, and one of the wheels is in a puddle of oil, it makes really smokey burnouts with both wheels, at least for a few times, before only the wheel in the oil smokes, and the posi no longer works. Not that I've ever done either of those things, my BIL broke a lot of rear ends (he's not on here). I have no idea what that has to do with a speedometer reading....

As for the Hudson, that is a really bright yellow. Gene

 

People with superpowers do exist with the ability to penetrate solid bone. (as in my case. )
So my theory of the 'tall' tire dictating the speedo readout is now off the table. I can see how the answer to the original question when using mismatched tires should probably be, "Neither tire. It's some other blended, in between number that makes the speedo not quite accurate to the actual road speed".

 

^^^^^ Principle that supposes most future events are likely to balance any past deviation from a presumed average.

 

Averagin' along fer sure! The spiders come into play around each turn/curve as the outer axle turns more, and inside axle less.
So the Hudson as equipped in tire dia. helps to clear (along w/Sq's insight) this up.

 

I know a guy who actually has one leg shorter than the other. he has boots made with a big clunky sole on one and regular on the other. he got hit by a car a few years back, broke his short leg and it ended up even shorter than before.

 

I have one leg shorter than the other but no one has ever called me Nemo. I does give me back problems though. Weird right?

 

There is no such thing as a weird question, just weird answers.

 

I used to date a girl with one leg shorter than the other. Her parents originally named her Cynthia, but when they discovered the leg mismatch they changed her name to Eileen.

 

Weird answers?
On the HAMB?
Who woulda thought?
Just for the record, there have been some pretty weird questions over the years as well.

 

Eileen Dover? Did she have a brother named Ben?

 

No, actually her full name was Eileen Bakken Whakett.

 

Then there is Eileen, the one legged waitress that works at iHop......

 

Did you get 1st and reverse working yet???

 

Well, that's the long and short of it.

 

Thank you all for the kind words and of course some deep thoughts & humor! Not yet on 1st & reverse but hopefully soon I’ll get a look at it.

Today was an adventure of sorts as I went to get new rubber on the rims for my coupe. A few minutes after I sat down in the lobby I was informed there was a dent in one of my rims. Curious & in doubt I went back to check it out. This is what I was presented with....



I knew it didn’t come in that way as I’d just wiped down both sides of all the rims prior to coming in but was told the rim hadn’t been moved off the ground. One of the 4 rims was without a tire due to the other rear tire going bad which lead to my question on this thread. Getting no where with how it occurred eventually I had them try to fix it. About half way through the repair, I noticed the rim we were trying to fix was NOT the rim I brought in without the tire on it but was actually the one that had a tire on it. I knew this because that rear rim had some pits & chrome discolored which I spent a ton of time trying to fix a few months before. As I was bringing this up to the manager who was working on straightening the rim, the guy who bent the rim came up & proceeded to deny what I was saying & deny that I knew which rim had a tire on it. I about came to blows with the JACKASS because I knew he was the one who had damaged it & tried to cover it up!

Pits in picture on rim:


Now I have around 2,000 pictures of everything I’ve done on the coupe over the last 3 years but naturally I couldn’t find a picture of rust repair I did to that rim with the tire on it to show the manager. Then I remembered I’d taken a few pictures of the coupe from the side with the good rim & actually could enlarge it enough to see the valve stem, wheel weight & no damage to the rim. The manager then determined where the wheel weight was attached to the damaged rim & on the tire side of the lip he could feel exactly where the wheel weight was placed. Now I had proof positive that the damaged rim was the rim which came into the tire store with a tire on it and the tire tech not only lied about damaging it but tried to cover it up as well. The manager was now more than willing to pay for a replacement rim!



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Wow.

 

So if Eileen had corrective surgery, she would be Noelene?

 

Wow, that picture saved you a few bucks and maybe a trip to the hoosegow!

 

Great job! It makes me really proud when liers get caught. How many wheels has this "tech" screwed up before being caught.

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