Motor cycle tires... whos ran them?

From what I could find out ant typical 450/18 motorcycle tires are rated at 740 LB @ 32 PSI load capacity. That's 1480 LB for the pair. A typical 60/40 weight ratio in an Model A with a SBC puts about 1450/1500 LB on the front end. So might be doable but barely and with no margin for error. Also the typical diameter is 27".
By comparison the stock 475/500x19 Model A tire is rated at 1750 LB per pair and the classic 650x15 are 2200 LB per pair.

 

But rated at 740 lb is under rated only at a stand still. Take a corner hard and the load increases exponentially. Hit the brakes in that same hard corner and you're in for some real tire testing! We're not talking all 1800 pounds the car weighs on that one tire, we're talking several tons of LATERAL PRESSURE on a tire that's not designed to take lateral pressure.

Sure its been done, but that doesn't mean its a good idea. I was holding a piece of sheet metal in my bare hands one day drilling a small hole with the drill press... It was a few years ago so now its traditional but that doesn't make it right! Laid my hand wide open.

 

The Exsecior 450-18 is a car tire rated at 740lbs. I weighed the car and its 950 up front and 1000 on the rear. Just wondering if anyone has used them. Thanks

 

Coker wide whites on the front of my '36 Special. Despite the nay-sayers opinions, it handled surprisingly well. I'll admit I didn't push it anywhere near the limit, but it was pretty neutral in corners. I didn't treat it like a Porche, but it was fun after the bias-ply "thump" disappeared after about 10 miles!

 

we ran VW bug tires on some of our race cars
Not Hamb cars mind you, but the 165/15 work very well, there cheap and may be what you are looking for.

Godspeed
MrC.

 

I think you might have missed something when you weighted your car. Your "A" should weigh somewhere around 2500 LBs with a SBC. Add a couple of people and per your numbers that comes out to to about 850/900 LBS unaccounted for. That weight has to go somewhere.

All math aside, bottom line is a 740 LB rated tire are simply not rated high enough to carry 2800 LBS of people and car with any margin of safety. Yes, people do it and live to tell but as for me, when I'm driving my A Coupe at 70 on a hot day the last thing I want to worry about is will my front tires hold up.

 

I've got a pair on the front of the car in my avatar. MC tires are the only ones you can get with white walls on BOTH sides, I think. The ones I have are for a HD. At the speeds I will be driving with a banger, and as light as this car is, shouldn't be any problems. The guy I got them from ran them on two different cars, a roadster and a sedan I believe. He said they were ok for slow driving, but wouldn't corner too well, they had a tendency to push through the corners. The one thing you need to realize is that mc tires are designed to corner on the sidewalls, car tires are not. Unless you can get your car to lean in the corners, it ain't gonna work too well, hence the push through the corners.
When I can afford it, they are coming off to be replaced with bias 5:50's. I wouldn't run them with a heavier, or a faster car. Is your life or the life of your wife or kids worth the cool look of a tire?

 

Diamond back will put white walls on both sides if you want them that way.

 

Unlike the 450/18 tires, the 16" Harley tires spec out around 900 lbs per tire. That's a better margin for error on the front of a rod.

 

Awesome, I had the same question. That helps alot. Thanks guys.

 

A few more things to consider when running very small front tires, whether they are motorcycle tires or the very small automotive ones.

Braking: You never know when you are going to need maximum stopping traction. The very small contact patch of these tires gives you very little stopping ability and they will lock up and slide when you need them most. 75% of your stopping power comes from the front wheels.

Cornering: Don't think of driving freeway speeds and pushing hard into a corner, especially if you need to use the brakes. Oversteer is a definite possibility.

Bad Roads: Do you ever run into those square edged potholes at the pavement joints? Is it worth ruining a wheel and the tire if you hit one?

I would stay away from the very small 125R15, 135R15, OR 145R15'S. Even the Firestone bias 450/475-16's only have a load rating of 660 lbs. I like to drive my cars and not worry about wrecking what I've spent lots of money and time building.