Hot Rods Shortest Wheelbase

Don't know if this has been talked about.. probably.. but what is the shortest wheelbase that will give you a good ride and not try to swap ends and all your usual shortcomings of a too short wheelbase..never driven a tbucket or like just wondering and does width have anything with it...thanks

 

Wheelbase will have a LOT to do with directional stability and something to do with ride quality, but a more detailed answer depends on numerous variables. Weight distribution, unsprung weight vs sprung weight, center of gravity (CG), seat placement vs axle positions, spring rates, tire size(s) and composition, steering ratio and geometry, etc.,etc.

Just as a general proposition though, I'd suggest a 100" wheelbase be a minimum to start with.

Ray

 

At one point NHRA had a rule of 100 inch wheelbase for altereds, That got changed at some point so Anglia's could run. '70 Gremlins were 96 inches. They could be a handful with a strong 360 in them.

 

My Morris Minor has a 87 inch wheelbase. I had a pro street version that I drove every day . Took it on trips and it drove fine. 5.0 Ford with AOD .

 

I know people that either have or, have had the below cars as street cars.

Anglia's run on the street today, their stock wheelbase is 90".
American Austin's run on the street today, their stock wheelbase is just over 93".
American Bantam's run on the street today, they're about 75".

Mike

 

A model's were 103-15/32". Deuces up around ~106. Shorter WB, at speed? Careful there.

 

smart car.

Rear wheel drive, 55% rear weight bias, Backed by Mercedes engineering, 74 inch wheelbase .

 

No-- anything under 100" was required to have suspension

 

There isn't ANYTHING that one could say on here about recommended procedure, recommended safer components, recommended whatever, but what some people will post and say"Hell, I've been doing that for years and never had a problem", "hell, my car is all %$*& up suspension and geometry and it handles just great". etc., etc., as if they'd actually know a good handling car from one that isn't. All they really know is that they find theirs acceptable to themselves.

No one who posts about what it takes to have a well engineered and generally safer vehicle is saying that anything less will crash and burn the first time out. Though it might.

No, what is being suggested is to follow proven 'best practices' to up the odds of getting the best from what you have spent your time and money on. And, if you aren't going to follow proven, sound engineering and safety principles, just be aware that you have a sub optimal setup and be prepared to make allowances for that.

Do what you want, but don't confuse past good fortune as proof of anything in the future.

edit: as for Smart cars....they were designed for urban use. Low speed, congested areas, etc. Yes, people use them on the highway....and not all of them die doing it. But the car is definitely out of it's intended element in those conditions and the risks to occupants rise substantially. The most consistently successful gamblers play with the odds in their favor as much as possible.

Ray

 

A-F----N-MEN!!!

 

Nope, it was the gasser class that the Anglias were excluded from. The minimum for a /G class car was 92" and the Anglia was only 90". From 1963 there was a clause in the rules that allowed the Anglia to run but only with small block engines and not with superchargers. In 1967 the rules changed to allow any engine but still no superchargers. In 1968 the minimum wheelbase for all bodies (in the gas classes) became 90" and the no supercharger clause was deleted.
Dating back as far as 1961 the minimum wheelbase for altereds was 92" and prior to that it was 86". Currently the minimum is 90" for all classes.

As late as 1970 (at least) all classes were required to have front suspension regardless of wheelbase.

Roo

 

There was a know-it-all that built a Dodge bucket ('19, with the Dodge rails...shortened.)
'50 Merc rear, '40 Ford front axle with front-mounted spring on tube front member. Radiator just over front spring, NOT PRETTY. (clean construction, though...Melvin just didn't have an eye.)
Engine was a 318 Dodge poly, Dodge 3 spd. std., Spark-o-matic linkage.
Wheelbase was 82", rear too far forward...front too far backward.
He ran out of gas in the country one night, his 2 friends swiped a can of gas from a farmer, 'way out on Pomeroy Ave. (the 'sticks', by the 'S' turn around the pond)
Put the gas in, battery low...had to push start it. Melvin popped the clutch in 1st gear (!) the front went skyward! Melvin was flipped out over the back and landed on his head!
Car was idling away, one of the guys caught it...Melvin was 'hurt', but not injured.
The guys said that car would suddenly change direction 30 degrees! Squirrelly as heck.
Old Chevy pickup steering.
That story ran rampant around Goodies Speed Shop and Speed, Inc., (Sid Waterman was one of the guys there that night!)
Old hot rodding just got weirder and weirder...seemed 'normal' at the time...

 

If it's a hot rod, who cares how it rides.. The question is; is it fast...

 

Okay...so it has to be fast. Why can't it have other good attributes too? They are not mutually exclusive, are they? I would submit that if it rides and handles well (for what it is) that is the best way to maximize/utilize the speed potential.

Ray

 

OK, OK, your highness ^^^....

 

That is "Your Highness" (note, with caps) to you.........

Ray

 

Sometimes fast is related to quick and is a completely different animal... If a near stock wheelbase 34 Ford with a stock roadster body can go over 300 its fast (and one has) all the rest are just dreamers that see finish line lights.

 

Going back (my earliest book) at 120" could one have a rigid rear axle.
"unsprung" Elmer Snyder showed up with a short wheelbase dragster that was not suspended, Hence the name and was outlawed

 

Cobras are 90" and MG Midgets are 80"
You want the car to have a "low polar moment of inertia" or it will understeer entering corners and oversteer exiting corners [keep the mass close to the centre]

Short wheelbase cars are more susceptible to the effects of bad design [eg bump steer, and rear roll steer] and the camber and toe need settings to be compatible "bed partners"

On a street driven car it would be better to have positve camber and toe-in to make the front end less reactive [understeer feeling] and the rear end needs to be set up for slight roll understeer by having the chassis pivot points lower at the front [causing the wheelbase to shorten slightly on compression]

Bump steer is just basic good engineering, and the car would be better if it is set up softer sprung.
A short wheelbase car will try and "tramline" on uneven roads if to stiff [and roll oversteer and toe-out]

 

Depends how stupid the driver is.

 

AMC Jeep CJ5's with the 304 V8 were 83" wheelbase.

 

I ran this Jeep, 82" WB, 11.41 @ 117 in the quarter. Get a load of my race uniform, a blue "T" shirt, and a $16.00 Pip helmet. Times were different back then.

 

I always love the excitement when you guys start comparing apples and oranges and then someone throws a watermelon in the mix.
True when you are talking leaf springs and I beam axles short wheelbase rigs can get a bit squirrely . If you have ever ridden in a shortened wheelbase 55 Chevy wagon with a stout 327 under the hood you know what wild ride is all about.
That said, until it got shortened even more my daily was a 95.7 inch wheelbase sedan with a hot little twin cam 1600 CC banger in it that handled like a slot car. That engine will go in a little short wheelbase roadster in the next year or so that will be so OT it will never be seen here but should be fun to go carve corners with.

 

Where's the extra inch? Stock is 86".

 

It's not only inertia which has a polar moment; grip has too, and the important thing is how the polar moment of inertia relates to the polar moment of grip. Worst case would be a big car with heavy ends on a short wheelbase – think '80s Lincoln Town Car. That sort of arrangement has been a way to a soft ride ever since Rolls Royce began experimenting with sand bags piled on bumpers around WWII. While that delivers wonderful results in side elevation for very little money, it's a complete disaster in plan.

Far better would be a little car with all the weight concentrated in the middle, on a long wheelbase. The ride angle can be solved if we could decouple the pitch rate from the other modal rates, which is known to be amply practical. But the very approach militates against a condition of structural insanity in which shortness is for all practical purposes a greater virtue than lightness. In a sane world it would be the other way around.

 

Yes, and could be squirrelly as as all get out!! Combination of high Center of gravity, short wheelbase, crude suspension and surplus of power (for certain conditions)........my comments aren’t theoretical......I have experience with Jeep CJ’s back in the day.

Ray

 

Shorter wheelbase will be nippy and maneuverable but also less stable, everything else being equal (which it seldom is).

Every design is a compromise. There is no answer to your question. It is impossible to say "this wheelbase is fine, one inch shorter is undriveable".

You have to take a lot of things into consideration. Is it for the street or track? What kind of driving? How powerful is the engine? What about track width, suspension design, tires, etc etc.

If you don't want to strain your brain the simplest answer is to copy a car you know is successful. If you are building a T bucket and the good ones all have a wheelbase of 106 - 115 inches that should tell you something.

Building a budget T bucket for laughs? Plan on bombing around town but never going over 50 MPH? Don't mind a cramped driving position since you won't be going far at a time? Using a 4 cylinder, V6 or stock small block V8 under 200 HP? You could have a lot of fun with a wheelbase of 100" or so. Building a car that you want to be able to drive on the interstate, several hours at a time? Better go for a longer wheelbase, try to arrange more leg room, and pay more attention to suspension, steering and brakes.

 

Portland International Raceway.
There's a real good chance I'm in this shot.
If not, I was on my way from the pits to watch Marty and his crazy wheelie machine.

 

My 40 Willys pickup with a Mll front end didn't ride well at all. With the short wheel base bumps came quickly. My 33 Plymouth PD coupe (long wheel base) with a Mll front end and Nova rear end is one of the best riding cars I've had.

Gary

 

VW Beetles and early Porsche 911's are a good [or is it bad] example of this. High polar moment of inertia and short polar moment of grip and the rear end only.

A sane world would just about eliminate most of us HAMB members