Scrub line solution?

Put titanium blocks so you'll make a huge shower of sparks while you skid off the highway after you hit the spike strips. It won't make the car any safer, but it'll look awesome on "America's Wildest Police Chases". Sheriff John Bungholio will say something like, "He thought he could play games driving with an illegal scrubline, but thanks to hard work from law enforcement, his game playing days will now be spent in the County JAIL!".

Just kidding. I think it's a lame idea though. Might be good for getting a lowrider or long-tailed motor home up a steep driveway without dragging in the gutter, but I wouldn't trust them as any sort of safety device. For one thing you'd have no rear brakes all of the sudden. You might be better off just dragging on the ground than flying along on some unstoppable roller skates in back. It'd probably look like those pickup trucks that are rigged to be able to drive on railroad tracks.

 

ok im a minitrucker from way back.........ok u done laughing but laying the fram on the payment at high speed not that big of a deal to control do it all the time and rarly wreck! hell i got vidio of my 61 caddy layed out at 80+ trhowing sparks 400ft bhind it and no control issues! just my .02 cents

 

Unless your Batman building another Batmobile, I don't see the point in all this. But if you are Batman and you got the Joker chasing you and if he shoots out both your rear Bat Tires. It would be nice to flip that Bat switch, down go Bat Casters and your on your way back to the Batcave.

 

That would be attractive...However you are correct that would not be a Rat Rod it would now qualify as a Clown Car

Gary

 

that right there is the best reply on this entire thread so far..I got a good chuckel out of that one
not to mention those ultralight wheels would not hold up under that type of driving situation..
what is the load capabilities of those tires? or those bearings?

A picture is worth a thousand words..show us a drawing or a picture of what you are talking about and maybe it will become something a Good Chassis Builder on here could solve any scrubline issues for you and still give you the look and maybe even a decent ride out of your Rolling Chassis

 

batastic

 

OK, time to get the Carrol Smith books (all of them) and read them, THOROUGHLY, over, and over, and over again. Then maybe you'll understand why you are getting all the flack. You might just learn something you didn't know about vehicle construction and vehicle dynamics, too.

In short, just because you can, doesn't mean you should.

 

Here's whatcha do to truly understand the consequence.

Give your bag controls to a passenger. Tell em to "suprise ya" with random blowdowns. Any speed, any road condition, corners and bumpy areas are preferred. Once your drawers have been cleaned out come back and tell us what it's like to lay frame somewhere other than smooth and straight sections of road.

 

The purpose of a skid on an LSR is to prevent something from digging in and causing an end-over-end pogo, not "to keep it straight".
Replacing the wide rear tires with anything but 2 more wide rear tires will give instant and fatal oversteer - the car will loop or flip.

 

Hi Ned -

Not for nothing, but are you like three years old? Because all you seem to be doing is to provide one 'yeah, but' after another.

100 years of automobile development has provided absolutely no traction (pun intended) for your idea. Neither has anyone on this thread.

It's not a good idea, and it won't work. Is there any part of that statement that is ambiguous?

Go ahead and build a few roller-skate, double diametered tire cars, and send us some videos of them in action.

 

What about a blown bag or line?

 

Bag it. Slam it low when you want it and have clearance when you drive it for real. Band aids fixes before the car is even built is just dumb. Build it right or just don't.

 

I thought this would come up to, I was going to address it in my other post but didn't.
My car is about as low as it could be without actually making contact with the ground in the event of a blown bag or line. The car is off the road right now, and before it goes back I'll be adding bump stops to make it a little bit higher when aired out, just for good measure.

 

been there few times switch box fell on floor couple times my then 3 yr old snuck the box when i wasnt lookin' yea fun times but hea it happens.
but hey scrub line law is why hines put hydros in sub sonic and it change the world as we know it! i dont know if i'de go as far as rollars but , all im saying is if and i mean "if" u get 2 rear flats at once and thats a huge IF! It's not going to be a for sure wreck

 

AHAHAHAHAHAHAHAHAHAHAH...OMG, I almost fell out of my chair!

 

Not that i Condone what the original post is about,

But what the Hell is the difference of what he wants to avoid as to if ALLLLL you Lay'in Frame Air Bag Heros ?

Blow A tire on His Rig and your on the frame, Blow a Bag in some these Layin Frame Rigs and guess what ..... YOUR ON THE FRAME !!!!

Either way, Your Fucked & there are wayy more Bagged cars in the U.s. Than this guys Wreck in So. Africa

How many Over Low Bobber Trucks & Model A sedan have you seen ?

About a million in Mags & Even on the HAMB ... So why Pound This guy for his over size skate board Plans ?

I agree, It sounds Stupid & Un-Safe ... But there are plenty just as unsafe here on this Board that so many of you say "BITCHEN BUILD", Think about it.

Over Low Hot Rods & Fully Bagged Frame Draggers are just as stupid & Dangerous.

 

I think you have a good idea.

Let's say that you've built a car that has a frame that is 1 inch off the pavement when the tires blow. Now I'm typing the word, "scrub line" so that all the people who like to argue can focus on that one word and ignore the rest of this post.

For the rest of you who are still reading...

You've built a car that still has 1 inch between the pavement and the frame when the tires are flat.

The only thing providing directional stability when one or more rear tires blow are the flat tires. (Remember, there's still 1 inch of clearance between the frame and the pavement.) The tires do a terrible job because the side walls are squishey and flat. The rear of the car fish-tails from side to side as you struggle to maintain control. God help you if you're going around a corner!

If only there were two small safety rollers at the back of the car that hung down 1.5 inches. They would act like a rudder on a ship! Everyone has known for thousands of years that it only takes a very small rudder to turn a very large ship, or keep it going straight. The farther they are towards the rear, the more directional stability.

If they only hung down 1.5 inches, they'd be pretty easy to hide if you put them inboard just a little. No one would ever see them.

It certainly wouldn't hurt anything to have a couple of extra safety wheels hanging down, ready and waiting in case the normal tires blew. It would be better than trying to maintain control with nothing but flat tires.

I think 2 inch wide steel rollers coated in rubber would be the bee's knees. As for engineering such a "complicated" device, may I suggest the following:

 

Sorry dude, I know it was done in the day but that is a FAIL.

 

If it were that simple, you'd see your $20 solution touted on a high end luxury car as a safety device. Yet that's not the case. I mean why would they go to all that money for run flat tires and pressure monitoring systems when a couple casters would suffice?

Flipside....you're right and the rest of us are wrong. You better get to making that shit right now so you can be a millionaire in 2 years off retrofit kits sold to the masses.

 

small diameter wheels at high speed won't roll like they do at .015 mph under a pallet jack on smooth cement warehouse floors. Build a low car and drive without fear or get a volvo. Don't be a pussy. It's called PURPOSE BUILT for a reason.

 

Ok, I don't know why I wasn't remembering this. 25 years ago I had a 71 dodge dart that was lowered. I was cruising through a parking lot and the center crossmember which stuck out in front of the wheelbase caught the edge of a heaved concrete segment and the car came to a dead stop from 20 mph in about 10" which is how much the crossmember caved in. My face bounced off the steering wheel and I bit completely through the inside of my mouth and lips enough of the way through that I looked like a Goddamn fish untill they sewed me up with a few hundred stitches. I was lucky and got an artist to sew me up and there is almost no scarring. I would NOT design a car such that anything but the rims without tires touched the ground. About flat tires flopping all over the place I forgot about safety beads.

 

The idea of using 3" diameter castors sounds good but in real life
I think that they would be no better than a piece of steel hanging
down from the frame or whatever. You've got to get the wheels up to
speed for them to work. You wouldn't have enough time. They
would act as if they were solid steel. They would slide until the fell into
a small depression then they would stop the car real quick. I wouldn't
want to be in that car.

 

How about wheelie bar wheels! Gary

 

oh all cars dont drag.....

 

If you're that worried about tall sidewall tires going flat, how about a 'safety liner' like the NASCARS run?

As I understand it, it works like a tire inside a tire (never worked on a 'cup car, just know what I read and have seen from the spectator's side on those).

As I understand it several other racing organizations mandate them as well, but I'm not coming up with proof of any at the moment.

Not ideal, PITA to mount I'm sure, not cheap, heavier and higher maintenance, but it's been proven untold thousands of times at comparitively high rates of speed and in turns as well (yes, even to the right).

I expect this would be better than an external set of tires / wheels / rollers as it's designed to do what you describe you want (keep the vehicle under control in case of a flat at speed, unless I read it wrong).

It doesn't help a scrub line issue, but would make it that much more difficult to get down to the scrub line.

IMHO it's better all around to heed the mountains of advice here and build it not to have a scrub line problem in the first place (if scrub line is actually what you were asking about and not the colossal 'red herring' I suspect it is in this case).

 

Closed

 

Thanks. That's what I'm saying. Rubber won't work, though. The load capacity isn't up to the job. Polyurethane might - if the wheels are capable of giving enough lateral reaction.

That's useful information, thanks.

I do appreciate all the advice, even if a lot of it is of the form, "That won't work because that's not how it's done." I was hoping for more reasoned argument, though.

(Like: "Hey, has anyone thought about running a blower from a two-stroke diesel as a supercharger on a car engine?" "You shouldn't be running no truck blower on a car engine! Do it right, get yourself a car blower!")

And at the end of this I think I've identified the parameters for the idea to work: that is, the lateral grip characteristics of a wheel that will take the load and impact. What usually causes an apparently good idea not to work is that satisfying those parameters takes it to an impractical or undesirable configuration. I still don't know if this will work in practice because I don't know what those grip characteristics are. Could we leave it there?

 

I'll leave the whole "extra wheel" thing alone.

As a solution to your issue, what about using one of the run flat devices such as is designed for a military Hummvee?


...or the newer more streamline version they are considering:


This would require the use of a modified rim, but that would be relatively easy to accomplish if you are insistent on incorporating this level of safety, and far safer than tempting the rules of physics to a grudge match

 

I would go with an anti-gravity device...........