Scrub line solution?

Do what ever you want..just dont drive it near me..I guess with you being in Cape Town South Africa ,I wouldnt have to worry about that, would i?
and no this is not like saying a roll cage is a short cut to building a stonger roof ..so dont even go there ( there is more to a roll cage than just adding integrity to the roof, ie..ch***is strength, reducing twisting forces, and its an engineered safety device..not an after thought)

this is not a "scub line solution"..its a short cut, and one that will probably take up alot of time that you could be using to design the Ch***is to not require this from the get go

 

why don't you post some pictures or sketches of what you are working with?

 

Atleast you can steer flat tires!!!

 

sxdxmike, as I said to Thunderace, I don't have any specific situation in mind. It's just the principle, in theory, at the moment.

I heard you the first time, Von Rigg Fink. You still haven't presented an argument. See the question mark in the thread ***le? That's an invitation for answers. Convince me. Explain stuff. Don't just repeat yourself, only louder.

dvanecek, not if they're on the rear wheels, you can't.

 

I think the answer to your question is probably yes. I'll bet someone has thought of it. In 80 plus years of hot rodding there have been many innovations that have fallen by the wayside simply because they don't work in the real world as well as they look like they should on paper. It's good that you're thinking. It has become obvious that forethought is completely absent in some of the builds I've seen lately. By the same token, there's no reason to re-invent the wheel, as it were.

 

This is lame...I'm going to put a 3 point hitch on the back of my '25 Dodge speedster, and put a plow behind it...That way I won't have to run brakes, when it gets going to fast I'll just drop the plow so it rips into the asphalt.

 

All building practices are ways to get around something. Some just get around things more soundly than others.

That sounds useful, thanks, but I'm not sure I quite understand. Could you elaborate?

 

This idea might be useful to me. I'm building a 91 Camaro for my son. He has a steep driveway at his house. I might consider mounting a frame under the nose with some wheel surface hanging just below the nose so the spoiler doesn't get ripped off the front of the car.

 

Wicked50Coupe, why not just get one of them big thick sheets of steel to lay over the curb at the driveway/gutter?

Kinda' like a ramp?

dv

 

So were other British cars like my TR's... but the wheel is lower than the frame so there's no problem.

 

First off like most questions with non specifics the answers won't mean anything usefull, till you tie things down to some actual numbers you are just wasting your and everyone else's time largely.
( how long is that piece of string ? )

Secondly it strikes me that you seem determined to dismiss known succesfull answers to pursue the complex and difficult to engineer, don't get me wrong I am all for being diffrent, breaking new ground, doing things difffrently to everyone else, pushing the bounderies, but there has to be an aim, what are you trying to achieve ?

 

I thought about a skid plate on the car. It's at his mom's house, I'm sure whatever I do will cause damage to something of hers - or just be wrong.

 

Sorry I dont have time to spell it out for you..and even if i did, you probably wouldnt acept it anyways...seems you have already decided that your solution will solve a poor design so there is no point in arguing it. nothing any one on here has said to you has sunk in..so I have reached the IDGAF mode

good luck..stay in Africa with that thing

but as far as explaining stuff goes..you can use the search function and find alot about the scrub line issues people have delt with..or not..and that will give you some food for thought.
I think when your sliding down the e-way side ways out of control and barely walk out of the wreck alive..that will be the only thing the will "convince" you..or a real bad law suit..if they do that kinda thing over there

 

I think you might have something there.

This is getting a bit weird, but: how about a dually rear-wheel set-up with different tyres, chosen for different performance characteristics? Perhaps they have different tyre profiles on different rim diameters, the larger of which is safely below the scrub line? Just an idea ...

 

OK. Here's my understanding of what the whole scrub line thing is about. Because static friction, like between the tyre and the road, is much more effective than dynamic fiction, like something skidding on the road, you want to keep a vehicle supported by rolling wheels, even in the extreme case of four flat tyres. That way a measure of directional control, however little, is retained. If a car with flat tyres skids along the road, there is no way even to try to control its direction.

If scrub line is about something else, please correct me.

This idea (I'll admit it might not work: just tell me why not) is about getting small wheels to "take over" from the rear wheel(s) in case of a rear blowout. In fact the scrub line would be defined not tangent to the bottoms of the front and rear rims, but to the bottoms of the front rims and the auxiliary wheels.

It revolves around whether those auxiliary wheels will be up to the job of maintaining as much directional controllability as the flat tyre would. I think Von Rigg Fink was trying to tell me that he didn't think they would. That might be true: one would have to find out. But they might be fine.

 

Torchman's idea is a little easier to comprehend..Disc bolted to back of wheel or hub(any rotating part back there should work) put a strip of hard rubber around said disc..and tada!

But an idea like that has NO place on a hot rod, it's more fit on a newer vehicle.

Just build your damn car right, and you won't have to worry about failsafe devices.

 

Scrub line: The lower edge of the car's wheels. Frame and suspension components should not be below this line, as they can come in contact with the pavement in the event of a flat tire.

 

Ned
Im not trying to pick on you..I am trying to help..
It might not seem that way..but I would rather you build something safe..and be safe in it..than to read about a bad accident you had..and heaven forbid we lose you in our HAMB community

Look at this thread..I didnt go thru it completely but im sure there might be some explanation that might make sense to you..or help you understand the risks

good luck..show us what your building you have peaked my interest

http://www.jalopyjournal.com/forum/showthread.php?t=77804&highlight=explain+scrub+line

 

Your understanding of term scrub line is fine,
my understanding of why you want to put little wheels on the rails still fails,
due to lack of any numbers to evaluate.
sure it could work,
industrial skate wheels would take the load of a light machine and on a dry smooth road would give some control, better than a flat tyre does ? unlikely, unless the suspention holding the flat is very poor or the skate extremely good.

As I said before how low to the black top all you thinking of making the rails ?

 

Casters under the front bumpers of customs to ease over speed bumps and up driveways is an old trick from way back. I'm not sure how you would employ it on a late model car with plastic bumpers though.

 

as soon as the solid part hits the airbags could deploy. How about taller tires, or air over struts. They are gaining popularity in the sport compact crowd.

 

here is one post..and a good reason why you dont wanna mess with anything below scub line

<TABLE cl***=tborder id=post942644 cellSpacing=0 cellPadding=6 width="100%" align=center border=0><TBODY><TR><TD cl***=thead style="BORDER-RIGHT: #e5e5e5 0px solid; BORDER-TOP: #e5e5e5 1px solid; FONT-WEIGHT: normal; BORDER-LEFT: #e5e5e5 1px solid; BORDER-BOTTOM: #e5e5e5 1px solid"><!-- status icon and date --> 11-03-2005, 11:22 PM <!-- / status icon and date --></TD><TD cl***=thead style="BORDER-RIGHT: #e5e5e5 1px solid; BORDER-TOP: #e5e5e5 1px solid; FONT-WEIGHT: normal; BORDER-LEFT: #e5e5e5 0px solid; BORDER-BOTTOM: #e5e5e5 1px solid" align=right> #19 </TD></TR><TR vAlign=top><TD cl***=alt2 style="BORDER-RIGHT: #e5e5e5 1px solid; BORDER-TOP: #e5e5e5 0px solid; BORDER-LEFT: #e5e5e5 1px solid; BORDER-BOTTOM: #e5e5e5 0px solid" width=175>gowjobs<SCRIPT type=text/javascript> vbmenu_register("postmenu_942644", true); </SCRIPT>
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</TD><TD cl***=alt1 id=td_post_942644 style="BORDER-RIGHT: #e5e5e5 1px solid"><!-- icon and ***le --> Re: Explain scrub line
<HR style="COLOR: #e5e5e5; BACKGROUND-COLOR: #e5e5e5" SIZE=1><!-- / icon and ***le --><!-- message -->Okay... the actual term "scrub line" measures from each wheel lip to the contact patch of the other three tires. Scrub line only takes into account ONE flat tire. Common sense, however would dictate that if you plan to allow any loved ones to ride with you, or you actually value your own life enough not to risk it, that anything hanging blow the plane defined by the lower edge of all four wheel lips is a danger in a catastrophic failure.

A friend of mine in high school was killed when a dump valve failed on his hydraulic-equipped Camaro while coming down the Conejo Grade on the 101 freeway. I've never considered building a car that could "lay frame" since.
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Bad news: Casters on the rear won't stop it from coming around on you. The reason is that touching the brake or steering even slightly slows the front, while the rear has Newton's Second Law to send you backwards.

 

Three words....

Magnesium Skid Plates..

 

To me the only extra wheels you "may" need in the rear is a couple wheelie bars if your car is that bad. Otherwise don't build it to where anything hit's under a flat tire condition. nuff said, just dumb!

 

Thought about the air struts - $1,200 for the kit for a sixteen year old.

 

when both tires blow and that thing hits the ground, you are gonna leave a trench in the tarmac, no matter if it's sliding on wheels, or on a spring bolt. How about those run-flat tires like on race cars?

 

I call it the "SCRUBLINE SPECIAL"

 

I can't believe I just read 4 pages of this nonsense. Stop smoking so much weed guys, it makes ya' think too much.

 

Hey Wicked50Coupe, I've got the solution for you!!!!

attach the spoiler to the front facia of the car solidly, then only connect it to the upper crossbar of the radiator with a big *** hinge, then put them little rollers on the bottom of the spoiler.

That way, whenever you go up a drive way, the whole front "face" of the car tilts up and rolls on them little casters and you won't wear away the plastic spoiler....


NAAH, that's a DUMB idea.

dv