Scrub Line

[T-Test]

For all those that want to build a low car, please abide by the scrub line rules of building a car safe. I thought there was a article in the chassis section? Oil pans and tranny pans are replaceable, but if a radius rod hits the pavement, you better be belted in and hold on.
You can go to[search forums] at the top of the forum pages and type in scrub line to find a few articles about the scrub line.

Please be safe when building your car!!!

 

[choppinczech]

Good advice.

The way I'm getting around it is by going with 20" and 18" wheels with low profile tires.


A blowout with 15" wheels on the freeway would leave me sledding on my frame rails.

 

[EX JUNK]

Here is a copy from the NSRA handbook on how to check scrub line.



Jim

 

[baddawgcustoms]

I really like the Murphy's law version of scrub line best. Sit the sucker on bare rims the size you are using and make sure NOTHING touches the ground. (You could just use a tape measure but I like the visual). That Murphy guy pops up when you least expect it. Overkill maybe, but I still like the Murphy test best!

 

[AmericanGraffiti]

Great post thanks for suggesting it. My car is low so I'll definitely check for scrub line...plus, I learned a new term...THANKS!

 

[RPM]

When we build these low cars. We set the rails on the jig, then everything is 3/4" above the bottom of the rails. Then by using 18-20" wheels there is no problem at all.

 

[T-Test]

Here is a copy from the NSRA handbook on how to check scrub line.



Jim

Thanx, Jim, this is what I [thought] was in the tech pages/ chassis section !!

When we build these low cars. We set the rails on the jig, then everything is 3/4" above the bottom of the rails. Then by using 18-20" wheels there is no problem at all.

All good with that except if there is a raised portion of the road 3/4" high and a radius rod bracket hits it. I like a little more clearance myself!!

 

[RPM]

Thanx, Jim, this is what I [thought] was in the tech pages/ chassis section !!



All good with that except if there is a raised portion of the road 3/4" high and a radius rod bracket hits it. I like a little more clearance myself!!

Well the frame is 4-5" off the ground. So that little hump will be 5-6" high. A lot of cars don't have that much to start with.

 

[bamabucket]

I've seen that NSRA scrub line diagram before and didn't understand why the line was from the bottom of one rim to the bottom of the tire on the other end of the axle. After thinking about it, I realized that it assumes it is more likely that only one front tire will deflate. I like Dale's method, which addresses the worst case scenario of both tires deflating at once (or even coming off the rims). I hadn't thought about front to rear/rear to front scrub line but will make sure to check it in the future. My car was built with a 6" dropped front axle and has 165 tires on 15" wheels and is way too low - the end of the lower 4-bar would hit the road in the event of a flat and I intend to correct this by going to a 4" dropped axle and fatter tires and possibly going to a 16" rim. I know I should make this a priority for safety and should do it sooner rather than later - have been lucky so far but that could change in an instant. This thread is a reminder that I have put this on the back burner for too long. I should know better and agree with T-Test that safety is priority.

Ron, this started me thinking about the Donk concept again - the larger the rims the more ground clearance. It looks like the Donk T-Bucket would be safer in terms of ground clearance even if it probably would have very poor handling characteristics. I'm still hoping you will build a prototype.

 

[EX JUNK]

A "true" DONK would be one goofy or ugly bucket in my opinion as are all the other DONKS in the Sanford, Florida area that I can see most any day. (Sanford seems to be the DONK capital of Florida.) This is 0nly my opinion and everybody is entitled to their opinion. ( I know what they say about opinions, "they're like butt holes, everybody has one and they usually stink." IMHO

Jim

 

[ellis8500]

Ya mean like this one???

 

[EX JUNK]

They're not quite that goofy YET, Bill. Who knows what this season will bring though. LOL

Jim

 

[bamabucket]

I hope nobody takes the Donk T-Bucket idea too seriously. It came up during a conversation among a few bucketheads when we were in Pigeon Forge and I completely agree with Jim - every Donk I have seen (there are a few around here too) is ugly. I don't think anyone will ever build a build Donk T-Bucket - they are usually old full-size American cars that are worth less than the cost of the wheels and tires.

 

[rodder25]

I agree, in most cases the rims are worth more than the car they are on.

 

[fletcherson]

I agree, in most cases the rims are worth more than the car they are on.

Makes me wonder where the $2500. Wheels came from that are on a $500.00 ride...

 

[bobs66440]

Ya mean like this one???

View attachment 10908

Ha ha ha ha! Oh man!

 

[Francis Blake]

I had not heard the term donk but I have seen some cars around like that , really look silly. On a different note the bottom left pic in the illustration shows an extreme angle in the rod end, if I have reason to put any amount of angle in a rod end I use tapered cones and I always use seals with them. Maybe overkill?

 

[joecool]

I read several diffent forums and websites. The one that baffles me is the low riders, now I like a lot of their cars. The fit and finish, detail on some of these is out of this world. But when you get to reading it takes a while to interpret what they are saying. The older 40s fat fenders are called Bambas. Late 70s big Gm cars are called "Glass Houses"But the one that makes me smile is the Continental kits . They call them "Booty kits"