scrub radius??

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railcrzy
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scrub radius??

Post by railcrzy »

Ok i recently bought this car and it has some issues with turning.
I sent some pics out and got some unwanted responses, that the scrub radius is way off.
I need some help.
Im in riverside co. ca. and im looking for someone to help fix my problem.
If any fab.. is willing to take it on and fix my problem i sure would appreciate it. I know it will cost a few bucks, but i need all the help when it comes to steering from a spinal core injury.
Here is a link for some pics.

http://flickr.com/search/?q=crs+fabrication&m=text

thanks Larry
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Post by BHenry »

Hey Larry,

I know its a bit of a drive for you, but I have had some pretty good service from Sand Car Services, in La Habra. They're the ones who have done all of the chassis rework on my car.
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Post by Winston Cup »

I don't know of anyone in particular in your area but your gonna have to find someone that understands ackerman quite well rather than just a fab person. In a front steer car, such as yours, it's a bit more tricky to get the ackerman in the ballpark because you don't have much room to play with the steering arm positioning, length etc, so it'll also likely entail moving the rack around a bit along with spindle mods and then you toss in the bump steer factor. Find someone knowledgeable in that area for sure. You got any down shot views of your front end setup?
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Post by OBSESSED »

Hey Larry,,

Obsessed here...

Call up and talk to Chris at Wizard Fab
Right in Riverside, near "Rainbow" bolt

951 505 3195
Tell him you got his cell # from Steve Brooks

Wizard understands ackerman, to the point of "Fixing" many named sand rail manufactures rails.

good luck, Steve
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Post by crash »

There are MANY things that effect how a car steers. Weight distribution, ackerman, bump steer, heaviness of springs(weight transfer), chassis rake......etc, etc. One of the MOST common problems that I have seen on rails is that people frequently set their springs too heavy and the preload too high. It appears this may be the case with your car. While having the front suspension all the way at the top of its travel is good for compression when hitting transitions at the bottom of hills, it WILL MAKE THE CAR UNSTEERABLE over the flats or small whoops. Make sure you have no more than 70% of the shock travel available to you when the car is ready to go with you and your passanger in it.

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Post by railcrzy »

Thanks Brian and Steve, I think ill give chris a call.
I also have a small (VERY) small rack & pinion, i wonder if i went with a slight bigger one if it would help with all the feedback in the steering? Its alot of virations.
thanks again
larry
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Post by Winston Cup »

railcrzy wrote:I also have a small (VERY) small rack & pinion, i wonder if i went with a slight bigger one if it would help with all the feedback in the steering? Its alot of virations.
thanks again
larry
Your getting a bunch of "feedback" in the steering because of very little spindle inclination, might be the angle of the pic, but I see virtrually zero inclination. If you look at the spindle from the front, sight the upper and lower a-arm pivots, now draw an imaginary line from the top center to the bottom center of the pivot points. This line shound intersect within the contact patch where the tire meets the ground. The more your contact patch is outside of where that line meets the ground, the worse your feedback is gonna be. It will also cause your front end to push in the turns as well, and it's really hard on the rack. I've seen people break their wrist when it's really out.
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Post by Sand Commander »

Larry, I think you also need some form of power steering to go along with the refined steering geometry. I have heard that Yamaha has a power steering kit for the Rhinos that could be adapted to your car
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Post by SANDMAN »

Hey Larry,
That car is Sweet. :) when you get that going....let's go Dunin. Mine should be ready in a couple weeks. 8)

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Post by railcrzy »

Hey Pete, How ya doin? long time.
I have driven the car already, and were going out for pres. day.
The car needs to be re designed in thefront. Im going to call that guy brian mentioned as well, builders and fab.. are busy now.
Im going to check into that power steering u mentioned, that would be awsome.
Thanks for the comments.
Larry
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Larry
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Post by crash »

Sand Commander wrote:Larry, I think you also need some form of power steering to go along with the refined steering geometry. I have heard that Yamaha has a power steering kit for the Rhinos that could be adapted to your car
This is a two seat rail that weighs what, 1000-1200 lbs? Any able bodied individual should be able to steer this without power steering unless they have some sort of disability.
Last edited by crash on Tue Jan 23, 2007 8:18 am, edited 1 time in total.

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Post by BHenry »

Larry,

I've been looking for components (and a donor bike!) for when I finally get to build one. If you want to look into changing out the rear end for a diferential (so you can add turning brakes), Quaife (out of the UK) is probably the best known manufacturer. I found a few others as well, but the Quaife unit I think would work best for you.
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Post by crash »

I think BHenry hit the nail on the head. Unless you unlock that rear, it will always understeer unless you can get extreme amounts of weight off the rear and on the front. That's the only reason quads steer OK. One can move their body weight up over the front end.

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