I just isntalled Hotchkis springs on the front and rear. Only dropped .75"/1.5" (so far). I am thinking about 2" drop Western Chassis a-arms (perhaps with some spacers to bring the ride back up if too low).

Here is the question: lowering causes bump steer, right? What exactly causes the bump steer? How can I get rid of it?

If it is because of the arc of the a-arms, will getting both top and bottom a-arms cure the bump steer?

Thanks,

TLS

 

Lowering the Lightning causes the bump steer to get worse. The geometry of the this suspension is the cause. Here's a brief and simplified explanation:
If you picture a front wheel turned and unconnected to the steering linkage, the suspension will travel up and down on an arc. The wheel will also tilt while moving on the arc from the upper and lower control arm geometry. But, if you connect the steering linkage, the direction that the wheel is pointed is forced to follow another arc which changes as the wheel moves up and down.

Ruslow has fixed it, but that kit isn't for sale. I have pics someplace.

Spike
BTW, where you at California Speedway last month (SoCalSVT)?

 

George,

When's your next event?

 

The date changes weekly. The only ones for sure are in November (Laguna Seca) and Sears Point (December). If a miracle occurs, the engine will be ready the first week of August and I'll run Willows and maybe Thunderhill that same week. But, if that doesn't happen and I'm lucky, I'd like to run one of the Silverstate events and get a feel for the truck in a low speed class. I'd still like to run one of them in my Lightning if "thumper" isn't ready.

I got your email and want to reply, but since you requested no replies...
Congratulations on doing great and not running out of gas!

Are you in town this weekend?

G

 

A good way to avoid bump steer is to refrain from lowering your Lightning (or any vehicle for that matter) further than the design of the suspension will tolerate. In this case, 2" seems to be the threashold. The easiest way to visualize this is to draw lines on pictures of your suspension that follow the control arm body, the mouting axis, the pivot points, and all of the actual range of motion arcs, and see how all these parts interact. It's very interesting stuff.

(To answer your question more directly . . .you need to change some of the angles and/or mounting axis points on a few of the suspension components to compensate for the change in geometry created by lowering the vehicle.)


Hope this info helps. . .

---WrongdayJ

 

The threshold is actually the stock height. Beyond that, it gets worse. At 1.75" front drop, it got bad enough that Ruslow needed to make a bumpsteer kit.

 

My bad. . .you are totally correct.

I guess I should clairify. . .2" (if the drop is created by the spring alone) is the point where it becomes obnoxious and annoying and frustrating and potentially dangerous and could lead to soiled shorts. (don't ask me how I know this. . .)

---WrongdayJ

 

Jay,
You're correct when your answer is qualified with how the Lightning will be used. Because Stan is cornering 50 mph (posted) corners at over 140 mph, bumpsteer would be deadly (not just dangerous). On the other hand, some may never drive a road course and would rather drop the lightning for looks and not consider the side effects.

Tim's interest appears to be more performance oriented than looks (I've read his questions and they are always well thought out). So, I pointed out the extreme at the expense of correcting you.

Spike

 

And be ready to pay shipping charges back to them and restocking fees when you find out the Western Chassis arms don't bolt up PROPERLY to sway bar ends without modifying.

 

Thanks for the heads up, Lightstuck. I will make sure noe that I ask the right questions when ordering.

However, a more accurate statement would be that the retailer had better be prepared to come to Los Angeles and defend a lawsuit if I am in any way mislead as to the fitment of the arms. One of the benefits of being a lawyer--I don't have to take any sh*t from anyone.

 

Spike is 100% correct. Performance is by far the number one consideration. Ride comfort and looks are a distant second and third. I want a competent autocrosser that can still be driven daily.

Spike, please e-mail me with any info you have on bump steer cure. I have seen some kits for other cars like the Mustang, but can't picture how they work. Might be time for some more 'Net research.

Thanks to all,

TLS

 

Thanks for the info, Spike. Yes I was at the SVTOA. Went Saturday from about 11-4. Watched you guys in the L's from the fence.

That's where I was bitten by the racing bug--the SCCA guys were having a blast autocrossing. (Re)joined the SCCA the next day. Hope to race by my 40th on August 2--midlife crisis in motion.

After I get the brakes sorted out, I intend to dabble in some open track stuff as well. Laguna Seca, Sears Point . . . it doesn't get any better than that!

Please see my response below. Thanks again.

 

I was down on Sunday and had a fun time, although I took it easy on the new truck. Hope to see you at some track events!

Spike

 

I was going to stay out of this post but..........
I still have some bump steer but it is a third of what it was after I dropped the truck.Its designed into the vehicles so they understeer since for the average person the natural instinct is to turn the wheel more when you are not making the turn.Same when you hit the brakes.You push harder when you are sliding.
As for what I did I will say this the kits out for the stangs require you to drill the tie rod hole out to 5/8 and install the bolt.Which works but I wanted to have a good tight fit.So I made a tapered sleeve that is split down the side and has the correct taper and the correct size hole for the heim when you tighten the bolt it squeezes the bolt around the shank and holds it tight.
There have been a few who have wanted the kit or asked if I would make one for them.The problem is finding an alignment shop that will take the time to install rite.Because you can hurt it more if you install it wrong,than if you left it alone.I have done several on olthe rvehicles that I own or owned and the average time to install correctly is about 3 to 4 hrs.Since spacers have to milled. Stan

 

Which is the reason why I stopped asking Stan to make me one. I figured if it took him 3 to 4 hours to get his correct, then it would probably end up worse. And, another practical reason to limit how much the truck is lowered.