Drop Spindle Discussion

[Grant]

Feel free to correct my mistakes.

For those of you wondering what a drop-doo-hickie is, it's using a section from 1 pair of spindles to lengthen another below the spindle. The object is to have your lower control arm slightly angled downwards (just about like they are from the factory, although strangely enogh, my car had horizontal A-arms and I don't think it was ever lowered) so that when the car is cornering hard, the A-arm goes horizontal. As the A-arm swings horizontal, the base of the rim gets pushed outwards...which gives you negative camber. This in conjuction with the upper control arm swinging more towards vertical will give a considerable amount of negative camber on a fully loaded front end.

What I've gone and done with my suspension, is lowered the car so low that both my LCA (lower control arm) and my upper control arm are already in the upwards direction. When I compress my suspension by going around a turn hard, the LCA become even more vertical...which pulls the rim inwards, resulting in less negative camber, or positive camber.

So, what's the point of giving your car negative camber at stock ride-height if it's going to be replaced with positive camber when you're cornering and actually need it? The entire point of the negative camber is to keep the tire tread flat on the pavement as the tire is pulled away away from the rim as you screech around a turn to maximize lateral or side to side traction.

Now, you could just pile on TONS of negative camber (like -4 or -5 degrees!) to maintain some negative camber with a knackered front end like mine, but then only part of your tread would be touching the ground, greatly reducing your traction in the foward and back direction (read: braking). With drop spindles, apparently you can run as little as -1.5 degrees of negative camber, but once you load up your suspension, it could increase rather than become positive...a win-win situation basically.

The other way to get around having a decreasing camber curve would be to make your spring rates ultra stiff! You won't gain much positive camber if your LCA's barely move after all. I belive this would be the approach of the RSR system. It seems to work great so it can't be disregarded (not to mention the look and quality of the system is said to be top notch!) but I think it's more suited for smooth tracks than our rough CA roads. Greg Gordon has recently installed this system on SuperRedVerde with stock torsion bars, and he says the ride is even better than with 27.3mm T-bars, so I might be wrong here.


First pic is of my car, slammed with my suspension mods in the sig. That's as the vehicle rests, with -1 degree of camber.

Second pic is what my camber might look like when I'm cornering hard (my negative camber turns into positive camber, decreasing my front end grip drastically). The end result is a car that seems to want to terminally understeer unless I make the rear end ridiculously stiff.

Third pic is my idea of what a drop spindle will do to the front end geometry. You can see that the lower control arm is slightly angled downwards (yet the car should still be low...something you can't do with the stock geometry). This is better for bump steer also..something I'mnot going to get into because I don't think I understand it yet.

Fourth pic is what I think the suspension will do when thrown around a corner. The LCA goes horizontal, pushing the rim out (which adds more negative camber...usually good when cornering) and even keeps the steering arms at an acceptable angle (I think this is a good thing?).

[slyalfa]

Hmm just looking at the drawings it seemed wrong to me with the top having a shorter length.
so I drew it out.
And I get more -° of camber with what looks like the stock setup.
I drew it on grid paper with equal distance on the spindle as on the car. 4 square

then did a arc for each.
started with one square compressed then went to 3 square compressed

so am I missing somthing?

[Grant]

My drawing is definitely not to scale. I'll go take a picture of my actual setup tomorrow.

[slyalfa]

I guess you need to know the length of the top A vs the bottom

also if the car is twisted like in real life then some or all of the camber will be removed. so the role of the car needs to be also factered in too.

the best way is to draw it to scale and put everything in the states you want to look at.

a CAD program can come in handy. look at the digital drive trane for the spider
Digital Drivetrain

it looked very cool. the pic seem to not be loading for me anymore. did the bb delete the pics?

[Potenziato]

Here is a good link about lowering and roll centers:

http://e30m3performance.com/myths/We..._transfer2.htm

No one here has mentioned it, but the spindles do increase suspension travel. The problem is the tire will now be touching the top of the fenders! If you have regular shocks, this may be an improvement. The RS kits have the shock rods shortened at least two inches so they can be used at super low heights.

The RS kit can use firm springs but the ride is excellent for this type of product. Lower rates springs are easily swapped in if you prefer more ride comfort. The Koni and Bilstein shocks are really harsh by comparison. You can change springs in an hours time max. Plus you can again change the balance of the car by changing spring rates front to back.

I'll stop talking or people will think I'm on the payroll of RS Racing!

[junglejustice]

Grant, sounds to me like Larry has the setup - you should go with his complete package...

(It is worth mentioning that NONE of the 25 transaxle cars in Ron's fleet of Ring-burners run a drop-spindle modification - NOT EVEN HIS FULL-RACE 24 valve TOURING GTV6!!!)

Listen, 15-20 years ago - Shankle was it! That's what was available for these cars; that's what worked and it is still pretty good by today's standards however, technology has changed. Should we all still run carbs, just because that was what worked 40 years ago!?

That's like saying Alfa knows best what's good for your Alfa and you should run the setup the way the system designers well, designed it!

Five years ago RSR did not exist the way that it does today. You simply have better technology available to you today, than what many of us had for these cars 5-10-20 years ago; USE IT!

Quote:

Originally Posted by Grant And does anyone know how the RS system make a car tail happy? Are the spring rates really stiff in the rear or something? Do I just need to increase my rear spring rates to something much higher?

[Potenziato]

Quote:

Originally Posted by junglejustice Well, Colin Chapman HIMSELF wrote that this is NOT necessarily true for ALL cars. It has also been proven in race-applications that if you can control the roll-center somewhat (and more importantly - the body-roll), it becomes less of an issue! Ron's setup is living breathing evidence (Grant, empirical evidence if you will), that it means NOTHING on THESE cars BECAUSE you have gained control of the roll!

[nizam]

Quote:

Originally Posted by junglejustice It has also been proven in race-applications that if you can control the roll-center somewhat (and more importantly - the body-roll), it becomes less of an issue! Ron's setup is living breathing evidence (Grant, empirical evidence if you will), that it means NOTHING on THESE cars BECAUSE you have gained control of the body-roll to a large degree by addressing BOTH roll-bar stiffness AND springs-rates front AND rear!

[Grant]

Yeah, I can do that. I'm totally cool with trying out something new if it works better. But here's another idea...anyone wanna let me drive their RSR car??

I do want to update this thread in the future to let others know of my findings. I'll try to be as unbiased as possible.

"This is all theory and based on the popular belief that running larger rims and/or lowering the ride-height of any given car creates an undesirable effect of a lower control-arm that does not sit perfectly parallel to the road surface and by extension poor handling characteristics.."

This is not just a theory JJ. This IS what is happening on my car.

"Listen, 15-20 years ago - Shankle was it! That's what was available for these cars; that's what worked and it is still pretty good by today's standards however, technology has changed. Should we all still run carbs, just because that was what worked 40 years ago!?"

It's not just Shankle that sells uprated Torsion bars and springs...which is the onlything Shankle I have BTW. I just can't afford to buy even larger T-bars from OZ or Sweden, hence the use of Shankle. So it's not like I'm trying to target old technology (your carbuerretor example) but there's nothing that's convincing me that Ron is using "new" technology or whatever. His stuff IS NEW, and seems to work. That's reason enough to buy it, but not because it is NEW technology and mine is OLD technology. You could even say using just torsion bars and springs is the most elegant way to run a dual purpose transaxle car (I'm not adding coilovers onto an existing suspension system). I DO think that an all coilover front would be great though.

I want to point out that while I seem against Ron's coilover ontop of t-bar method, I actually know it has many merits, including a smooth ride before the springs kick in...I think that is quite cool actually.

Now, ofcourse Ron's cars are fast with RS kit. ANYTHING with stiff spring rates can be fast on ultra smooth roads. Anything. I'm even hearing my own points being given back to me in the above posts, infact (my VW bug example?). If you don't let the LCA's move, of course you're not going to run into geometry problems. And besides what looks like tremendously high build quality, what about Ron's stuff is new technology? Tacking on a coilover onto a torsion bar, and making some adjustable spring perches? I think what the appeal is, is for not a huge amount of money, you can pay for this man's R&D and get something that controls body roll, really, really, well. That still doesn't change the fact that the geometry is fuxored. If you run a car really stiff just to get around poor suspension geometry, you ARE losing potential. It's my belief that if Ron set up his Ring cars for better suspension geometry (Roll centers don't just create more or less roll after all, they also put force on the tires in sometime undesireable ways -- laterally versus putting load ontop of the tire) and used his kit, his cars would be even faster. Ron might not have changed his geometry on his race car, but the IMSA racers and the SZ engineers sure did. Why is that? And even with an RSR kit being around, why to people like Barry and others (on the gtv6.com/bb forum) go through the hassle of making their own control arms?

"Colin Chapman HIMSELF wrote that this is NOT necessarily true for ALL cars. It has also been proven in race-applications that if you can control the roll-center somewhat

You're saying the Lotus man said that the control arms don't have to be in proper angles on all cars, all of the time. Can you be more specific, so we can see if Colin meant his theory for cars like ours? Show me that what Colin said applies to us, and I think we can all take this statement with a bit more credibility.

The only RS kit I've gotten a ride in was Louis' 24V and and along time agon when Nizam drove me in Louis' Red Verde. I remember the Red Verde gripped like hell around some turns but my recent experience in the 24V tells me the suspension is WAY stiff. Too stiffy maybe for real roads? I believe Louis was mentioning the same thing when I was riding along with him. Maybe I was just riding in an example of Ron's kit that had too stiff fo springs, but in Louis' car the car felt over springed and underdamped (no offense please! I'm just stating my opinion of riding for half an hour in his car).

So I have to go now, but believe me, if I can't figure something out that is acceptable to me and Ron's kit is the best thing out there a year from now, I will be buying it. I mean, I've already have his sways, there's not much left


And how the devil do you make a proper quote?

[nizam]

Grant - I just found out a friend of mine has a GTV6 with the whole RSR kit. I'm going to go do a "swap-a-drive" tomorrow with my Beninca-equipped Milano. Sure, the GTV6 has a slightly shorter wheelbase, but this is just a "get to know" session. I will, however, put lightweight wheels and the same tires on his car (I have another set) to even out the equation a little.

I'll share my very subjective observations soon.

[Grant]

I'm looking foward to it. What suspension are you running/will be running on your race car?

Will you guys be driving around on the street or do you have some track time lined up?

[nizam]

I think we'll play tag on HWY 9.

[Grant]

This is asking a bit, but anychance I could tag along and observe?

[nizam]

We have a car project to complete first. I'll call you if we get around to playing.