Mark T

iTrader: (1)

Do you know of a web site that has pics of this set-up?

WailinOnYa

iTrader: (4)

RedFoxRacing: Essentially it is a castorblockless setup. There is no Castor block on this suspension system, instead it uses new arms and a small pivot block that the steering knuckle attaches to. The steering block has a ballstud kingpin that goes through the knuckle and threads into this small block which in turn has a long kingpin that pivots through the A-arm and also threads into the small block. The kit comes with its own shock tower as well. It's a bit hard to picture, I have pics of this sytem on my car, if you want P.M. me your email and I will send you some pics. I don't know how to post pics on forums.

silence360

That is actually a pretty damn good explanation. As soon as I get my B4 up and going and start racing again I am going to put both to the test. I feel that I will put better lap times with the Double X w/ the active caster system. The car just felt that much better, but it has been many years. I just like the feature and think that it works really well.

Cl - 1 Brodie

iTrader: (2)

yep, i used the SACS suspension way back in the day on my xx & it realy was dialed. i think there was only one way that i think they could have improved on, & that was to do with the way the wheel runs inline with the king pin, apart from that i think it'd be great to see something similar on 2wd's today.

silence360

That is exactly how I feel. Again after 7 years you would have thought someone would try to improve it and actually put it on a better car.

I don't see how it would work if the kingpin was anywhere else. Care to explain a lil more?

WailinOnYa

iTrader: (4)

I think he may be referring to an inline axle, like what Associated makes for the B4, where the kingpin/hingepin actually goes through the axle. Only thing is you would need to run an associated type of axle for this system with the bearings in the wheels. The losi axle couldn't be used because the kingpin would have to run through the bearing supported axle, unless you made a new knuckle that used an attachment like a xx4 with pivot kingpins/screw that would not entirely go through the axle, this would allow the inboard bearings and the losi axle.

mfishel

I'm sure the inline set up is what is being referred to. I also got out of racing around the time of this system. I returned a few years ago and had the same reaction to the way designs have gone. The difference is that I was surprised that they had gone to a trailing axle set up. I have the in line steering knuckle for my B4 but have never run it. This car has all the steering I could ever need. Currently I have my steering dual rate set at 80%.
Theoretically, and in full size racing an in line design should be better. However in application with these cars it does not seem to be. I believe the problem is with friction. With 1/10th scale cars on off road tracks THERE ISN'T ANY. They don't weigh enough to load the tires on their own. A full size racer uses the weight of the car and lateral loading of the tires to create grip. With these little machines you must induce this by dragging the tire across the track surface. That is what a trailing axle will do.
This may also be the reason the Schumacher design hasn't been used. It just doesn't work in these conditions. If the track is loamy like tracks often used to be, and the tire wasn't dependant on mechanical grip it may work. I think you would find that with a modern car on a packed clay track you would experience a LOSS of grip.

Mark T

iTrader: (1)

Wailinonya- YGM.

silence360

Well I raced the system in many different track conditions, and it really shined at every track that I have raced the system on. Most of our tracks here are really hard clay. But there is a few tracks back in the day where it was somewhat loose, that's because the track use to be in a old barn at the Country Fair. I just don't understand how it would not work in any condition with the way you explained it.

The way I look at it, the more tire to the ground, the better the traction. Well that is the way I think about it, to keep it simple.

WailinOnYa

iTrader: (4)

One thing that needs to be cleared up about how this system is different than a conventional system is not just how it looks but how it actually works! A conventional castorblock setup sustains the same amount of castor angle for what ever degree the turning radius is under suspension compression and rebound. On the SACS system the Castor angle does not remain the same, it alters its angle depending on turning radius and the amount of suspension compression or rebound, hence the word Active in its name. Standard systems have a fixed castor angle, The SACS system changes its Castor angle through turning radius and compression or rebound of the suspension.

mfishel

Tell a guy that builds full sized road racing cars and has no experience with these types of machinery that your car has 30 degrees of caster up front and he will politely tell you that you must be mistaken.
The point is that there are a lot of things going on with them that negate the logical thought that keeping the wheel upright is going to cause greater contact patch.
Think about a broom. Hold it straight up and lightly drag it across some concrete. It will just sort of skim across the surface. Now hold it at a sharp angle towards you. Use the same pressure and see what happens. It will quickly 'dig in' and bend the bristles and resist your trying to move it. In a tire that resistance is 'grip'.

silence360

That is a great explination. But from my personal experience driving the car, that just doesn't seem to happen or come into play.

Maybe I need to make a video once I get both cars running.

bender

iTrader: (4)

I tend to agree with mfishel.

I ran a Schumacher Fireblade buggy for a number of years and found that it had more steering once I took the SACS system off and replaced it with a "Normal" setup.

silence360

See, the thing is, I saw the opposite with my experience and I raced with it quite some time.

WailinOnYa

iTrader: (4)

I found an old Product Watch review in a July 1995 RC Car Action Magazine that tested this system and it's description is as follows:

(This first part is referring to the XX original front end setup or any other cars for that matter) "The problem with this setup is this: when the nose of the car dips in a turn, the caster angle stays steady with the cars nose and not the ground. With the SACS, the caster angle increases as the suspension is compressed; caster is kept constant in relation to the ground. This allows my test Double-X to go into and come out of turns harder, especially off power."

The end result of the review in this article basically gives the SACS system praise and the guy says at the end of the article:

"The Active Caster System is one of the best performance-enhancing hop-ups I've seen. With its modified front end, the cars cornering rivals that of the best cars at my local track."

Also an explanation of why it works:

"The angle of the SACS pivot pin is the key to this kit's geometry (referring to the kingpin that goes through the A-arm). It's at approximately 45 degrees to the chassis (the conventional caster block style suspension is a parallel setup.)