Race car suspension Class

[Maliwagon99]

Notice my postscar were gone? I gotwas deleted forand being a spammer somehow? Anyway now that I am back up and running I can ask more questions. On the rear ARB will a aftermarket stock mounting one suffice? I have seen some that mount to the rear end with similar bushings as the front mounted on the housing then the ends hooked to the LCA ahead in the front with some adjustable links ie http://www.hotchkis.net/_uploaded_files/78-88_gm_g-body_extreme_sport_rear_sway_barproducts455image_2.jpg . Since it doesn't say anything in the rules about it id like to try but I have a good feeling if I start winning that will be the first "gray" area fixed and that bar mounting system isn't cheap. Your thoughts?

 

[Ranger Mike]

I would mount a stock appearing ARB on the rear as close to " stock " location as possible and I do not think they will say anything because the car came with one from the factory..right?

 

[Maliwagon99]

You know I bet that ol wagon did "wink" :) thanks RM

 

[John LNZ]

Hi Mike. A question for you please... We have a car that is still struggling for side-bite on a flat slick trac. I am considering reducing my front roll couple by either reducing my right front spring or lowering the rate of my swaybar. I figure that this should transfer more weight onto the right rear through the first part of the turn. Am also considering reducing the rebound on the left rear shock and increasing the gas pressure hopefully speeding up the weight transfer left to right. What would be your opinion on this?
Thanks

 

[Ranger Mike]

Welcome and thanks for reading the notes.
I assume you want to hook up faster and better to drive out of the turn..right?
Flat track needs a lot of stagger and this is what drives you off the turn.
Don’t forget when you increase stagger you have to add cross weight to keep the same down force in the car.
Spring change- As stiffer left rear spring will tighten the car from middle of the turn to exit by keeping the cross weight in the chassis. Side bite and traction usually are a factor of the rear lower trailing arms and we need to look at these. Are you running 3 link or 4 link? Torque link? Do you have spring loaded radius rod on the rt rear?
Raising and lowering the front of the rear trailing arms impacts the amount of load placed on the rear tires under acceleration. The trailing arm up hill angle adds more load because the rear end wants to move under the chassis as it hooks up against these links. The uphill angle of the arm reacts against the twisting motion of the rear end and ultimately loads the tire. Classic axel thrust. If you want more right rear side bite move front of the rt rear trail arm up hill a few degrees. But if you wil be taking load off the left rear when you do this. Typical setting are 3 degrees on the left rear and 2.5 degrees on the rt rear. Watch out for roll steer and know what the change does when you change this. See post 116 on page 8 of this forum.

 

[hariss]

Formula Suspension Design

Hallo Mr. Mike, I read your post and that was really helping. I just read about how to design good RC location for double wishbone suspension and I've been tried to design suspension for formula SAE. I assume that good RC location is 1 inch above ground (minimize jacking effect and non rolling overtunning moment) is that correct? That I don't understand is how to get optimize length for upper control arm (find inner pivot location on upper ball joint / find final IC location) so that my design with RC 1 inch above ground and initial fsva length approx 78 inch has optimize length for upper control arm.

Thank's

 

[Ranger Mike]

Hariss welcome and thank you..many people and racers have posted here...I think 1 inch abov pavement is a good start...I recommend the chassis software as a very good tool to get the proper height and location as well as seeing the RC migrate thru bump...it is worth the $ 100 or so...well worth the effort to get the checker flag!
if not possible send me provate message
rm

 

[tscott8]

Ranger Mike, what do you know about the new "Weight Jacking" setup taking the asphalt late model series by storm. I notice the guys running it use short upper arms for fast camber change and a ton of lf upper angle. People running this have a ton of travel and I've seen upwards of 12 to 15 degrees of lf camber become 0 at mid corner. What is going on here that I can use to be successful?

 

[Ranger Mike]

TSCOTT, i am currently in Europe and do not have access to my notes. Will return in a week. I will be able to give better reply with notes but suspect the trend has some merit. How do you know the camber goes to zero at mid turn? any more insite on what and where the weight is jacking to?

 

[tscott8]

I just know from observation that the lf stands up for proper camber because I've measured old tires in the trash pile from the top team doing this. It is suppose to load the lf i assume, because that car can turn really good. Just from basic observation they use a short rf spindle where the rf lower is all the way down and the rf camber change is very minimal while the lf is really tall where static angle on the lf upper is probably 25 to 30 degrees. I've also heard that the pin angles on these trick spindles are less than 5 on the rf and 15 on the lf. This team runs hillbilly on the front with a 2" bar and hardly any spilt in the back springs, sometimes hillbilly back there. We race Nascar late model stocks around nc and va

 

[tscott8]

I think it is called "weight jacking" because when the side force is applied to the cg and the cars chassis wants to roll to the right but the tires pull to the left, the lf suspension jacks down on the spring because of the high angle in the upper

 

[Ranger Mike]

Long plane ride home...ok...when we swap in the taller left frt spindle we shift the front roll center to the left, which is what we want to plant the right front tire..a lot of previous posts on this a few pages back. Typical NASCAR spec late models run around 17 degrees upper A-arm angle while the outlaw series run 20 degrees rt top and up to 26 degrees lft ft top A-Arm. If you look at post 325 and 332 on page 21 at King pin inclination angle you can gain more insite. Bottom line is when going into a left hand turn you are pivoting on the scrub radius ( see post 325 i think). This makes wheel base longer on the right side. When in a left turn, Scrub lengthens the right side wheel base and tends to loosen the car. When you counter steer, it shortens the wheelbase and adds understeer. This is a driver friendly situation as it has a very stabilizing effect to the cars handling in driver feed back. The driver needs feedback in a turn because it tells him how heavy the tires are loading and when they are on the edge of traction. We need more scrub on the left side due to posative camber we run. In outlaw series we run all kinds of trick upper and lower A-Arm combinations but in restricted series you have to look at what is still " open" and go with radical king pin angles and scrub radius tricks to help the front pivot. If you look at the camber build on an outlaw super late model is really goes to zero at mid track on rt ft and darn near same on lft ft...remember..it is all about the tire contact patch.

 

[mustngthundr]

tscott8: I've been digging into the setup you're shooting for myself. We don't have any locals at the tracks I run at using it, but at the invitationals the out-of-town cars run a setup like this and they are extremely fast. Considerably faster than our top regulars. I haven't found a whole lot of info on it either, mostly gathered info from eavesdropping and observing what they were doing from a distance, cause they certainly weren't going to show you, matter how nice you asked. I've heard terms used with it like "camber thrust", "jacking force, are the most common. I've been told a correct shock and bumpstop package is a must. I've experimented with copying this setup, but I can't say I fully understand it. I've recorded the fastest times our current chassis has ever turned, but I struggle with consistency, partly due to being a rookie in a SLM, but definitely because there's more to it than I understand. Anyone that could give more insight, either by posting on here or private email, I'm eager to learn and would be happy to share any info I have. Also thanks Ranger Mike for your help on this forum, it is a great source of information

 

[Ranger Mike]

Doc Hathaway wrote one great piece on this whole scenario.
It is a must read. It is a mandatory read before you do another thing today.http://ismasupers.com/downloads/Tech-02%20Suspension%20Geometry%20relations%204.pdf

Everybody else sets up the car with your typical camber setting, caster splits and recommended “ hot set up” Kingpins and spindles. Some may even know enough to add the proper offset on the front Roll Center. The car gets around the track pretty good if you hit on the close spring rates and shock package. And you wil be competitive with every body else because you have copied every body else “ hot set up”...maybe better because you have the proper RC height and offset...but..
all this stuff is static set up where as the suspension moves and we are trying to use a static setup in a kinematic ( moving ) world. The guy who understands what is happening in this kinematic world will be able to set up and run a lot better.

Basically the new " hot set up" is to run very soft springs that will hit the rubber bump stops ( post 220 on page 14 above) just when you make mid turn. You want the springs to take the max load before bottoming BEFORE the rear end comes around on you.

This setup uses the King pin Inclination Angle to crank in caster to " weight jack" from the inside rear tire to the outside front tire to build proper camber. But, KIA adds camber to the LF and takes away camber from the RT FT unless you have accounted for this by compensating for it during suspension movement. Hence. the different KIA. Min camebr loss on RF by low KIA, where you want the LF to ad more Pos camber so larger KIA on left spindle. You want the max tire contact patch on both front tires at mid turn. Scrub radius and caster do this weight jacking. If you set up your particular chassis correctly, with differing Kingpin Inclination Angles (KIA) and scrub radius ANNNDDDDD you run softest spring rate to rubber bump stops, you will be using the transferred weight to the max to plant both front tires to turn the car. Don't forget the Roll Center offset which comes from the different spindle heights. One more thing. Static caster and camber does not tell the whole story. Depending upon your set up, different outcomes happen when we have a tire contact patch acting thru the scrub radius as the suspension moves. You must know what is happening at the tire contact patch while this whole compression / weight transfer is happening.

Because there are so many variations of A-arm lengths, spindle / ball joint heights, spindle heights, etc..it is impossible to replicate the fast guys set up unless you have an identical chassis. You must understand the theory to make it work ON YOUR car!

It is like it has always been. Tires, Tires , TIRES..and the guy who makes the max tire contact patch on all four tires a higher percentage of the time will run faster and better and win.
hope I did not confuse you..clear as mud?
rm

http://ismasupers.com/downloads/Tech-02%20Suspension%20Geometry%20relations%204.pdf

 

[mustngthundr]

Thanks Ranger Mike, your response was definitely helpful, as was the article in the link. After reading I'm sure my caster setting was off on both sides, probably camber settings too. I've invested a lot of time and money into (attempting) to educate myself on the kinematic aspect of the sport, and admittedly have a long ways to go before I'm happy with my personal level of understanding of the chassis and dynamics involved to make a fast race car. Our fast and consistent regulars have new chassis set up by their respective manufacturers, and they don't change anything on the car without calling them. There are few respectable cars that are set up by years of trial and error but not much understanding of what is actually going on. I don't want to be one of those guys, and I've come a long ways in the last few years, but there's a lot of aspects that I definitely don't understand. We did try to more or less copy what the super fast cars that came up a couple times a year were doing, hoping to eventually figure out what they are doing that works so good, and use it to my advantage as a regular until everyone else figures it out as well but try to stay a step ahead. We were close a few times, super fast and just trying to fine tune, and somewhere in the fine tuning throw something way off and struggle to get back. We did go as far as checking what was going on static and in dive, use performance trends software to map the geometry and a chassis r&d program to balance the chassis and set wedge. We have an awsome shock package, and more power than we could ever use at the tracks we run at. The biggest problem we keep running into is a corner entry push, and as we know a poor entry results in a poor corner overall. I've been told I drive in too hard, and that may be a portion of the problem, but we did get it to work really well a few times so I think a setup error is definitely more of the problem. To try to reduce the chance of it being a brake system issue, even though everything was rebuilt before last season, everything is new for next season except the pedal, and a package recommended by an extremely seccusseful team that races all over the country. We run 10 inch Hoosier tires, spline 1 7/16 3 piece sway bar, 10 degree spindles, bump steer set to near zero through the full range. Tire temps were always pretty decent, showing good use of the contact patch, but I've since learned about measuring the tire wear as well so our camber on the right may initially be a little low. Roll center about 10 inches left and 2 inches above ground, about 2 inches of movement through travel.

Thanks again for all the info you put on here, it definitely helps. If there's anything else I should be looking into based on this info or if you need more info about the car is be happy to put it up.

 

[Ranger Mike]

Mustngthundr...thanks you..

question- is car pushing going in and loose coming off turns?

 

[mustngthundr]

Typically not loose on exit. From about mid- turn off its usually pretty decent unless I get held really tight to the inside, then it will get a little loose.

 

[Ranger Mike]

When we have Roll Center too far to the left of centerline, the car will not turn well. We have to load the right front tire with down force to assist the tire. See Post 251 on page 16 Body roll does not give enough leverage to stick the rt ft tire. It slides sideways thru mid corner. When we exit, there is not enough lift from the Lft Ft on to the RT Rear to add traction.
Your roll center is 10 inches to the left. You are right on with the suspension software as thsi is the tool to figure out the set up.
We must locate the RC to the right of centerline so at least half the left side mass sprung weight is rotating thru it to stick the Rt Ft. Unless you have Aero adding a lot of down force at the end of the chute, you need this to stick the rt. ft. So we run 3 to 4 inch offset to the right of centerline just for this purpose.
As a minimum relocate the RC to center...3 inch to the right is ideal. This means you will have a little more than 55% left side sprung weight wil rotate thru the RC ( on 66" track width car). This will make your set up consistant and you can fine tune from here.

 

[mustngthundr]

Ok that makes sense. I'll give it a shot. Thanks again!

 

[NaLLa8705]

Hey mike!

Finishing up my race car build, found a friend with chassis software, now wondering where to measure my upper control arm pivot points so i can determine roll center. The upper control arms on my car are angled so at what point do I pick to plug into my software? Dead center?

 

[Ranger Mike]

welcome and sounds like a good plan. On all the chassis software i use, i have to measure the height and location from center line of the top outer pivot point and top inner pivot point and the software calculates the angle. The better and more accurate you measure, the better. I had to make stop blocks to jam under the lower A-arm to maintain exact height and slipped off the front tires on occasion when running wide tires and big wheel offsets masking the outer pivot point. Eventaully I borrowed a portable cmm arm.

 

[NaLLa8705]

Perhaps my question wasn't clear enough, or maybe because I haven't I looked at the software I am confused, but what I am having trouble understanding is where on the pivot do I pick the point to put in. The arm is angled like I drew up in paint.

That is in a two dimensional plane...

 

[Ranger Mike]

on circle rack analyzer use attached..i use suspension analyzer which requires 3D input

 

[rohitsr987]

hi..i am building a groscope sysytem to balance two wheelrs..i need to know what is roll torque and how it can be countered?

 

[07superstreet]

Mike,
Hello, i am new to the discussion. I stumbled across this website and forum, luckily i might say, trying to find some information to help my race team. We have a stock snout, camaro frt. clip, tubular 2x3 tubing, chasis. It's been difficult getting the handling on this chasis. Before, we had a stock camaro chasis and we had figured out what it took to make that chasis work, but we were behind everyone else. They had swicthed to the chasis that we have now. With the old chasis, we would run 49-50% frt. and rear percentages. Only reason for that was that was all we could get. On this chasis, we run 55% rear percentage and 52-54% left side. The issue we are having is with ride height. We can not find anyone that can or will give us ride height numbers for this chasis. In reading all the information on this thread, i see that ride height and all related to that are very important. I know that if we can get the proper ride height, everything else will fall into place. Thank you so much for all the information you give. I have been glued to this thread since i found it.

 

[07superstreet]

Mike,
I failed to mention that this is a dirttrack car. Sorry for the omission.

 

[Ranger Mike]

welcome 07superstk and thanks for the kind words...I am not the only contributor here and we have a lot of racers on this post!.
my opinion for what its worth ...
Ride height – distance of track surface plane to four reference points of the bottom of the race car chassis. This Ride Height will allow the race car to go faster than any other height setting for a particular track. Typical ride height has 3 criteria.

1. Chassis clearance –You need enough clearance to accommodate suspension travel ( 3 inch for stock car classes paved, 4 inch for dirt) yet keep the car as low as possible without bottoming the suspension components.

2. Front camber build. As the body rolls we build camber. For every 1 inch body roll we build 1 to 1 1/2 degree camber because the bottom A-arm is longer than the top A-arm. Set the ride height and check camber build over 3 inch travel ( paved). If the camber build is over 1 1/2 degree per inch the car is too low. If the change is less than 1 degree the car is too high and I do not believe this rule of thumb. More on this later.

3. Rear Steer- We want minimum to zero rear steer at desired ride height UNLESS WE INTENTIONAL DIAL IT IN. We want rear trail arms as level to the pavement as possible. Leaf springs will most likely be slightly down hill to counter anti squat.


My opinion – I think it best to change the Roll Center Height and location with the applicable suspension components. Drop the RC to at least 2.5 inch above track surface and 3 inch offset (paved, 4 inch dirt) to the right to help plant the RF tire, reduce camber build, and reduce weight jacking effect. If you can afford it get the spindles that will give your set up minimum camber loss due to King pin Inclination angle (KIA) on the right side and max positive camber build on the left side AS YOUR SET UP REQUIRES. I like Ackermann and zero bump steer. Once you got all this you should roll steer the car at the rear to see what is happening through your suspension travel and correct to zero. Then see where things set. Pick your 4 bench mark points and permanently mark them. A grease pen is not permanent and paint grinds off is you suffer an off track experience ( get into the marbles or out in the weeds). Weld a big washer at each point. Now you got a permanent bench mark at each corner. Finally, cut a piece of 2 x 4 board the proper height to slip under each bench mark and mark them RF,LF..etc... When at the track you can use a level concrete pad and check the established ride height should you crash and need to swap out suspension parts.

Personally, I am not a great believer in ride height as much as being aware of what is happening thru suspension travel.
Chassis Rake - not so much on door slammers as Formula Cars, Rake is a setting where the front is as low as possible and the rear is an inch higher to try to channel air properly under the car. With todays disfussers and belly pans, level is good and the hiked up rear is old school and can hurt aero.
If you need specs, here they are-

Typical ride height is LF – 4”, RF – 4.5”, LR - 5”, RR, 5.5”. paved
dirt needs a little higher to gain overturning moment
LF- "5, RF - 5.5", LR -5.5" , RR - 6"
One alternative to ride height blocks is to make clearence blocks that will fit between front A-arm to chassis points and trail arm to rear end tube points on the rear. Paint large arrows at these points so you can duplicate measurements at the track.

 

[07superstreet]

Thanks Mike. Can you give me some points to make the measurements from? The stock snout is connected to the tub chasis where the rear clip bolts would be bolted to the stock camaro chasis. That is what the snout is from. A 1979-81 camaro. The 2x3 tubing chasis is that from an older Dirt Late Model. The frt. suspension is stock lower A-arms, tube upper A-arms with the mounts relocated more forward and shorter racing springs with screw jacks on top of springs. We have racing shocks all around. The rear suspension is Chrysler style multi-leaf leaf springs attached to the chasis with Sliders. We just added the Sliders this off season, so we don't know what the car will act like with them. Any advise on the best/easiest way to make the RC measurements would be great. The car doesn't have the body on it, but it does have the engine and everything else in place. Thanks again for your help and time! If anyone else is reading this that might have some helpful information, that to would be greatlt appreciated. I am trying to get away from the"good ole boy" information from the locals.

 

[Ranger Mike]

Now is the time to do all the hard work on measuring the suspension. Taek out the front coils and unhook the ARB.
Use the easy acess to record bump steer, ackermann, camber build, rear steer and the like thru at least 3 inch travel, more for dirt. Suspension bind will kill you on handling. Pay close attention to shock travel and make sure they are not rubbing at max travel. And make sure you don't have shock that limits your required suspension travel. It happens. Same with ARB (swaybar). You don't need the body on thecar to get some good scale data but you should have weight added for fuel and driver. Once you set ride height go thru the drill of cranking on the wedge bolt to see how much cross weight you gain. Record it. Your penci lis your best friend during this time.

read page 19 post 290 and the rest on benchmarking the car.
Ifin you get the Roll Center height and location close and it does not migrate all over the place, and you get close on the spring rates, you can tune in the rest at the track.
But you must bench mark the car to get there.

 

[Ranger Mike]

Nascar Gen 6 car

Couple of things about Daytona this year. First up – You can thank Nascar for making as good and safe a race as possible in spite of the bad crash that saw an engine and various components end up in the stands. Dales death was a loss but we all gained from it by efforts made to make the sport safer.

Generation 6 Car - The Car of Tomorrow (COT) has been raced for 5 years and Nascar decided to try and make the actual race car look a lot closer to the production cars. One reason - Dodge dropped out of the series, another rumor is that GM threatened to leave if the cars did not resemble production cars.. NASCAR allowed the three manufacturers to develop unique versions of the Gen-6 car. That led to cars that closely resemble the Chevrolet SS, the Ford Fusion and the Toyota Camry. Grills and body lines are similar. Silhouettes are within millimeters of their showroom counterparts. Hence the new G6 car and you saw Ford, Chevy and Toyota all show case their Nascar entry in a show room with the production model during the race.

Last year they mandated ethanol and fuel injection and that gave the engine room boys a full load. This year they decide to cut 160 pounds off the car and re-engineer the rear end package. The hope is, with less weight, Goodyear will be able to build a softer tire that will provide more grip, create more tire wear and make the cars racier while using the same chassis from the current car.

One team crew chief said the center of gravity will be off from last years set up and all new bench marks have to be established. NASCAR is doing all it can with the new car to improve handling and reduce the aerodynamic push that makes it hard to pass with the current car. The center of gravity for all these cars will be off (too) because they (NASCAR) are taking weight out of the cars: 100 pounds off the right-sides, 60 more pounds off the left-sides. The intent was to ease the load on the right rear tire.


Another significant development with the Gen-6 is the attempt to do away with “crabbing” — where the rear of the car is skewed to the right.

Crabbing was achieved by altering several rear suspension components and it improved handling by increasing down force and side force.

“Everybody did it to some degree,” Germain Racing crew chief Bootie Barker said. “Instead of having moveable bushings, you don’t have those anymore, you’re limited on your truck-arm split and you cannot run a rear sway bar (except at the road courses). Elements that went into crabbing have been taken away. Crabbing' is the long-familiar chassis trick in which cars appear rather sideways down the straights, in order to have better cornering. That's part of the trick that Rick Hendrick's teams, particularly the Jimmie Johnson-Chad Knaus team, have used so successfully.

NASCAR changed, again, the 'skew' of the rear-ends of these cars and wants basically a 'straight-up' rear-end housing. 2012 cars run rear-ends with a half-inch of toe-in on the left and a half-inch of toe-out on the right. This year 'zero toe.' means the 'crabbing' around the race track will go away.

In addition, NASCAR will be allowing teams more 'camber' in the rear-end, four degrees instead of just two degrees in an attempt to get grip back in the car. And no rear sway bars. According to one crew chief , “The rear of your car will be more 'stuck' with four degrees." Here is the wrinkle- The COT was designed for aero grip but did not look like a stock car. Todays production cars do not have the same aero grip as the COT so the G6 rear spoiler is bigger to aid rear down force. Had to since you are taking aero-grip away from the car ( G6 vs COT) and putting mechanical-grip back in the car. That's good, though Goodyear may have to make some tweaks since the changes force teams to design new drive-plates and rear axles because when you start 'bending' rear tires further, things that want to run straight don't run very well.


2013 changes include new Windshield package. The windshield frame is oriented to position the test windshields at 37° from horizontal. Both the monolithic and laminate windshields were tested. All test windshields had a single layer of Mylar tear-off applied. A steel projectile passed through the monolithic windshield but did not pass through the laminate windshield. Analysis of the high-speed video reveals that the steel projectile was traveling at 110 fps after passing through the monolithic windshield. This equates to 161.6 ft·lb (219.1 J) of kinetic energy. While the monolithic windshield allowed the projectile to pass through it, the projectile kinetic energy was reduced by more than seven times. As a result of testing, the laminate windshield is being implemented for 2013 NASCAR vehicles. FYI - Simply increasing the thickness of a single-layer monolithic polycarbonate windshield is feasible only to a point. Acceptable optical clarity becomes increasingly more difficult to achieve as material thickness increases. Secondly, as the windshield weight increases, more emphasis must be placed on windshield retention.

Other changes include a redundant Halo bar and backwards Petty bar to stiffen the roll cage.

While the wheelbase remains at 110 inches, the length of the car was reduced by 6.3 inches—from 198.5 inches to 192.2. The width also was increased by three inches—from 74 inches to 77. There were no significant changes to the height (54.2 inches) or ground clearance (3.5 inches).


http://www.nascar.com/en_us/2013-car.html

 

[sierra76]

A Arms

Hi Have not been on forum for some time. Thanks for the 3 link advice Ranger Mike your set up worked really good with our car winning 7 Features in a row.
Just working on front arms and was wondering is there a ratio to the length of top to bottom. Also ideal front roll centre height for space frame 4 cylinder dirt track car . Any help would be a appreciated.

 

[Ranger Mike]

changing front RC and cheating the scales

Thanks much for the kind words but we have a lot of contributors here and the credit goes to them too,,
I would not change a thing..until,,,I measured your front end setting and found out exactly where you are now with the RC height and location...
ifin it aint't broke , don't fix it...and you got 7 checkers...i really recommend you find out where you are before changing a thing..then get the software and figure out what the Roll Center migration is and where it is moving within your suspension travel...there is no ratio on upper to lower A-Arm length in a purpose built car as they all are different and unique..hence the need to benchmark a winning set up so you can come back to a base line after a crash or going off in the weeds regarding new " trick" hot set ups...

one more thing..I got a private message asking if a race car can be too light...in my opinion..no...you can never go too light ..as long as safety is maintained..in my early days we ran a roll cage set up where only the main hoop was to the required wall thickness..the other bars were “ exhaust tubing” wall thickness...dumb dumb dumb...this action was when I was always seen at tech inspection at the scales with my clip board. I would lay it on the right side of the car when we pushed it on the scales...surprising what you can do with a acetylene torch and a bunch of old wheel balance weights on a winter night...ask me about the 50 pound helmet that was an exact copy of the one our driver wore in the race and ALWAYS hung on a hook on the right side of the cockpit..left side weight rule, huh! ...takes practice to swap out things on the way to the scales after the feature...but that would be cheating...

 

[Ranger Mike]

200,000 views

200,000 views of this " race car suspension class"...wow!

Thank you for the support over the last few years...what ever small contribution I have made here is due to the books and references I have tried to note along the way. Credit goes to those authors as well as various software programs related to chassis set up. Like I have always said..You can set up a winning race car your self..all I did was shorten the time a little...
RM

 

[NaLLa8705]

Thank you so much for the picture, it helped immensely.



Here is a theoretical question for you. On a small 1/4 mile track with a 7-10 degrees of banking, which car would be more successful.

Car A) 52% Left side weight, 2300 pounds total
Car B) 55% Left side weight, 2450 pounds total

Assuming all other things similar (rc/cross/ect), fwd chassis, stock everything

 

[Ranger Mike]

lighter is faster

thank you...in my opinion, lighter is faster and what you said. this is a bone stock class...which means power to weight ratio is everything...if bot hcrs have same engine..i.e .power out put...go with the light one.