Is there such a thing as too much left side weight when racing 4 cell oval? if so, under what conditions (class, running surface (carpet vs. paved)? Just curious, as I can't think of a time when running a pan car where I have felt I had too much left side weight...dirt oval, well, that is a different story..;)

Comments?

Good question. I'd like to know as well......

My car is right at 60%. One guy is supposedly running closer to 70%. !!!

When I ran at the Velodrome two weeks ago (the first time ever) all the guys said to run the batteries as much inboard as possible. So, I'm thinking on High banked Oval you could have too much left side weight. I'm a roadcoarse racer that just started racing Oval about a year. So, I'm still learning myself. Maybe we can hear for some of the vetrens here?

In my experience, the further out the battery, the looser the car. It effects the car mostly coming off the turn. Good tuning aid, especially on banked tracks because the bank often makes the car turn too much.

70%?? i have had mine around 63%, thought that was high, not sure what someone would have to do to get 70%...? I agree on the velodrome/hi bank stuff. found that out at Major Taylor a few years back

Generally for capped tires depending on the track you dont want a ton of left side weight.. i run a 50/59 split for rear weight.. You will also see alot of guys moving the batteries alot more forward, and in on the tray... you dont se that to much with flat tracks..

Flat carpet track , L4 based car , 63-64 % left side , much more than that and your not going to transfer the weight to the rt. side enough thru the corners.
Perfect world --Car should be 50 / 50 thru the corner on oval.

Just my opinion ????

R.S.

I personally think that we are getting plenty of weight transfer to the right side. Look at my car for example:
http://www.comparecenter.com/photodata//James/Hobbies/640/IMG_6918m.jpg
I've got the weight to the left as much as possible, and yet my right side tires always wear faster which suggests they have more weight on them in the corners.

Katana Man the tire that wears the fastest is the one that is sliding across the surface of the track. Tires that bite the track will not wear as fast as a tire that is sliding across it.

Although the front right wear could potentially be a few different things, I don't buy it when it comes to the right tires. I don't see how the right rear would be sliding and the left rear biting. Especially when my diff is buttery smooth :)

Flat carpet oval, I don't think you'll ever get TOO MUCH left side weight.

How did you get that large picture to load? If I try a picture that large here, it says the file is too large.

How did you get that large picture to load? If I try a picture that large here, it says the file is too large.
The file is hosted on my site. It doesn't take up any HobbyTalk.com space or bandwidth. Full size pic is here (http://www.comparecenter.com/photo//James/Hobbies/IMG_6918m.jpg).

Flat carpet oval, I don't think you'll ever get TOO MUCH left side weight.

Well maybe if the car flops over on its left side while waiting for the tone? LOL
Just scaled my 1/10 BL car that ran pretty well on a 270ft flat asphalt oval this weekend ...67 percent left side weight!

Actually, that was my thought...on flat carpet oval, i can't see how we can get too much left side weight, esp in the lower HP classes. I am sure in the extremely high HP classes that the added stability of having a more even L:R weight split may be of some advantage, esp in traffic.

I started a thread asking about the use of scales for setup if any of you guys have some info.
Thanks, Rick<><

With 4 indentical digital jewelry scales rated 500g each (http://search.ebay.com/search/search.dll?cgiurl=http%3A%2F%2Fcgi.ebay.com%2Fws%2 F&fkr=1&from=R8&satitle=500g+scale&category0=), it's important that the surface is perfectly level for the scales to be accurate. I use an Integy setup board for easy leveling. Then I put the 4 scales on the board.

4 scales right here hobby shopper. Great price.have 4 and work flawless.

So what is a good overall crossweight percentage to use? I've seen a figure somewhere but can't remember what is was, and a formula for figuring crossweight.

Not sure what the ideal crossweight would be haven't figured it for a long time but would guess most of the cars are in the mid 40% range. Just a guess. To figure crossweight rf tire weight +lr tire weight divided by the cars total weight. rear weight 2 rear tires divided and left two left tires divided.

Not sure what the ideal crossweight would be haven't figured it for a long time but would guess most of the cars are in the mid 40% range. Just a guess. To figure crossweight rf tire weight +lr tire weight divided by the cars total weight. rear weight 2 rear tires divided and left two left tires divided.

To start with you need this:

Front total weight 45%
Rear total weight 55%
crossweight 50-52% or about 32-33% left rear weight. :thumbsup:

To start with you need this:

Front total weight 45%
Rear total weight 55%
crossweight 50-52% or about 32-33% left rear weight. :thumbsup:

Thats a good starting point along with 58-60% left side Thats what we used to run in the Karts the IMCA modified the asphalt late model......... funny how that works out :)

With 4 indentical digital jewelry scales rated 500g each (http://search.ebay.com/search/search.dll?cgiurl=http%3A%2F%2Fcgi.ebay.com%2Fws%2 F&fkr=1&from=R8&satitle=500g+scale&category0=), it's important that the surface is perfectly level for the scales to be accurate. I use an Integy setup board for easy leveling. Then I put the 4 scales on the board.

I bought a bullseye level made by Starret it cost only $3.98 from MSC Industrial Supply. If a Starret level isn't accurate, then nothing is.
One thing I have noticed however (the machinist in me comes out!) is that all these tweak boards use 2 scales and a piece of something (particle board, MDF, etc) to support the other two tires, albeit the fronts or the rears. I measured the height of my scales and they are .768" high at 0 ozs (they are shorter as more weight is applied). The board usually used to support the other two wheels is almost always 3/4" thick and so unless you shim up your front end (put something under the tires not being weighed) you won't be level no matter how well you level the board. I think 4 identical scales is the way to go.
Another way around this is to take one of those shorty torpedo levels (about 8 inches long) and level from the top of the scales to the support board. Forget about the platform, the car doesn't sit on that. It's the 4 places that have tires on them that matters. Just my $.04 (.02 shipping & handling!)

I never have understood why most R/C racers use scale boards with 2 scales and a platform because of that reason, especially when you can buy high quality digital scales cheap nowdays?
http://www.hobbyshopper.com/shop/product.php?productid=16144&cat=0&bestseller

To start with you need this:

Front total weight 45%
Rear total weight 55%
crossweight 50-52% or about 32-33% left rear weight. :thumbsup:

RPM you might want to try getting that cross weight number down to 48%

RPM you might want to try getting that cross weight number down to 48%

Hey Dave,

Getting ready for FOCAR first race of the year?
Can't wait to race at MTR...

The 48% crossweight might be where you want to be but you have to
be really smooth through the turns.
Some racers may not be at this point with there driving skills so thats
why I put the 50%-52% crossweight.. :)

Well I don't know if there is an ideal crossweight 50% is a good starting point, I threw that mid 40% range out there because I knew I had dipped below 50% many a time. I think it really depends on track bite tires etc. Looked up some info on my best laps at a local track with high bite and was at 45% cross 65% left 55% rear in abrushless car with a wing. I just don't pay that much attention to cross because it would scare me.

It seems to me that people are too worried about cross weight %. A starting point is all it is. Once you hit the track it will go up or down. The best thing to do is just keep note of where all your weights are after your best run. As mentioned above, use those weights to put you back at a starting point after rebuilding the car. Even then you might change things during the following race day. Same thing with rear weight. Until the motors become lighter, the rear weight will stay the same unless you move the batteries forward or back. The only other is to change the wheel base which is effecting more than just the rear weight. A couple of ideas about how much left you need. You'll need more on tight corners than wide, a track with more bit requires more left. More leftside may require softer rightside springs and more tweek(cross weight) to help the car drive off the corner. The biggest thing to remeber is that all track, cars, and drives take different setups.

Z main rear and front weight both change as tires where. also changing front springs and the amount of pre load changes weights. oh yah and so does chassis rake. you might want to you think that theroy

My car is pretty well dialed right now and I found the left to right ratio to be 56%. Every track is different and every car is slightly different also. I think it comes down to the total setup. Some guys (the former record holder) at our track ran his batteries all the way back, most run them all the way up front (the current record holder). There are a lot of variables. No one method works universally.

Front, rear, and left side weights do not change unless you physically move weight in the car. Regardless of springs, tires, preload, rake, etc.

You are kidding right?

Front, rear, and left side weights do not change unless you physically move weight in the car. Regardless of springs, tires, preload, rake, etc.

You're right Jim ... only cross weight can be altered unless you physically move the weight around.

Steve.

Ummm, have to agree with Jim here. The overall weight distribution of the car front to rear and left to right will not change with tire size changes or pre load changes. Tire spacing changes, battery placement changes, gear(i.e. motor position changes) will affect your side to side and/ or front to rear.

ok here are some facts.

go out and run a 4 minute race come back put the car on scales the weights change.

pre load the LF spring more weights change.

lower the rf chassis height once again weights change.


i think it shows that alot of you guys haven't played with your scales alot. I put my cars on them before and after each run.

Of course they do. However, if you calculate the rear or ls percentage, it hasn't changed. The individual weights and, thus, the crossweight have changed.

Of course they do. However, if you calculate the rear or ls percentage, it hasn't changed. The individual weights and, thus, the crossweight have changed.

I think most people scale there car wrong...

(1) Level the scales turn on and zero out.
(2) Center tires on the level scales.
(3) Push down on the car to let shocks rebound to there natural state.
(4) Read, and record weights

Just setting the car on the scales will give you different readings if you
do not rebound the suspension!! ;)

Z main rear and front weight both change as tires where. also changing front springs and the amount of pre load changes weights. oh yah and so does chassis rake. you might want to you think that theroy

All of these do change the weights I agree, but only a small amout, say .5%. As Jim said, moving physical weight will help change the % enough to make a change in the handling. Consider how your can feels throughout the race. If it looses or tightens up, it is do to traction compound wearing off, cross weight change do to tire wear which also changes your stagger and rake in all directions, and even the voltage going down or motor lossing power. Electric cars have an advantage as they do not loose any physical weight doing a run do to energy consumtion. A stock car, which is different and similar to 1/10 pan cars,weighing 2800LBS starts with about 51% rear weight. This includes a full fuel cell. After a 40 lap feature(main) and using about 8 to 10 gallons of fuel, gallon equaling about 7 pounds, thats 70 pounds lose from the rear, the car now has a distinct loose feeling do to lose of rear weight. Thats a lose of 2.5% of rear weight and total weight. Your car won't lose that much weight after a race.

Some people over look what a light weight car can do for you. If you have to add 2 or 3 oz or more to make weight, now you can place weight in areas of the car to help get the left and rear % that you want. A car that makes weight with no added weight can have a disadvantage to a light car because now you can only work with what the car gives you. Again, I stress the fact that all cars, tracks, and drivers are different. What someone does to their car to go fast isn't right or wrong, it just works better for them.

All of these do change the weights I agree, but only a small amout, say .5%. As Jim said, moving physical weight will help change the % enough to make a change in the handling.





I have very little change in wheel weights between runs, not enought to
notice a change in car handling or lap times.
Although, we run 4 minute oval races...car balance is key!

I use tire temperature to balance the car. :thumbsup:

For the most part, I think guys are OVER thinking there setups. :cool:

ok here are some facts.
go out and run a 4 minute race come back put the car on scales the weights change.
pre load the LF spring more weights change.
lower the rf chassis height once again weights change.

i think it shows that alot of you guys haven't played with your scales alot. I put my cars on them before and after each run.

I think most everyone is missing the real point that was trying to be made.

If you have 450 grams total on the 2 front scales, say 300 and 150,
no matter what you do to the springs, unless you move an object on
the car it will always weigh 450. HOWEVER, after a race, or if you tweek
a spring, most certainly you could have 325 and 125, but you will ALWAYS
have 450 total.... until you move something.

Same holds for side weights.
If your left front weighs 300, and your left rear weighs 300,
you can make them 250, and 350, but the left will ALWAYS be 600 until you
move something physically...

Just because those little 20 dollar scales show you a different reading,
doesn't mean it disproves science....

I think most everyone is missing the real point that was trying to be made.

If you have 450 grams total on the 2 front scales, say 300 and 150,
no matter what you do to the springs, unless you move an object on
the car it will always weigh 450. HOWEVER, after a race, or if you tweek
a spring, most certainly you could have 325 and 125, but you will ALWAYS
have 450 total.... until you move something.

Same holds for side weights.
If your left front weighs 300, and your left rear weighs 300,
you can make them 250, and 350, but the left will ALWAYS be 600 until you
move something physically...

Just because those little 20 dollar scales show you a different reading,
doesn't mean it disproves science....

I get what your saying now...

You are saying that the wheel weights on the car doesn't change unless you move physical weight around on the chassis.

Well you are both RIGHT and I will try to explain why...

There is a term called weight jacking which Dave Pull was trying to explain.

Think of it as your sitting on a stool with four legs and I cut one leg on the stool shorter then the other three legs ... I just move the weight around.

By moving any wheel on the race cars chassis corner up or down to redistribute weight is called weight jacking.

So yes you can move static weight or weight jack weight around.. :thumbsup:

___________________________________
No, I just stayed at a Holiday Inn Express last night!

Just leave the scales at home. When I started doing that, I got a lot faster. You guys know what works, just drive the car. Use the scales to build the car, and don't bother with them at the track.

The scales are just too scientific. You'll be better just "feeling" the car

Just leave the scales at home. When I started doing that, I got a lot faster. You guys know what works, just drive the car. Use the scales to build the car, and don't bother with them at the track.

The scales are just too scientific. You'll be better just "feeling" the car

My car was alot faster when I stayed at a Holiday Inn Express last night! LOL :thumbsup:

Just leave the scales at home. When I started doing that, I got a lot faster. You guys know what works, just drive the car. Use the scales to build the car, and don't bother with them at the track.

The scales are just too scientific. You'll be better just "feeling" the car

what do you do if you have to change a spring?

what do you do if you have to change a spring?
Just keep the preload the same. Then your intended spring change will do what you wanted it to.

I read an artcle in stock car racing some 30 years ago by a famous northeast mod driver named Will Cagle. He said the only way you can take weight from the right front to the left rear was to cut it off the right frt and weld it to the left rear. Sure you screw down on the right frt weight jack it is going to put more weight on the lr but that weight going to the left rear is coming from the rt rear. And it also takes weight off the lf and puts it on the rf. It will change your crossweight but won't change your rear weight or the left side weight.

I think most everyone is missing the real point that was trying to be made.

If you have 450 grams total on the 2 front scales, say 300 and 150,
no matter what you do to the springs, unless you move an object on
the car it will always weigh 450. HOWEVER, after a race, or if you tweek
a spring, most certainly you could have 325 and 125, but you will ALWAYS
have 450 total.... until you move something.

Wrong..... deteriation of your t-plate and/or center shock spring and oil will alter the front to rear weight.

And that definitely holds true with the sideshocks that we use as far as the cross weight is concerned.

That is why the "PRO's" will tell you that you need to rebuild your shocks often. Consistency!

Also, comparing scale weights between others' scales is like comparing dyno's........ You just don't.

Kenny@RAPTOR

I will have to do some playing with the toy cars but in the real world of big car racing the left and rear percents don't change no matter how high or low a corner of the car is, you could have 2 flat tires and the weights will be the same, PERCENTAGES, not actual weights. DAVZ, so when you make that spring change and just reset the preload how do you know it is the spring change that helped and not the change in cross weight? Just curious. Easy way to do it with a big car is to set your ride height back to what it was if you only change one spring at a time, then the percents will be the same.

One for thought.......

If "big cars" we're running our scale speed, how much left percentage or rear percentage do you think they would run?

Don't know, do you?