Speedie

Hi I am looking for a free roll center calculator for regular or rc cars. If you know of any please let me know thanks.

Brian McGreevy

iTrader: (10)

That'd be a rather hard thing to come by. Roll center depends on a minimum of 4 separate variables (inner and outer camber link and arm pin heights), and realistically as many as 6. Not only that, you'd have to know those heights before you plugged them into the said calculator.

DrOlds

iTrader: (4)

They're out there-full size dirt oval racers use them all the time.Don't know if you're going to find one for free though.

sosidge

I did once find one that had been done in a spreadsheet for RC cars. However as I recall one of the calculations was wrong so it needed a little correcting. Unfortunately I have now forgotten where I found it - but it may still be out there.

elvo

Didn't john Stanahan make that spreadsheet ?

trilerian

iTrader: (51)

I googled roll center calculator and came up with this.
roll center calculator
There are a lot of measurements you need for it though, I hope it works.

mattnin

iTrader: (44)

That one isn't free though :/ Are you just looking for a spreadsheet that shows you height or looking to get the thing actually plotted? I think I can get access to all the proper formulas to calculate it.

John Stranahan

iTrader: (27)

Here is a link to a free roll center spreadsheet calculator that I wrote. You need Microsoft excel for it to work. The link goes to a post on the Pantoura Thread. Down lower in the post is a link to the free download. The post has an example of its use and a sample output. I had the wrong units on one of the outputs in the very first draft. This has long since been corrected.

http://www.rctech.net/forum/showthread.php?p=2981627&highlight=roll+center+cal culator#post2981627

John

Speedie

Thanks John Ill give that a try. At one time I had found a nice calculator that was free but I cannot find it or remember where I got it from. I can figure it out manually but just looking to save some time as I use roll centers alot racing dirt late models.

rcfoolz

iTrader: (22)

up till now, i didn't understand the reason behind the inner pivot point on the front of the car. now I understand why when I raise it up, steering goes away.

John Stranahan

iTrader: (27)

Here are some adjustments and their effect on roll center.

Inner upper pivot up - roll center down
Outer upper pivot up - roll center up
inner lower pivot down - roll center down

When using a standard front ball diff on an electric 4 wheel drive touring car I have found that lowering the roll center will give more traction to that end of the car.

When using a locked front diff on an electric 4-wheel drive touring car. Torque steer seems to be the predominant force driving the steering. In this case lowering the roll center in front will give less torque steer and as a result less steering traction. This assumes you are cornering with good power applied mid corner.

John