Reinventing the OneLapCamaro...

[ironworks]

I just got done trying some 3" back spacing wheels, on my dirt car. They say a narrowed track width helps to get the car to turn in. We start with one wheel inset and go to 2 if we want more. It is truely amazing what wheels spacers and changing offset Will do to the handling of a car. My dirt car can go from being a rocket to a car I cannot turn with just one too many 1/2" wheel spacers.

[dontlifttoshift]

If Ferrari thinks 2" more width in the front is okay it will probably work for what I am doing.

That is something I had not considered. By widening the front track it will transfer corner weight to the rear? In that case its a win/win.....right?


If the starting point was a relatively narrow car and outside widths of 67.5f/66.5r so I don't know that we could ever get too wide in the front......narrow rear = fast slaloms.

Sorry for the slight hijack......Isn't it time for more pictures?

[James OLC]

Originally Posted by James OLC

Some slightly dated examples:

Noble m15 89mm wider at front
Ferrari F430 53mm wider at the front
Lamb Gallardo 30mm wider at the front
Porsche Cayman 42mm wider at the rear

J

Originally Posted by dontlifttoshift

If Ferrari thinks 2" more width in the front is okay it will probably work for what I am doing.

I was typing this quickly last night and it needs a bit more clarification... We have to keep in mind that what I quoted above is the technically correct track width - which is properly measured from the centerline of the wheels and not the outside edge of the wheels.

So... the most consistent info I could find:

Noble m15
Car Width = 72.8" Front Width = 62.8" Rear Width = 59.2" So the difference in track width is 3.6" wider on the front BUT...
Front wheels = 18 x 8 Rear wheels = 19 x 10.5 Making the difference in wheel width 2.5" wider on the back.
So in reality, measuring from the outside to outside, the front is 0.55" wider than the rear.

Ferrari F430
Car Width = 75.7" Front Width = 65.7" Rear Width = 63.6" So the difference in track width is 2.1" wider on the front BUT...
Front wheels = 19 x 7.5 with +31.5 offset Rear wheels = 19 x 10 with +39 offset Making the difference in wheel width 2.5" wider on the back.
So in reality, measuring from the outside to outside, the rear is 0.4" wider than the front.

Lamborghini Gallardo
Car Width = 78.8" Front Track = 63.74" Rear Track = 62.57" So the difference in track width is 1.17" wider on the front BUT...
Front wheels = 19 x 8.5 Rear wheels = 19 x 11 Making the difference in wheel width 2.5" wider on the back.
So in reality, measuring from the outside to outside, the rear is 1.3" wider than the front.

In the case of the OLC...

Front Track (old) = 65.0" Rear Track (old) =65.0" So 0 difference in front to rear when measuring proper track width...
But...
Front Outside (old) = 68.0" Rear Outside (old) = 71.25" So to be where we wanted we needed to move the front out ~3.25" at the outside

[James OLC]

Originally Posted by dontlifttoshift

That is something I had not considered. By widening the front track it will transfer corner weight to the rear? In that case its a win/win.....right?

If the starting point was a relatively narrow car and outside widths of 67.5f/66.5r so I don't know that we could ever get too wide in the front......narrow rear = fast slaloms.

Sorry for the slight hijack......Isn't it time for more pictures?

Technically correct although we'll have to see if it is practically correct as well...

More pics coming soon.

[James OLC]

Quick pic...

[bdahlg68]

Originally Posted by James OLC

In the case of the OLC...

Front Track (old) = 65.0" Rear Track (old) =65.0" So 0 difference in front to rear when measuring proper track width...
But...
Front Outside (old) = 68.0" Rear Outside (old) = 71.25" So to be where we wanted we needed to move the front out ~3.25" at the outside

Did these old outside measurements fit under stock fenders and quarters?

[James OLC]

Originally Posted by bdahlg68

Did these old outside measurements fit under stock fenders and quarters?

"yes" with a but... we did do some work to the lips (but we did not change their shapes)

[James OLC]

[Flash68]

Originally Posted by James OLC

Aw yeah...

[David Pozzi]

Originally Posted by James OLC

Slightly would be something like 0.25 to 0.5" wider on the front vs the back.

Some slightly dated examples:

Noble m15 89mm wider at front
Ferrari F430 53mm wider at the front
Lamb Gallardo 30mm wider at the front
Porsche Cayman 42mm wider at the rear

I would think (and I may be wrong as this seems to be a bit of a point on contention among some engineers) that if you get "too" wide then you're going to have a car that probably wants to understeer (more than it may do now)... because as you increase track width you decrease tire loading and, at some point, you will lose front traction.

BUT, in actual practice, I think that it is somewhat dependant on your starting point... as think that it will reduce (or at least correct) some understeer up to a point. (I think) that the OLC understeers in some environments because I am overloading the front tires (too much weight from being to close together). My hope is that by increasing track width then the (marginal) weight reduction on the tires will result in a more stable front geometry.

You can look at it this way... By increasing the front track width you should decrease the front end weight. So if you start at 53/47 then you might end up at 51/49 or ??? If you go to far then, in theory (I think) then you will end up with too much weight on the rear...

I honestly don't know where that happens and I may be completely off here...

J

With a wider front track: Less front cornering load (the term weight should not be used here) is transferred from inside tire to outside tire. This reduces load on the outside front tire, increases load on the inside front tire in a corner and so increases front lateral traction available to the front tires. It will reduce under steer and increase over steer. What can then be done is to re-balance the handling by reducing rear anti-roll bar stiffness, or lowering the watts or Panhard bar. End result is more total cornering grip for the whole car.

There is no change in static weight F/R, but there is in dynamic load transfer percentage front to rear.