G-body track width

[project hotrod]

With modern suspension upgrades like SPC uppers, AFX spindles, and a three link rear with watts. I wonder if the G-body modified geometry would also benefit from a wider track width?

Body modification aside of course

[astroracer]

Track width is relative to wheel width and offset. The center of the tire/wheel is normally refered to as "track width". This is readily adjustable with different width and offset wheels.
Handling can be affected, good or bad, by using an appropriately designed wheel. Setting up a suspension with a wide "deep dish" wheel (say a 10 inch wide rim with 4 inches of backspace) will ultimately widen the track but it will also have severe affects on bearing life and road feel. Look at as extra leverage on the bearings and steering gear. This is refered to as a negative offset wheel.
On the other hand a positive offset wheel like a 10 inch rim with 7 inches of backspace can narrow the track, pushing the tire centerline inboard. BUT it will also improve bearing life and road feel by reducing the leverage.
This is why you see all of the purpose designed race cars running wheels that are wide with a deep positive offset.
Designing a suspension to use a deep positive offset wheel is a challenge in it's own right to develope steering geometry and parts that will package and work as designed inside that deep wheel while still allowing full suspension and steering travel.
Without a complete redesign of your G-body suspension points a "wider track width" will probably hurt performance and hardware more then it will help.
Mark

[70bird]

Project hotrod, are you referring to track width by the hub to hub measurement?

I've been kicking this track width question around in my head also
Would liketo get some more tire under the rear without tubbing. Obviously. I need to move the wheels out.

I have run deep dish wheels in the past, and it's true that bearing failure is common, so not a good option.

What if the axle were to be widened accordingly?
This would allow you to run a nearer to zero offset wheel, so bearing failure would be a non-issue, I realize this goes against common practice and will require wheel flares.

I wonder how this might effect the suspension.Good? Bad?

What about front track width? What If it was left stock in front with increased track width in the rear?

[project hotrod]

Astroracer,
Thank you for the input. And, I really dig your project;)

Mark,

I will be the first to admit my ignorance on this subject as I am only a few months
into the study of suspension geometry outside of drag racing,
which has been my career for the better part of my life.

As with anything I work on I like to know what makes it tick and always
take the time to develop a good understanding.

With this vehicle I am torn between the normal bolt on stuff or leaning
toward something more on the max effort side.

If you look at the G-body the rear suspension is junk for all out handling.
Hence my decision for the three link watts combo.
Problem solved. I can setup any geometry I want.

The front can work very well with AFX spindles, and an adjustable upper.

But as I ponder different concepts my mind wanders towards track width.

I do understand side load and the negative effects it can have with
a severe offset wheel. Plus the C5 vette bearing pack used with the
AFX spindle will not like this at all so any track width discussion would
pertain to changing the hub to hub dimension front and rear.

With this discussion I'm not talking about a huge change as too much
will hurt the rotation of the chassis in corners but enough to improve
the handling of this vehicle.

As far as just changing the rear track width contains many variables.
Some which I understand, some which I yet to understand.

I would think altering the rear track width beyond a point would have
a few negative effects including understeer. On a front engine car I see
the rear of the car pushing the front through a corner at speed.

But I could be wrong... And if so, someone clarify.

In all reality I'm not afraid to fabricate a total new suspension for the
car if it will net excellent results. I have the fabrication skills and just
need the places to put the dots. Connecting them isn't a problem

It all boils down to whether or not...

time+effort or bolt on stuff = better
happy in the pants feeling while tearing it up on a course while
producing better lap times.

[rq375]

I have put some thought into this issue, I want a wider track for better brakes (C5) and wheels (ZR1s) without body mods, and Gs are long for their width to begin with, this is the direction I'm, headed:

1st gen camaro or 68-74 nova lower A arms (same thing) will increase your track by 1.75 per side, use howe ball joints or modify the lowers for screw in. (dirt mods use the nova arm on a metric frame to increase bite on the right side) You could use Allstar nova lowers with heim ends for more width and caster adjustability. Use SPC uppers to compensate for the longer lower, standard g arms should adjust that far, but you can order them with longer adjuster rods. You can use the Howe ball joints up top too to pick your neg camber increase if you use the g or blazer spindles. I would also think about cutting the spring pocket bulge out of the frame and boxing it in square and running a conventional coil over with the lower mount moved out towards the ball joint for better wheel rate. The conversion coilover kits are a poor solution in my mind and the spring is so far from the ball joint the rates need to be huge, and changing springs is still a pita. Universal coil overs use a standard (cheap) spring that is available in many more lengths and rates than the tapered adapter kits. The circle track suppliers all have tie rod couplers in various lengths to compensate for the longer a arms (stock= 4", 6" couplers are readily available).

For the rear, 68-72 A body 12 bolt would get you about the same increase in width (1.5 IIRC), but you have to use conversion arms. A better solution may be a made to order 9" and three link/watts and some frame fab. The only problem I see here is that the coil overs will probably have to run in front of the axel which makes adjustmnets more difficult, and most likely further complicates over the axel exhaust routing. If you still have the itch to drag it, Greg Weld has a 15x10 with 6.5 back space, fits a 28x10.5 or a 275-60 DR, that would still work with the wider rear.

[project hotrod]

I have put some thought into this issue, I want a wider track for better brakes (C5) and wheels (ZR1s) without body mods, and Gs are long for their width to begin with, this is the direction I'm, headed:

1st gen camaro or 68-74 nova lower A arms (same thing) will increase your track by 1.75 per side, use howe ball joints or modify the lowers for screw in. (dirt mods use the nova arm on a metric frame to increase bite on the right side) You could use Allstar nova lowers with heim ends for more width and caster adjustability. Use SPC uppers to compensate for the longer lower, standard g arms should adjust that far, but you can order them with longer adjuster rods. You can use the Howe ball joints up top too to pick your neg camber increase if you use the g or blazer spindles. I would also think about cutting the spring pocket bulge out of the frame and boxing it in square and running a conventional coil over with the lower mount moved out towards the ball joint for better wheel rate. The conversion coilover kits are a poor solution in my mind and the spring is so far from the ball joint the rates need to be huge, and changing springs is still a pita. Universal coil overs use a standard (cheap) spring that is available in many more lengths and rates than the tapered adapter kits. The circle track suppliers all have tie rod couplers in various lengths to compensate for the longer a arms (stock= 4", 6" couplers are readily available).

For the rear, 68-72 A body 12 bolt would get you about the same increase in width (1.5 IIRC), but you have to use conversion arms. A better solution may be a made to order 9" and three link/watts and some frame fab. The only problem I see here is that the coil overs will probably have to run in front of the axel which makes adjustmnets more difficult, and most likely further complicates over the axel exhaust routing. If you still have the itch to drag it, Greg Weld has a 15x10 with 6.5 back space, fits a 28x10.5 or a 275-60 DR, that would still work with the wider rear.

I do find this concept interesting. I've been trying to find a post from Marcus but I thought I read something about the lower you metioned not working on the G-body. I could be wrong.

As for my combo I intend to run the AFX spindle not only for the improved geometry but also bolt on brake ability. It would be way cool if the longer lower arm worked. I also already planned on thinning the frame rail and moving the shock out towards the ball joint. Not only does it allow better angles but it will make adjusting much easier.

Rear suspension wise I'll be purchasing a nine inch housing so length isn't an issue.

Thanks for the input man. It seems we are on the same page.