I discovered that my left v. right wheelbase is .25" apart. Measurements indicate that the delta is at the front end. Car: RF88.
Poll: Leave alone or tinker.
Leave it alone
Attempt to adjust
Wheelbase difference
I discovered that my left v. right wheelbase is .25" apart. Measurements indicate that the delta is at the front end. Car: RF88.
Poll: Leave alone or tinker.
Although it may be of no significance, I think you should keep measuring things until you find out where the difference is coming from. I mean, if it is resultant from some huge difference in front caster left-to-right, yeah, it probably matters a lot. If on the other hand, the rear radius rods are adjusted asymetrically, probably not great, but probably not deadly either, but also easily fixed.
Bottom line, dig until you find out why. At the very least, you'll feel more confident that nothing is terribly wrong with the car and you may save yourself from bad consequences.
Note: Renault built LeCar with intentionally different wheelbases L to R. Go figure.
Maybe they were using different wheelbases left to right to tune out torque steer.?
That is evidence of either crash damage or imprecise assembly. I discovered a big wheelbase difference on my first FF, which led to a complete reassembly. The car handled a lot better after that.
Could it be due to a side to side difference in caster?
“Racing makes heroin addiction look like a vague wish for something salty.” -Peter Egan
I'm with Neil on this one, mine was off about that much and that was when I looking at the suspension and noticed the a lot of the heim joints were just off, just a half turn here or there and the next thing you know BAM! your good.
Ben
The old Mondiale was 5/8" shorter on one side. Quick simple measurements didn't turn up why. Car drove great so I didn't worry about it.
My Reynard is not terribly symmetric. It has shown to be easy to drive and plenty fast. Focus on the things that really matter (camber, caster, toe, corner weights, roll centers) and don't worry much about small imperfections. If you can find and fix them great. If not, focus on the bigger stuff.
Attention to detail absolutely matters on the big stuff, though. Tenths of a degree on camber/caster/toe can really mess up a car.
Andy
I'm w/ Andy. Mine was about that much off and the professional alignment people did not touch it. Car has been in action 4 yrs w/o a fix.Originally Posted by ahowe
Mark
1990 Van Diemen, the Racing Machine, CM AutoX, 2016 Frontier
You can try to make a street car into an autocrosser or you can do a lot less work and make a race car into a great autocrosser
The car has crashed in the distant past.
I'm working on other issues now with old CV joints. Well see. I've got 40 days if I want to attend the first Solo or test day.
My apprehension is that the frame side rod end points are a fixed distance apart. So, one arm can lengthen and one arm must then go shorter keeping the frame side of the triangle the same length. Same for upper and lower arms. Caster will likely change as the unequal arms rotate in relation to the frame.
Thanks!!!!!
Last edited by TeamFRD; 12.15.16 at 8:41 PM. Reason: sp
Rear "caster" is often the bump steer adjustment. With suspension alignment, everything depends on everything else. I recommend a full disassembly and reset, measuring everything along the way as accurately as you can.
"Throw it in and hope it sticks" is a bad plan. Knowing that it will stick is a much better plan. Knowing that your tires all agree on which way to go all the time helps that plan immensely.
Your alignment technique if not well thought through can result in discrepancies like 1/4 inch difference in wheel base. And as Neil pointed out, bump steering a rear wheel might result is a wheelbase discrepancy.
When you do an alignment, setting one variable such as camber, then moving to say caster and finally set toe in, can result in nothing being exactly as you intend.
What I recommend is that you set toe and ride height, then measure all the other settings, camber, caster and bump steer. Next, make adjustments that bring each variable closer to the target. Now, reset toe and ride height, then take all the measurements again. Repeat this process until you get each and all setting as you want them. It does take some practice to get the technique worked out but the end results is way more accurate than setting each variable sequentially.
I like to use the "flag" system to align my cars. I replace the shocks with struts and remove the wheels. The car is up in the air on chassis stands. Making adjustments is easy and quick. And I don't have to deal with the inconsistencies in tires as I do the alignment. When I am done with the alignment and place the car on the ground, with the shocks and springs, I then reset the ride height as I balance the car on the scales.
With experience, using this system, I can get the car within 15 pounds of being balanced and the ride height within 1/16 inch of target before I go the scales to finish the job. Close enough to go to the track for the first practice session and before I get the alignment pad setup at the track.
I know this sounds complicated and tedious but it works and is very accurate.
Taking my time has been a big key for me and it being complicated and tedious should not be what holds you back I mean you didn't buy a FF because for it's ease of maintenance.
I love the process you have to go though to make these cars feel right, the tinkering has been the most fun. I go out to the car every single day and walk around the car even though I may not do anything you never know what you may see or think about you want to do and then I put a red tag on something to fix or look at later.
Ben
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