Isolated Change of Camber at Trackside with Longacre?
08-30-2018, 10:23 PM
#1
Rennlist Member
Thread Starter
Isolated Change of Camber at Trackside with Longacre?
Hi All,
I don't do any alignment work myself but would eventually like to.
Before the season ends I want to do a tire test on my Formula Mazda between Goodyear 255 (which is all I run) and a Hoosier R35.
The experts say that I need to change my rear camber from +0.8 to +0.3 to use the Hoosiers (yes, positive camber is run on my car). Can I buy something like the Longacre gauge shown below or the magnetic version and make this change trackside? Is it an inaccurate thing to do?
TIA
http://www.longacreracing.com/products.aspx?itemid=2446&prodid=7252&pagetitle=Digital-C%2fC-Gauge-w-AccuLevel™-and-Quick-Set™-Adapter
I don't do any alignment work myself but would eventually like to.
Before the season ends I want to do a tire test on my Formula Mazda between Goodyear 255 (which is all I run) and a Hoosier R35.
The experts say that I need to change my rear camber from +0.8 to +0.3 to use the Hoosiers (yes, positive camber is run on my car). Can I buy something like the Longacre gauge shown below or the magnetic version and make this change trackside? Is it an inaccurate thing to do?
TIA
http://www.longacreracing.com/products.aspx?itemid=2446&prodid=7252&pagetitle=Digital-C%2fC-Gauge-w-AccuLevel™-and-Quick-Set™-Adapter
08-30-2018, 10:41 PM
#2
Instructor
Yes you can perform accurate camber changes at the track.
1st, you must start with a level surface at the shop and keep very accurate notes.
2nd, at the track measure the camber and note that it won't be the same at the track because you are not on a level surface at the track. That doesn't matter because you know at the shop your camber was x˚ and you want to change it .5˚
You use the measured amount at the track and adjust .5˚ from that.
Measure the other side, it will be different because you are not on a level surface. Write down the new camber you need. Now make your adjustments.
Remember to adjust toe after changing camber. Everytime you change camber, you alter your toe.
As an example, I have a car that was -1.5 at the shop. At the track, the RR measured -.2 and the LR measured -2.8. Knowing the car was originally at -1.5 and I wanted to go to -1.8, I adjusted the RR to -.5 and LR to -3.1. When I got back to the shop, I double checked the camber and found that I had accurately made the changes to -1.8.
I have friends that mark their pit area with tire boxes for a repeatable system to make ongoing changes.
It is a little more work, but if you start with a known value and do your math, you can adjust camber, caster, and toe at the track.
1st, you must start with a level surface at the shop and keep very accurate notes.
2nd, at the track measure the camber and note that it won't be the same at the track because you are not on a level surface at the track. That doesn't matter because you know at the shop your camber was x˚ and you want to change it .5˚
You use the measured amount at the track and adjust .5˚ from that.
Measure the other side, it will be different because you are not on a level surface. Write down the new camber you need. Now make your adjustments.
Remember to adjust toe after changing camber. Everytime you change camber, you alter your toe.
As an example, I have a car that was -1.5 at the shop. At the track, the RR measured -.2 and the LR measured -2.8. Knowing the car was originally at -1.5 and I wanted to go to -1.8, I adjusted the RR to -.5 and LR to -3.1. When I got back to the shop, I double checked the camber and found that I had accurately made the changes to -1.8.
I have friends that mark their pit area with tire boxes for a repeatable system to make ongoing changes.
It is a little more work, but if you start with a known value and do your math, you can adjust camber, caster, and toe at the track.
08-30-2018, 10:49 PM
#3
Rennlist Member
Thread Starter
Yes you can perform accurate camber changes at the track.
1st, you must start with a level surface at the shop and keep very accurate notes.
2nd, at the track measure the camber and note that it won't be the same at the track because you are not on a level surface at the track. That doesn't matter because you know at the shop your camber was x˚ and you want to change it .5˚
You use the measured amount at the track and adjust .5˚ from that.
Measure the other side, it will be different because you are not on a level surface. Write down the new camber you need. Now make your adjustments.
Remember to adjust toe after changing camber. Everytime you change camber, you alter your toe.
As an example, I have a car that was -1.5 at the shop. At the track, the RR measured -.2 and the LR measured -2.8. Knowing the car was originally at -1.5 and I wanted to go to -1.8, I adjusted the RR to -.5 and LR to -3.1. When I got back to the shop, I double checked the camber and found that I had accurately made the changes to -1.8.
I have friends that mark their pit area with tire boxes for a repeatable system to make ongoing changes.
It is a little more work, but if you start with a known value and do your math, you can adjust camber, caster, and toe at the track.
1st, you must start with a level surface at the shop and keep very accurate notes.
2nd, at the track measure the camber and note that it won't be the same at the track because you are not on a level surface at the track. That doesn't matter because you know at the shop your camber was x˚ and you want to change it .5˚
You use the measured amount at the track and adjust .5˚ from that.
Measure the other side, it will be different because you are not on a level surface. Write down the new camber you need. Now make your adjustments.
Remember to adjust toe after changing camber. Everytime you change camber, you alter your toe.
As an example, I have a car that was -1.5 at the shop. At the track, the RR measured -.2 and the LR measured -2.8. Knowing the car was originally at -1.5 and I wanted to go to -1.8, I adjusted the RR to -.5 and LR to -3.1. When I got back to the shop, I double checked the camber and found that I had accurately made the changes to -1.8.
I have friends that mark their pit area with tire boxes for a repeatable system to make ongoing changes.
It is a little more work, but if you start with a known value and do your math, you can adjust camber, caster, and toe at the track.
Do you use the typical plates and measuring tapes for toe or something fancy?
Are you using Longacre products for your camber and toe measurements?
08-30-2018, 11:01 PM
#4
Instructor
ART laser
Longacre plates and tape
I have the measuring tapes with plates and also a laser set up.
I get the same results, but the laser allows .1˚ toe adjustments whereas the tape does not. The tape is close enough IF you are very careful and measure 3 times just to be sure.
Here is a low cost laser
https://www.ebay.com/bhp/laser-wheel-alignment
08-31-2018, 12:46 AM
#5
Three Wheelin'
I have and use a SmartCamber device. One of the benefits in this application is that you can set the camber on a level surface (I use roll offs on my garage floor), and then measure the camber relative to some part of the car. So trackside you can make changes relative to the car. My 911 has a fuel cell and that is a convenient place to measure as its relationship to the suspension is fixed. You can do this with any digitaol level, but I prefer the SmartCamber as it is well-designed and convenient for this application.
On a 911, toe changes with camber. You can measure and record the change per degree and then set the toe trackside using the numbers.
For toe, I made a SmartStrings-like set up that attaches to my car in a repeatable way. The cross bars are $2 lengths of 1" OD electrical conduit, and I use fishing line.
SmartCamber and SmartStrings are excellent products. They were designed and are sold by someone I have known for years, and the documentation is excellent. He is a longtime PCA member, and an accomplished racer and professional racing engineer.
On a 911, toe changes with camber. You can measure and record the change per degree and then set the toe trackside using the numbers.
For toe, I made a SmartStrings-like set up that attaches to my car in a repeatable way. The cross bars are $2 lengths of 1" OD electrical conduit, and I use fishing line.
SmartCamber and SmartStrings are excellent products. They were designed and are sold by someone I have known for years, and the documentation is excellent. He is a longtime PCA member, and an accomplished racer and professional racing engineer.
08-31-2018, 07:57 AM
#6
Rennlist Member
08-31-2018, 08:06 AM
#7
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I'm not positive about your FM, but I'm pretty sure it's a shim arrangement on the upright. When the car is on the setup pad, it's easy to measure what shim to use. The shims come in standard thicknesses, so you will know how much change each one makes. Talk to Moses Smith Racing and they will tell you for sure.
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08-31-2018, 08:15 AM
#8
Three Wheelin'
Good advice above. A couple additional notes:
- On your car, I'd guess camber is adjusted either by adjusting one of the heim joints in the suspension, or by swapping shims. Either way it's repeatable and precise. If you want to minimize down time at the track, you could consider practicing the changes you want to make at home and realigning as detailed above. E.g. one turn clockwise on a heim joint = .5 degree change in camber, 1 turn of the toe adjuster = 1/16" toe in change per side, etc. In fact, for a car like yours, this information should be commonly available.
- Agreed that you can use any surface for aligning, but preferably it should at least be flat even if it's on an slant, if that makes sense. I'd guess that a garage spot is more likely to be flat than a paved surface.
- On your car, I'd guess camber is adjusted either by adjusting one of the heim joints in the suspension, or by swapping shims. Either way it's repeatable and precise. If you want to minimize down time at the track, you could consider practicing the changes you want to make at home and realigning as detailed above. E.g. one turn clockwise on a heim joint = .5 degree change in camber, 1 turn of the toe adjuster = 1/16" toe in change per side, etc. In fact, for a car like yours, this information should be commonly available.
- Agreed that you can use any surface for aligning, but preferably it should at least be flat even if it's on an slant, if that makes sense. I'd guess that a garage spot is more likely to be flat than a paved surface.
08-31-2018, 09:32 AM
#9
Rennlist Member
Thread Starter
Thanks for all of this advice! I should call Moses Smith and post in the Apex FM forum I'm on. There's just so much more 'action' here on line!
08-31-2018, 10:28 AM
#11
Addict
Rennlist Member
Rennlist Member
I believe there are 2 concrete pads at the Glen that are built to be level.
08-31-2018, 10:32 AM
#12
Rennlist Member
Thread Starter
08-31-2018, 10:44 AM
#13
Addict
Rennlist Member
Rennlist Member
One is located opposite the track side of the garages. The guy that drives the Lambo and the Vette at Trackmasters and PCA normally parks either next to, or on-top of it. About 50 meters from the shed where you dump used fluids.
I'm not sure where the second one is.
I'm not sure where the second one is.
08-31-2018, 11:10 AM
#14
Rennlist Member
Thread Starter
I'll look in a few weeks out of curiosity!
08-31-2018, 01:42 PM
#15
I don't do alignments at the track but do some at home. I found strings are far more accurate compared to toe plates. Once you know the difference between the front and rear hubs compared to the car centerline, you can just stretch a string between two jack stands.
