Too much camber?
06-20-2015, 09:15 AM
#1
Gasoline Addict
Thread Starter
Too much camber?
Is there such a thing as too much camber on a track prepped C5Z? If so, what is that value and, more importantly, why? Does it differ between R-comps and Slicks? Does it apply mainly to rear axle, or both front and rear?
I'd like to understand that phenomenon a little better, so please show your work that leads you to your answer
I'd like to understand that phenomenon a little better, so please show your work that leads you to your answer
06-20-2015, 09:49 AM
#2
Melting Slicks
Is there such a thing as too much camber on a track prepped C5Z? If so, what is that value and, more importantly, why? Does it differ between R-comps and Slicks? Does it apply mainly to rear axle, or both front and rear?
I'd like to understand that phenomenon a little better, so please show your work that leads you to your answer
I'd like to understand that phenomenon a little better, so please show your work that leads you to your answer
Of course there is a thing as too much negative camber, just like there is not enough... The only difference is that if you have a bit too much negative camber you can often drop the pressure a bit and get some more rollover to make up for it. If you don't have enough you will end up running more pressure and that just makes the car skiddish..
Tire temps tell the story and for every tire and suspension setup there is a correct amount of negative camber and tire pressure. Spring stiffness, sway bar stiffness, ride height, tire size, inflation pressure, bushing stiffness and a number of other things all enter into it.
For R comps on a stock C5Z, and depending on the tire size and setup, somewhere around -2 to -2.5 in the front is about right. In the rear a bit less (like -1.5) is a good starting place.
Real slicks are a different story. They generally require less negative camber to work properly. This has to do with the basic construction of the tire.
Start by asking someone who has a setup similar to yours and then get on a skidpad and use that to check temperatures across the tread.
06-20-2015, 06:13 PM
#3
Race Director
Negative static camber is used to get the tire more upright when the car rolls during hard cornering. As the car rolls the tire becomes more upright and the tread surface is now square with the surface so that it can be more effective in generating side force.
Of course there is a thing as too much negative camber, just like there is not enough... The only difference is that if you have a bit too much negative camber you can often drop the pressure a bit and get some more rollover to make up for it. If you don't have enough you will end up running more pressure and that just makes the car skiddish..
Tire temps tell the story and for every tire and suspension setup there is a correct amount of negative camber and tire pressure. Spring stiffness, sway bar stiffness, ride height, tire size, inflation pressure, bushing stiffness and a number of other things all enter into it.
For R comps on a stock C5Z, and depending on the tire size and setup, somewhere around -2 to -2.5 in the front is about right. In the rear a bit less (like -1.5) is a good starting place.
Real slicks are a different story. They generally require less negative camber to work properly. This has to do with the basic construction of the tire.
Start by asking someone who has a setup similar to yours and then get on a skidpad and use that to check temperatures across the tread.
Of course there is a thing as too much negative camber, just like there is not enough... The only difference is that if you have a bit too much negative camber you can often drop the pressure a bit and get some more rollover to make up for it. If you don't have enough you will end up running more pressure and that just makes the car skiddish..
Tire temps tell the story and for every tire and suspension setup there is a correct amount of negative camber and tire pressure. Spring stiffness, sway bar stiffness, ride height, tire size, inflation pressure, bushing stiffness and a number of other things all enter into it.
For R comps on a stock C5Z, and depending on the tire size and setup, somewhere around -2 to -2.5 in the front is about right. In the rear a bit less (like -1.5) is a good starting place.
Real slicks are a different story. They generally require less negative camber to work properly. This has to do with the basic construction of the tire.
Start by asking someone who has a setup similar to yours and then get on a skidpad and use that to check temperatures across the tread.
Only thing I would add is to much neg. wears the tire faster on the inside edge. Tire temps correctly taken will tell you all you need to know.
06-20-2015, 10:44 PM
#6
Gasoline Addict
Thread Starter
I have poly bushings and over the off season had the alignment changed to -2.9 up front, while the rear is at - 1.3. The tires are R888 (275 front and 305 rear) and I have been struggling with finding optimal psi rating to make the car work.
Last season, my specs were -2.2 up front and -1.0 in the rear. I noticed that my lap times are slower by about 1.5 seconds this year, even though I am pushing the car harder than last year. Thus my too much camber question. I am really wondering if the more aggressive caber settings (especially in the front) are affecting the way the car handles...
Last season, my specs were -2.2 up front and -1.0 in the rear. I noticed that my lap times are slower by about 1.5 seconds this year, even though I am pushing the car harder than last year. Thus my too much camber question. I am really wondering if the more aggressive caber settings (especially in the front) are affecting the way the car handles...
06-20-2015, 10:46 PM
#7
Racer
I ran -1.7 upfront and -1.0 with factory bushings and R comps and the tire wear was ok. The outside edges did wear more in the front which led me to believe it needed more negative camber even thought the tire temps indicated even temps. I recently swapped to the Phoenix delrin bushing upgrade and started with -2.5. WAAAAAY to much for me at least. I went down to -2.1 and will see how the car behaves. Castor plays a large role too. I have a feeling with the delrin bushings I will go back down to my initial -1.7 upfront and and -1.0 in the rear as the rear is -1.3 and seems to be ok for now. I'm still testing and really haven;'t had to much time to hit the track.
06-20-2015, 10:53 PM
#8
Racer
I have poly bushings and over the off season had the alignment changed to -2.9 up front, while the rear is at - 1.3. The tires are R888 (275 front and 305 rear) and I have been struggling with finding optimal psi rating to make the car work.
Last season, my specs were -2.2 up front and -1.0 in the rear. I noticed that my lap times are slower by about 1.5 seconds this year, even though I am pushing the car harder than last year. Thus my too much camber question. I am really wondering if the more aggressive caber settings (especially in the front) are affecting the way the car handles...
Last season, my specs were -2.2 up front and -1.0 in the rear. I noticed that my lap times are slower by about 1.5 seconds this year, even though I am pushing the car harder than last year. Thus my too much camber question. I am really wondering if the more aggressive caber settings (especially in the front) are affecting the way the car handles...
06-21-2015, 09:17 AM
#10
Melting Slicks
With stiffer bushings you need less static negative camber since you don't lose as much in deflection as you load up the suspension.
High static negative camber hurts braking and as froggy noted tends to wear the inside of the tires a lot more, so if you get greedy you can mess things up from that standpoint too.
Caster becomes negative camber at high steering angles. For lower speed work (like autocross) the effect of high caster angles comes more into play. At higher speed (like faster road courses) the steering angles are lower so caster doesn't play into it as much. Running big caster and less static negative camber is one way to take off some static negative camber and improve braking in autocross.
High static negative camber hurts braking and as froggy noted tends to wear the inside of the tires a lot more, so if you get greedy you can mess things up from that standpoint too.
Caster becomes negative camber at high steering angles. For lower speed work (like autocross) the effect of high caster angles comes more into play. At higher speed (like faster road courses) the steering angles are lower so caster doesn't play into it as much. Running big caster and less static negative camber is one way to take off some static negative camber and improve braking in autocross.
06-21-2015, 02:12 PM
#11
Race Director
Member Since: Oct 2000
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Ty, the next time we are together at the track, I'll find a pyrometer to measure your tire temps when you enter at the hot pit after a good session. That is really the best way to see what is going on.
As was stated above by others, with poly bushings you don't need as much neg. camber as you might with OEM rubber.
As was stated above by others, with poly bushings you don't need as much neg. camber as you might with OEM rubber.
06-21-2015, 02:20 PM
#12
Gasoline Addict
Thread Starter
Ty, the next time we are together at the track, I'll find a pyrometer to measure your tire temps when you enter at the hot pit after a good session. That is really the best way to see what is going on.
As was stated above by others, with poly bushings you don't need as much neg. camber as you might with OEM rubber.
As was stated above by others, with poly bushings you don't need as much neg. camber as you might with OEM rubber.
I need new front rubber too, so before I put it on, I will get the camber adjusted back to around -2.4 and see what happens... however, it may be a while, as I will be quite busy at work for the next few months.
06-21-2015, 07:01 PM
#13
I have poly bushings and over the off season had the alignment changed to -2.9 up front, while the rear is at - 1.3. The tires are R888 (275 front and 305 rear) and I have been struggling with finding optimal psi rating to make the car work.
Last season, my specs were -2.2 up front and -1.0 in the rear. I noticed that my lap times are slower by about 1.5 seconds this year, even though I am pushing the car harder than last year. Thus my too much camber question. I am really wondering if the more aggressive caber settings (especially in the front) are affecting the way the car handles...
Last season, my specs were -2.2 up front and -1.0 in the rear. I noticed that my lap times are slower by about 1.5 seconds this year, even though I am pushing the car harder than last year. Thus my too much camber question. I am really wondering if the more aggressive caber settings (especially in the front) are affecting the way the car handles...
06-22-2015, 12:04 AM
#14
Gasoline Addict
Thread Starter
Not particularly old; '13 born on dates. Have about 45-50 heat cycles on them. One of the front ones is worn down quite a bit more than the rest. Will just get new ones for the front axle. Wondering if I should go with NT01s instead...
06-22-2015, 02:02 AM
#15
Sorry I meant heat cycles/days of use, not calendar age. In my experience the R888 can fall off a lot from day to day, so be careful making setup choices without controlling for tires carefully.
