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Discussion Starter #1
Currently running yoko a052 195/225 on track (probably -2.8 camber all around) and I've shredded through my rears with very little wear up front!

Does this suggest an imbalance with the car? Everyone talks about upsizing the front to 205 for more grip, but if I really want more overall grip shouldn't I actually be getting some big fatties on that rear?

Anyone run 195 up front and 245 in the rear? My car is oversteery as-is, so will it really make my car too understeery?

Granted I want balanced grip during turns. It is possible the rear is wearing in the straights and the turning balance is fine?
 

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Camber doesn't tell us much. What is your rear toe? Also, are the rear endlinks fine? No play? What is your front Sway bar set to? What shocks? Are they adjustable? What are they set to? Tire pressures?

What kind tire wear do you have? Can you post a picture?
 
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Like Matt said, the real question is why you're oversteering so badly with that setup. Answer that first then address that particular answer. What's your power level at? I'd get it if you are at 300+whp but not the stock ~160-ish.
 

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Discussion Starter #4
Like Matt said, the real question is why you're oversteering so badly with that setup.
Well okay I wouldn't say oversteering badly. The rear get's light on two downhill turns at my local track (Pitt Race). I'd like to be able to put down some power going down those hills. Otherwise the car is relatively neutral right now. A little more understeer is fine, I just don't want to ruin the balance of the car!

What is your rear toe? Also, are the rear endlinks fine? No play? What is your front Sway bar set to? What shocks? Are they adjustable? What are they set to? Tire pressures?
What kind tire wear do you have? Can you post a picture?
rear toe ~1/8". toe links are new, no play.
trackpack front sway, full hard.
penske DA 550/800, Front: 5FFHC,10FFR, Rear: 20FFHC, 40FFHR (Fred's settings, but hardened rebound up front to induce throttle-understeer)
tire pressures: 25F/26R hot
Wear is even-ish (I had them over-inflated one session, so did wear down the center).
Photo coming soon...

What's your power level at? I'd get it if you are at 300+whp but not the stock ~160-ish.
stock S240 power. I'm not so concerned about power in the straights, just want to get the best contact patch in turns. Given the 32F/68R weight distribution, maybe it makes sense to put more tire in the back? Then if I'm getting understeer or oversteer, tune those out with alignment/shock settings?
 

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Interesting. You have similar hardware but your shock and sway bar settings are much different than mine.

My setup:
Penske DA's, 550 front/800 rear, track pack (adjustable front sway bar), Hoosier A7 tires (205/45/16 front, 225/45/17 rear), EP uprights and steering arms (ride heights approx 110mm f/115mm r, before corner weighting, camber -2.8* front, -3.3* rear). So same shocks and springs, same sway bar, different uprights (assuming yours are stock) and probably different ride heights.

My shock and sway bar settings:
Front sway bar one notch stiffer than softest setting
Front and rear shocks 5 FFHC/14 FFHR (same settings front and rear)

FYI according to my notes Fred's recommended track settings for the 550/800 springs are 5 FFHC/12 FFHR (same settings front and rear), so based on my notes your rear settings are far different.

So the big differences are your stiffer front sway bar setting and your much softer rear shock settings. I would think if anything your car would push with those settings. FWIW I feel my setup is very neutral/balanced in mid-corner, when near the limit on a "carousel" type corner I can do a 4 wheel drift while using my right foot to maintain my line. Regarding the sway bar, IMO the stiff springs allow less sway bar, which I think is a good thing; certainly its a good thing for front end grip, but I also find that a stiff sway bar can be problematic when you hit asymmetric bumps (like raised apex curbing), where a more independent suspension avoids excessive body roll and even a "skip" if the impact is too abrupt.

Maybe we need to know more about these 2 downhill turns? increasing radius, decreasing radius, or uniform? Are they continuous downhill (uniform slope), or...? Positive camber?

HTH, -Ed
 

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In general, the shock settings mostly change the car in entry or exit for a smooth surface. Once the car takes a set, particular in a long sweeper where it is more obvious, the sway bar settings are changed to alter f/r balance. If it is a shallow turn then more likely that shock changes are recommended to start from. There are so many deltas between cars that Fred's recommended settings are just starting points to tuning. Even changing brand of tires with same sizes we twist the knobs. I recommend using a tire pyrometer to measure across 3 points on each tire; that can show you whether you need more or less camber.
 

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In general, the shock settings mostly change the car in entry or exit for a smooth surface. Once the car takes a set, particular in a long sweeper where it is more obvious, the sway bar settings are changed to alter f/r balance. If it is a shallow turn then more likely that shock changes are recommended to start from. There are so many deltas between cars that Fred's recommended settings are just starting points to tuning. Even changing brand of tires with same sizes we twist the knobs. I recommend using a tire pyrometer to measure across 3 points on each tire; that can show you whether you need more or less camber.
Agreed, but I'd say my car is close to neutral on corner entry and exit as well, though as you say our difference in sway bar settings should show up mid-corner. Sure, tires (and tire pressures) will make a difference, but we have the same shocks, springs, and sway bar, and camber is in the same ballpark, so I still question his rear shock settings and sway bar settings given the extreme differences. A few clicks different, sure, but 15 clicks softer on compression? I could tell a difference when I only changed things a click or two (I'm not married to Fred's recommendations, I've done plenty of tweaking, I didn't even realize until I looked his recommendations back up that I saw I've settled on his compression settings and just 2 clicks softer on rebound).

And I agree about tire temps, last time I checked my inside temps were about 15*F higher than the outside temps, which I think is OK (on straights the negative camber heats the inside, so I don't expect uniform temps, esp after a cool down lap).
 

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I can tell austin is actually fast from his setup ideas here, I like it!
 

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Currently running yoko a052 195/225 on track (probably -2.8 camber all around) and I've shredded through my rears with very little wear up front!
You say "probably -2.8* camber" that implies to me that you may not know for sure? That in itself can have one chasing the wrong tweaks.
It's not easy (in my case anyway) to get -2.8* camber in the front without going to aftermarket arms and milling. (again this is the direction I went)
The rears were much easier because all I had to do were remove the shims (yielded -2.8* camber)

Just my .01
 

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Discussion Starter #12
After 4 track days...
front 195 -
1267536


rear 225 -
1267538


So, obviously a little over inflated in the rear, whoops. Outer edges have odd wear because I had less camber the first two trackdays.

My shock and sway bar settings:
Front sway bar one notch stiffer than softest setting
Front and rear shocks 5 FFHC/14 FFHR (same settings front and rear)

FYI according to my notes Fred's recommended track settings for the 550/800 springs are 5 FFHC/12 FFHR (same settings front and rear), so based on my notes your rear settings are far different.
I have hand-adjustables, which alters the rebound count. I was skeptical so I emailed Fred, and he thought those settings worked because they kept the rear planted on throttle. The reasoning checked out. But now I'm skeptical again. I might need to go back to the drawing board on shock settings! Anyways, stiffening compression in the rear should only induce more exit oversteer. You have more rear negative camber (-3.3 vs -2.8), I may give that a go (and perhaps I could remove some bar). I was hoping fatter rear tires would have a similar effect.

Forgot to mention, my ride height is ~120F/125R

Maybe we need to know more about these 2 downhill turns? increasing radius, decreasing radius, or uniform? Are they continuous downhill (uniform slope), or...? Positive camber?
The turns are increasing radius, off-camber. Obviously there will be a limit to how much I can accelerate down those, but other cars do tend to shake me there.

You say "probably -2.8* camber" that implies to me that you may not know for sure? That in itself can have one chasing the wrong tweaks.
It's not easy (in my case anyway) to get -2.8* camber in the front without going to aftermarket arms and milling.
I'm using V2 arms. Fronts measured -2.8 by a shop. Rears measured -2.4 and -2.1 so I removed 2 and 3 shims respectively. So I dunno... -2.8ish? I'm starting to think I could do more rear negative camber, but tire wear doesn't suggest I need it? Or maybe it does?

So all this to ask - does my tire wear suggest I could take advantage of wider tires in the back? I could mess with rear alignment and front sway, or shocks (my problem is on-throttle), but ultimately I want to make sure I have a good tire balance to start with.
 

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Currently running yoko a052 195/225 on track (probably -2.8 camber all around) and I've shredded through my rears with very little wear up front!

Does this suggest an imbalance with the car? Everyone talks about upsizing the front to 205 for more grip, but if I really want more overall grip shouldn't I actually be getting some big fatties on that rear?

Anyone run 195 up front and 245 in the rear? My car is oversteery as-is, so will it really make my car too understeery?

Granted I want balanced grip during turns. It is possible the rear is wearing in the straights and the turning balance is fine?
First thing to note is that all cars, drivers, AND what the driver's want the car to feel like are a bit different. Looking at this from afar having driven/tuned many an Elige, I have some ideas but I want to know more. I think the car is too soft in the front.

Realkiran, when is the car loose? Corner entry, mid-corner, or corner exit? Refer to the BWR shock tuning guide we sent you for those definitions. The 550/800 is a good track setup with a stock cambered elise. It is also a good AutoX setup as it can be make more loose. Camber(esp front) is very powerful in these cars, so you can add front grip quickly. With that much front camber, tire sizes, and relatively soft front bar(Lotus track pack is fairly soft), the car will tend to be looser. The additional front rebound you added will tend to make the car loose on corner exit, not pushy. To start with, I would take out the additional front rebound and in the rear, I would soften compression and rebound 5 clicks and see how it feels.
 

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A few general notes:
As RoHo said above, what I provide is a starting point. Every car is different and every driver is different. The BWR dampers have a huge range of adjustment, but the static balance has to be close to what the driver wants before the dampers can dial it in for the 3 phases of the corner.

As we've done more and more track work ourselves(stock and Optima car) and worked with serious drivers like EldonZ, Kfennel, TurboPhil, and others, we've learned a few things. On the track, not surprisingly, the car wants more front roll stiffness in many cases. On the Optima car we ran our Hardcore bar + 600lb springs in the front. Probably due to more rear aero. On the street car on the track, IIRC, I think we were using the Hardcore bar with 550s. Stiffer front springs and softer bar works too. If anyone wants to try 600s we stock them.

Camber is very powerful. I don't think I've found the limit of lateral grip with camber, but you start to trade off longitudinal grip. Additionally, just because you are wearing out the inside of your tire and it runs hotter doesn't mean that it doesn't make more grip vs flatter w/ even temperature. Grip is grip and the car wants what it wants. F1 cars rarely wear the outside edges of the tires before the front. Since most of us are not sponsored by a tire company, we want a good balance of performance and wear. Only you can be the judge where that line is.

The SINGLE most important thing to making any given car fast is balance. Make the car handle best for you with the package you have. If you are at the track and the car is loose and you believe it is a steady-state problem, take out front camber or put in rear camber. Yes, it isn't optimal, but it will be faster if the car is doing what you want. Use it for learning. If you take out 1 degree of camber in the front and now your formerly loose car is sublime, then you know that with a stiffer front bar or springs with MORE camber will probably be the ticket.

Guys running more than stock power but no limited slip diff, be aware of spinning up the inside rear tire on corner exit. If you are not sliding the rear everywhere but are burning up rear tires, this could be the cause. Not surprisingly, we have solutions for that too! :)

Beware the extremes and beware of rebound. If you are running full stiff or full soft on shocks, you are putting a band-aid on another problem. Rebound is very powerful, but should only be used to fix problems compression can't fix. Remember get it close with Compression, polish it with rebound.
 

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After 4 track days...

So all this to ask - does my tire wear suggest I could take advantage of wider tires in the back? I could mess with rear alignment and front sway, or shocks (my problem is on-throttle), but ultimately I want to make sure I have a good tire balance to start with.
I really suggest you don't do anything until you find the correct rear tire pressures with a tire pyrometer and some hot lap testing. You can't draw any conclusions IMO when your rears are that over inflated. I've never managed to wear out my track tires anywhere near inside first on any settings.

Side note, I wish I had experimented with this earlier, but more rear camber seems to always be better until you get to the point that you cant put power down.
 

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Also to expand on what I think Fred was trying to say. For 99% of drivers the fastest setup is what they are comfortable in. If YOU think the car is over steering you need to fix it, regardless if I would think its faster, if its too much for you to drive its too much.
 

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My preferred tire set was Hoosier R6 in 205/225. Great balance and wear. I experimented with the A048s for a short while. Tried going to 225/245 to get a bit more front bite and found it a miserable setup. Zero steering feel. Simply too much rubber.
 

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When I use to work with a shop that prepped circle track cars, we would put a setup in the car that we knew was fast. When we gave it to a new driver, we typically ended up dialing out most of the tweaks that made the setup fast. Why? Because the car felt uncomfortable to the driver therefore he would not drive near the limit where it was fast. So, the first half of the day was getting the driver comfortable with the car. The second half of the day was spent slow putting the "Fast Stuff" back in the car. How well does this process work? I had two crew members of the driver thought I was in the car the last session because the car was turning respectable lap times.

Now, I agree that Fred has done considerable work with shocks and knows his stuff. You do not become a 7+ National Solo II champion without figuring things out. The interesting thing is what you learn tuning cars by crossing racing disciplines. I have done serious data acquisition on drag cars, circle track, tractor pulls and road race cars and I'm still learning. Get the springs and roll bar settings correct before playing with shock settings. Put in a known good setup for the shocks, Fred's, and adjust the mechanical aspects before trying to playing with shocks. Shocks control the velocity of the motion of the car. They do nothing once the car has taken a set. When you start adjusting shocks, you are typically adjusting for how a driver drives the car. When adjusting shocks, you have to decide if you are loosing traction because the tire does not have weight or you are overloading the tires grip potential. The interesting part of that statement is that a tires grip potential is based on the weight that the tire has. This why you will see shock adjustments suggest adding rebound to one end of the car and/or adding compression to the opposite end of the car. So, think about what you, as the driver, are doing with the controls at the point you are having a grip issue. Are you asking for grip before the weight has transferred or are you transferring weight to quickly.

Wearing out the rear tires faster than the fronts is normal. The rear carries 60% of the weight of the car and also provides the acceleration. On the 260, we go through rears about a 2:1 ratio. When we wear out a set of the rears, we replace the fronts and rears at the same time. Why? To maintain the balance of the car. If I put new rears on and kept the fronts, the car would have a tendency to understeer.

Later,
Eldon
 

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Discussion Starter #19
Wow, great responses so far. You guys know your stuff! I want to be clear - the car handles pretty reasonably, I'm mostly wondering if there is more overall grip available if I go with a bigger rear tire, and if I get a little extra grip on two downhill turns I know I'll be very happy ;). So against all wisdom, I just pulled the trigger on fatter (245) rears. My justification is the Elise comes with 175/225, so 195/245 should have a similar balance. I'll update the thread once I've had a chance to take them out!

As an aside, I've been doing rental-kart leagues recently - each kart handles/drives different, so I'm learning to adapt quickly and not blame the equipment. My "perfect" setup is throttle understeer, (mild) lift-off oversteer, and dunno about steady state... whatever gives me the most grip!

when is the car loose? Corner entry, mid-corner, or corner exit?
corner exit, most notably downhill ;)

The additional front rebound you added will tend to make the car loose on corner exit, not pushy. To start with, I would take out the additional front rebound and in the rear, I would soften compression and rebound 5 clicks and see how it feels.
Wow, I'm an idiot. I was distracted making that change, right before I hit the track. I made the wrong adjustment! I'll definitely stiffen the front rebound back to the suggested settings. I'm a little intrigued with @AustinP suggesting similar compression front/rear. I may try it, but not a top priority.

Guys running more than stock power but no limited slip diff, be aware of spinning up the inside rear tire on corner exit. If you are not sliding the rear everywhere but are burning up rear tires, this could be the cause.
Fairly certain not a problem since I'm wearing the outside tire (left-rear on clockwise track)

My preferred tire set was Hoosier R6 in 205/225.
I've heard 205/225 (hoosier) is extremely fast! I saw a video of a member here put down an unreal time with that setup at my nearby track. That's roughly equivalent to normal tires in 225/245.

Get the springs and roll bar settings correct before playing with shock settings.
I hear ya, I'm not really concerned with the shock settings right now. I've got no plans to change springs or replace the rollbar right now, so my variables are ride-height, alignment, tire size, and tire pressure.
 

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A couple of comments:

Interesting to see what you think about additional front rebound. If there is too much, weight transfers slowly and causes oversteer. If there is too little, it overloads the rear tire by transferring too fast.

205/225 Hoosier. Yeah, Hoosier's are amazing. I've been running them for 15 years. They call them "Purple Crack" for a reason!
 
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