How adding negative camber can improve lap times and tire life

Terry
By Terry Fair
Jun 10, 2024 | suspension, Camber | Posted in Suspension & Handling , Features | From the Aug. 2024 issue | Never miss an article

Photography Credit: David S. Wallens

An easy adjustment that can unlock both increased speed and tire life? Likely just adding more negative camber, especially up front. 

Increased negative camber–how much the tops of the tires tilt inward– simply places more of the tire’s tread against the pavement during cornering. The result: increased efficiency courtesy of more grip.

Most street cars are delivered with very little, if any, …

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Comments
Fair
Fair New Reader
6/11/24 9:15 a.m.

I'm here to answer any questions about this article...



It is my first one written for GRM, so be gentle! ;)

Colin Wood
Colin Wood Associate Editor
6/11/24 9:17 a.m.
Fair said:

Love the triple red.

theruleslawyer
theruleslawyer Reader
6/11/24 9:40 a.m.

In reply to Fair :

Covered everything I can think of option wise. How do you go about reading a tire in order to determine the correct amount of camber? How do each of the options impact inner and outer tire clearance? Camber is often directly related to being able to fit those chonky bois on there.

Andy Hollis
Andy Hollis
6/11/24 1:27 p.m.
Colin Wood said:
Fair said:

Love the triple red.

The gloves seal the deal

madmrak351
madmrak351 HalfDork
6/15/24 7:09 a.m.

Good job on the article. First time I have seen anyone mention the toe changes with a reference to front steer vs rear steer. Well done.

Fair
Fair New Reader
6/15/24 2:56 p.m.

In reply to theruleslawyer :

Camber does sometimes get pushed to the limits just to be able to fit wider tires under stock fenders - we get that compromise - but it rarely causes "bad things", and often opens people's eyes to how much camber they REALLY needed after all. More camber is still better than less. The big myth is "big camber" will cause adverse tire wear (it doesn't - most premature wear on street cars is toe out) or that it will impact grip under braking (I have tons of data to show that this is absolutely not the case - the best braking g traces we saw on this '24 Darkhorse in multiple stages of testing was with the most front negative camber).

Of course direct probed pyrometer testing is "the gold standard" for dialing in camber, but in my experience, this can give somewhat misleading data. When you have used real time spread sensor IR tire temp readings, correlated to some GPS data, you will see HOW MUCH tires cool off on just a short straight after a hard corner. These real time tire temps focused on the loaded (outside) tires only in cornering tell you so much more. Even coming into the hot pits straight from a hot lap and having someone quickly probe the tires directly - by then your tires may have cooled off 30-50°F or more. How can you trust that data? The IR array sensors + data collection and crunching is a relatively expensive way to dial in camber (and air pressure and toe), but it beats everything else.

I like to look at "alternative sources" for camber data, and it has paid off over time with potentially better data than the old school probe pyrometer. My first method is to look at the loaded (outside) tires mid-corner, like the images above and below. This SHOWS me the dynamic camber (vs static), with the tires loaded and bushings at max deflection. THAT tells me when I need to add more camber better than a probe pyrometer could hope to.

This image above of our '23 BRZ (SCCA TT T3 class) shows our "massive" camber settings all get gobbled up in bushing deflection and roll. This was loaded up in the fastest corner (Big Bend) at our test track MSR Cresson. When you can visualize what the car is doing dynamically, loaded mid-corner like this, these alignment settings don't seem so radical anymore.

Another method is monitoring tire wear over the life of every set of tires. I will take pictures like this above and mark how many events were on the tires, to show folks what careful tire management, proper static camber, and correct tire pressures can give you. That car (2018 Mustang GT prepped to NASA TT3 / SCCA TT T2) was driven hard for 2 seasons and I marked how many track days we got out of each set, and I could tell by lap times when they had fallen off. We rotate the tires after every event, and do tend to "flip" the tires on the wheels once during their life (this doesn't affect the feel or performance, just extends the life). It is still a challenge to get perfect shoulder wear on most cars, even with -4° camber like we ran on this car, so flipping them once can extend their life by 50%.

After 36 years of running competition events, with 25-30 events per year in a variety of cars, we've moved to these standard + "alternative" camber (pyrometer + loaded visualization + tire wear monitoring) testing methods. And those methods have pushed us to "run more negative camber" than most folks think works, but most people don't test as much as we do, or won't even attempt the camber settings we end up at. I share this experience with as many racers who will listen.



I hate seeing people shred the outside shoulder of any tire prematurely, which is why we pushed SO HARD for SCCA TT "Sport" category to get camber adjustment for every car. This finally passed in 2023 and we're seeing more Sport class racers move to adding camber within the limits of that class. And that is pushing my crew at Vorshlag to develop more camber options for the OEM style suspensions that Sport class limits racer to (like this 718 Cayman setup we made last month). I just wish SCCA Solo Street classes would finally move to the same rule set. #CamberForAll

Cheers, Terry Fair (Camber Junkie)

Tom1200
Tom1200 PowerDork
6/15/24 4:13 p.m.

All solid advice.

I use a combination of tire temps and tire wear to set things and yes I always check the toe.

As an aside the Datsun only uses -1.5 degrees of camber (it's what the Hoosier vintage tires require) and even that little bit changed the toe.

buzzboy
buzzboy UltraDork
6/16/24 9:52 a.m.

I need the article, "How to add more negative camber than the suspension system allows." I'm maxed out at -1.5° and still seeing the need for more

Tom1200
Tom1200 PowerDork
6/16/24 1:14 p.m.

In reply to buzzboy :

On the Datsun we originally slotted the strut tower itself. That is what the Nissan Competition prep manual said to do.

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