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Parts of the guide date to FM3 and FM4 where this mattered more. Regardless, the issue is that some may remember the opposite from a fading part of their education. In school, we learned that all other things being equal, reducing pressure by reducing the mass of a gas in a container will result in lowering the temperature of the remaining gas.

The huge difference with tires is that all other things are not equal. They are flexible containers being rubbed against pavement. The sidewalls are constantly being flexed, and a lower pressure tire has more sidewall flex. As Clutch noted, a lower pressure tire also has a larger contact patch which increases friction of the tire against the road. This additional flex and friction create heat much greater than any cooling expected from an ideal static situation. Long story short, it works as described in the guide, but it is less noticeable as implemented in FM5 and FM6.

Edited by user Wednesday, October 28, 2015 3:56:23 PM(UTC)  | Reason: Not specified

Oh I see what your saying now. I must have been doing it backwards. I thought the more tire pressure I added the hotter my tire would run.

I was following the description in forza 6, I could of swore it said int he short paragraph that gives you a hint about tuning that if you increase your tire pressure would increase your tire temperature and increase oversteer.

It's the other way around. It says that as the tire heats up, the pressure will increase. If this topic's guide were tailored a bit more for FM6, it would get closer by saying that low pressure tires heat faster rather than more. Regardless of initial pressure, each FM6 tire type seems to eventually heat to its own equilibrium temperature. For example, race tires heat to about 210 degrees F. Sport tires should be similar, and normal and street tires will be lower.

The pressure at this temperature will vary based on initial cold-tire pressure. The tuner's goal is to get this final pressure to the point that provides best grip. The consensus view is that this is somewhere in the low 30's PSI, so the initial pressure will often be in the 28 to 30 PSI range. Based on the various tuning posts, you may find other tuners that prefer lower pressures.

Just wondering if there's any input on this. I've recently been tuning by sound/feel/laptime but results have been inconclusive.

The loaded tires are on the outside of the turn, so left side tires for right hand turns and vice-versa. Front moreso under braking and initially, then both through apex or a constant speed section, then rear for exit under acceleration.

Edited by user Sunday, November 1, 2015 4:33:09 AM(UTC)  | Reason: Not specified

I think I missed something. Is there a section for tuning the gears?

I'm seeing very little physics-based discussion on these forums since the game has launched. Other than a thread about tuning calculators and another about camber there hasn't been much discussion at all about the most effective tuning philosophies for Forza Motorsport 6.

Has the game already been "figured out"? Is it simply an updated physics model from Forza Motorsport 5, and the conclusions from back then still apply? Is it simply the fact that the forums aren't as active as they were in years past? Who knows.

I'm seeing very little theory discussion about the game anywhere (compared to several threads on other forums for Gran Turismo 6, some of which are still active) so I'm curious.

hi great write up, i have a slight issue with some cars i tune where they dont feel connected to the road, i have tried really soft springs and im using the damper ranges as per the guide, the cars turn in fairly quick times but dont feel right to me

i mainly race b class, any advice would be appreciated, thanks

I'm finding the majority of the few tunes ive done work best with higher spring rates than what I'm used to since FM4, also high 20's on the ARBs, low bump between 1-3.5 and high rebound 8.5-10. I'm still learning, there's things I don't fully understand like the diff settings, that's more trial and error for me.

I'm not understanding these adjustments

Adjustments Decrease Understeer Decrease Oversteer
Front Wheel Camber More Negative More Positive
Rear Wheel Camber More Positive More Negative
Front Wheel Caster More Positive More Negative

Rear ARB soften = decrease oversteer or increase understeer
Rear ARB stiffen = decrease understeer or increase oversteer

With FM6 the warm tire pressure is key when evaluating telemetry data. Moreover the best way to know your pressure is right for the car is how it behaves during a turn. If you stick a turn during lap 1-2 but skid and loose grip as if the tred is magically worn off in lap 3 and later (sometimes lap 1 sticks and lap 2 plus skids). You need to reduce the pressure.

When tire pressure is to high they will loose grip and skid/slide when fully warmed up. When tire pressure is to low it will cause unpredictable grip during turns which can result in sometimes drastic fluctuations of grip.

Best thing to do is keep aware of how fast you can take a turn between laps 1-3, if you seem to loose grip then lower pressure. Avoid lowering the pressure after you reach a sweet spot when you have consistant cornering grip from about lap 2 and above. Any lowering of pressure will be a waste and risk unpredictable cornering. Your troubleshooting best friend is the tire pressure telemetry data. You want tire pressure on turns to be even between your tire sets, straights data is only useful when drag racing.

what about in drifting???have excellent setup for FM4...but the damn thing wont work on FM6

What a helpful post, just getting back into forza and really enjoying tuning. Nice to get some more in site in to how it all works and the effects.

Just noticing this from a while back. It's supposed to be a table, but the forum formatting makes it hard to read. It is saying this:

Front Wheel Camber: Make it more negative to decrease understeer OR more positive to decrease oversteer
Rear Wheel Camber: Make it more positive to decrease understeer OR more negative to decrease oversteer
Caster: Increase to decrease understeer OR decrease to decrease oversteer

Note that these are subtle effects, and the settings are better for maintaining the quality of the contact patches and steering responsiveness than trying to directly correct oversteer or understeer.

The rear ARB notes should be easier to interpret, but here and anywhere dealing with ARB, springs, or damping, increasing the rear tends to shift away from understeer and toward oversteer while decreasing the rear shifts away from oversteer and toward understeer. The opposite is true for the front: increases shift toward understeer, and decreases shift toward oversteer. Along with springs and damping, ARBs are better suited to help with understeer & oversteer than camber and caster.

I don't see it mentioned here, but in my experience, Camber is something you want to watch telemetry for, not guess, or set to any particular number. The posts here seem to indicate you should just set this to a negative number on front / rear and be done with it, but it's not that simple. The amount of camber you need differs wildly from car to car, just like in real life, because of varying suspension designs, torsion beam, vs MacPhearson, versus independent, versus dual a-arm, and so on. For instance, a modern Lotus Elise, and other similar cars built for track racing with independent suspension, will have more consistent camber necessary between front and rear and less of it needed too (about -0.4 on both IIRC), but an old Trans Am might need -1.5 in the front and -0.7 in the rear, due to the very different suspension design front and rear, and it being an "inferior" design for racing. I find it rare that any car needs more than about -1.8 in the front.

You can actually dial in camber perfectly for each car, if you watch the telemetry screen - and this makes a HUGE difference to max grip in high speed corners. I find it to be pretty easy and it's one of the first things I do when tuning a car.

All you have to do is go to the telemetry screen that shows on screen degrees of camber for each wheel. Then go to a track with long, sweeping, high speed corners (I like WGI, as I know it best too). Watch the OUTSIDE tire in the turn. During a high speed, sustained, max G turn (basically full suspension loading), you want the camber to be as close to zero as possible on that outside tire, but still just a little negative (you want it to never go positive). I usually aim for about -0.20 on front and rear outside tires - that gives a little wiggle room to stay negative, but not SO negative that you're losing grip (too negative is just as bad as not negative enough!). Again, you have to do this during high speed, high G turns. Watch the camber numbers thru out the whole turn, start, apex, and finish. It should never go positive, and if it does, only if you hit a curb or bump. Basically take an average. It comes easy with practice, should only have to hit a few turns to get a good baseline. Check it at each corner on the track.

Remember to check and set this again if you change ride height, or tire size, or even other grip mods (tire type, etc), as being able to throw more grip on the car means you'll load the suspension more, and changing tire width can change tire to track angles. In fact, check it once you're done with all other adjustments (roll bar, spring weight etc), as it's easy to verify it's still in spec.

Do this and you'll get a lot more grip!

Edited by user Tuesday, February 2, 2016 12:56:17 PM(UTC)  | Reason: Not specified

Whats going on is that Forza 6 added much wider tire upgrades available.

Tire width however is less PI efficient than compound.

But in A and S class, many cars need the extra grip even at inefficient PI. So you end up with these super wide tires on circuits. Thus the ridiculously low PSI some people run to get the most grip. The caveat to this is that some people are putting super low pressures on skinny tires out of habit.

I want to chime in on camber/caster/tires etc...

While guides may be simplistic, I was never a fan of statements along the lines of increase x to decrease oversteer...

When dealing with settings that change your contact patch with the ground it's important to understand you never "decrease oversteer" you are either decreasing grip to the front of the car or increasing grip at the rear of the car. But every setting change will have a trade-off that may not be readily apparent.

There are also multiple ways to adjust camber angles, while direct setting change is obvious. ARB adjustment will change camber, spring rates and damper setting can if they allow excessive movement in the car body, tire type and tire pressure (more grip = greater mechanical load on suspension, increases tire lean out which will create more camber mid-corner).

Also Caster is evil, I prefer to run 3.5-4.5 with my camber max around 2.3 depending on tire. Caster is tricky, high caster can create awful low grip situations in hairpins. I prefer a straight camber adjustment instead of variable camber created by caster.

Most importantly, every track is different.
I've seen a couple people say just look at telemetry and don't allow camber to go positive mid-corner. The problem with this logic is not every corner is a long sweeper that will have max side load. Tuning to extremes will leave you at a grip deficit for most of the track. You have to tune to a high median. Find a setting that works for the majority of the track and then understand your limitations in sections of the track you aren't set up for. This is how it's done in real racing and is clearly obvious when watching guys go at it on a track. Driver A will tune his car for a specific section of the track and constantly make passes and moves in that area. He will know his secondary and tertiary corners where his tune allows him a little wiggle room and he will know the areas he is weak and take defensive lines during those times.

I agree with this. As much as driving style has a huge effect on how a tune works, I believe in a build that has just that but more than really needed, making it a car that can easily be over driven giving slower times. Either with over steer or understeer or unnecessary gear changes or not being smooth and steady. Granted I am still relatively slow compared to all you fast dudes, but I'm getting faster, lol. Maybe I look at it wrong but I would rather have a car that if I really needed that little extra I had it as apposed to being able to drive flat out all the time. Kinda like having your amp always at 11. Where can you go from there? But as I said in the beginning, driving style has tons to do with a tune.

Driving style is an excuse for not being good enough to drive a given car and the way it is set up (in most cases). There are some cars I absolutely couldn't drive, something that b0x could to #1 I couldn't deal with. That isn't a driving style, that's me not being able to drive something someone else can to #1 but I give them my car and it might be 5th. I could do the same with others that are capable of #1's everywhere and the same thing would happen.

Not driving style.


BTW, telemetry in Forza isn't an accurate representation of tuning adjustments. A lot of times it will hold you back. Basically, and this is a blanket statement, cars fit into certain areas. FWD, mid engine RWD, RWD muscle, etc. The same exact tuning settings work for every car given the "area" or "type" because Forza, when upgrading a suspension, puts the same generic suspension under every single car in the game. The only difference is going to be the amount of spring weight based on the stock weight but if you look at 1/2, 1/3, 1/4 up the bar it will all fall in the same space.

Some people like their cars tight. Some like their cars loose. Some prefer an early apex, or late apex. There are differences in how people drive a car. So, in my lowly opinion, style, or HOW you drive the car has something to do with tuning. But what do I know, right?

Obviously not as much as you think.

You feel good for that one now? You seem like a really nice person!

I'm a fantastic person and I feel great.

Back on topic...



This is how the more prolific tuners (Raceboy etc.) can push out a large number of setups. Once you know the ideal range on each slider you can create a good handling tune in less than 5 minutes. After that you can do a few laps and make minor tweaks but the "heavy lifting" has already been done with only minimal gains to be had.