Differential Tuning Discussion

WARNING this will be long.

I have explained some basics to enough guys that had no idea, and also gave tips to enough really quick guys who didnt seem to have ever messed with it, that I figured I might reveal some of the secrets to the mystical art differential tuning. Especially after hearing a lot of people complain about how "bad" some of the stock setups are. A lot of these things can be drastically changed by diff tuning.

But I didnt want to start this to alien-splain differential tuning to the plebians, because I am no alien, and I am not a setup wizard. When it comes to springbounds and damprates and bumper stoppers, I dont really know. It's magic to me. But I do have a little better grasp of differential tuning than several other things, so I wanted to share what I know, and hopefully the real aliens might chime in and share as much as they care to share. Anything you guys know, feel free to add. If there's anything I have gotten wrong, or glossed over (and I will!) please correct and add to the discussion! Maybe we can all get faster! I am not an authority on this at all.

For lower downforce vehicles, differential tuning has a PROFOUND effect on the behavior of the car. Its one of the biggest changes you can make. The more mechanical grip you have compared to aero grip, the bigger difference this will make. So road cars, old F1 cars, this is one of the first things I go to to adjust these things to my "Driving style". Consider even high downforce cars, at low speeds, the aero df isn't going to be as big of a player as the mechanical grip you have. So keep this in mind!

Note in the setup screen, you have several options of different differential types. You click each of these to off or on. I have not tried to break the game and turn multiple on at once, do that at your own risk. Each type of diff has whatever setup parameters applicable to it underneath it. If you're perusing through TT setups, be sure to take note which diff type they are using by looking for which is set to "On" and then check and see what their settings are so you can see how different things feel. From memory, the options are Spool, Geared, Clutch, Viscous, and ratcheting.

Read more here if you're curious: Limited-slip differential - Wikipedia

All a differential does is take power coming out of your transmission, and then send it to the drive wheels. One shaft to an input(pinion) gear, this turns a "ring gear" (traditionally, modern F1 stuff gets crazy) at a 90 degree angle. (These two gears determine your “final drive” ratio in game, which is why sometimes you can adjust individual gear ratios in the transmission, but not the final drive ratio in the differential.) This is attached to what is sometimes called the "differential", which is actually inside the axle housing (much like how a CPU is a processor, but some people refer to the whole computer box as a cpu) and this is what we are concerned with. This differential connects the ring gear to the axle shafts, and allows the axle shafts to turn independently of the ring gear and a each other.

Any discussion from here on about driving characteristics is from the point of a rear wheel drive car. Things get slightly different in some cases for front wheel drive.

OPEN DIFFERENTIAL:

Operation:
The most basic is the "open" or "non limited slip" differential. Most basic, cheapest, simplest, most reliable, and by far the most common. Your personal car most likely has one of these. From a stop, if you drop the clutch, or apply brakes and go wide open throttle, you will get a lot of smoke and noise from one corner of the car, and not a whole lot of movement. All the power of the engine is just going into spinning the tire.

Characteristics:
The problem with the open differential is that as soon as you lose traction with one tire, all the power goes straight to that wheel. If you've ever gotten a passenger car stuck in some mud you've seen this. American stock cars often use these, because at high speed, it's much more difficult to break traction due to the gearing at those speeds. If you have more traction than power, a limited slip is unnecessary.

SPOOL:

Operation:
In this case, we lock the ring gear to the axle shafts, and the axle shafts are locked to each other.

Characteristics:
Doing a u-turn, you will hear the inside tire skipping over the pavement as it's forced to turn the same rate as the outside tire. However, in a straight line, if you drop the clutch, both tires will turn at the same rate, and even if you lose traction on one tire, the other tire will be helping and will minimize the amount of wheelspin as long as you dont overpower the combined grip of both tires. Whereas before all you had to do was overpower the grip of one of them. Drag race and drift cars often use this method or they accomplish something functionally equivalent. This is one of our options in game. The problem with a spool, is if you try to turn, the car will not want to turn. The grip of the rear tires is fighting the car during the entire corner. It will only want to go straight, but it will do that very well! It will be stable under braking, and stable under acceleration, but it will understeer always.

NOTE: From here we must make the distinction from POWER and COAST. These are FUNDAMENTAL to understanding how your diff settings affect the car behavior. The following types behave entirely differently depending on whether you are applying power, or if you are decreasing the engine power into the diff relative to the car's movement. If you're ACCELERATING, you are on the POWER side. As soon as you left off the throttle, and the car begins COASTING (or braking), you are on the COAST side. POWER settings only affect the ON-THROTTLE BEHAVIOR, and COAST settings only affect OFF-THROTTLE behavior.

RATCHETING:

Operation:
I am not positive, but I believe this is what we americans call a "locker". It means it functions as an open differential in a corner, somewhat, and locks to act as a spool in a straight line. It is either locked or unlocked. Digital, on or off. There is also a “cam and pawl” type differential, which was one of the oldest limited slip type designs, but they function very similarly, except that the transition between locked to unlocked, while still very abrupt, is not quite as instantaneous. They are relatively primitive but when in new condition they will have similar characteristics. These were common in very old f1 cars (think early 60s).

Characteristics:
There is no transition state here, so they can be prone to unsettling cars as they operate into and out of corners. The key here is you either have a spool, or an open differential. There is no transition zone between the two. its digital, on or off. And can lead to violent behavior IRL, and I dont know that they are used often in road race applications these days, but they may be. They are often built extremely tough, and are durable (modern, not cam and pawl), but make a lot of noise in use and can sometimes lock or unlock unexpectedly. They are popular in street-driven hot rods in the US as they give you the benefits of a spool when drag racing, but allow you to go around corners without the tires being locked to each other.

GEARED:

Operation:
These are based on a Quaife design. I had originally believed them to be variants of the "torsen" differential. These two are both geared, but the Quaife design is more common in European and Japanese cars, while the Torsen is more common in American cars. The version in game appears to be a Quaife type, but I am still trying to wrap my mind around how the bias ratios are adjusted. They are purely mechanical geared devices, they either function properly, or they are broken. There are no clutches or friction surfaces, and they use internal planetary worm gear arrangements, and relative sizes of these gears to determine a "Bias ratio". How these can be adjusted independently for coast and power situations is something I am currently struggling with.

Setup:
These have settings for how they are "biased" on the power and coast side. I have found through experimentation that the bias on each "side" goes from 1-8. Lowering the bias down to near 1 will result in a car that behaves as if it has an open differential on that side (power or coast), whereas setting it to 8:1 is as close as it can be adjusted to a spooled differential on that side.

Characteristics:
I LOVE this diff for the Formula Retro cars! These have the unique property of only allowing the outside wheel to turn exactly the amount "more" than the inside wheel turns "less". IE if the inside tire turns a half turn less, the outside tire MUST turn a half turn more, due to them being geared to each other, so they can promote almost violent corner entry rotation in some cases. Note open differentials have this same property, they just are unaffected by torque going into them the way that geared differentials are. In general though, these really are almost a best of all worlds type LSD. The only drawback to these are that their behavior is not as customizable as a clutch diff, and they cannot achieve 100 percent solid lock (Quaife type, not Torsen). For street-driven sports cars any type of geared differential is an excellent choice as they function well and do not have friction surfaces to wear out. You'll find them in a lot of modern performance cars for that reason.

There is more good information provided by Shadak in the thread below!

CLUTCHED:

Into The Red - Limited Slip Differential
Plated limited slip differential explained. – KMP Drivetrain Solutions
Operation/Setup:
These are probably the most common racing differentials. The link above is excellent and includes some cool diagrams of the ramps.

These are so popular because of how tuneable they are. You can adjust the amount of clutch plates, preload, and ramps.



Clutch plates: (increases friction surface) to adjust how hard one axle grabs the other. They are very similar to a motorcycle clutch if you've ever seen one of those. the axle is splined to a series of clutch plates, while those plates are sandwiched by a series of clutch plates that are splined to the differential unit itself that the ring gear is attached to. The net result is that either axle is locked to the carrier (And therefore each other) unless enough force is produced to overcome the friction.

Preload: The preload applies extra pressure to the clutch packs and affects how eager your differential is to completely lock. "negative" preload is where you dont have any spring pressure against the clutch plates/clutch packs, but it’s kind of a weird way to look at it. I don’t think this is a very common terminology and would be extremely uncommon in practice. This applies a minimum of friction force as well, regardless of ramp settings. So it sort of "narrows the window" between the coast and power side, making the transition faster, and also provides a minimum amount of locking force with a given number of clutch plates.

More clutch plates - More friction surface
More preload - forces friction plates together more, preloading them against each other. Note in real life if you remove several plates, the preload is what is adjusted to adjust for the height of the "stack" as well.

The key to the adjustability of the clutched differential, is that you can make it behave entirely differently on the power side vs the coast side. Thats accomplished by setting the RAMP angles. Ramp angles closer to zero apply much more pressure to the pressure rings, which are opposite the preload pressure. So you have preload on one side, and pressure rings on the other, with your clutch pack stack sandwiched between them. As you apply power, it applies a reaction force to these internal mechanisms against the housing they are in. A 90 degree angle applies ZERO pressure to these pressure rings, leaving only preload to apply a minimum amount of friction. A theoretical 1 degree angle (0 is impossible, there would be no window then) would apply a massive amount of pressure to the pressure rings. The internal mechanism is forced into a wedge (of the angle you choose) , and each side of that wedge is a pressure plate.

RAMP Angle -
- 90 Degrees - NO LOCKING BEHAVIOR AT ALL - "Loose/Open"
- 01 Degrees - COMPLETELY LOCKED - "Tight"

Characteristics:
So you can adjust how quickly it locks, how hard it locks, and how eager it is to do those things in both the COAST condition AND the POWER condition INDEPENDENTLY! Don’t get overwhelmed, though. You can leave it at 6 clutches and just play with ramp angles and get a lot out of it without getting into the weeds with the rest of it. The ramp angle adjustment is probably the biggest one here. But shallow ramp angles closer 90 with more clutches will behave somewhat similarly to ramp angles closer to zero with less clutches. There’s just a LOT of adjustment in these. But hopefully from here you can play with it and see what you like with a little more understanding of what the changes do.

VISCOUS:
Operation/Setup: I dont know much about this one, but it appears it is essentially very similar to a clutch plate style differential in construction, however the clutch plates are not providing friction to each other, but instead applying friction to a viscous liquid that is between axle plates, and the differential plates. I imagine this may be somewhat similar to how a torque converter works in an automatic transmission. At lower speed discrepancies between left and right wheel, they are able to spin freely, much like how your engine can idle in gear when RPMs are low, and you can easily hold the car in place with the brakes. As the speed differential increases, the force is too much and the viscous liquid begins to heat up from friction created by the clutch plates and transfers force from the spinning wheel to the gripping wheel.

Characteristics:
While I am not sure what the Nm setting for the viscous diff does, it doesn't appear to be able to be adjusted independently for power and coast, which may be fine for you, but it's also going to lack the adjustability of the other options. It also may never get complete lock from side to side, at least not without allowing some wheelspin first. On the plus side, if it functions like a fluid clutch, it should engage very smoothly and may be less likely to upset the car (the opposite, for example, of the ratcheting diff, which will suddenly engage and disengage).




APPLICATION:
So now you have some idea of what some of these settings do, here are some general rules of thumb based on my limited experience:

COAST - "tight", or like a spool - Car will not want to turn OFF throttle. More stable under braking, more understeer.
COAST - "loose" or like an open differential - Car will turn much more aggressively off throttle. Sometimes you'll feel as if the back of the car is trying to come around the front of the car. More unstable. Perhaps better for aggressive trail braking.

POWER - "tight" - Car will have much more understeer ON THROTTLE. One you're accelerating, the car will want to go where it is pointing and you will fight to make it turn. Point and shoot. Much more stable under heavy acceleration, even if you get wheel spin, you have both tires providing strong traction. Faster acceleration, less turning. If you get a corner very wrong, it will be more likely to step out, but if you get it mildly wrong, it will be more likely to go the direction you're pointing as it gains more traction. Think four-wheel drift. Can make the car feel much more stable through high speed corners, at the expense of turning ability.
POWER - "loose" - Car will turn much better on throttle. Turning through high speed corners will be better. High speed corners may be more unstable though, with the car more likely to spin. Too much throttle at low speed will cause much more power to get transmitted to the spinning wheel, leading to poor acceleration. Car will be slightly less likely to get out of control in this case, but you pay for that with less acceleration performance.

If you set power and coast angle to the same value, there will be no change in static cornering behavior aside from changes made by simply increasing speed. This would probably make it more predictable during throttle transitions.

Conclusion:
1. Most racers are going to use a clutch style differential. This is the most common.
2. What is ideal? Depends on your driving style and car and even the track. Do you need more stability on corner entry? Corner exit? Acceleration? Braking?
3. The default diff settings on most default setups seem... very curious to me. I wouldnt recommend most of them, but these settings are FAR more subjective than almost every other setup variable. Feel the differences, see what you like, dont worry about laptimes with this until later.
4. Start with spool and clutched. You can experiment more after you have an understanding of those.

For example, for the new historic Hockenheim 77 track, I tightened the coast side of my F-Retro setups so the car would be more controllable going into the chicanes after such aggressive braking. The drawback is that I get more off throttle understeer now, so the car isnt as eager to steer into a chicane. Also not as eager to spin. Hockenheim 77's Ostkurve is a long high speed sweeper. If you're powering through most of that corner, you may find the car is more planted and stable with a tight power side of the diff. If it's easy to overpower your traction level in a high speed corner with throttle, then ensuring your power gets evenly distributed to both sides of the car may be beneficial. The drawback is that you get more understeer in the stadium section when accelerating out of corners.

I recommend you make EXTREME adjustments. Try a completely tight coast and loose power (clutch diff, power ramps at 10, coast ramps at 80, 6 clutches), then opposite, and mix in the spool, and try to pay attention to the differences in car behavior. Hopefully this overview may give you an idea of what you're looking for, and when you might feel it.

Hopefully that helps some of you! Feel free to make additions, corrections, insights, which cars got which types normally, etc. I hope we can have a nice discussion about that, and about driving styles and how they play a role in this.


Edit: I am making adjustments and tweaks as I find things. For some reason I've enjoyed this little project! Hope you like it!

 

Thank you for taking the time to post that. I'm pretty un-educated with diff setup and that helps to understand things.
Insert <thumbsup.jpg>

 

Great thread, thanks for taking the time.
One thing I would add that confuses people is that when a diff is locked it can produce oversteer OR understeer, depending on how aggressive the driving is/how much power the car has.
Corner exit with gentle throttle may produce understeer, but floor it or add throttle when the car is unbalanced and you'll snap into oversteer.

 

Absolutely! That’s why it’s so important to understand what the settings are actually doing so you can have an idea of why you’ve got under or oversteer. I absolutely think you must know your diff settings to drive a car quickly, whether you adjust anything or not. You have to drive them very differently depending on settings. That’s the main reason I think a quick and dirty overview of this may not be helpful. You kind of need the explanation of what it’s doing to intuitively understand what is happening better.


Probably a good way to experiment with this is to turn “spool” on and see how the car behaves with mild and excessive throttle at corner exit!

 

Btw careful with geared LSD. As the bias isnt unlimited, it can never fully lock so make sure you use it with cars and tracks where its very unlikely to have a wheel off ground (possibly very wet too depending on ratio). Afaik its not used on race cars a lot.

 

I happen to know a lot of amateur level racers that use these, but I also know they have their indiosyncrasies in practice and sometimes behave “funny” and unpredictably even though they shouldn’t. It makes sense that you say not many race cars use them. Just my personal experience with them is enough to make me see why.

 

This is EXACTLY the information I was looking for! Thanks so much.

 

I actually like the "predictable" behaviour of gears as it does what you set it to do. And IRL it has more use imo because you have to look after clutch plate wear in other LSD, or fluid etc. the Geared LSD is much more comfortable in this regard. In a game though where a lot of maintanance (pre or during race) isnt required, you would mostly use clutched. With historic or retro though, since there is still the annoying understeer in slow to medium-slow turns and you really have to use unrealistic end of setup to make it turn, geared feels better ... Retros in RF2 or AMS1 feel much better in terms of diff tuning.

You can read @Maser V6 transcript from the real driver where he mentions on real retros there is no issue with turn in and there shouldnt be such resistance, even with a default LSD setup.

 

Yeah I loved the interview @Maser V6 did! Some good differential setup info and real world experience in it too!

You mentioned it already, but the geared diffs I’ve used did not have bias adjustments. Do you know more about what exactly the “bias” does? You say they can’t 100% lock, but theoretically they must. For them to be unlocked under power, a cog gear has to be able to turn a worm gear. I just know that empirically, things get odd from time to time. I’ve even watched some of my drag racing friends do one wheel burnouts and holeshots with these diffs and theoretically that should be impossible. It’s like you say, if there’s water or odd conditions they sometimes behave in ways that don’t make sense.

 

OK Im not a diff expert but Ill try
As the geared LSD works off bias, it means when one of the wheels has less traction, it will determine the torque sent to the tyre with more traction based on the bias. So for example in 4:1, it can receive 4 times more torque than the tyre with less traction, its limiting slip but not locking completely as the max is I think 8:1? thats still not 100% lock, its just 80% of the torque transfered. If the wheel gets 0% traction, you basically multiply by 0 so thats 0 limit of slip = works like open diff (when 1 tyre is in the air). 1:1 bias for both power and coast would be total differentiation I believe, so open diff - oversteer on entry, understeer on exit, except for snap situations.

Maybe those you worked with/saw were welded to be locked always?
Like I said though, Im not an engineer so could be wrong about how it works.

 

This is what I used:


I did some more digging and found that the differential in the game is not this type, and is instead a "Quaife" type geared differential. This is likely what you're referring to, and is distinct from the Torsen type geared differential. I elaborated more in the post below.

 

I just did some more digging, sounds like the differential in the game is actually a Quaife Automatic Torque Biasing differential. It may not be a torsen, worm-gear type differential at all.

Note the diagram above looks radically different to this one:



Found this cool video too:

It amazes me how clever some people are to come up with these things. It appears they use a ratio of gear sizes to promote limited slip inside the diff. So they will function similarly to the geared differential I am familiar with in cornering, but the lockup is likely not as a "solid"... And according to the video, it seems to be able to transfer load to the wheel that has traction. This is the same as the Torsen, but Im not sure how different they are in this regard. So you trade off having a positive lock, for the ability to send power only to the wheel that has traction. Fascinating. I'll have to update my original post.

From what I can tell, these are common in a lot of performance front wheel drive cars, the Toyobaru 86, and several Japanese and European cars.

The Torsen geared differential is commonly in a lot of American muscle cars and trucks (and Mazda MX-5s)

I am still a little lost as to how either of these could have independent coast and power side bias ratios, but I understand better now how the bias ratio works after reading into the Quaife design, which would absolutely work differently as it cannot achieve 100 percent lock the way a torsen can.

This is a fascinating paper I found on the Quaife design that Im parsing through now:
https://s.race.fi/data/quaife/quaife_thesis.pdf

 

haha yeah sorry I didnt read your OP too much
just assumed when we say geared we mean the one in AMS2.

 

I wanted to write up a setup strategy post. You can carry these concepts with you to other games as well.

Your entire setup approach to the differential should be 100 percent "How does it feel?". Dont worry about lap times, if the car feels good to you, better laptimes will come with it. Fortunately, differential settings dont have very much interplay with the rest of the car's setup, so you really can just set aside a session just to mess with the differential alone without trying to balance a bunch of other factors.

I think for the purposes of the demonstration, a higher power car, with less aero grip and more mechanical grip is probably going to be the best for this. Maybe a Caterham would work well? A circuit with some hard braking zones, but alot of sweeping high speed corners is also good. I suggest Spielberg/Redbull Ring. But you can do this wherever and see the same results.

Start with the spool. Turn everything else to off, turn on spool. This locks the rear wheels together. Remember we will separate the car's behavior into power and coast. Power is when you're accelerating, coast is going to be decelerating/braking.

Go out and do a lap at your favorite car and circuit. You may notice:
Power characteristics:
- better acceleration out of tight/slow corners, even with too much throttle.
- The car feels more stable in high speed corners
- Corner exit understeer, you may get some mild oversteer you're not used to when you nearer to the limit, but you likely wont have much in the middle.
- Power oversteer will likely be more predictable and progressive.
Coast characteristics:
- Very stable in aggressive braking scenarios.
- Very stable when turning into corners.
- Trail braking requires stronger inputs.
- Very reluctant to turn in steady state cornering situations. You'll feel like you need to apply a lot more steering angle than usual, and you'll have to wait too long after apex to start feeding in power.

That's how a "tight" diff feels.

Next we play with with the clutched diff. Put in 4 or 6 plates, and from the stock car tuning thread I am reading, you may want to back off on the preload and set it to 20. Remember this is how much our clutch plates are "pre-loaded" against each other before we take into account our ramp angles. Set ramp angles to 80 for both power and coast.

Go do another lap. You may notice:
Power
- Easier to get wheelspin on hard acceleration.
- Car is far more "darty" during high speed corners, maybe to the point of being hard to drive. (Anything at Spielberg 76 may be a struggle for example)
- Far less corner exit understeer, can feed on power much earlier, as long as you maintain traction.
Coast
- Car turns MUCH easier into corners.
- Car is far more unstable under braking. Trail braking should now be almost treacherous, but gets definite, obvious results.

You should find the car barely ever wants to go the direction it's pointed. It just wants to spin like a top all the time. This is the difference between a spool and something close to an open diff.

Here is where you're now learning how the ramps affect how the car drives. You are going to leave everything same, but change your power ramp to 25. This tightens the power side, making closer to a spool. Leave the coast at 80. You'll see the car still wants to spin off throttle, but you should find that the car will stabilize on throttle. It doesn't have to be full throttle, just enough to load the diff onto the "power" side.. It'll settle down and go where you are trying to steer it, even if you have to apply more steering angle. Try this in corners 3-6 at Spielberg. If you find you have too much understeer, hop off the throttle completely to engine brake, and you'll feel the car start turning in dramatically and may start sliding a little. Get back on the throttle and it will start settling down again. Try this for high speed corners that dont require so much braking, but do require you to come off the throttle. You can let off the throttle to promote rotation, and then apply throttle to stop the rotation.

The idea now, is that you can adjust the ramp angles independently, and get spool like behavior on throttle, and open behavior off throttle.

Now you can try to flip the ramp angles around. Change the Coast ramp to 25, and the power ramp to 80. You should notice it's dramatically more stable into all the hard braking zones, and you have dramatically less understeer in all your high speed corners on throttle. Off throttle, you've traded maneuverability for stability.

And that's really probably the closes thing to an overarching philosophy on this. As the axles are locked together more, the car will be more stable at the expense of steering response and maneuverability. As the axles are locked together less, the car will be much more maneuverable, but at the expense of stability and predictability, and you'll likely lose acceleration performance due to excessive wheelspin. It's up to you how you want the car to behave. What is so unique is that you have the ability with some of these to get different behaviors on or off throttle. This gives you a lot of interesting driving style options.

Hope that helps.

 

Thanx for the setup strategy. I am curious to experience the differences of the various diff settings.

 

Found an amazing video showing how clutched differentials work (at least the type we are discussing here).

I added this to the main post, but if you havent seen it yet, I highly recommend.

Note the "1-way" vs "1.5-way" vs "2-way" discussion at the end. Those angles in the "windows" there, those are the ramp angles. In game we can adjust those to pretty much any degree we want. The smaller the angle, the harder the differential is going to push the pressure rings into the clutch packs. In the video, "1-way" has a 90 degree coast ramp, and a 45 degree power ramp. The animation does a great job of showing it, but I wanted to explain that 1-way vs 2-way etc is just a more basic of way of talking about ramp angles. Note when 1.5 way type is mentioned, you can see the difference in ramp angles in the animation, it appears to be something like 45 degrees power, 75 degrees coast.

 

I didnt want to bring this up but honestly I still think there is something odd going on with classic/historic open wheelers (F1 retro,classic,historic, etc.)

The corner entry particularly, even when I tune the diff to a very lenient setting, lowest locking, (high coast ramp angle, lowest preload, 2 clutch packs and 0 viscuous lock) there is some kind of force working against wheel differentiation, this should technically leave the diff open until there is a fair amount of slip (ie. its very hard to over come 89 angle) .. there is a huge amount of understeer on entry and I have to come to almost a stop to make the car turn. There is a certain threshold, around 30-40 kmh where it actually does turn VERY willingly all of a sudden. But im sure thats not something these cars did back then.

In the @Maser V6 interview, the guy who drives F1-retros says the LSD settings are actually quite high and they even use more clutch packs due to wear. Plus I believe he does say the retros never had issues turning in. So with this low locking setting, you'd expect the car to keep wheel rotation independed most of the time on coast. But it does not.

Now of course you can throw the car into the corner and use power to rotate. But its not a very intuitive feeling and none of the other sims have it like this (ams1,rf1,rf2,iracing,etc.)

 

I agree this is absolutely the case with the F-Retros. The F-Vintage just doesnt have enough grip for it to be immediately obvious, so Im not sure if it has the same issue, but there is a massive understeer with the clutch diff in teh F-Retros even when adjustments should tune it out. Switching to the geared diff makes it obvious how much the diff plays a role in that behavior.


Note viscous lock shouldn’t affect the clutched diff. It may in the game, but clutch diffs like this are different than viscous diffs. They work on different principles. Did you back off preload as well? That would essentially be your static, all conditions anti slip adjustment. I know I lowered mine quite a bit, down to maybe 20 or so and was a little miffed about how much understeer was still prevalent off throttle so I went back to the geared diff. These just don’t work the way they should. Damian now just sets some of his to spool and is done with it! I hate the understeer though.

I don’t know if this affects other cars as much as the F Retro though. I kinda doubt it.

 

it appears that setting steering lock to 26 helps turn the 72E. Not saying it feels good or right but cranking steering seems to help keep on the line. Note no claim to skill or knowledge. Just trying to find a setup around understeer. Also note running max caster as well as extreme diff settings.