Just rolled these settings on this M4 GTS and it feels planted. Correct.
Springs - 400F/342R
Bump 8.9F/9.9R - Rebound 3F/2R.
I have yet to just take T10s default tune and flop their damper settings tho.
Anyone else care to tinker with this?
In my experience high rebound always made my cars very unstable on rumble strips. Low bump always felt very grippy compared to high bump settings. But then again I have trouble catching a few of those fast drivers on some tracks, so maybe your setup is more grippy…?
I wish i knew how to tune so i could understand you guys
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Any time I’ve set the rebound higher than the bump my car is unstable. Doesn’t make any sense, but here we are. I’ve tested a good dozen cars so far and they all give me similar results. Much more grip when I flop the dampers around.
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You also think the Dolby app changed the sounds
Don’t you have anything better to do? All I’m doing is reporting my experience.
They’re not reversed, I’m sure. But there’s nothing wrong with running whatever settings feel right with your driving style.
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I agree theyre not reversed and yes use whatever works
Whatever it is, these default tunes have less traction when adjustable aero isn’t in play. Like say I just want to slap adjustable suspension on a E46, and only suspension. This car handled better when I swapped the damper settings. Maybe it’s just too stiff, Idk. I’ll test that next.
Why do all the telemetry numbers instantly turn green when I do this? Explain that one. Everything improves. Acceleration, and braking distance.
Why, when I do this, does this car just feel like a stiffer version of itself like it should? I’m telling y’all that something is up here.
To be honest I hardly trust the telemetry/benchmark numbers. There’s been more than a few occasions where its displayed nonsense numbers for 0-60, 0-100, etc. The only thing I trust when it comes to whether a setup change has actually improved performance or not are lap times. What I’d really like is if the game allowed us to plot data from our races/test drives in order to determine improvements that way, but oh well… If only there was a game built from the ground up that could support that stuff! 
Well having a stiff bump and a soft rebound setting will do that. I guess in this circumstance the soft rebound might allow the car to transition in and out of corners quickly, but I’ll still have to give the car a test drive with these settings to really have an opinion on how it handles.
The specific relationship between bump and rebound settings might differ from IRL by a little or a lot, but I’m positive that bump works like bump should and rebound works like rebound should. Set the bump to maximum and rebound to minimum, and the car will jack up like a monster truck in the corners. Do the reverse (minimum bump, maximum rebound) and the car will try to dig itself into the ground. That there is enough evidence for me at least. But I’ll try and get around to testing the feel of that setup
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Well, I can tell from my testing this evening that the majority of my understeer woes have disappeared. Couldn’t seem to get that done at all by setting these dampers the way the game’s instructions say or any other info said on the web ( I’m no suspension specialist, I leave that to my tuner IRL ). I do, however, know how quite a few of these cars should feel with coilovers and when I set them up the way I described, they feel that way. When I try to use them in their T10 default tune state, they don’t feel correct at all.
Wanna trail brake? Not gonna happen with the T10 tune defaults. I try that with their tunes and my rear end loses traction almost instantly. I can do this with ease after swapping the dampers around.
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Yeah the default tunes aren’t great, most of the time there’s just so much understeer. I spend way too much time setting up the suspension so it handles the way I want it to lol, but you know how the saying goes… If you want it done right, you gotta do it yourself 
No
There is something to said for using higher bump settings than typical in previous Forza’s.
I have found good results can be achieved with stiffer bump settings, giving a solid road feel with out being to sketchy.
Typical softer bump higher rebound setups still work just as well and are easier to keep compliant, but some cars do seem to perform better with stiffer bump setting. still need to compensate and have a balanced tune to make it work though.
Generally ive found stiffer bump settings work better on flat tracks with harsh curbs, and softer bump for the more undulating tracks. Kinda obvious I know.
In the end, as long nothing drastically silly is happening with the setup, and you can get it feeling predictable and slightly optimise the gearing enough most setups will be pretty comparable on the time sheet, just a matter of learning each cars quirks and adapting to them.
Edit: To the point, Bump and Rebound im fairly certain are not reversed but do have some interesting outcomes with different settings.
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I remember that thread. That was a fun one.
You do you man.
Well, every time I set rebound higher than bump I don’t get good results. Like this 997 GT3 here. I set the spring rates to that of Ohlins R&T. Then tried setting the rebound damping the way that T10 does and instant rear end skitter. Couldn’t trail brake or brake in turns at all without losing the rear end. I set the rebound lower than bump, boom, cleared all that right up.
With higher speed cars (P-X) I found cars to be much more stable at extremely soft spring rates.
It seems the less your suspension bounces in the telemetry during long straights, the more stable and grippy the car is, every single time.
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Rebound should be (providing T10 has programmed it correctly) the speed at which the suspension recovers from the bump. You always want your tires in contact with the track surface. I can’t think of any real world scenario where you would want rebound higher than bump. Yet many of the T10 stock setups have rebound set higher than bump.
As for the T10 green guideline numbers, I find them to be rather pointless. You can a an adjustment one click and get all green, go one more click and get all red, go one more click and get all green again, go one more click and get some red some green. It’s very unpredictable and very unhelpful.
IRL the general consensus seems to be “rebound stiffer than bump”, as well as some sim racing forums.
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Precisely. And I get better results rolling the opposite. This is why it seems like they’re reversed to me.