Are your tranny gears a bit off, but every time you adjust them, they seem to get worse? I worked out a technique that works every time. I go with a 3.00 first gear bc it’s near the middle and you end up at 1.01 for 5th gear, and .87/.86 for 6th/overdrive gear. I’m going to use a 2.76 1st gear for this example bc it illustrates the math a bit better. Speaking of math, l was terrible at it in school, so if my terminology is off, don’t be petty, bc the end result is correct. Ok, the key number is .666, or .67 if you sloppy. Set your first gear at 2.76, multiply 2.76 by .666, and you get your second gear. Once you get this number…1.838, round up to 1.84, then you’re going to use 184, not 1.84. You’re also going to turn 2.76 first gear into 27.6. You’ll be using this 27.6 throughout. Or whatever your 1st gear is. After you have your 1st and 2nd gear, you’re ready to get started. 2nd gear is at 1.84 (184). You’ll continue to add your 1st gear derivative from here on out. So, 184+27.6=211.6 multiply this number by .666, you get 140.9. So, 3rd gear is 1.409, round up to 1.41, continue this process. So, 141 (not 1.41) plus 27.6 (not 2.76) get your number, then multiply by .666. This works, with any powerband, any vehicle. It’s not a fluke, l don’t know the significance of .666, and l don’t know why you move or remove the decimal point to do the math, but l do know it works with any first gear setting, in any vehicle. I don’t wanna do the math on a 2.76 first gear, but l have the 3.00 first gear progression memorized, and l’ll list it here. I have found that 6th gear ends up looking short, so, l’ll make it 1 point taller, but usually end up going back to the original number. Here’s a 3.00 first gear progression using this formula. 1st: 3.00 2nd: 2:00 3rd: 1.53 4th: 1.22 5th: 1.01 6th: .86. I know this works because, like l said, l’ve tried multiple first gears, on multiple cars, and it’s the same beautiful progression in the sweet spot on everything l have. To get close on your final drive, divide 10 by your first gear, and move to the accel side from there. For a 3.00 fg it’s 3.33 final drive, but there are factors that affect this supposed optimal 10:1 first gear ratio, such as tire diameter (on trucks you’ll be between 12.5 and 15:1) or your accel/speed or torque/hp relationship. There are highly complex ways to factor these in, but it’s far beyond my knowledge. start at 10 and move right…lol or divide by 10, divide by 15, and your final drive will be somewhere between. I haven’t gone over a 15:1, but you might check all the way to 20:1 if your accel number is super low, and/or tires are super tall. I put the 3.00 fg progression on here, so you could try it without committing to a buncha math. Just trust that l got this progression using the math illustrated, and it consistently works out the same with a beautiful arc. Btw, if anyone can tell me why this works, the significance of .67, or why you move or remove the decimals, l’m pretty curious about how l…not gonna say stumbled bc l flip flopped numbers and decimals for a good bit before discovering this. Yeah, that’s it. “Discovered” has a nice ring. Makes me feel like a pioneer, or explorer

To recap… if first gear is 3.00…


Second gear is 2.00. Now we can either multiply by 10, to turn that into 20, or use 1/10 of first gear (0.30) to add to 2nd. This second method saves a step in calculating each successive gear.

2.30*(2/3)=1.53 < third gear

1.83*(2/3)=1.22 < fourth

1.52*(2/3)=1.01 < fifth

It is a nice looking formula and I wish I had it in me to remember what I learned in high school about functions/graphing. I have a strange urge to pull out some graphing paper and a pencil and play with this and similar formulas but my disposition for mental math is not what it used to be and I don’t know how far I would get.

I usually set my final to optimize reverse gear, 1st for standing starts and/or hairpins, then top gear, then everything in between. Don’t really care for the curve. If I’m always in the power band (I check telemetry often) and not shifting excessively… it’s a good gearset. With the exception of 2nd and sometimes 3rd gear, the distance between the max speed between gears (the tops of the lines) is more important to the feel of the gears in practice than the pickup points.

There will not be much of a “slope” if you put this into a graph. And you do not need a calculator to check this. Just by looking at what you did, you can see there is no curve on the y axis. Also, you can go to and plug in each of your equations onto the x axis and you will see what I mean. Here is what you put it…

  1. X = 3 3
  2. X = 3 * (2/3) 2
  3. X = 2.3 * (2/3) 1.5333 (repeating)
  4. X = 1.83 * (2/3) 1.22
  5. X = 1.52 * (2/3) 1.01333(repeating)
  6. Y = X

What this will do is put a line on each of the X’s and then draw a line through the entire Y axis and show you this. Or, if you really want to go out, plot your own points going in reverse order starting at 0 and you can get a line through it all. Each will work but since you are using a constant (the 2/3’s) then you will pretty much have a straight line for everything. And another thing, it will give you the x/y coordinates on which the lines will pass through each other as well.

  1. 0,0
  2. 1.013,1.013
  3. 1.22,1.22
  4. 1.53,1.53
  5. 2,2
  6. 3,3

Not much for a graphical representation, but the math is right at least.

Since everything is AWD swapped (which is disappointing) and the race tranny is free PI (except for Ferrari) I use this standard gear set for the 6sp. Adjust the final drive gear ration to have 6th gear not hitting the rev limiter.

S2 cars can gain as little as 1/2 a PI point from race over sport, and custom gears can be well worth the PI especially for the holeshot. I recently re-built my '05 Ford GT, RWD in S1. Full aero. The sport transmission costs 7 less PI than race and performs 95% as well everywhere but launch thanks to the flat power band. The extra 40 peak hp filling that PI don’t go to waste.

In cars with more flat torque production and peaky horsepower, custom gears can improve average power output at speed by 5-10% and are worth it even in some A class cars.

1 Like

Thanks for the replies, guys, but l figured it out. Take your total weight into your hp. Repeat for torque. You’ll get 2 numbers add them, divide by 2. This is your center of your final drive. Divide your final drive by .70. You want to end up between 66 pct and 75 because the difference between your first gear and final drive will also be your actual differential number. In you invert your original formula you’ll get a pct. It’s your range of optimal diff settings, and everything l’ve tuned has been between 25 and 35 pct. This is power to weight ratios, and differential in a nutshell. The gear progression formula l figured out still works perfectly. Set final drive center/average. Multiply by .70, proceed with gear formula 1st multiplied by .66, that’s 2nd gear, multiply first gear by 10, add that to 2nd gear multiply by .66 that’s 3rd gear. Repeat. Work final drive towards .66 or .75 differential to 1st. It’s actually a 33 or 25 pct diff. The logic is, once you find center using torque and hp to weight ratios, you establish the power/curves and powerband. You’ll always be in the powerband with minimal differential. Message me on Xbox for more details or clarification. Your gear progression will always be .666, and the pw and wp ratios work with exception to 10 speeds, and some a class cars where you’ll need to multiply your final drive ratio by 1.5 if you don’t fall into to 25 to 33 pct diff range. Hmu on Xbox. I figured out ar bars and brakes, as well. If you have 6.8 handling, take your total weight, multiply by .68. This is your front ar bar. Multiply by weight distribution for your back. Optimal spring height formula. Try brakes at 67 pct. Lay on them. They stop you and offer a controlled lock. Let off in the apex. Butter. Drop your rear decel by 1.5, drop the front 1.5 from that. Butter. This is assuming your gear progression is .666. Crazy, but all this works. Try my offroad tunes. Grp.1 or Grp.A file names. Creator: slid3show

You’re right about brake pressure. I start at 65% and adjust if necessary. 52-53% front. Can’t figure out why the bias adjustments are so sensitive. 50 to 55 is all I’ll ever use. And technically “50%” is about 75% front bias… weak logic.

FH4 stock brakes are OP in general. Almost all of my builds get race brakes. FM7’s brakes are more reasonably powered.

Much easier to learn to understand the simple graph in the game than all this crazy nonsense.

Better yet, an understanding of how gearing works.
Just for example, the basic concept that there is no “one gearing set that rules them all”. Powerbands and gear change time, engine characteristics, no sir, one gearset will not rule them all.

Learn how to move a slider left or right? I got that covered. You’re right that one gearset doesn’t work in everything. If you divide your power by weight, then torque by weight, you’ll get your range to stay in the powerband. You can add them, then divide by two to get your average or if you’re lacking in one department you can compensate here. I should have edited this after l discovered how to apply power to weight ratios to my gearsets. I could explain further and even tell you how to figure the perfect differential setting every single time, but since it’s nonsense, l’ll let you work that out. Keep using sport transmissions. Seriously, please. I steady walk off and leave basic drivetrains. Pulling hills, launching out of corners, off the line. But you’re right. One basic gearset doesn’t work on everything. It is fully dictated by power/torque to weight ratios.