Tutorial DIY 3D printed Sim Racing Hydraulic pedals SRT

Hi !

I have been working on sim racing pedals for two years now. Now I am ready to share with you the result : a reliable and easy to build pedal set, yet very affordable. You got a nice hydraulic feeling, sturdy parts. You can adjust the geometry. Most non-3D printed parts can be found on Aliexpress, and the whole will costs less than 150€.
I built last year a 2DOF with stepper motors, you will be able to see the earlier versions
Every informations are available on my website : https://lebois-racing.com/srt-pedals



1) Videos

Presentation in (my poor) english :

Presentation in french :

2) Features
a) Accelerator pedal
Angle can vary from -20° to 35° The starting position is tuned by a screw and a knob (no tool needed).
The end position is tuned by steps.

There is a preload for the metal torsion spring.
Pictures of v5.8 :




Thingiverse page : https://www.thingiverse.com/thing:4461145


Here is the pictures of the brake pedal (v5.3) :

Nice work mate!

Already working on v5.2 :

good job and very detailed tutorial!! thanks for sharing this

accelerator V5.2 is coming :

Accelerator v5.2 is online :

Hello,

I'm interested in your project using hydraulics but have a few questions before I put it in a long list of projects I'd like to do lol.

I've currently got the csl elites with load cell, similar to the V3s and am wondering how do they compare? In what way are they better or different? If you've tested them or have used something similar?

What's the throw and the initial bite? My CSLs has a short distance between full and none along with about 10% where there's no pressure.

Also how much pressure do you need to use until maximum? Or does this depend on the pressure sensor?

I can't compare this to a real car or a racing car as I ride bikes and haven't driven a real car.

"I've currently got the csl elites with load cell, similar to the V3s and am wondering how do they compare?"
You mostly got something more realistic.
"If you've tested them or have used something similar?"
I just tried G27 pedals, and Simtag... My pedal are more realistic than Simtag ones. You really have the same feeling as a real car.

"What's the throw and the initial bite?"
It would be hard to describe. Otherwise, you can tune the preload while keeping the same starting position on the brake 5.1. There is a screw under the lever, but isn't shown on the pictures.

"Also how much pressure do you need to use until maximum?"
The thing is : there is no maximum, like in a real car. The point is, you tune the pedal signal in your software (I will add the different possibilities during the following weeks : arduino, leobodnar, simucube etc) so that the maximum is at 110% of your maximum pressure. Then ingame, you will want to tune the brake so that you use 90% of the pedal brake on the strongest braking.
That way, if the grip conditions improve during the race, you will be able to brake stronger, and you will never it the maximum of the pedal.
In a real car, you don't have maximum, you can brake as strong as you want, but you will quickly lock the brakes.
On my setup, max signal is around 35% of the signal coming from the pressure sensor. So you have plenty of room for a stronger pedal. You can even use a 1000 psi pedal, that will result in my case in a 17.5% use of the signal

"I can't compare this to a real car or a racing car as I ride bikes and haven't driven a real car."
You mostly got the exact same feeling as using hydraulic brakes on an mtb bike.

Final thought : You won't get a great improvement over the v3. It will be better, not far better. Otherwise, maybe you can built this set, sell the fanatec, earn some money while improving your experience...

Already working on accelerator v5.3

Thanks for that information! And good to see your still improving it

I'd like an improvement mainly in the throw and customisation of the pedals. I'm a small guy and pretty weak so even with the softest rubbers in the CSLs I can't fully press the brake normally it's around 50%. This gives a rather small difference between the initial press and my maximum. Although this could be a placebo effect and I just need to use the pedals more.

With the initial bite is it pressure straight away or is there a few % where it feels like nothing then suddenly hard brakes? On my pedals it feels like nothing for the the 5%-10% then hitting a wall where the load cell come into play more so. On my bike I can feel every step of the way where it just gets gradually stiffer.

How much adjustment can you do on the preload to adjust the throw? If I understand that part correctly.

When you say mine are more realistic is that because mine simulate a racing car while yours pedals simulate brakes in a standard car?

If yours simulate a standard car is there adjustability to make it more towards a racing car but not to the same extent the V3s are?

I love the sound diy stuff as you can make it exactly how you want and not something that is 80% there and being stuck to a company to fix things.

Also with 3d printing them don't they flex at all?

"With the initial bite is it pressure straight away or is there a few % where it feels like nothing then suddenly hard brakes?"
You can tune this from like 40% before pressure to only few % before. It's a bit hard to explain how it works without drawings, but the screw under the pedal allows to push the piston into the master cylinder before you start to push on the pedal. So when you start pushing, your system is already preloaded. If you untight the screw, you get more travel without pressure.

"On my bike I can feel every step of the way where it just gets gradually stiffer." Well... it depends a lot of which brakes you use ^^ (I was in the bicycle business year ago...)

"When you say mine are more realistic is that because mine simulate a racing car while yours pedals simulate brakes in a standard car?"
No, V3 isn't near of race car nor normal car. It's because it uses springs and rubbers to simulate a real brake system. Mine just use a real brake system, it can't be bitten.

"Also with 3d printing them don't they flex at all?" Well, accelerator could be stiffer, that's why I am working on it. Otherwise, it's only 50% infill, with a lot of empty spaces. The brake lever is 100% infill with almost no empty space. To be clear : now I use the old v5.0 lever (replaced by the 5.1) as an hammer.

"I love the sound diy stuff as you can make it exactly how you want and not something that is 80% there and being stuck to a company to fix things."
Yeah ! You don't have to buy a new one to upgrade
On top of that, even if it's already a great pedal set, there is still a lot of room of improvements. I am working on the v5.3 accelerator pedal, and almost everything has be redesigned.

BTW. On the brake pedal, you can add a preload, but for the moment it's quite hard to change the way it behaves after that.
It can be changed, but for the moment it's not my priority as it's the feeling is plenty satisfying for me for the moment. Maybe later with a kind of financial support I could go back to it.. (my girlfriend doesn't like too much when I throw away a working pedal set to build a new one ^^)

Thanks Lebois!

That's exactly what I wanted to know about the preload! You explained it perfectly without the need for any drawings. I thought that might be the case but just wanted to check if I had a completely different picture of what it is in my head somehow.

Just wondering how much would you say it costs in total to make this using all the materials you've used?

Like you said earlier I could sell the fanatec pedals and make this and still make a profit with better gear.

Well it's between 100€ and 150€. It depends on if you need an interface or not. You could probably solder a connector on plug it directly to your fanatec wheel.

I will also try to create a 3d printed 12mm axle. It would save the cost of a steel one, and because we can create complex shapes, it could add a feature to preload the assembly and reduce the risk of a play between the lever and the bearings.

At the moment I've got the thrustmaster t300 and fanatec pedals, so I'll have to get an interface which is pretty easy.

Im already going to make a DIY DD wheel using a stm32 board for it so the pedals should just plug right in to it using EMC firmware.

The pricing is perfect concidering what the competitors pricings are for worse quality. Hydraulic pedals start at £1300? For something that is very very basic.

For the build, everything is basically like a normal brake except the caliper is a pressure sensor? Pedal to mc, reseviour to mc, mc to pressure sensor? Is there anything else that helps with compression as most other, I think, still uses rubber to compress to give feeling of using a real brake.

Also I read your previous thread and you used a caliper with a load cell where the brake disk would be. Is there a reason why your not doing it this way anymore?

In fact, I never managed to get something satisfying with rubbers.
I tried a lot of things, but finally went back to use a brake calliper.
Then you can also add a spring on the mc axle, or rubber in the brake calipper..
Yeah you can easily plug the pedal directly to the stm32, I aldready done that before

So with your current build your using a normal brake caliper with a load cell inside it? Exactly the same as a real car?

I don't use load cells anymore. You need to amplify their signals and i always struggled to do so. Know I use hydraulic pressure sensors that are plug and play : they just act like an potentiometer.

I think I'm getting a little confused by how you've configured this.

Where is the pressure sensor? Is that connected to where the caliper and brake lines connect?

Does the caliper have a metal part between the brake pads to simulate a brake disk?

Yeah the sensor is between the mc and the brake calipper.
I printed a 3d part that replace the disk and brake pads.