We've heard this question a lot. We know it seems weird
, but you have to try it to really see and feel the benefits. Here is a response from another forum (edited for context):
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I'd like to take this opportunity and address the many questions about the clutch and clutch bell setup being used in our conversion.
We were intent on building the fastest 1/8th scale brushless vehicles around. Believing that if it's fast at the track, it'll be fast most everywhere. After looking at some current direct drive setups and having been into 1/10 scale electric truck racing back in the day, we saw a need for better traction. Add brushless motors and lipo battery packs to the mix and you have a considerable issue.
Drawing on years of nitro racing and tuning, we noticed the gas cars didn't want to spin around as much. The clutch system didn't only keep the engine from stalling, it aided in the traction and power delivery. We decided a clutch system like that would also benefit an electric vehicle in exactly the same way. The only difference is the motor can't stall.
A centrifugal clutch is different than a 'slipper' or friction clutch. Slippers only slip when the input power exceeds the friction force being applied between the plates. So, a slipper doesn't slip at low RPM, but rather only at high RPM or high power input. Contrast that with a clutch bell setup where it slips at low RPM and engages at higher RPM and higher power input. The systems are nearly complete opposites in how they deliver power. As a result, the driving profile and characteristics are different and the centrifugal clutch system is better suited for larger vehicles as proven by the absence of slipper clutches on 1/8 scale vehicles. Through testing we found that the clutch works best when the shoes are flipped over in the leading position. This is because with an electric motor that doesn't stall, we don't need to wait until we build 1-3000 RPM to build power. When set up like this, the clutch engages quickly, but still provides all of the benefits of a centrifugal clutch. The obvious benefits are easing the stress between the drivetrain and motor and of course better traction.
A lot of ESC's have power limiting features, why not just use that?
Yes, this is true. However, the ESC has no physical connection to the vehicle whereas a clutch can still respond to the driving conditions. This is handy say, when you are on throttle trying to land a jump. It will subtly respond to bumps and ruts as the loads on the tires change.
What about the added weight and rotational mass? This is a valid question. While the difference could be measured with equipment, it simply hasn't been an issue. Again, there is so much power and torque in these motors that the added rotational mass is negligible. We've never been in the situation where we needed more power than what the system could deliver. On the flip side, one could argue that mid-range punch may be enhanced with the addition of the extra weight. Nitro clutches are even heavier and nitro cars don't have trouble getting around the track.
What about clutch wear and clutch bearings?
Great question. Our clutch shoes have lasted well over 8 months of hard running. As long as you are running them in the leading position, there should be no issues. Bearings will fail eventually and should be replaced every 2 to 3 months or as necessary, but we can assure you it's absolutely nothing like if you were running a nitro. There is no fuel and oil for the dirt to stick to and foul things up. Additionally, the clutch isn't 'dragging' like it is on a nitro, which is evident in how long the clutch shoes and bearings are lasting.
What about wasted power due to slippage?
This is an issue whether you run a 'slipper' clutch or a centrifugal clutch. Any clutch system will have some wasted power. Which one wastes more under normal use would be hard to measure. Of course you could run the centrifugal clutch below it's engagement point for a whole pack and say it wastes more power and generates more heat, but how much fun would that be
Why not use motor brakes, they're just as powerful or more powerful than mechanical brakes?
Putting the front/rear brake bias ability aside, mechanical brakes are easier on the motor and ESC resulting in less heat. Subsequently, they are easier on the drivetrain as well. Mechanical brakes are just as reliable and some say more predictable than motor braking. Adding the front/rear bias back in and you have a cool operating system that can out-handle motor brakes alone.
So the clutch system is actually quite a difference compared to direct drive. We realize it's new and people are comfortable with how it's been done for all these years. The results were so good that we have basically staked the future of our company and our reputation on using a clutch and clutch bell in an electric car. How it goes from here is anyone's guess, but the race results don't lie. We hope it becomes the new norm.
Thanks for reading and please let us know if there are any questions.
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To sum up - cooler operating temps, smoother power delivery, true front/rear brake bias, better jumping and handling (no drag brake), less wear on drivetrain and motor bearings.
Recently we've discovered another benefit. We have yet to wear out a clutch bell. We have hundreds, maybe close to a thousand test hours on our systems now and still have not had to replace a clutch bell. We are running the stock steel gears, no need to switch to plastic and risk stripping a gear during a race. Contrast that with the wear that some people have experienced using pinion gears.
All that aside,
you can still use our kits with pinion gears if you have absolutely no interest in the clutch system.
Tekno RC 1/8th Scale Brushless Conversion Thread
But if I plan to start racing would it be fairly straight forward about how to change parts of the clutch to suite your driving style or track?
I am in San Diego too, so I can't really complain about the drive (although I wish I can 
) since its probably the same for us. I just need to wait for my MMM ESC's to finally come. At the moment, I only have two trucks running (rc18 and CRT.5... both brushless), so its not even worth going there with two trucks and one I can't even drive on the track since its too small. My Revo and 8ight are both ESCless... 
What days do you guys usually go to practice at the track as well? I think Matthew Armeni told me on Wednesdays...?
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