Researching the web I’ve found comments like “most people run 2 black and 2 white springs” and such. Here in Australia our LO206 endurance class are mandated to run 4 white springs.
I’ll be driving a sprint class and so wondering how fellow US sprint karts behave with 2 black and 2 white springs. As I understand it, the full engagement will be at a higher RPM than with 4 white springs.
Does that mean the whites make the engine chug whereas the 2 black 2 white will hook up closer to usable torque?
Note that we have some less flowing circuits than what I’ve seen on youtube of US racing.
I’m also guessing the extra RPMs of 2 black 2 white would wear the clutch shoes quicker?
Basically yes but the only difference is a few hundred rpm, and this only matters if you have slow enough corners (or standing start) that your clutch ever disengages. Otherwise it doesn’t matter because your clutch is fully engaged anyways.
Overall I’d prefer a fixed setup as it’s one less thing to worry about.
Hi all, after my first outing I want to revisit this subject.
I’ve watched multiple LO206 sprint racing videos. The seem like standard type closed circuits using normal sprint kart chassis like TonyKart etc.
In my first experience I had the shoes trailing and all white springs.
If I had the momentum and rpm no problem, but if I was somewhat slow and going up a hill the engine would still pull but not at what I would call high enough rpm. Note that my gearing may have been a little to tall and I only hit the limiter right before the straight end. I’ve noticed LO206 sprint racers hit the limited sometime 100 yards before the same point and ride the limiter.
I’ve changed to leading shoes, but wondered how other sprint racers have their clutches set up. Specifically the springs and any weights.
This is a good example of the type of track layout we have regarding corner speed mix.
Short version, you should switch to 2 black 2 white no weights. 4 whites may be more appropriate for the junior classes, but for an adult it would engage too early, and you would be engaged at low rpm exactly as you experienced. 2 black 2 white will push it a few hundred rpm higher than you are currently, and right about into the power band of the 206.
I don’t think that’ll change any behavior the previous post described. When geared correctly, the clutch will not disengage with the black/white combo, nor will it disengage with white/white. Aside from the start itself, the clutch will be fully locked either way. A lack of building speed is a power or a gearing problem, not a clutch problem.
Look at it this way, the factory Briggs curve has peak torque at a whopping 2,500 rpm. Any slip beyond that is going to give you less torque. The only exception is during a disengaged start when you can sort of give the clutch a ‘kick’ by running it up past the engagement point and then rpm drop.
Clutch should only matter for starts. If geared correctly for the track you should stay locked up for an entire lap once you are racing. If you aren’t then it is driver error resulting in loss of speed or incorrect gear selection.
