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Old 03-25-2020, 10:11 PM
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Default TC abuse question.

So we know how a TC works to deliver power from engine to wheels.

What about forces from the other way.

Flying along at high speed and you lock up the drive wheels and initiate a slide. What happens to the TC? Can damage happen?

Wheels stop, chain connected driven unit stops.
The belt is wedged down in there and wants to stop abruptly also.
The engine is wound and the drive is still engaged.
I forsee the now stopped belt is gonna force the drive back open overriding the fly weight. Untill the belt slips, it would be high load on the crank.

Besides undue stress on all the keys, could harm come to the TC? Or would it just wear spots in the belt?

Discuss.....
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Old 03-26-2020, 05:36 AM
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weakest link fails first

Most likely you just wear a blank patch in the belt
since that load is what makes TCs shift down it's "expected up to a degree"
at worst the driven just quits and the cam snaps over the buttons
(removing almost all friction between driven and belt)

So a set of buttons, maybe a new compression spring for the driven at worst,
more likely just a belt..

'sid

PS since we've seen one chinese clone TC fail in the past due to a bad weld on the drivers fixed sheave... I think that could happen to cheap chinese clones on heavy impacts albeit unlikely
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Old 03-26-2020, 07:54 AM
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my thoughts are

1) belt can slip on the driven unit pretty easilly when in overdrive. Ive had this happen on built motors going full throttle. The slipping can happen on either drive or driven unit depending on how much contact area it has at any given moment

2) most crank snapping forces happen with race clutches and chain driven systems only. E.g. running a 20+hp predator 212 bored and stroked with engagement at 5k rpm with 3 disc race clutch to chain.

3) belts help dampen forces that chain only systems cannot. There is a bit of a "stretch" that belts can undergo vs steel on steel have a point where they dont stretch, and the full forces go to the axle/crank.

4)ive locked things up going full throttle and slamming on brakes. It just helps the engine reach idle a lot faster than it would normally. i only see the scenario you are talking about as a problem if for some reason you floored the engine, while stomping on the brakes. You might get a bit of smoke on the belt as it slips in this case. I have only smoked the belt in a different scenario, where i couldnt climb a hill and the engine was at max rpm, causing a bit too much slippage and it let out a bit of smoke. I dont have a habbit of locking up the brakes while going WOT either, so i couldnt say that i have ever done this. You gunna try it? haha
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Old 03-26-2020, 03:53 PM
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Quote:
Originally Posted by KartFab View Post
.... I dont have a habbit of locking up the brakes while going WOT either, so i couldnt say that i have ever done this. You gunna try it? haha
That's the only way I ride!

WOT, steering reversed to the direction of travel and actually steering with the throttle.

I start tight turn by locking the rears and throwing the @$$ end around.

I've hopped a 301 and are probally close to 20hp and running a genuine 40 series TC. I've also had to stiffen the frame and engine mounts considerably.

I'm not easy on it at all. But that's the whole point right?
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