Buddy started racing lo206 so was wondering if you guys could explain what is going on with cutting axle?
What’s the reason/logic?
Looking for a noob explanation so folks can understand.
well, with a 50 mm axle, to move the wheels inward further, you need to cut the axle, as the hub wont allow the axle to pass through like a 40mm axle will
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There are two very different reasons to cut the axle, and one reason the topic is confusing is because people talk about both reasons somewhat interchangeably. To narrow the track width is one reason, but another is to soften the hub stiffness (while keeping tracking with the same).
@KeslerDesignWorks and @mtbikerbob do a good job in their recent responses of distinguishing which they are talking about, but I think the readers don’t always see that nuance.
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Ah. Thanks. So if understand correctly, it’s not so much about needing to go narrow rear. The folks with cut axle are generally running max width? But if they on a 50mm axle they have to lop the ends off to not exceed max?
Presumably there’s advantages/disadvantages to 40 vs 50mm axle else why would folks run 50s and chop?
See, this is not a true statement. Some people like the response directly above do it for the sole reason of going narrower. Other people for going softer instead. It’s critical to just be on the same page, whichever page that is
Picture holding a shovel horizontally straight out away from you.
First you start with a full grip at the end of the handle. So all your hand is wrapped around the handle. It’s tough but you can just hold it out straight.
Next we chop 2” off of the handle. But you are still keeping you hand the same distance away from the shovel head. Now you’ve only got two fingers wrapped around the handle and suddenly it’s much harder to hold the shovel horizontal.
Same principle. Chop the axle and everything else being equal. Less axle length engaged in the hub, the hub (tire,wheel,hub combo) can no longer exert as much force on the axle. Therefore less total axle flex.
And vice versa the axle can no longer “shove” the tire into the ground as hard. Softer connection between the two objects.
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Cutting the axle and keeping track width equal will change where the axle flexes within the hub, changing how the tire interacts with the track surface. Generally, this is going to provide some of the benefits of a narrower rear track width (increased rate of lift, more ‘dig’ at apex), without the negatives of a narrower rear track width (instability in the rear, over-aggressive weight transfer).
It’s usually a pretty subtle change. But we’ve run short vs. long axles for years on a variety of karts and that type of handling change has been pretty consistent for most cases.
And there’s also the consideration for getting your overall track width narrower for low HP classes like 206.
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The only explanation supported by statics and mechanics is that the stiffnes of the hub is reduced with a shorter axle.