Talion Physics lesson: Why does the Kraton wheelie more than the Talion

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
Messages
180
Reaction score
195
Location
Westminster, CO
Arrma RC's
  1. Talion
Short Intro: I'm in the market to get my first basher and was dead set on a Kraton until someone pointed out the Talion. After watching a video or two of them running, it was evident that the Talion puts the power to the ground better vs the Kraton which has a tendency to wheelie more. I wanted to make a thread to discuss why the Talion doesn't wheelie as much, and the vehicle dynamics of why the two vehicles handle so differently even though there are only a couple differences.

This is very important so please correct me if I'm missing anything, but to my knowledge...

These are the ONLY physical differences between the Kraton and the Talion:
1) Tire Size - The Talion has a narrower and shorter tire with a different tread pattern.
2) Shock Towers - The talion has shorter shock towers, putting the shocks at more of an angle.
3) Gearing - The talion runs a taller gear, but smaller tires. I don't know the net effective difference in gearing, but this could be important to figure out.
4) Electronics - Obviously this is infinitely variable on both trucks, but is something that should be pointed out for weight and power reasons.
5) Body - The talion has a lower profile body. It's probably lighter because it looks like less plastic.

Why do wheelies happen:
From a physics standpoint, a wheelie is caused by having a center of gravity (the center of the vehicle's weight) above the center of the rear axle, and a force pushing that weight to the back of the car. I think this is easy to visualize if we think about tying an imaginary string to the center of gravity, locking the tires in place, and pulling that string straight back. The higher up that string gets tied, the easier it will be to pull the tires off the ground. Also, the harder you pull that string, the lower it could be tied, and still have the force to get the front wheels off the ground.

Important: Notice that the height or width of tires themselves DO NOT have an effect on how much force is required to pull the front off the ground. We are pivoting around the center of the axle. It doesn't matter if you have 3" tires, or 33" tires, everything is relative to the center of the axle.

Now lets discuss each section and its effect on wheelies:

Tire Size
- First off, I want to point out what might be a misconception in case you skipped the short physics lesson above. Everything else being equal, tire diameter alone does not have a direct effect on whether a vehicle will wheelie. I say "everything else being equal" because it does have some indirect effects. Clarification needs to be made... thank you to Mr. Duke. I didn't mention that larger tires have a larger contact patch which does give you more traction. I've added that below.

1) Weight - the heavier the tire, the more it will want to resist accelerating. This means that the turning force being put into that axle is more likely to lift up the body instead of being able to turn the tire. That's wheelie forces folks.
2) The gearing effect of tire diameter - The smaller the tire, the more torque it has relative to the ground. Think of your tire as a pinion gear. The smaller that pinion is, the more torque you have. This makes it easier to turn that tire.
3) Traction - The less traction you have, the harder it will be to wheelie. Ever try to lift the front end while on a patch of ice? Not gunna happen. A taller tire is going to have a larger contact patch and therefore going to give you more traction compared to the same tire in a smaller diameter.
4) Squish - What I mean here is how squishy are your tires? This is important because as you accelerate you're transfering more weight from the front of the car toward the rear of the car. This additional weight will likely make your tire squish at least some, but depending on the tire it might be a LOT. Push down on the back of your car with a couple of pounds of force. See how much the tire flattens when you do this. Ok ok, but why is this important? Two reasons: 1) As the rear tires compress, you just lowered the rear axle. Your suspension may or may not have also allowed the center of gravity to change but squishier tires allowed the axle's position relative to the center of gravity to change. 2) Traction. As the tire gets more weight on it, it gets more traction. As the tire flattens out on the bottom because of more weight on it, it gets more surface area, and therefore even more traction. See #3 above as to why this matters for us.
5) Width - The narrower the tire, the less traction you will have. As we noted above, less traction makes it harder to wheelie. Nuff said.

Shock Towers - The shorter shock towers on the Talion do two things for us. 1) They lower the center of gravity. We've moved the weight of something lower to the ground. Remember our string example above? Any time we move weight down we are moving our string lower on the car. It makes it harder to pull back and get the wheels off the ground. 2) They change the angle to which the forces it has to cope with are being applied to it. I don't know, but I'm assuming that these two vehicles have identical shocks, they've just changed the angle of the shock. If this is true, then the effective spring rate (and damping rate) are increased. This would help reduce the amount of weight transfer from front to back assuming that the shocks are set the same. I don't know if they are or are not though.

Gearing - The Talion has taller gearing in the transmission. Now, the overall gearing when the tires are factored in might be a net neutral, but I'm doubting that given that the top speed of the Talion is so much higher than the Kraton. Assuming that the overall gearing of the Talion is taller, you're going to have less torque to the ground, and therefore less force on your imaginary string.

Electronics - There are two things that came to mind with regard to electronics. Weight and performance. 1) Weight - depending on where this weight is placed, it can be good or bad for wheelies. The batteries are heavy, but the motor, esc, and everything on there has weight. The higher this weight is, the easier it will be to wheelie. The farther forward this weight is, the harder it will be to wheelie. 2) Performance - We are talking about how snappy the acceleration on the car is. Snappy acceleration produces good wheelies, as long as you can properly put that power to the ground. If your acceleration is more than the tires can handle then forget wheelies at all.

Body - You thought the body was just for looks right? Well think again. That body has weight to it. Notice how much taller the Kraton body is than the Talion? That's raising the center of gravity and since we're all experts on CG now, we know that CG has a huge effect on wheelies. Another thing to note at higher speed is that there is air hitting that body, and the faster you go, the more force it's acting with. That force of that wind is definitely above the axles, and we know that force pushing rearward above the CG is assisting our wheelie string.

Summary - There are other things that affect wheelies, but the point of this article was to discuss the difference between the Talion and the Kraton specifically, and why one wheelies more than the other. The conclusion is that it's a cumulative effect. The largest contributors in my estimation are the center of gravity, and differences in traction due to tires. There are other contributors but the amount of which is more or less... I don't know exactly. Heck, I've only seen both of these cars in videos, but this is my best analysis based on what I know. I'm sure there are things I missed and it would be fun to discuss... Ready... GO!
 
Last edited:
I did learn the hard way that having the wider tires did make me wheelie easier. I put wider and yes slightly taller tires on and went out and was driving it like I did with the stock tires. I punched it at 100% and with the wider tires gave more grip which flipped it over and got some road rash lol.
 
Having the NOTO (which is a wheelie monster stock) I can tell you that the center diff fluid plays a huge role. Stock this thing would ride the wheelie bars forever. With 500k it still wheelies but puts the power to the ground.
 
The reason the Kraton wheelies easier than the Talion is because the center of gravity is higher and the tires offer significantly more traction.

A correction needs to be made though…

“Tire Size - First off, I want to point out what might be a misconception in case you skipped the short physics lesson above. Everything else being equal, tire size doesn't not have a direct effect on whether or not a vehicle will wheelie.”
This is incorrect ^
All things being equal (width and tread design), a taller diameter tire will have a larger contact patch which increases traction and the vehicles ability to wheelie.
 
No one mentioned that the Talion chassis Layout is different. Different F-R weight bias.
Its chassis is exclusive to the Talion. All its own.
Has a lower CoG. Sits way lower than a Kraton. And comes with Truggy sized tires that are narrower/lower. Having less bite. Why its less of a wheely demon. And fine by me. I hate rigs that want to wheelie all over the place. A novelty that wears off real quick IMHO. Talion appears to be designed more like a Track Truggy. Better for confined technical track driving, much like the Typhon Buggy. (TLRT)
 
The reason the Kraton wheelies easier than the Talion is because the center of gravity is higher and the tires offer significantly more traction.

A correction needs to be made though…

“Tire Size - First off, I want to point out what might be a misconception in case you skipped the short physics lesson above. Everything else being equal, tire size doesn't not have a direct effect on whether or not a vehicle will wheelie.”
This is incorrect ^
All things being equal (width and tread design), a taller diameter tire will have a larger contact patch which increases traction and the vehicles ability to wheelie.
Thank you! I was trying to say that in the traction section but it was definitely unclear. Hopefully it's clearer with the edit. If you still think I'm saying something incomplete or wrong, slap me again! I'm not afraid to be wrong. :)
 
Old Thread: Hello . There have been no replies in this thread for 90 days.
Content in this thread may no longer be relevant.
Perhaps it would be better to start a new thread instead.
Back
Top