Wheel Base - Question

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mclewis_13
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Wheel Base - Question

Post by mclewis_13 »

I have been looking at items from different sales site, eBay, and even some of the cars that have been shown on here. Is there a reason that the Wheelbase isn't longer than 5"?

Below is how I completed the wheels for my last street beast. Am I missing something? This is how i've been doing the instruction at our pit days for all the racers that show up.

Image

Please let me know. Thank you for your help.
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whodathunkit
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Re: Wheel Base - Question

Post by whodathunkit »

mclewis_13 wrote: Image

Please let me know. Thank you for your help.
From your pic angle looking down.. it looks like you have some toe out and toe in issues.
also hard to tell which way the front of your car facing with the carbon fiber cover? ( to me I'm guessing the front of the car is facing to the left.)

Are any of the front wheels lifted?
If the non dominant front wheel is lifted you need to toe it in.
So it won’t catch the air in the wheel cavity.
And it helps tighten up the gap between the front wheels to the rail.
Long wheel base cars help with how the car steers
Think of drag racing strip and the top fuel long dragsters.
( don't know of your rules.. 4 wheels touching or..
If the car is set up as a 3 wheel rail rider.. The dominant front wheel should have some toe in to steer it to the rail and hold it there.
The rears need to be straightforward with no toe
BSA rules the front wheels cant stick out starting gate pen. Back in the 50's- to mid 70's the could .
Your Awana car looks like the front wheels stick out past the front of the car.

Randy Davis the original owner of Max V did a news letter some time back about extended wheel base cars.
https://www.maximum-velocity.com/pinewo ... es-v10i13/
What type of automobile can be spelled the same forwards & backwards?
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Vitamin K
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Re: Wheel Base - Question

Post by Vitamin K »

Wheelbase is a balance between stability and better potential energy utilization.

A longer wheelbase gives better stability. A shorter wheelbase moves more energy up the slope.

The default BSA wheelbase is much too short, IMO. I usually go for about 5" for wheelbase these days, which has seemed to be a nice sweet spot for our cars.

Even if I went "full extended" wheelbase, I think I would pull my front wheels back a bit just so there was less chance of a hard stop realigning my steering axle.
mclewis_13
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Re: Wheel Base - Question

Post by mclewis_13 »

whodathunkit wrote: Wed Mar 29, 2023 3:14 pm

From your pic angle looking down.. it looks like you have some toe out and toe in issues.

- This is due to the Fish Eye Lense.

also hard to tell which way the front of your car facing with the carbon fiber cover? ( to me I'm guessing the front of the car is facing to the left.)

- That is correct.

Are any of the front wheels lifted?
If the non dominant front wheel is lifted you need to toe it in.
So it won’t catch the air in the wheel cavity.
And it helps tighten up the gap between the front wheels to the rail.

- It is lifted, but i did not toe it in, i will for next year.

Long wheel base cars help with how the car steers
Think of drag racing strip and the top fuel long dragsters.
( don't know of your rules.. 4 wheels touching or..
If the car is set up as a 3 wheel rail rider.. The dominant front wheel should have some toe in to steer it to the rail and hold it there.
The rears need to be straightforward with no toe
BSA rules the front wheels cant stick out starting gate pen. Back in the 50's- to mid 70's the could .
Your Awana car looks like the front wheels stick out past the front of the car.

- This car is running 3 wheels - Did not toe in the front.
- The rear is canted at 2.5 degrees
- The front of the wheels does not stick out past the front of the car.
- Our rules only require that the wheels do not extend past the end of the vehicle in the front or the back.

Randy Davis the original owner of Max V did a newsletter some time back about extended wheelbase cars.
https://www.maximum-velocity.com/pinewo ... es-v10i13/
I appreciate all the questions and advice; I think Vitamin K answered my questions. I guess I wasn't very clear. So, I'll try to be clearer with my question.

Why don't league cars have their wheel installed as close to the ends of the front and rear of the car as possible. It seems like they only use (at max) a 5.25" wheel base. Mine is much closer to 6" based on 1/2 the diameter of the wheel being where I have installed my axel.

It seems what Vitamin K is saying is there is a balance between stability and speed. Although the longer wheelbase gives you greater stability, it scrubs speed because it is on the flat section of the track before your engine is done accelerating.

So a shorter wheelbase removes stability, but improves speed and it is a balancing act between them.
Eagle
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Re: Wheel Base - Question

Post by Eagle »

VK said it. You said it.

Just know it is more about moving the weight of the wheels and axles back then it is about when the front wheels are on the flat.

Also, you significantly reduce aerodynamics with no fenders. The only "pro" cars without fenders are the ones where the rules do not allow them.
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whodathunkit
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Re: Wheel Base - Question

Post by whodathunkit »

mclewis_13 wrote: Fri Mar 31, 2023 11:34 am I appreciate all the questions and advice; I think Vitamin K answered my questions. I guess I wasn't very clear. So, I'll try to be clearer with my question.
Why don't league cars have their wheel installed as close to the ends of the front and rear of the car as possible. It seems like they only use (at max) a 5.25" wheel base. Mine is much closer to 6" based on 1/2 the diameter of the wheel being where I have installed my axel.

It seems what Vitamin K is saying is there is a balance between stability and speed. Although the longer wheelbase gives you greater stability, it scrubs speed because it is on the flat section of the track before your engine is done accelerating.
So a shorter wheelbase removes stability, but improves speed and it is a balancing act between them.
mclewis,
Your not the only one to ask these questions about wheel bases. Glad VK answered your questions.
I was looking for one of his older topics : https://www.derbytalk.com/viewtopic.php?f=11&t=7748
If anything I learned as well. Thank you for clarifying your camera lens.
And I was not picking on you or on your car build photo when I said your Awana car wheels look like they stick out past the front.
Like VK also Said.. hate to see you lose your steering axle alignment with a hard stop.. if the wheels stick out past the front.
What type of automobile can be spelled the same forwards & backwards?
Loud2ns
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Re: Wheel Base - Question

Post by Loud2ns »

Why don't league cars have their wheel installed as close to the ends of the front and rear of the car as possible. It seems like they only use (at max) a 5.25" wheel base. Mine is much closer to 6" based on 1/2 the diameter of the wheel being where I have installed my axel.
I think Eagle hit it pretty close to dead on. The wheel and axle weight is more towards the rear of the car.
League cars are mostly 4.5- 5" wheelbase depending on class and builder preference.

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