Ok I'm looking into building myself some wheelie bars and I need some help. I'm leaning toward a single wheel design because that would not interfere as much with the loading of the car on an open trailer. I also have a question about how long the bars should be? I'm leaning toward a length between 60" and 70". Any longer and I won't be able to get them into my 6' truck bed (if removed). And I'll be crowded for space in the garage (overall length). If the two wheel design is head and shoulders above the single wheel I go with that design. As of now the car is not wheelstanding but is carrying the wheels out about 60-80' about 6" off the ground. I'm increasing the HP level and will be adding a second stage. So I plan to be in the air a little longer and could be higher. The car is 4-link car so I can change the instant center pretty easily. Also what size tubing (OD and wall thickness) do you guys recommend? Looking for experienced feed back.
wheelie bars
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Wheelie bar
One thing you loose with a "single wheel" bar is some adjustability. With a dual wheel bar you can stagger the wheel heights right-to-left a little (as a tuning aid) if you have to in order to straighten out a slightly crooked launch with out making a 4-link change. With a single wheel bar the 4-link needs to be adjusted "dead-perfect" for the track you are at that day.
If you are going to use all 'moly tubing, I wouldn't use a bar shorter than 70". At 70"+ long I would use at least 1-1/4" o.d. X .058" (or .065")wall 'moly.
For a single wheel design that only has three bars (two top & one bottom) the single bottom bar needs to be a little bigger o.d. because it's doing the work of two bars, at least 1-3/8" o.d. in my opinion.
DAVID.
One thing you loose with a "single wheel" bar is some adjustability. With a dual wheel bar you can stagger the wheel heights right-to-left a little (as a tuning aid) if you have to in order to straighten out a slightly crooked launch with out making a 4-link change. With a single wheel bar the 4-link needs to be adjusted "dead-perfect" for the track you are at that day.
If you are going to use all 'moly tubing, I wouldn't use a bar shorter than 70". At 70"+ long I would use at least 1-1/4" o.d. X .058" (or .065")wall 'moly.
For a single wheel design that only has three bars (two top & one bottom) the single bottom bar needs to be a little bigger o.d. because it's doing the work of two bars, at least 1-3/8" o.d. in my opinion.
DAVID.
adjustability
I forgot about needing to adjust from track to track. I've never had a car this fast so this is all new to me. I really hate tweaking the 4-link if I don't have too. A simple adjustment on the wheelie bars makes more sense. The car was pulling to the right and installing an anti-roll bar fixed that. If the car had a slight pull would you make a wheelie bar adjustment or a shock adjustment?
I forgot about needing to adjust from track to track. I've never had a car this fast so this is all new to me. I really hate tweaking the 4-link if I don't have too. A simple adjustment on the wheelie bars makes more sense. The car was pulling to the right and installing an anti-roll bar fixed that. If the car had a slight pull would you make a wheelie bar adjustment or a shock adjustment?
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1,960 Posts
shock vs wheelie bar
Because you now have an anti-roll, I doubt "stagger-adjusting" the shock's spring heights or the shock's valve dampening side-to-side will have much effect on correcting a launch that pulls or rolls to the right or left. So you are left with using either the 4-link, the wheelie bars, or the anti-roll to move weight/preload around to adjust a cars right/left launch problems.
If the car launches slightly to the right or left, BUT drives straight as a string (at speed) at half track & the finish line , then just staggering the wheelie bars is probably best to try first. On the other hand if it launches right/left, AND ALSO tries to drive to the right/left down track, then the 4-link needs attention.
I feel the anti-roll should be adjusted to "neutral" (no weight on the rod-ends) with the driver's weight in the car. In my opinion it should never be used to move or shift weight/pre-load from one slick to the other, (but some people do). Use the 4-link instead.
Because you now have an anti-roll, I doubt "stagger-adjusting" the shock's spring heights or the shock's valve dampening side-to-side will have much effect on correcting a launch that pulls or rolls to the right or left. So you are left with using either the 4-link, the wheelie bars, or the anti-roll to move weight/preload around to adjust a cars right/left launch problems.
If the car launches slightly to the right or left, BUT drives straight as a string (at speed) at half track & the finish line , then just staggering the wheelie bars is probably best to try first. On the other hand if it launches right/left, AND ALSO tries to drive to the right/left down track, then the 4-link needs attention.
I feel the anti-roll should be adjusted to "neutral" (no weight on the rod-ends) with the driver's weight in the car. In my opinion it should never be used to move or shift weight/pre-load from one slick to the other, (but some people do). Use the 4-link instead.
chassis tweaking (fine tuning).
Yes I noticed that once the anti-roll bar was installed the back started acting as if was no longer independent on each corner (guess it worked, ha ha). Really tied both sides together. Once the car went straight I didn't worry about changing the shock settings because it was working. But it is really stiff now. The current setting of the anti-roll bar is neutral with me sitting in the car. And the drivers side shock is 2 clicks stiffer on rebound than the passenger side. 4-link is set neutral. If the car continues to work as good as it currently is, all I need the wheelie bars to do is ensure that the car does stand up too high. I don't plan to touch them (ride on them) if I don't have too. But as I'm finding out when you start making bigger HP these things change and it's better to plan for future now than later. This car is just a toy, and if I can make loading it and unloading it easier I was going to go that way. I'm getting to old and to fat to climb around under a set of bars on the rear if I don't have to. I guess the Pro-mods only use one wheel because their frame rails are so close together they really don't get any benefit from two wheels.
Also thanks for the tuning advice.
Yes I noticed that once the anti-roll bar was installed the back started acting as if was no longer independent on each corner (guess it worked, ha ha). Really tied both sides together. Once the car went straight I didn't worry about changing the shock settings because it was working. But it is really stiff now. The current setting of the anti-roll bar is neutral with me sitting in the car. And the drivers side shock is 2 clicks stiffer on rebound than the passenger side. 4-link is set neutral. If the car continues to work as good as it currently is, all I need the wheelie bars to do is ensure that the car does stand up too high. I don't plan to touch them (ride on them) if I don't have too. But as I'm finding out when you start making bigger HP these things change and it's better to plan for future now than later. This car is just a toy, and if I can make loading it and unloading it easier I was going to go that way. I'm getting to old and to fat to climb around under a set of bars on the rear if I don't have to. I guess the Pro-mods only use one wheel because their frame rails are so close together they really don't get any benefit from two wheels.
Also thanks for the tuning advice.
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