Wheelie bar newbie

[Todd Geisler]

Hey guys,

I just installed a set of S&W 54" long tubular (spring loaded) wheelie bars and have some questions on the proper setup.

This is kinda long winded, so bear with me.

I recently installed the bars as well as swapping a set of 4.10 street gears for a set of 4.33 Pro gears. I did this with the rear out and before painting the housing I decided to take some measurements. As it turns out the housing was bent, enough so that it was 1/8" to 1/4" toe out. I measured using two pieces of angle iron 28" long clamped to the axle flanges. I worked with a local chassis shop and I cut the housing ends off and used the housing jig to properly locate and reweld them making the housing centerline/bore perfectly straight.

Fast forward to this past Sunday. First run the car came up real quick with decent air, mostly my fault for having the front shock extension too soft for the track/air conditions. It banged the bars pretty hard which wasn't too big a deal, but the car made a hard right pointing me at the retaining wall and I had to lift, then the front came crashing down. This flattened three header tubes, but luckily I see no other damage.

Next pass I take the bars off and darn if it don't go hard right again, but this time I'm able to complete the run, but used up a good deal of blacktop correcting the car direction. What I believe happened was with the rear tires toe out all these years, the car would naturally go straight, but when I fixed the housing, it uncovered a chassis mis-adjustment. With a simple adjustment to the anti-roll bar, the car went dead straight the rest of the day.

Now, a little background on the car. It's a stock suspension '79 Malibu with 10.5 x 28" stiff sidewall Hoosier slicks. It sometimes also runs on a 325/50-15 M/T Et Street Radial DOT tire. The car runs mid 9's with 60's in the low 1.3x's and best of 1.294 footbraking.

In real good spring/fall air it really wants to go on the bumper and I have to tighten down the front end and limit some travel. I figured I'd take the NHRA Stocker approach and install a set of wheelie bars as a safety device to allow the front end to come up and allow the small tire to stay planted, but use the bars to keep the car off the bumper.

After this recent "accident", I'm gun shy of trying the car with the bars again. I know with better air coming, it's gonna start pulling up higher and higher.

I did some layout on my CAD program simulating wheelie bar heights vs front wheel wheelie heights. The bars are as high as they will clear the bumper with the springs compressed. The static height is 7" to the bottom of the wheel or 9" to the axle centerline. With the springs compressed it adds 5" of static height to the wheelie bar. According to my drawing simulations, that should yield a wheelie of approx 18".

With no bars in average to decent air it'll pull the wheels anywhere from 18 to 24" and higher in real good air. It's been real close to the bumper several times, but luckily no contact and no reason to lift.

I was gonna speak with the salesman at S&W, but he wanted the bars set pretty low. My thinking is that works OK on chassis and back half cars, but goes against what I know how my car works on small tires and stock suspension.

So, do I keep the bars high as they are, or drop them down to start and raise them a little a time?

Also, I'm told the W/B's can steer a car while on the bars. I understand you stagger the left to right wheel height to steer the car. What is the recommended method to tune this?

I will give any more info you may need.

thanks for any help.

I'm real close to taking the bars off and let them collect dust, but would like try and make them work to add a bit of security of not hitting the bumper or having a reason to lift again.

Todd

[Todd Geisler]

Anyone???

TTT

[Run to Rund]

Get a good alignment shop to check the rear end. If installed a little crooked, easy to happen, it will steer the car. Also check that the wheelie bars aren't steering the car when the front end is up. does the front lift evenly or is the left side higher?

[Todd Geisler]

Well,

I can't seem to find anyone who is willing to offer some insight on setting up wheelie bars on a small tire stock suspension car. Car goes straight now, no issues there. Just the car hasn't hooked once since the bars were installed, gears swapped and bent housing fixed.

The problem is I don't know if the bars are the root of the problem, or if the 10.5 x 28 Hoosier stiff sidewall slicks are shot (sidewalls broken down) after 32 runs.

Guess it's time to shyt can the bars and go back to what I used to do before.

[Todd Geisler]

Took the bars off this weekend and the car hooks fine without them again. Two runs on the stiff sidewall Hoosier slicks were 1.306 and 1.303 60's. That also tells me the tires are fine and the sidewalls aren't shot as some told me that could/would be after 35 runs.

Bad thing is on the third run I swapped the bias ply stiff sidewall slicks for a pair of Hoosier DOT D/R tires and proceeded to try and put the car on the bumper, lifted and flattened the headers again.

Guess I'm on my own trying to figure out these wheelie bars. Just hope I figure it out before I tear up much more stuff.

I fixed the headers today and need to schedule a front end alignment this week before next Saturdays race.

Wheelie bars are back on, just need to figure out a compromise of front end travel, shock settings and wheelie bar height to get it to not unload the tires.

[Kenny Wigington]

Dang Todd, You've still got a rocket ! I dont have the exp with wheelie bars to give you. Theres guys on here that know how to get yours right , but I think you are working up to level of performance, on your own.

Good luck !!

[Keith 944]

put some weight in the front of the car.

[Todd Geisler]

Went back to the track again this weekend for our last MSRA race. I was hoping some of the suspension tweaks made this week would help tame the launch and avoid the high wheel stands. The cars not leaving perfect, but I'd say it's much, much better. The car will now run with the wheelie bars on and not unload the rear tires. The air quality was worse today as compared to last weekend, so the performance fell off a small amount.

All runs today were made on the new Hoosier 325/50-15 DOT Drag Radial tires.

60's were 1.296, 1.294, 1.299, 1.292, and1.308. The first four runs were shallow staged and the last I bumped in pretty deep in an attempt to help R/T on the .400 pro tree.

Here's some videos I had a racing buddy film so I can break down the launch frame-by-frame and study to see if any tuning changes are in order. Be warned they are a larger file size, approx 1.5 megs each. They were saved as a larger image size and higher quality.

http://www.qis.net/~geislert/Qualifying1.wmv

http://www.qis.net/~geislert/Qualifying2.wmv

http://www.qis.net/~geislert/1stround.wmv

http://www.qis.net/~geislert/2ndround.wmv

http://www.qis.net/~geislert/semifinal.wmv

BTW, changes made were tightening the front shock rebound by 4 more clicks. With even better air coming (hopefully) I expect to have to either tighten the shocks even more, or take some more travel out.

[FED 387]

looking at some of your runs it looks like the front end is "bouncing" a little bobble just as it comes down from the launch a little which maybe makes the rear tires load/unload---Look at the car as it settles down from the launch---It looks like the front is TOO stiff a little up and down motion too like a little stutter---see what I mean???? also are you holding the steering wheel straight or are you kinda steering to the right a little???? have somebody film the car from behind too----maybe raise the bars a little more let the car come up see what happens you can always go back to the previous setting---Comp 387

[FED 387]

Second qualifying pass it sounds/looks like you got off the gas---Did you???? are you lifting or are you keeping your foot in it???? comp 387