Tire and wheelie bar length recommendation....

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Tire and wheelie bar length recommendation....

Post  jbozzelle on January 3rd 2018, 8:55 pm

Recommend a tire for me.  Backhalved Fox body, 15x14 wheel, BBF about 800-850 HP, glide, 4 link rear, 4.30 gear, factory style strut setup up front...  will mostly run 1/4 mile around here...

Car currently has a set of 32 14.5 MTs on it.  I've never run it with these tires so I'm looking for recommendations on diameter that'll work well with my rear gear and compound... I think I can fit a 15" wide wheel on there and plan to test fit one soon. I was thinking of running a 33 x 15 or 16 slick.


Also, how about a recommendation on a good length (and wheel height) for wheelie bars...?


Thoughts?

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Re: Tire and wheelie bar length recommendation....

Post  DILLIGASDAVE on January 4th 2018, 4:06 am

If it's a bracket car, (or a faster power-adder deal, but you value longest possible slick life over fastest ET) then put the biggest slick/wheel combo on it you can fit in there. But if you want the fastest possible ET at the lowest slick/wheel weight possible you might just have to spend a few bucks & do some experimenting with a few different sizes.

TBH a "smaller" size slick in the 14x32 range should probably be more than enough for 800-850hp if the suspension is right......but a bigger 33/33.5 XX slick should last a lot more passes. Hell depending on how the suspension is setup slicks smaller than the 14x32 range could also hook well at 800-850. The flip side to that is a real small slick might not fit/set/look right if the car was built for a bigger tire.

If you end up needing wheelie bars don't forget to use them along with adjustable valving front struts (an/or travel limiters) for more adjustability. I don't like short wheelie bars, 70" (or more) is a good starting point IMO. Ideal W/B wheel height depends on what the car want's/needs for the best launch possible given the amount of "at-launch" power/torque that is on hand (adjusting dead-hook vs wheel-speed launch). Some guys start anywhere in the 4.0" to 5.5" range. And some guys just use their fist with the thumb knuckle at the highest point (like you're holding a beer bottle with your thumb plugging the opening) as a wild-guess height starting point.
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Re: Tire and wheelie bar length recommendation....

Post  jbozzelle on January 4th 2018, 9:42 am

Thanks Dave. So, would i be wrong to stick a set of wheelie bars on there set at say 6-7" of height for the initial passes? I don't want it to go for the sky and tear up the front end...

It's already got a full setup up front from PA Racing. Tube K-member, 1" narrower lower arms, drop spindles, Pinto Rack and Strange single adjustable struts. I also plan to chop the nose off from the strut towers forward and go all round tube up there. That'll knock off another 50 lbs or so.

Not sure what it weighs yet though...

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Re: Tire and wheelie bar length recommendation....

Post  DILLIGASDAVE on January 5th 2018, 2:35 am

jbozzelle wrote:.......would i be wrong to stick a set of wheelie bars on there set at say 6-7" of height for the initial passes?......

Meh, for the first pass you could always try a lower height setting than that for a more conservative approach. Better to blow the tires off on the first hit (assuming a rev limiter is used) than having to deal with a surprise moon shot.
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Re: Tire and wheelie bar length recommendation....

Post  Curt on January 5th 2018, 1:23 pm

If you limit the front end travel, you probably won't need a wheelie bar.
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Re: Tire and wheelie bar length recommendation....

Post  jbozzelle on January 5th 2018, 10:00 pm

I picked up a 15" wide wheel with a 32 x 16 mounted on it to test fit.

and by controlling the front end travel are you talking about just tightening up the extension valving on the struts or installing physical limiters?

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Re: Tire and wheelie bar length recommendation....

Post  biglucky on January 6th 2018, 8:42 am

I would tighten the front struts up first John if you have adjustables.I sometimes bolt a little lead on the front 10 or 15 pounds really makes a difference.
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Re: Tire and wheelie bar length recommendation....

Post  pmrphil on January 6th 2018, 9:54 am

A bracket car leaving around 4,000 with that gear shouldn't even need wheelie bars, can't hurt to have them at first, just have someone video from the side to see what it's doing. A tie-wrap around the rear shock stem will record compression, and using physical limiters on the front is an effective way to prevent big wheelstands, as well as keeping your reaction times a bit more consistant.

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Re: Tire and wheelie bar length recommendation....

Post  DILLIGASDAVE on January 7th 2018, 3:27 am

jbozzelle wrote:..............tightening up the extension valving on the struts or installing physical limiters?

If you have both (and if you need both) then install/adjust/use both. Two different jobs, two different tools.

The adjustable strut valving controls the speed at which the suspension travel is allowed to happen, but not the total length of that suspension travel.

The adjustable travel limiters control the total length of suspension travel, but not the speed at which that suspension travel happens.
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Re: Tire and wheelie bar length recommendation....

Post  Curt on January 11th 2018, 11:59 am

jbozzelle wrote:I picked up a 15" wide wheel with a 32 x 16 mounted on it to test fit.

and by controlling the front end travel are you talking about just tightening up the extension valving on the struts or installing physical limiters?  

I was talking physical limiters. You shouldn't need any travel down from the sitting position on a drag car. Using the valving only, might not help because you would still be losing part of the weight of the front end on launch. When we ran SG, we had zero movement down, but ran mostly on good tracks. If you're racing on a track that needs the shock to extend past neutral, you're a better man than most.
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Re: Tire and wheelie bar length recommendation....

Post  jbozzelle on January 17th 2018, 1:00 pm

Thanks Curt. I'll look into what I can do for some limiters. Some of the Mustang specific limiters are damn expensive. Have to see what I can do with some chain and a shackle or two...

As of now the car is just about bottomed out on the struts with a 14-175 spring. There's very little movement down.

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Re: Tire and wheelie bar length recommendation....

Post  Curt on January 17th 2018, 1:30 pm

jbozzelle wrote:Thanks Curt.  I'll look into what I can do for some limiters.  Some of the Mustang specific limiters are damn expensive.  Have to see what I can do with some chain and a shackle or two...

As of now the car is just about bottomed out on the struts with a 14-175 spring.  There's very little movement down.  

With 1/4" stainless cable and a couple of ferrules and stops from Lowes, you'll be set up for less than $10 per axle.
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Re: Tire and wheelie bar length recommendation....

Post  99zx9r on January 18th 2018, 9:41 pm

I agree with those that say wheelie bars will likely not be needed. I ran a similar setup (backhalf foxbody, ~850hp 557, glide, 31x10.5) and even with a loose converter the car would just hang the front wheels a few inches at launch. The combination of the glide and the weight of the BBF up front was enough to keep the front end down. What may have helped also is I was running a QA1 coilover up front which stiffened up the front end.
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Re: Tire and wheelie bar length recommendation....

Post  jasonf on January 18th 2018, 10:10 pm

I would think wheelie bars on a car like that would be "insurance". Not needed till you need it. I remember Blake standing his foxbody up at Bowling Green one year. With suspension tuning he was able to settle it down but that is reactive not proactive if you know what I mean.
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Re: Tire and wheelie bar length recommendation....

Post  jbozzelle on January 18th 2018, 10:43 pm

Yeah. I remember hearing about that. But I also remember seeing Damon Sea’s Fox body shoot the moon at Windy during one of the first Bash races. Tore up the headers and something else if I remember correctly.

I plan to stick some on there and just hope they end up being for looks...

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Re: Tire and wheelie bar length recommendation....

Post  jbozzelle on January 19th 2018, 6:41 pm

And Damon's car had a similar engine to mine. But he may have still had a C4/6 in there too which I'm sure didn't help due to the low 1st gear...

I'm running a 1.80 first gear in my glide...

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Re: Tire and wheelie bar length recommendation....

Post  99zx9r on January 21st 2018, 1:22 am

I can't imagine my 79 pulling the wheels like that.  It went a best of 9.13 @ 147 with a 1.33 60ft (footbraking) and would just carry the fronts just a few inches.  

Here's a vid of my buddy racing it off the transbrake.  Skip to 3:10 to see the launch.
https://www.youtube.com/watch?v=ZHDrD7R3B9E
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Re: Tire and wheelie bar length recommendation....

Post  jbozzelle on February 7th 2018, 12:02 pm

99zx9r wrote:I can't imagine my 79 pulling the wheels like that.  It went a best of 9.13 @ 147 with a 1.33 60ft (footbraking) and would just carry the fronts just a few inches.  

Here's a vid of my buddy racing it off the transbrake.  Skip to 3:10 to see the launch.
https://www.youtube.com/watch?v=ZHDrD7R3B9E


How high was your engine in the chassis? I've seen Fox body's that use the swap mounts that stick the crank angle pointing extremely up and the damper real high in the front. Those are the cars I've seen do huge wheelstands...

My car is a bit more like a chassis car with the engine actually running slightly uphill as the driveline goes to the rear... The tall tires and lack of floorpans allowed me to stick it where I wanted. Whereas the other cars I've seen ended up with the nose high crank angles due to the transmission having to fit under that stock, unmodified floor...

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