tire height

[low&slow]

What are you guys running height wise in the front?

I'm thinking of running a 4 or 5 inch wide rim, but not sure how tall I should go.

Post pics of your front tires as well. I'm a visual type of person lol.

My truck is a 69 c10 currently.

[Marv D]

I think frontrunners only come in a few heights,, (20-24" tall or so)

I drive on the street and with the 3650 pound hulk,,, wanted a real tire. I'm running a 26.5" tall hooser radial up front. Obviously... I drive AROUND the waterbox and back in, but she still hooks.,

Acouple of pics are at....

http://www.small-block-chevy.com/ima...0/MDNovtrk.jpg

and

http://www.mousemotor.com/8_98b.jpg

.....but don't know how realitive that all may be to your 69

[RICKSRAT]

My 72 with 28" x 4.5 tire on 4" Centerline . Goodyear 315/60 drag radial on a 12" on rear.

[low&slow]

Oh man that looks good. That front tire size fits the fender opening perfect. That's what I was looking for. Might run a 28" in the future, but for now a 28" tire is taller than the slicks I got on the back lol

[LSPWRD67CHEVY]

Mine are 28x4.5x15 up front and 29x12x15 in the rear.

[low&slow]

That's not to bad looking either.

Unfortunately my rear slicks are only 26.5 inches tall. Wasn't my first or last decision for that size, but I found them on CL and got a good deal. Got 2 Hoosier Radials that are 26.5 by 8 for $10 each and 2 Goodyear Eagle slicks that are 26.5 by 10.5 for $10 each. And all 4 tires have 90-95% tread left.

[Juiced68]

Do these trucks have to be tubbed to fit a 12" wide wheel?

[low&slow]

Originally Posted by Juiced68

Do these trucks have to be tubbed to fit a 12" wide wheel?

12" wide rim or 12" wide tire?

[hotrod 80]

If this is a street ruck then looks are key, but the taller the front tire the more roll out . In effect the taller the front tire the slower reaction time . Just throwing that in there .

[Super73]

Hotrod,

I have never been in to class racing so things like roll out of front ties and the affect on reaction time has never been some thing I have looked in to. You have peaked my curooysity how a front ties roll out would affect reaction. The only thing I can think of is the beams height and the circumfrence of the larger tire. The shorter tire perhaps more optimized based on beam height.

But I would think the rt between a 26 and 28 would be negligible. I could see a 22 vs 30. In addition to that, if you just light the staged lights, the beam for staged should be hitting the same point on the tire as the start beam.

So I guess my question here is, is it a function of tire height or staging depth? I am going to guess you will say both.. how much really goes to the tire?

I like little trivial things like this it helps me think of other things.

[hotrod 80]

The difference between 24 and 26 inch front tire is more than you might think . Even tire pressure has a big effect . An example . This weekend a buddy who runs a 26" tire for the look was -.001 and .004 . I took 5 lbs ( a big move ) out od the fronts and he was .036 next pass . I went up 2 lbs and he was .024 . I run a 25 inch tire with 40-44 psi . My new S-10 will be set up with a 24 . 22" tire changes the caster to much for me . Rear tire pressure has an effect on reaction time also .

Remember when you light the pre stage you have just broke one beam . As you move into the second beam you have about 4.5 inched before you put the prestage out . If you just tickle the second beam the tire has to move more before it triggers then say taking a bigger bite at staging were you ar 2.5 from triggering .

Typically what you take out of your reaction time adds to your 60' .

[hotrod 80]

Not to get off track , but tire size and air pressure are only one reaction time tool .

[Super73]

Your mention of tie pressure got me thinking about sidewall squish vs roll out. That dynamic makes more sense. The bigger the sidewall and or lower the pressure could cause the vehicle to move up more before moving out.

I was not trying to take away from this thread but rather learn something in it.

[hotrod 80]

I tried to write somrthing up , but this is from Summits web site . It explains it much better than i could .

Adjusting Rollout With Tire Size
You can modify your rollout by changing the size of your front tires. The
height and width of your tires, measured at the height the staging light
beams are from ground level, determines the amount of rollout. This
illustration shows where the lights are set at a typical track sanctioned
by the International Hot Rod Association (IHRA). The IHRA sets its light
beams approximately 1 5/8 inches off the ground. The larger your front
tires are at that height, the more rollout you will have.

Here's an example: Let's say your front tires measure 12 inches across at
the light beam height and you are using a shallow staging technique. When
you launch, you have a “rolling start" of 12 inches before you pass the
stage beam and trigger the ET timer. If you replace those tires with ones
that measure only eight inches across, you have effectively decreased your
rollout factor by four inches (12–8=4) and also increased your chances of
cutting a better light. Remember, less rollout means better reaction
times.

You can also alter tire size by playing with air pressure. More air
pressure increases tire height, but reduces width and the size of the
contact patch. That will reduce your rollout. Conversely, reducing air
pressure reduces tire height and increases tire width and contact patch
area. As you probably guessed, that will increase your rollout. Air
pressure is an easy and inexpensive way to see how tire size affects your
staging technique and reaction times; the slide show has photos showing
the effects of tire pressure on rollout.

Like anything else, the best way to apply these staging and rollout
techniques is to practice, practice, practice. Once you find a staging
routine that works for you, stay with it. When you stage the same way for
every run, the more consistent you will be-and consistency wins in bracket
racing. Happy rollout hunting!