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Front Roll out

  1. martin0660
    martin0660
    I pretty much know what I want to do, but thought this might make a good discussion ....

    Does anyone play much with front tires and roll out?

    I had run 26" tall MT Sportsman fronts and was pretty good on the tree.

    Last year I replaced them with 165/80 Fusions. I usually run them up at 40 psi, do okay on the tree, but have spells where i'm red a lot ... typically let some air out of them (28 psi)when I'm struggling and can pull a little cushion that way.

    Thinking about going back to a full 26" tire (must be DOT so likely back to Sportsmans or the new MT radials).

    Anyone else play around with tire size and pressure for roll out? What say you all??
  2. mmb617
    mmb617
    I've never played with this but am interested in learning about it. I know it's a little different for me on the pro tree since I can't move up the tree if I'm late launching. I almost never red light because I'm just not quick enough. Staging normal with my 408 and going as soon as I detect the flash will net me a good light most of the time.

    However, since I plan to run my 351 this year I will need a different strategy for staging because the car reacts a lot slower and no matter how fast I try to launch, I wind up being late. I plan on experimenting with deep staging to correct this, but maybe there's another way?

    I'll be all ears!
  3. martin0660
    martin0660
    The theory would be for you to go to a shorter front tire Mike.

    The two primary factors that affect this are the front tire diameter and height of the beams at the starting line ... some will say that weight, gears, etc should be factored, but IMO, those are what they are ...

    We had an issue here the beams seemed odd. The heavy hitters kept going down in tire size (like 24") to cut strong lights. The track said everything was right, but after an IHRA run Pro-Am, everyone was red the next race.

    I have played with mine, assuming the beam height, you can use a framing square to mark the spot where the front tire would be in the beam, then the distance moved to break that with the back of the tire. A shorter tire makes this dostance less, so it will "react quicker".

    Still not sure i'm going to try anything until after we get going this year, then I can test, change, test, then make a decission.
  4. mmb617
    mmb617
    I'm presently running a 165/80 front tire with 40 lbs of air too. Due to not wanting to spend money for new front tires right now I'm going to experiment with changing my depth of stage as a way of getting a quicker R/T. Maybe not all the way to a deep stage though. Normally I just nudge forward till I light the stage bulb and stop. I assume that if instead I were to continue forward a couple inches, but not enough to turn off the stage light it should pick me up something, right? I just don't know how much.

    The last time I ran this motor I was really slow on the tree, like almost a tenth. That seems like a lot to pick up so maybe deep staging will be necessary. What sucks is that I have to work on this problem on race nights because they use the full tree at all the T&T's which does me no good in figuring out what's going to happen on the pro tree.
  5. martin0660
    martin0660
    Your issue will be with consistency Mike ... Go to TNT and stage normal, then put it in deep ... you might be shocked with the ET change. Once you know that, how are you going to put it in on the same spot taking a bite? If i'm confident in my first time trial, I will take a bite for my second to try to get a good RT for the 1st round bye ... Id I chunked my 1st TT, I stay shallow.

    It will help your RT to take a bite, but affects your ET ... Tradeoff's
  6. mmb617
    mmb617
    I see your point. If you just light the stage light or if you just turn it off, you know exactly where you are either way. When you're somewhere in between it will be impossible to be in the exact same spot each time.

    I never bother trying to work on R/T's at the T&T's because they use the full tree. Some people have said if you just drive off the last light it's the same as a pro tree, but I find it impossible to not see the other lights and anticipate the last light, which you can't do on a pro tree.

    The T&T's at the Beaver tend to not be very busy at all. Lots of times I make a solo pass. Perhaps I could ask if they would run the pro tree for me if I'm willing to wait till I can make a solo pass? Couldn't hurt to ask I guess. I'd go to more T&T's if I could work on R/T's at them.
  7. mmb617
    mmb617
    Bob, I know the class you run has a much smaller window for R/T's. In my class all I really need to be competitive most of the time is a sub .050, I don't have to kill it. The last time I ran the 351 I was getting R/T's in the .1xx range which will not get the job done. The car just won't react as fast. Must have something to do with the missing 150 or so HP!
  8. martin0660
    martin0660
    My suggestion for TnT was just to understand the differences in ET based on where you stage. I do it just to have a better guess in what it would run if I take a bite or roll in deeper. I will sometimes dial the car up a little, then take a bite if I'm worried about the other lane (we have some murderes on the tree).

    They used to have a lane for pro tree at our TnT, and will still do it if you ask, but they complain and forget to change the tree over at times. Usually the week before a NMRA race there are a few of us that want pro tree hits.
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