Stopping Distance NEEDED from 1/2 mile?

bazooki

bazooki

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This will be my 3rd year in a row doing a charity speed event called Race The Runway in Smiths Falls, Ontario, Canada. It's to raise money for an airport and it takes place on a runway, hence the name RTR. Its a standing start 1/2 mile run with measurements of time at the 1/4 and speed at the 1/2 mile. My best is 10.1 at the 1/4 and 251 km/h at the half. I am able to win the 1/4 mile both years but want to win overall. Last year I lost to a $700,000 Lambo Aventador that posted 258 km/h at the 1/2.

Here's the issue. There is a 1/4 mile braking area before you reach the end of the runway and then it becomes grass and then a swampy area. Bad in a sports car but really, really bad on a bike. We had a 900 hp Nissan GTR and a 1000 hp Corvette go off the end at previous events. Both sustained some front end damage as they turned into plows. I am considering going to an RCC Stage 1 kit this year and winning overall top speed as well as dropping my 1/4 mile considerably. Problem is stopping. Does anyone know how fast I can go while still being able to stop in the 1/4 mile braking zone? I am still running stock brakes w/ ss lines on my 2005 busa. Experimentation would solve this issue but we only get 3 runs per year so there isn't much time for that type of research.

BTW, 251 km/h is 156 mph
1/4 mile is 1320 ft.
 
Thats the front straight at Barber....I could stop from mach 3 over that distance.
 
1/4 mile stopping area is a pretty good distance. Just make sure everything braking is 100%, downshift as you go and sit up in the seat when safe to do so. You would be amazed at how much sitting up in the air reduces your speed.

You could always find a long straight somewhere, mark it off and give it a few test runs before going to the event. I'd rather do that instead of going into the marsh
 
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The exact braking distance is: whatever it takes to stop .00001 inch before you run off the edge... :)
 
There is no exact stopping distance. Any number given would be a false number when it applies to your specifics.

Your stopping distance is just that, your stopping distance...not someone else's. It'll have to do with how you handle your brakes, grip at that given time, your weight, bike mods, etc, etc.

That being said, like DOD stated it's best to practice somewhere safe but a 1/4 mile is a tremendous amount of allowance to slow down a bike with no other surprises or obstacles coming into play until the end of the stretch.

You said a couple cars went off the end but how did it feel to you on your bike?
Did you have plenty of room as it sits?
 
Make sure you check out the slowdown area well. Pebbles sand and trash in general would not be a good thing to slow down in.
 
They do seem to be pretty good at cleaning up the runway so I am not too worried about debris. Generally you are accelerating right through the finish line so you really don't have a 1/4 mile for braking. As soon as I see that I have crossed the line I sit up to serve as a sail and get on the brakes hard with the emphasis of course being on the front. At 250 km/h I am comfortably able to slow enough to turn with about 10 yards to spare before the end of the asphalt but my concerns are if I am turning 280 km/h passes. It would be nice to have target speeds but as I said you only get 3 passes so you are kind of making it up as you go and adapting quickly.
 
I would use that as a starting point to judge the distance...30 feet to me is getting a bit close. While still a lot of room, a small mistake with a little more speed under your belt can wipe out a few feet pretty quick.

At the same time, how much grass before swamp?

With enough speed shaved off grass isn't too bad as long as it's smooth before the bumper robbing humps start...but I would not count on a grassy area to end my slow down run unless in an emergency situation. The only thing left after that is a bath.
 
EBC HH "Extreme Pro" ceramic embedded front brake pads.
They WILL stop you sooner. How much? I have no idea, but just say 10' in a 1/4 mile for the heck of it...that's still 10'.
If you have good braking ability you will certainly notice being able to slow down and stop sooner.
Every little bit counts! Good luck with it!:beerchug:
 
How wide is the track/runway?
I would think if 1/4 mile of stopping wasn't quite enough, surely you would be at a speed to easily turn left or right(assuming it's wide enough).
 
Sounds like a lot of fun, we need a few charity events like that around here!!!

Have fun, be safe, and good luck on your goal
 
sixpack577 said:
How wide is the track/runway?
I would think if 1/4 mile of stopping wasn't quite enough, surely you would be at a speed to easily turn left or right(assuming it's wide enough).
Click to expand...

Yeah, there is a circular area at the end that the planes use to turn around so if you are set up for your run on the right side you can turn to your left with some speed if needed.
 
outlawbusa said:
There is no exact stopping distance. Any number given would be a false number when it applies to your specifics.

Your stopping distance is just that, your stopping distance...not someone else's. It'll have to do with how you handle your brakes, grip at that given time, your weight, bike mods, etc, etc.

That being said, like DOD stated it's best to practice somewhere safe but a 1/4 mile is a tremendous amount of allowance to slow down a bike with no other surprises or obstacles coming into play until the end of the stretch.

You said a couple cars went off the end but how did it feel to you on your bike?
Did you have plenty of room as it sits?
Click to expand...

our local 1/4 mile has a 1/4 mile shut down, and it can get slightly scary at 140mph. I can slow down enough for the first turn off, but sometimes I need the second turn off. Add 20mph and it would need maximum braking(and the surface is less than ideal).
 
sixpack577 said:
https://www.hayabusa.org/forum/general-bike-related-topics/180135-tire-buying-2.html#post3101341

I see OutlawBusa here, LSR guy.
What's recommended psi for 1/2 mile LSR?
Above link is Bazooki asking about tires.:beerchug:
Click to expand...

I skimmed through the other thread and didn't see a pressure question right off...

On the 1 mile course we run about 60 PSI in both tires. This both helps with less resistance on the road surface and also helps avoid the tire from ballooning or expanding as much.

When the tire expands it rubs the inside of the front fender creating drag and the sidewalls tend to pull inwards eliminating pressure against the sides of the rim. The High PSI keeps good pressure against the sidewalls.

The half mile might be a bit of a different story, the speeds are a lot lower so the sidewall pressure is not needed as much and the tire is also not going to grow nearly like it would in the mile. Also take off traction is going to play a larger part. I spin quite a bit on the mile course, but on the 1/2 mile course you may lose too much of the course by blowing off the rear tire in second gear so I would consider a lower pressure than what we run. If good traction is available you might try around 50 PSI and adjust from there.

PS: If you think about it...running the 1/8 mile most people lower the pressure to 16-22 PSI and the 1/4 mile is still a lot lower than street pressure so traction is gained. On a 1/2 mile that's a good question. I think you are really going to need a good launch to be able to utilize the course and with a higher HP bike high pressure in the rear tire may kill your launch along with 2nd and 3rd gear with not enough time to recover the lost speed. That's going to have to be something to play with a bit. On the mile course the launch is not everything, in the 1/2 mile course I am thinking it will be a lot more important.

Sorry for the confusion, but I am second guessing high pressures on the shorter course.
 
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Thanks Outlaw. You have introduced a bunch more variables that I hadn't even thought about yet. Yes, my brain is going to explode. LOL. With the 1/2 mile I am more concerned about my launch, plus I need to win the 1/4 mile portion of the event, so I think I am more likely to keep pressures lower than higher. I am also working on my position on the bike, trying to lower wind resistance as much as possible.

Hi Karl!
 
Yup, that's my worry alright! Just substitute swamp for cattle path and that pretty much sums it up.:whistle:
 
dadofthree said:
1/4 mile stopping area is a pretty good distance. Just make sure everything braking is 100%, downshift as you go and sit up in the seat when safe to do so. You would be amazed at how much sitting up in the air reduces your speed.

You could always find a long straight somewhere, mark it off and give it a few test runs before going to the event. I'd rather do that instead of going into the marsh
Click to expand...

:laugh:
 
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