rtbain
Expert Class
old, fat and slow
Posts: 244
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posted October 23, 2009 02:39 AM
Tires
When running a 250 in roadracing I learned to use just enough tire to do the job. As my miler ZX and I go on diets I was wondering if anyone has downsized from stock to reduce rotating mass.
If my thinking is correct using a narrower tire on a stock rim would yield a larger contact patch and weigh less.
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Randy
   
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Shane661
Needs a life
Posts: 11494
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posted October 23, 2009 03:01 AM
 Edited By: Shane661 on 23 Oct 2009 11:02
My experience with Michelin Power Race tires is that the 190/50 and 180/55 tires weigh about the same. Regarding contact patch, remember that any more than you need for traction is just additional drag.
Did you take your bike to the mile, and if so, how did you run?
Shane
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rtbain
Expert Class
old, fat and slow
Posts: 244
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posted October 23, 2009 02:41 PM
Shane, good points thanks for the input.
Made my first mile. First I want to thank Karl and TFA for all their support. A first rate group of people and a helluva lot of fun. I wish there was more time to sit around and shoot the breeze.
My first day saw low speeds with my throttle hand refusing to cooperate with my brain. I kept backing off before the mile marker. Second day was much better and by the third day I was driving past the mile marker before easing off. Fastest pass was 169 and change.
I learned a great deal. What I should have brought, what I should have left behind. I hot lapped as much as possible to get seat time at speed. Gearing was way off (red lined 5th at the mile marker) and fuel map needed tweaking. Rather than tune and change gearing I just rode.
I am not certain which is worse, my tuck or my start. Never was really good at drag race starts but I need to learn. The bike and I are on a diet for the next round in March.
I may be able to make Maxton but have already maxed out the budget just building the bike. We’ll see what Boss Lady has to say.
I was out run but no one had more fun. Color me hooked.
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Randy
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Shane661
Needs a life
Posts: 11494
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posted October 23, 2009 02:45 PM
Congrats on your first mile! The tuck is way more important than the "launch"...so keep that in mind. 
Shane
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2000redrocket
Pro
Posts: 1662
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posted October 24, 2009 09:25 AM
the launch at the drag strip is more important. i and mike were talking about that. a lame pull out will produce a higher mph than nailing the 60ft. but a small amount of wheel spin on the launch will add up to 1 or a tad more mph on my bike usually. nailing the 60ft and 330 gives me a great 1/8mph with the same or a bit lower mph at the end. so a good but not likker launch on out typical bikes seem to be the best from what i seen there. the guys with 400hp i would think need the whole mile under power. shane am i on line with this. mike and i talk about the mile launch and the 1/4 launch a lot. mike is the man in the 60ft but his gsxr1000 has a better power to weight than my 12 even with same day dyno numbers haveing me8hp higher due to the weight.
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Shane661
Needs a life
Posts: 11494
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posted October 24, 2009 09:27 AM
Edited By: Shane661 on 24 Oct 2009 17:28
Well, I can personally run equal or better mph with an easy launch at the dragstrip. So, draw your own conclusions from that.
Some people still swear by that hard launch for LSR, though. Who am I to argue with them?
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