liveforphysics said:
My GSXR1000 used to iceskate down the drag strip too, because it's rear tire is made for corners and only rides on a small bit of an often harder tire rubber compound down the middle.
That gentleman at the end runs a 9.37 ET on a tire more narrow than my mountain bike.
You did not deflate the rear tire? Running 9's on a strip with a stock 160hp Gixxer? With a fully inflated tire?
My ZX did a 9.9 stock. Stock. Next to impossible to better that time. 188hp. Never used half of it, I bet. ON a track. Tire would break loose, or the front end would come up. We all have seen cars and bikes losing traction on the dyno, and what happens to the numbers.
So you think he has more than 120hp on that 1.25"? How much power do you think it makes, that 150cc two stroke? You really think more power would help make a faster time? Or just overcome the tire? I dont know how they make that kind of time on a tire with that footprint. That tweaky high rev two stroker engine must have like what, 23- 35 ft lbs of tork? Lol.
A Gix 1K will eat a Busa, off the line, every time. For some reason or another. IDk. Same rear tires, very similar bikes, in weight, much different power outputs rated. 160hp vs 200 hp. There becomes a point when the power just cannot be put down. ( its around 9ooo rpm on a 5th gear shift on a ZX10 at 160 mph.. Thats all Iknow.. Dont do that. ) )
Tire loading. Now we are getting somewhere. Enumeration. Lets look at it. I do not agree with your proportional scaling of tire loading vs power.
21 inch wide, ( two wheels, car) , 3500 hp =
3500/21 = hp/inch of width. 175? Hp/ inch of tire width. They break that loose.
200/1.25 = 160 hp / inch.
160 =/= 175..
However, compound temperature of tire, the available mass, the skill of the driver, erases that differences. Fundamentally. For all purposes, lets say 160 ~ 175, negligible difference.
So yeah They are very much the same. I see that.
I dont get it. Something bothers me, about that, fundamentally. Maybe its just ingrained in my brain, but I cannot imagine 160hp on a tire of that 1.25" loading. Something bothers me about that number. i dont know what it is. I would think any power excess would rip it loose from its mooring. Maybe I will figure it out by the end of the day. IDK.
If the car tires with the 3500hp have a (10.5 x 2")(2 wheels) contact, 42 square inches... doesn't that contact area go up? Now we have a greater amount of friction... 3500hp over the 42 square inches: ~83hp per square inch of contact.
The single TaiDrag 1.25" x 2 " = 2.5" squared... For that 200 hp... Yup you still have ~80hp/square inch of contact. So you are right there.
Do 3500 hp drag racers have more than 2" of contact upon application of the power? If the contact patch was ( reasonably) 4" x 10.5"... ( 10.5 x 4" )(2 wheels) = 84 square inches for that 10.5" wide patch ... Now wear e at a ~41 hp/square inch, much much lower than 83hp/square inch...
Do (3500hp) drag cars sit on 2" contact patches when they take off? Teh whole race? I would think it was more contact area.. ie why we deflate our 8" wide rocketbike tires for the drags. To get more patch. If you try to run a fully inflated tire you lose. Spin City. Deflate that effer. Double the patch.
I do not know. I'll figure it out. Somethings bothering me about all this, " 160hp/inch " stuff. Does not seem feasible with my experiences on rocketbikes, bicycles, and the like. Thanks for humoring me, Luke.
Something is still bothering me about it. IDK what it is.
For some reason I still think that. Also, I dont think drag tires on 3500 hp cars are.. 10.5 x 2".. More like 40hp/square inch, vs the 80hp / square inch.. of the prior eq... But I dont know exactlyhow that works. Maybe that is what bothers me, a car drag tire on 3500 hp is MUCh less (tyre) loading proportionally IF the tire has a 10.5" x 4" patch rather than a 2" patch. Maybe I am just fudging the numbers to make it work. IDK. Increase the dimension ( slightly deflate the tire) on the TaiDrag bike to 1.25" x 4" and you get the same result. 40hp/square inch, scaled like you said, almost equally.