Author Topic: Lightweight wheels (acceleration vs top speed)  (Read 5294 times)

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Offline shiphteey

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Lightweight wheels (acceleration vs top speed)
« on: November 12, 2006, 12:46:40 PM »
Having done Maxton and BUBS now, averaging 201.9 @ Bonneville and now squeaking 202.9 @ Maxton I am thinking about reducing the overall weight of the Kawasaki zx12.

As most know, the 12 and the Busa weigh in about 100 lb heavier than their new 1000cc brothers.  In an effort to help tilt the scales back in the big bike's favor I would like to know the potential gains that I can see in acceleration and top speed.

I have heard reports of a stock cbr 954 gaining 5 mph on top speed, hard to believe though.

Also Either a GP bike or a Ducati gaining 3-4 mph on the back stretch of a roadrace course.

In the drag racing world it is said one can gain up to .2 seconds and a couple mph off of this mod alone.  I am interested in going as light as possible (carbon wheels, about 2 kilos per wheel).  Lots of weight savings, especially on the outer part of the wheel (inertia).

What kind of gains can I see in the standing mile if I am consistently running 202.xx mph?  1 mph?  2?  How about at Bonneville where weight isn't much of a factor?  Anything?

Thanks

A.
Gemini Motorcycles
229.6 mph at Loring
201.957 mph 2-way average @ Bonneville;
203.85 @ the Maxton Mile
207.2 @ Maxton -- NAKED
200.2 mph @ TX Mile
195.6 mph on GPS @ the 9/10ths
9.4 @ 157 in the 1/4

Offline Sumner

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Lightweight wheels (acceleration vs top speed)
« Reply #1 on: November 12, 2006, 12:54:17 PM »
My gut feeling, and no more, tells me it could possibly help at Maxton (more of a drag strip situation--short run) and possibly hurt at B'ville (bad traction situation with plenty of time to accelerate.

I'll be interested to see what some of the bike guys tell you on this one.

c ya,

Sum

Offline shiphteey

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Lightweight wheels (acceleration vs top speed)
« Reply #2 on: November 12, 2006, 01:27:05 PM »
Quoted from:  http://www.zx14.net/shop/product_info.php?products_id=135&osCsid=3fbfcba7704304c200d3642069d85d97



"Drag racers are reporting .2 seconds in the quarter mile.  Some racers are foregoing additional engine and brake modifications and putting their extra money into these wheels.  "If you could compare both of these bikes side by side ... there would be no way to catch the BST-wheeled machine.  The difference is small to begin with, but the carbon wheels get the bike to 80 kph in 1 meter less than the standard bike.  If then builds with time and by 95 kph the BST wheels have taken 3.5 meters less, at 160 kph they have a 13 meter advantage and by 240 kph they are a full 108 meters ahead."



SUPERBIKE January 2006.



....Its hard to believe but it sure sounds good!
Gemini Motorcycles
229.6 mph at Loring
201.957 mph 2-way average @ Bonneville;
203.85 @ the Maxton Mile
207.2 @ Maxton -- NAKED
200.2 mph @ TX Mile
195.6 mph on GPS @ the 9/10ths
9.4 @ 157 in the 1/4

Offline Larry Forstall

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Lightweight wheels (acceleration vs top speed)
« Reply #3 on: November 13, 2006, 11:30:35 AM »
On the long course it is not necessary at Bonneville. In fact the inertia of a heavier wheel helps maintain speed when the course is soft. In the case of the Hayabusa the stock wheel with its' large rounded spokes is more aerodynamic than any aftermarket wheel.  At Maxton, the lighter the better. Most cost efficient would be to start with a used rear mag wheel with ceramic bearings in both wheels. Overall weight also affects performance. Mark DeLuca went 202.5 at Maxton and 206.1 at Bonneville with the same bike.  :D

Offline whitworthsocket

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Re: Lightweight wheels (acceleration vs top speed)
« Reply #4 on: December 06, 2006, 09:04:03 AM »
Would you give me some more information about the ceramic bearings.
I presume that they give a performance gain.

Regards
Whitworthsocket
Regards
Whitworthsocket

Offline Larry Forstall

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Re: Lightweight wheels (acceleration vs top speed)
« Reply #5 on: December 06, 2006, 01:11:00 PM »
Ceramic wheel and engine bearings for motorcycles are available from www.worldwidebearings.com in New Jersey. Their use originated in Production drag racing and have proliferated to all forms of motorsports. They have considerably less drag than a steel ball because of decreased mass. Those that use them swear they improve performance but perhaps it is because we spent the $$. Since rolling drag only accounts for 10% of total drag ceramic bearings are well down the list of mods unless you are N/A and looking for every HP.   Larry

Offline Dean Los Angeles

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Re: Lightweight wheels (acceleration vs top speed)
« Reply #6 on: December 06, 2006, 07:32:27 PM »
Boca Bearings offers ceramic bearings also.
http://www.bocabearings.com/default.aspx
Don't give up on reducing weight and drag. The horsepower equation is well known. Every fraction of an ounce you carry takes power. Don't forget the diet!
Well, it used to be Los Angeles . . . 50 miles north of Fresno now.
Just remember . . . It isn't life or death.
It's bigger than life or death! It's RACING.

Offline narider

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Re: Lightweight wheels (acceleration vs top speed)
« Reply #7 on: December 07, 2006, 11:14:04 PM »
The way i look at it Ali, is there's a happy medium. Too light is no better then too heavy, with the word "too" being dependent on the distance and horspower involved.
My thoughts and explanation on it go like this:
1. Take a duckpin ball, a softball, and a wiffleball(holes taped over), these will represent similiar areos.
2. Use your dominant arm at full strength each time, this will represent a common horspeower used.
3. Throw each ball as hard and straight as you can and see which goes the fastest.
My bet is the softball.... and because it's a happy medium in weight.
Too heavy may do better in a long distance headwind(simliar to Bonneville?).
Too light may get there quicker in a shorter distance(similiar to Maxton?).
But there is surely a better choice then the other that depends on the other factors... IE: how much horsepower, what distance it needs to pull itself through, how long it has to get there and the density of the air it needs to do this in(and this is without even taking traction in to consideration). In other words, a very probable changing set of variables(year to year and venue to venue) will have an effect on some level also.
I once thought about something like a set of wheels that would spin up easy for Maxton, and then have some thick bolt on perimeter rings for the salt? A second set of wheels may be a more viable option though.
I may be be wrong alltogether.. but it's been my thoughts for awhile and I'm sure I still have plenty of time before it's something that will have any beneficial relevance in my world(especially as I've never even been on the salt yet). But since you asked I thought this might be good time to get other's thoughts on it too.
Todd

Offline ddahlgren

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Re: Lightweight wheels (acceleration vs top speed)
« Reply #8 on: December 09, 2006, 08:40:38 AM »
Unsprung weight?? add more? :? makes little sense..
Dave