CBR 1000F "Hurricane" 1987-1996 CBR 1000F

Best Gearing For Highway Use

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  #1  
Old 10-04-2009, 01:28 AM
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Default Best Gearing For Highway Use

All,

Just finished rebuilding the front end of my project bike, it is now time to turn my attention to the rear.
New chain and sprockets are on my list but i would like to drop the rpm's at highway speed, what's recommended?
Will a 18t counter make much difference and will it fit?

Thanks in advance

Aussie Johnno
 
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Old 10-04-2009, 09:17 AM
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18 fill fit but you have to modify the chain guard/something.
Rather stay with the 17 front and come down to, say a 40 rear from 42.Much less work.
 
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Old 10-04-2009, 10:07 AM
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18 fill fit but you have to modify the chain guard/something.
Rather stay with the 17 front and come down to, say a 40 rear from 42.Much less work.
100% agree. I would just come down a couple in the rear.
 
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Old 10-04-2009, 05:39 PM
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You can do the math to find out what the % change would be.

Compare the stock ratio to the modified ratio - and then compare those fractions. It will give you a percent. A 10% change (FOR EXAMPLE) means that at 5000 rpm you'd be 500 rpm lower rpm than before.

Also note that Honda generally knew what they were doing - the question was, what was honda doing?
 
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Old 10-04-2009, 05:48 PM
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We used to have a chart and everything for that calc, woot. Can't remember where it went, though...
Edit: Here's the ratio chart. Don't have a calc chart, but maybe I'll make one?
 

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Old 10-04-2009, 05:59 PM
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I have an excel spreadsheet that I made.

Old_f = 16
Old_r = 46

New_f = 15
New_r = 48

(aka -1,+2)

OLD_ratio = Old_F / Old_R = 0.347826087

New_ratio = New_F / New_R = 0.3125

Change_Ratio = New_Ratio / Old_Ratio = 0.8984375

or the new ratio is 89.8% as tall, OR

Change_Ratio -1 = -0.1015625

Which means - 10.1% shorter (shorter because it is negative in this case)


For your bike the change will be a positive %, or Taller
 
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Old 10-04-2009, 06:04 PM
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Very nice, woot!!
 
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Old 10-06-2009, 09:51 AM
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It's funny, every big streetbike I've ever had I wanted taller gearing for hwy riding...except this one. I find the stock gearing to be perfect. The motor (on my bike anyway) has a few RPM zones that are pretty buzzy, but it smooths right out at an indicated 82 indicated (75 in reality), up to about 88 indicated. I like to cruise in this speed zone because it minimizes tickets but I still feel like I'm getting somewhere; probably because even though I know it's wrong, seeing 85 on the speedo feels like progress

I do understand that some peeps like to cruise faster than that, so in that case, I think 2 teeth will serve you well. Beyond that you're gonna be shifting a lot more. I love this bike...one of my favorites ever, and it does many things well including decent midrange torque...doesn't have much bottom for a liter bike though.
 


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