Sprockets for highway cruising?

[wordsmith]

7 hours ago, justplainbill said:

Using chitown's calculation of an 11.2% reduction with 17/43 sprockets in final drive ratio, you can multiply your observed engine speed (RPM) at a given road speed by 88.2 to determine engine speed with the higher (lower numerically) ratio at the same road speed.  So if your engine speed is 5000 RPM at 75 MPH with stock gears, it will be 4410 RPM at 75 MPH with  17/43 gears. (I don't happen to know the RPM at 60 MPH and it's too damn hot here to ride down the road to find out.😀 )

As a mathematician I would make a wonderful deep-sea diver, but - should that not be multiply by 0.882?   Shoot me if I'm wrong please!   To check - using your above example, 5000rpm @ 75mph x 0.882 = 4410rpm, which is what you say. 

On this basis, my GT's 4000rpm @ 100kph will be 3528rpm after the 17/43 conversion, the sort of reduction I'd like to achieve for long sustained periods of touring day-in day-out.

Edited July 28, 2019 by wordsmith

[texscottyd]

11 hours ago, wordsmith said:

...if anyone has observed the points of interest that I gave (rpm @ 100kph/ 60mph with 17/43) I'd like confirmation if you please!   TIA...

I’m getting ready to head out for a ride, so in the interest of science I’ll make note of stock gearing rpm at 62 mph and 100 mph.    

From there, we can calculate (A) the difference a gearing change would make, and (B) the USD amount of my traffic fines.  

[betoney]

6 hours ago, wordsmith said:

On this basis, my GT's 4000rpm @ 100kph will be 3528rpm after the 17/43 conversion, the sort of reduction I'd like to achieve for long sustained periods of touring day-in day-out.

@wordsmith - since you are now on your 4th Tracer, you are well aware of the higher revving characteristics of this engine as well as how it operates at lower rpm's, this isn't an FJR or Goldwing, nor was it designed to run like one.  This engine redlines well over 11k rpm while the FJR is 9k and  Goldwing is 6k, both designed for lower "touring" rpm's.

As an experiment, with your current stock gearing, go out for a ride today and get up into 6th gear @ maybe 5,000rpm then slowly drop your engine speed until you get down to your suggested 3500rpm or lower.  You will feel the engine start to work harder and "lug" or lurch, changing the final gearing is going to make things worse at such a low rpm. 

I have mine geared opposite of what you are suggesting, +2 teeth on the rear, to make the engine more responsive and don't like keeping the engine lower than 4,000rpm since I can definitely feel a load on the engine and immediately downshift, even with my gearing I cant effectively ride in 6th gear at 60mph.  I am sensitive to the feel of the motor, growing up on 2 stroke dirt bikes, being in the right gear for the powerband. 

I understand what you are trying to achieve but don't be disappointed if you cant get it with this motor, though I am definitely interested in hearing your thoughts and a ride review if you go through with this.

[betoney]

1 hour ago, texscottyd said:

I’m getting ready to head out for a ride, so in the interest of science I’ll make note of stock gearing rpm at 62 mph and 100 mph.    

From there, we can calculate (A) the difference a gearing change would make, and (B) the USD amount of my traffic fines.  

Scott.  I would definitely be interested in hearing your thoughts on the "feel" and responsiveness of the motor with stock gearing on level ground, 6th gear, dropping way down to the 3400-3600 rpm range.

[texscottyd]

1 hour ago, betoney said:

Scott.  I would definitely be interested in hearing your thoughts on the "feel" and responsiveness of the motor with stock gearing on level ground, 6th gear, dropping way down to the 3400-3600 rpm range.

It “feels” like you’re an incompetent putz who has no business riding a CP3-powered bike, in all honesty...   

So, interesting data points to share.  My stock-geared 2015 FJ goes 62 mph indicated (aka 100 kph) in all six gears.  Gear and rpm are as follows (remember that the FJ LCD tach works in rough-cut 200 rpm increments: 

1 - 10,800 

2 - 8,200

3 - 6,800 

4 - 5,600

5 - 5,000 

6 - 4,200 

Just the facts, ma’am.  That said, I can’t fathom going any taller on this gearing unless you routinely cruise in the 90+ mph range for extended periods.   

Your mileage may vary.  Discuss politely amongst yourselves. I’m now going to go ride some more...  

[betoney]

1 hour ago, texscottyd said:

It “feels” like you’re an incompetent putz who has no business riding a CP3-powered bike, in all honesty...   

So, interesting data points to share.  My stock-geared 2015 FJ goes 62 mph indicated (aka 100 kph) in all six gears.  Gear and rpm are as follows (remember that the FJ LCD tach works in rough-cut 200 rpm increments: 

1 - 10,800 

2 - 8,200

3 - 6,800 

4 - 5,600

5 - 5,000 

6 - 4,200 

Just the facts, ma’am.  That said, I can’t fathom going any taller on this gearing unless you routinely cruise in the 90+ mph range for extended periods.   

Your mileage may vary.  Discuss politely amongst yourselves. I’m now going to go ride some more...  

Scott, thanks so much for posting your "research" findings.  I would have done it myself but don't have stock gearing to accurately give factual results.

[texscottyd]

1 hour ago, betoney said:

Scott, thanks so much for posting your "research" findings.  I would have done it myself but don't have stock gearing to accurately give factual results.

A bit more research:  

- 20 mph comes in 1,200 rpm increments in sixth gear.  80 mph is 5,400 rpm, and 100 mph is 6,600 rpm.   Yes, this is real world test data. 

- It started to rain, so I took the direct freeway route home.  The last 40 miles I covered in light rain at an average cruise rate of about 85 mph, with numerous ventures up into the low-90s.  Perfectly comfortable, although the wind becomes more intrusive than the engine speed somewhere in the mid-90s.   Remember, I run a CalSci shorty screen on my FJ.  

So as expected, there isn’t a one-size-fits-all answer for gearing.  For me, I’ll stay with the stock ratio when it’s time for chain & sprocket replacements.   

[fddriver2]

On 7/26/2019 at 12:44 PM, dbeau said:

 It pretty much takes all the hooligan out of the bike

 

 

I'm out.... 😨

[wordsmith]

7 hours ago, texscottyd said:

I’m getting ready to head out for a ride, so in the interest of science I’ll make note of stock gearing rpm at 62 mph and 100 mph.    

From there, we can calculate (A) the difference a gearing change would make, and (B) the USD amount of my traffic fines.  

I will cheerfully contribute to your traffic fine, tex.   Will Monopoly money do?

[fddriver2]

1 hour ago, wordsmith said:

I will cheerfully contribute to your traffic fine, tex.   Will Monopoly money do?

I have some "Bunny Bucks". 

https://santadollars.com/bunny-bucks/