re-gear for turnpike speeds? - Kawasaki KLR 650 Forum
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post #1 of 21 Old 10-01-2015, 11:46 AM Thread Starter
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Question re-gear for turnpike speeds?

Bought 2012 KLR. I will only use it as a street bike, never off road. With current gearing, by the time I hit 35 MPH, I am in 5th gear. So going 70 MPH seems to really strain the engine. What would be recommended in terms of new gears to make it easier to cruise at high speeds?
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post #2 of 21 Old 10-01-2015, 02:19 PM
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My son went to a 16 tooth front sprocket. He said that lowered his RPM by about 500 when he was at 70 mph.

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post #3 of 21 Old 10-01-2015, 04:05 PM
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I used a 16t front sprocket with the stock 43 rear for a few years. Highly recommended.

I'm back to 15t for trails and the slower roads I use now. I'll certainly use 16t again for long trips.


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post #4 of 21 Old 10-01-2015, 04:20 PM
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Originally Posted by acidman1968 View Post
My son went to a 16 tooth front sprocket. He said that lowered his RPM by about 500 when he was at 70 mph.
If my calculations are correct, changing to a 16-tooth front sprocket (from a 15-tooth one) will lower engine rpm by a factor of 15/16 at all speeds.

To each his/her own; I find stock gearing adequate for my own riding style and environment, YMMV.

Got some healthy "max speed" readings off my GPS receiver, after riding the WV, "Road to Nowhere" (US 33/WV 55, eastern end, between Moorefield and Wardensville). Again, YMMV!

Last edited by Damocles; 10-01-2015 at 04:30 PM.
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post #5 of 21 Old 10-01-2015, 07:53 PM
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I put the 16 tooth front on my 2008 and love it,it lowered my rpm 400-500. And don't forget if your speedo is like mine it's about 5mph slow. So if your speedo says 70 your probably only going 65. Ride safe on the big road!
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post #6 of 21 Old 10-01-2015, 08:13 PM
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If, at a given speed, with stock gearing, the engine turns 5,000 rpm then . . . changing to a 16-tooth front procket, the engine will turn 4687.5 rpm at the same given speed.

Or, I invoke a flawed calculation procedure and/or mathematical error. 312.5 rpm reduction at old 5,000 rpm ground speed.

Corrections welcomed.
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post #7 of 21 Old 10-02-2015, 10:16 AM
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Originally Posted by Damocles View Post
If, at a given speed, with stock gearing, the engine turns 5,000 rpm then . . . changing to a 16-tooth front procket, the engine will turn 4687.5 rpm at the same given speed.

Or, I invoke a flawed calculation procedure and/or mathematical error. 312.5 rpm reduction at old 5,000 rpm ground speed.

Corrections welcomed.
From 5,000 or so, to 4,700 or so?
Hardly seems worth the trouble. But maybe if you spent enough time at 5,000 or so rpms, it would be worth the trouble. Probably not for others.

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post #8 of 21 Old 10-02-2015, 04:27 PM
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Another way of looking at it is that in 5th gear, 4500 rpm is 65.4 mph with stock gearing and 69.8 mph with the 16t. At 5000 rpm those are 72.7 mph and 77.5 mph.

So if you're in traffic and want to run 5000 or fewer rpm then an extra tooth gives you about 4.8 mph. That's not enough to make a KLR fun in fast, close Connecticut traffic, but it'll help a lot through Albany or Akron or Anchorage.

At the other end putting along in traffic at 2000 rpm would be 10.2 mph or 10.8 mph.
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post #9 of 21 Old 10-02-2015, 04:59 PM
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Originally Posted by Grinnin View Post
Another way of looking at it is that in 5th gear, 4500 rpm is 65.4 mph with stock gearing and 69.8 mph with the 16t. At 5000 rpm those are 72.7 mph and 77.5 mph.

So if you're in traffic and want to run 5000 or fewer rpm then an extra tooth gives you about 4.8 mph. That's not enough to make a KLR fun in fast, close Connecticut traffic, but it'll help a lot through Albany or Akron or Anchorage.

At the other end putting along in traffic at 2000 rpm would be 10.2 mph or 10.8 mph.
Could you show your math, Grinnin?

In fairness, I'll show mine:

16/15 is the "overdrive" in final gear ratio a 16-tooth countershaft sprocket gives the stock KLR650 drivetrain.

Thus, from your stock speeds of 65.4 mph and 69.8, and 10.2 mph, I get:

16/15 X 65.4 mph = 69.76 mph

16/15 X 69.8 mph = 74.45 mph

16/15 X 10.2 mph = 10.88 mph

Your calculations at turnpike speeds yield higher mph than mine (and may be more accurate); just wondering why.

Last edited by Damocles; 10-02-2015 at 05:03 PM.
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post #10 of 21 Old 10-02-2015, 08:24 PM
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Forget the math

just put a 16t on front and your fine, on my 3rd klr and just came back from east coast on my new 2015 cruised all day at 75 to 80 fully loaded, if you run a 17 its too close to the case and any failure will destroy your case. Hope this helps first hand information.
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