Torque and Max Speed

fjmartin · 10-06-2016, 12:17 PM

While cruising through this forum I've seen a lot of folks talking and doing changes to the front and rear gearing on the bike by replacing the 14T with a 13T and sometimes changing the rear of the bike to a 45T or 46 from the stock 44T. I found a website that shows the impact to speed and torque by making these changes along with what you will have to do with a chain. Pretty nice!
http://sprocketcalculator.com/

Weldangrind · 10-06-2016, 02:19 PM

Cool topic; thanks for the link.

It makes sense, since theoretically, you have more torque-carrying ability with lower gears. Old drag racers will tell you that a change to a car that increases trap speed is an increase in HP, while a decrease in ET is an increase in torque.

RedHawk47 · 10-07-2016, 01:46 AM

I believe that there have been posts that state that when they put a 13t on their RX3 that they got a higher top speed (which is counter intuitive).

This can happen because the RX3's relatively low power vs. the air resistance/drag does not allow max rpm before the drag exceeds the power available. By replacing the 14t with a 13t the engine is higher on the power curve when it reaches the 14t max speed and can go a few more mph before maxing out.

bogieboy · 10-07-2016, 05:57 AM

us kawasaki ke100 owneres see the same thing... drop your front from astock 15 down to a 13 and you gain 4-5 mph due to the engine actually being able to pull the gear instead of lugging it...

fjmartin · 10-07-2016, 02:11 PM

That would be really cool and maybe would offset the fact that I'm also doing a 45 on the rear. Can't wait to try it out but I'm waiting to change the cogs until I pull the wheels to change from the OEM rubber to the Shinko 244's I have for more offroad rides.

10-06-2016, 12:17 PM	#1
fjmartin Join Date: Sep 2016 Location: Redmond, WA. Posts: 534	Torque and Max Speed While cruising through this forum I've seen a lot of folks talking and doing changes to the front and rear gearing on the bike by replacing the 14T with a 13T and sometimes changing the rear of the bike to a 45T or 46 from the stock 44T. I found a website that shows the impact to speed and torque by making these changes along with what you will have to do with a chain. Pretty nice! http://sprocketcalculator.com/ __________________ 2017 BMW F800GS Adventure
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10-06-2016, 02:19 PM	#2
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Cool topic; thanks for the link. It makes sense, since theoretically, you have more torque-carrying ability with lower gears. Old drag racers will tell you that a change to a car that increases trap speed is an increase in HP, while a decrease in ET is an increase in torque. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
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10-07-2016, 01:46 AM	#3
RedHawk47 Join Date: Oct 2015 Location: Berthoud, CO Posts: 205	I believe that there have been posts that state that when they put a 13t on their RX3 that they got a higher top speed (which is counter intuitive). This can happen because the RX3's relatively low power vs. the air resistance/drag does not allow max rpm before the drag exceeds the power available. By replacing the 14t with a 13t the engine is higher on the power curve when it reaches the 14t max speed and can go a few more mph before maxing out. __________________ Dan CSC RX3 Cyclone, CSC TT250, Moto Guzzi V7 II, KLR650
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10-07-2016, 02:11 PM	#5
fjmartin Join Date: Sep 2016 Location: Redmond, WA. Posts: 534	That would be really cool and maybe would offset the fact that I'm also doing a 45 on the rear. Can't wait to try it out but I'm waiting to change the cogs until I pull the wheels to change from the OEM rubber to the Shinko 244's I have for more offroad rides. __________________ 2017 BMW F800GS Adventure
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10-07-2016, 05:57 AM	#4
bogieboy Join Date: May 2013 Location: finger lakes NY Posts: 2,042	us kawasaki ke100 owneres see the same thing... drop your front from astock 15 down to a 13 and you gain 4-5 mph due to the engine actually being able to pull the gear instead of lugging it...
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