I want to change my gearing - Revision history

Bokonon: /* Opinions on some gearing combinations */

2011-09-04T03:56:24Z

Opinions on some gearing combinations

← Older revision		Revision as of 23:56, 3 September 2011
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	:I had the 39 tooth rear on for a while and enjoyed "seventh gear" and 8000 rpm freeway cruising. However, this came at the expense of a serious lack of torque from a dead stop. If you lane split through traffic, then end up at a red light, when the light turns green you might find that the cars you just passed can make up all that ground while you're trying to get moving. It's both unsafe and humiliating at the same time.		:I had the 39 tooth rear on for a while and enjoyed "seventh gear" and 8000 rpm freeway cruising. However, this came at the expense of a serious lack of torque from a dead stop. If you lane split through traffic, then end up at a red light, when the light turns green you might find that the cars you just passed can make up all that ground while you're trying to get moving. It's both unsafe and humiliating at the same time.

	:Another drawback is that if you run 14/39 you'll run out of chain adjustment - the rear wheel is as far back as it can go and there is still a lot of chain slack. Installing the bigger 15T front to reduce the chain slack will make the gear ratio even taller. And my gas mileage did not go up significantly when on a 15/39 combo compare to the 14/45.		:Another drawback is that if you run 14/39 you'll run out of chain adjustment - the rear wheel is as far back as it can go and there is still a lot of chain slack. Installing the bigger 15T front to reduce the chain slack will make the gear ratio even taller. And my gas mileage did not go up significantly when on a 15/39 combo compare to the 15/45.

Bokonon: /* Opinions on some gearing combinations */

2011-09-03T17:10:29Z

Opinions on some gearing combinations

← Older revision		Revision as of 13:10, 3 September 2011
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	:When riding single I only felt the need to leave 6th if I was on a steep incline and traveling at less than 50 mph. When taking one of my offspring for a ride, 5th is sometimes needed to maintain highway speeds if heading into a stiff headwind or going up an incline. In 4th the bike will accelerate smartly up steep inclines. Just keep in mind that close ratio transmissions are meant to be shifted.		:When riding single I only felt the need to leave 6th if I was on a steep incline and traveling at less than 50 mph. When taking one of my offspring for a ride, 5th is sometimes needed to maintain highway speeds if heading into a stiff headwind or going up an incline. In 4th the bike will accelerate smartly up steep inclines. Just keep in mind that close ratio transmissions are meant to be shifted.

			'''Anything/39'''

			*In short: You don't need a 39T; consider a 41 as the smallest option.

			:I had the 39 tooth rear on for a while and enjoyed "seventh gear" and 8000 rpm freeway cruising. However, this came at the expense of a serious lack of torque from a dead stop. If you lane split through traffic, then end up at a red light, when the light turns green you might find that the cars you just passed can make up all that ground while you're trying to get moving. It's both unsafe and humiliating at the same time.

			:Another drawback is that if you run 14/39 you'll run out of chain adjustment - the rear wheel is as far back as it can go and there is still a lot of chain slack. Installing the bigger 15T front to reduce the chain slack will make the gear ratio even taller. And my gas mileage did not go up significantly when on a 15/39 combo compare to the 14/45.

Bokonon: /* What drive ratios are attainable? */

2011-09-03T16:36:34Z

What drive ratios are attainable?

← Older revision		Revision as of 12:36, 3 September 2011
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	15/44 Running a smaller rear reduces rpm at a given speed.<br>		15/44 Running a smaller rear reduces rpm at a given speed.<br>
	15/42 Reduces rpm even further.<br>		15/42 Reduces rpm even further.<br>
	15/41 For flatlanders only, although you can always kick it down into fifth if you have to.		15/41 For flatlanders only, although you can always kick it down into fifth if you have to.

			[http://www.dropbears.com/u/utilities/sprocket.htm Gear ratio Chart] for most motorcycle sprocket ratios.

	====Opinions on some gearing combinations====		====Opinions on some gearing combinations====

Bokonon: /* Opinions on some gearing combinations */

2011-09-03T16:36:01Z

Opinions on some gearing combinations

← Older revision		Revision as of 12:36, 3 September 2011
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	:When riding single I only felt the need to leave 6th if I was on a steep incline and traveling at less than 50 mph. When taking one of my offspring for a ride, 5th is sometimes needed to maintain highway speeds if heading into a stiff headwind or going up an incline. In 4th the bike will accelerate smartly up steep inclines. Just keep in mind that close ratio transmissions are meant to be shifted.		:When riding single I only felt the need to leave 6th if I was on a steep incline and traveling at less than 50 mph. When taking one of my offspring for a ride, 5th is sometimes needed to maintain highway speeds if heading into a stiff headwind or going up an incline. In 4th the bike will accelerate smartly up steep inclines. Just keep in mind that close ratio transmissions are meant to be shifted.


	~~'''Some gear configurations and their respective final drive ratios:'''~~

	~~13/47 = .27660<br>~~
	~~13/46 = .28261<br>~~
	~~13/45 = .28889<br>~~
	~~13/42 = .30952<br>~~
	~~14/42 = .33333<br>~~
	~~14/45 = .31111<br>~~
	~~14/46 = .30435<br>~~
	~~14/47 = .29787<br>~~
	~~15/42 = .35714<br>~~
	~~15/45 = .33333<br>~~
	~~15/46 = .32608<br>~~
	~~15/47 = .31915~~

	~~If you want to do the math yourself, [http://www.motorcycleanchor.com/motorcycle/how_to/mc_sprocketmath.html clicky].~~

	~~[http://www.dropbears.com/u/utilities/sprocket.htm Chart] for most motorcycle sprocket ratios.~~

Bokonon at 07:17, 3 August 2010

2010-08-03T07:17:06Z

← Older revision		Revision as of 03:17, 3 August 2010
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	====How do I change my gearing?====		====How do I change my gearing?====

	For about $50 you can get some new sprockets for the Ninja 250 that will lower the ~~RPM's~~ at highway speeds (which equates to better mileage). On a stock Ninja the front sprocket has 14 teeth and the rear sprocket has 45 teeth.		For about $60 you can get some new sprockets for the Ninja 250 that will lower the rpm at highway speeds (which equates to better mileage). On a stock Ninja the front sprocket has 14 teeth and the rear sprocket has 45 teeth.

	The first mod done by many people is replacing the front with a 15-tooth sprocket. If that doesn't drop your rpm's enough for you, you can try a 44-tooth or a 42-tooth rear.		The first mod done by many people is replacing the front with a 15-tooth sprocket. If that doesn't drop your rpm enough for you, you can try a 44-tooth or a 42-tooth rear.

	There are a couple other options. The JT catalog lists a 16-tooth front. '''Don't Do It.''' It will cause clearance issues. It's better to step down in the rear than go any bigger than a 15 up front. You can use a 41-tooth in the rear if you do a lot of commuting and don't have to worry about going up hills. Several members on the board have a 15/41 combo, but they are shooting for gas mileage~~, plus they~~ live in flat places like North Texas.		There are a couple other options. The JT catalog lists a 16-tooth front. '''Don't Do It.''' It will cause clearance issues. It's better to step down in the rear than go any bigger than a 15 up front. You can use a 41-tooth in the rear if you do a lot of commuting and don't have to worry about going up hills. Several members on the board have a 15/41 combo, but they are shooting for gas mileage and live in flat places like North Texas.

	See the [[What replacement chain/sprockets should I consider?\|chain & sprockets page]] for information on available products.		See the [[What replacement chain/sprockets should I consider?\|chain & sprockets page]] for information on available products.
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	====Gearing for the highway====		====Gearing for the highway====

	Duke: The F-model 250 (88-07) runs ~~the~~ best on the interstate between 8k and ~~9.5k~~. You can [[Speed @ rpm calculator\|play around]] with the gearing until you get this ~~RPM~~ and your desired speed to match. Personally, I like ~~70MPH~~ at 8k, which allows enough torque in reserve to pick up the speed if necessary.		Duke: The F-model 250 (88-07) runs best on the interstate between 8000 and 9500. You can [[Speed @ rpm calculator\|play around]] with the gearing until you get this rpm and your desired speed to match. Personally, I like 70 mph at 8000, which allows enough torque in reserve to pick up the speed if necessary.

	====Does installing a new front sprocket make a significant difference?====		====Does installing a new front sprocket make a significant difference?====
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	So, the twist on throttle has to be a little greater now to get a satisfying 0-60 run, but the high-speed cruising is noticeably improved. Until you get used to it, you may think you're in sixth at times when you're really still in fifth. This mod also makes first gear seem more useful.		So, the twist on throttle has to be a little greater now to get a satisfying 0-60 run, but the high-speed cruising is noticeably improved. Until you get used to it, you may think you're in sixth at times when you're really still in fifth. This mod also makes first gear seem more useful.

	[[How do I change the front sprocket?\|~~It isn't~~ too difficult a task]]: loosen the rear wheel, remove the countershaft housing, remove the 14-tooth sprocket, put the new sprocket in, torque the retainer bolts, replace housing, set correct tension to chain ~~and~~ torque rear wheel, and clean/wax the chain. The sprocket switch takes about an hour overall~~; just follow the process as outlined in the service manual~~. Popping the old sprocket off is a snap; putting the new one on takes a bit because the countershaft teeth are cut to very close tolerances. Cost= $15.		It isn't [[How do I change the front sprocket?\|too difficult a task]]: loosen the rear wheel, remove the countershaft housing, remove the 14-tooth sprocket, put the new sprocket in, torque the retainer bolts, replace housing, set correct tension to chain, torque rear wheel, and clean/wax the chain. The sprocket switch takes about an hour overall. Popping the old sprocket off is a snap; putting the new one on takes a bit because the countershaft teeth are cut to very close tolerances. Cost = $15-20.

	====Is there any advantage to installing a smaller front sprocket?====		====Is there any advantage to installing a smaller front sprocket?====
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	15/45 Replacing the stock 14-tooth front.<br>		15/45 Replacing the stock 14-tooth front.<br>
	15/44 Running a smaller rear reduces ~~rpms~~ at a given speed.<br>		15/44 Running a smaller rear reduces rpm at a given speed.<br>
	15/42 Reduces ~~rpms~~ even further.<br>		15/42 Reduces rpm even further.<br>
	15/41 For flatlanders only, although you can always kick it down into fifth if you have to.		15/41 For flatlanders only, although you can always kick it down into fifth if you have to.

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	'''15/44 vs 15/45'''		'''15/44 vs 15/45'''

	*I find the 15x44 is a good compromise, and it's perfect for 70-80mph riding. I have 2 bikes - One is 15x45 and the other 15x44. The 15x45 is (very marginally) quicker through the gears, pulls harder in top gear at terminal speed / has a higher top speed, but the trade-off is higher ~~RPM~~ on the highway. Either works just fine for me - I run the higher gear on the bike which I use for touring. However, I've also done local club rides (all 600cc+) in the twisties using the 15x44 bike and had no problems whatsoever (the trick to club rides on an underpowered bike is to stay as close to the front as possible to avoid the inchworm effect).		*I find the 15x44 is a good compromise, and it's perfect for 70-80mph riding. I have 2 bikes - One is 15x45 and the other 15x44. The 15x45 is (very marginally) quicker through the gears, pulls harder in top gear at terminal speed / has a higher top speed, but the trade-off is higher rpm on the highway. Either works just fine for me. I run the higher gear on the bike which I use for touring. However, I've also done local club rides (all 600cc+) in the twisties using the 15x44 bike and had no problems whatsoever (the trick to club rides on an underpowered bike is to stay as close to the front as possible to avoid the inchworm effect).

	'''15/42'''		'''15/42'''
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	*This works fine in twisties and on a track, although I do prefer 15/45 for that kind of riding. 15/42 can handle performance riding, too. You just have to keep the revs up. I'd imagine 15/41 is almost the same, but to me, 15/42 is enough. I wouldn't go any lower on the back.		*This works fine in twisties and on a track, although I do prefer 15/45 for that kind of riding. 15/42 can handle performance riding, too. You just have to keep the revs up. I'd imagine 15/41 is almost the same, but to me, 15/42 is enough. I wouldn't go any lower on the back.

	*I ~~ran~~ a 15/42..~~..didn~~'~~t like~~ it~~. I liked~~ the ~~longer gears around town~~, but on the ~~highway my mileage seemed to be worse than~~ the ~~15/45~~.		*I had changed my front sprocket to a 15, then about a month later changed the back to a 42. For me it was not good. I'm not sure if it is mostly my weight (~210) plus the weight and wind resistance of my loaded bike and touring windshield, but when I traveled long distance, loaded for camping and tools and pushing the bike for speed, I was running WOT all day and getting mpg in the 40's. That was the reason I missed on my Iron Butt Bun Burner Gold attempt: too many gas stops!

	:~~But~~, I ~~ran that combo for quite a while for most of my long trips~~. ~~Without quantitative info I can only say "I didn~~'t ~~like~~ it ~~as much as~~ the 15/~~45"~~.		:I later changed my rear sprocket back to the original, so I am now running 15/45. Maybe if you weigh less, don't load down so heavily, keep it a bit slower (less than 75-80) and miss the Midwestern high winds and hills, it will work better. Others have sworn by the 15/41-42. Definitely YMMV.

	~~:Screaming rpms don't bother me if they're 2-3k below redline......~~		*15/42 works great for me, but I'm only 150 lbs plus or minus. Commuting mpg (65-70) didn't go up noticeably from the 15/45, although it ''did'' go up noticeably when I went to the 15T front sprocket first.

	*I had changed my front sprocket to a 15, then about a month later changed the back to a 42. For me it was not good. I'm not sure if it is mostly my weight (~210) plus the weight and wind resistance of my loaded bike and touring windshield, but when I traveled long distance loaded for camping and tools, pushing the bike for speed, I was running WOT all day, and getting mpg in the 40's. That was the reason I missed on my Iron Butt Bun Burner Gold attempt: too many gas stops!

	~~:I later changed back my rear sprocket to the original, so I am now running 15/45.~~

	:Maybe if you weigh less, don't load down so heavily, keep it a bit slower (less than 75-80) and miss the mid-western high winds and hills, it will work better. Others have sworn by the 15/41-42. Definitely, YMMV!

	*15/42 works great for me, but I'm only 150# plus or minus. Commuting mpg (65-70) didn't go up noticeably from the 15/45, ~~though. (It~~ did go up noticeably when I went to the 15T front sprocket first~~, though~~.)

	'''15/41'''		'''15/41'''

	*The 15-41 results roughly in 1000 ~~RPM~~ per 10 ~~MPH~~ in 6th. The engine is doing about 5750 ~~RPM~~ at an indicated 60 ~~MPH~~ and spinning at about 6900 ~~RPM~~ at an indicated 70 ~~MPH~~.		*The 15-41 results roughly in 1000 rpm per 10 mph in 6th. The engine is doing about 5750 rpm at an indicated 60 mph and spinning at about 6900 at an indicated 70 mph.

	:The 250 engine has plenty of power, but is a small “peaky” engine that has a narrow ~~power band~~ compared to a big V-twin or an automobile engine. You just may need to spend a little more time in 5th than a stock bike if you live in hilly country or are battling a stiff ~~head wind~~ at highway speeds. Passing can be done comfortably in 4th or 5th. I would look at the 6th gear as an "overdrive".		:The 250 engine has plenty of power, but is a small “peaky” engine that has a narrow powerband compared to a big V-twin or an automobile engine. You just may need to spend a little more time in 5th than a stock bike if you live in hilly country or are battling a stiff headwind at highway speeds. Passing can be done comfortably in 4th or 5th. I would look at the 6th gear as an "overdrive".

	:When riding single I only felt the need to leave 6th if I was on a steep incline and traveling at less than 50 ~~MPH~~. When taking one of my offspring for a ride 5th is sometimes needed to maintain highway speeds if heading into a stiff headwind or going up an incline. In 4th the bike will accelerate smartly up steep inclines. Just keep in mind that close ratio transmissions are meant to be shifted.		:When riding single I only felt the need to leave 6th if I was on a steep incline and traveling at less than 50 mph. When taking one of my offspring for a ride, 5th is sometimes needed to maintain highway speeds if heading into a stiff headwind or going up an incline. In 4th the bike will accelerate smartly up steep inclines. Just keep in mind that close ratio transmissions are meant to be shifted.


	'''~~Here are some~~ gear configurations and their respective final drive ratios:'''		'''Some gear configurations and their respective final drive ratios:'''

	13/47 = .27660<br>		13/47 = .27660<br>

Bokonon: /* Opinions on some gearing combinations */

2010-04-19T04:21:05Z

Opinions on some gearing combinations

← Older revision		Revision as of 00:21, 19 April 2010
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	====Opinions on some gearing combinations====		====Opinions on some gearing combinations====

			You can check the [[Speed @ rpm calculator\|speed calculator]] for more information on speed, rpm, and gearing.

	'''15/44 vs 15/45'''		'''15/44 vs 15/45'''
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	'''15/41'''		'''15/41'''

	*The 15-41 results roughly in 1000 RPM per 10 MPH in 6th. The engine is doing about 5750 RPM at an indicated 60 MPH and spinning at about 6900 RPM at an indicated 70 MPH~~. You can check the [[Speed @ rpm calculator\|speed calculator]] for more information on speed, rpm's, and gearing~~.		*The 15-41 results roughly in 1000 RPM per 10 MPH in 6th. The engine is doing about 5750 RPM at an indicated 60 MPH and spinning at about 6900 RPM at an indicated 70 MPH.

	:The 250 engine has plenty of power, but is a small “peaky” engine that has a narrow power band compared to a big V-twin or an automobile engine. You just may need to spend a little more time in 5th than a stock bike if you live in hilly country or are battling a stiff head wind at highway speeds. Passing can be done comfortably in 4th or 5th. I would look at the 6th gear as an "overdrive".		:The 250 engine has plenty of power, but is a small “peaky” engine that has a narrow power band compared to a big V-twin or an automobile engine. You just may need to spend a little more time in 5th than a stock bike if you live in hilly country or are battling a stiff head wind at highway speeds. Passing can be done comfortably in 4th or 5th. I would look at the 6th gear as an "overdrive".

Bokonon: /* Is there any advantage to installing a smaller front sprocket? */

2010-04-18T07:46:20Z

Is there any advantage to installing a smaller front sprocket?

← Older revision		Revision as of 03:46, 18 April 2010
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	Some track racers have used a 13-tooth front for a little while. It makes it harder to keep lube on the chain because the chain is turning a tighter corner. Also, the chain eats into the keeper, even if you file it waaaay back.		Some track racers have used a 13-tooth front for a little while. It makes it harder to keep lube on the chain because the chain is turning a tighter corner. Also, the chain eats into the keeper, even if you file it waaaay back.

	The only advantage is ~~a) lower first~~ gear ~~b) puts~~ ratios closer together. Aside from that, it's all the same because you end up in 3rd when you would normally be in 2nd... etc.		The only advantage is it puts the gear ratios closer together. Aside from that, it's all the same because you end up in 3rd when you would normally be in 2nd... etc.

	====What drive ratios are attainable?====		====What drive ratios are attainable?====

Bokonon: /* Does installing a new front sprocket make a significant difference? */

2009-08-14T15:56:01Z

Does installing a new front sprocket make a significant difference?

← Older revision		Revision as of 11:56, 14 August 2009
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	====Does installing a new front sprocket make a significant difference?====		====Does installing a new front sprocket make a significant difference?====

	Changing the countershaft gear from a 14 to 15-tooth sprocket is the most common gearing mod, and it does make quite a difference. At first the bike might seem sluggish after the change; the torque you were used to isn't really there. As you ride around town for awhile, it may seem that the bike isn't revving as quickly as it used to~~- this~~ of course is to be expected, since the countershaft is now working harder. But the change in acceleration is really marginal; though the bike now takes longer to rev through the gears, each gear is putting out 7% more travel per revolution.		Changing the countershaft gear from a 14 to 15-tooth sprocket is the most common gearing mod, and it does make quite a difference. At first the bike might seem sluggish after the change; the torque you were used to isn't really there. As you ride around town for awhile, it may seem that the bike isn't revving as quickly as it used to. This of course is to be expected, since the countershaft is now working harder. But the change in acceleration is really marginal; though the bike now takes longer to rev through the gears, each gear is putting out 7% more travel per revolution.

	So the twist on throttle has to be a little greater now to get a satisfying 0-60 run, but the high-speed cruising is ~~noticably~~ improved. Until you get used to it, you may think you're in sixth at times, when you're really still in fifth. This mod also makes first gear seem more useful.		So, the twist on throttle has to be a little greater now to get a satisfying 0-60 run, but the high-speed cruising is noticeably improved. Until you get used to it, you may think you're in sixth at times when you're really still in fifth. This mod also makes first gear seem more useful.

	[[How do I change the front sprocket?\|It isn't too difficult a task]]: loosen the rear wheel, remove the countershaft housing, remove the 14-tooth sprocket, put the new sprocket in, torque the retainer bolts, replace housing, set correct tension to chain and torque rear wheel, and clean/wax the chain. The sprocket switch takes about an hour overall; just follow the process as outlined in the service manual. Popping the old sprocket off is a snap; putting the new one on takes a bit because the countershaft teeth are cut to very close tolerances. Cost= $15.		[[How do I change the front sprocket?\|It isn't too difficult a task]]: loosen the rear wheel, remove the countershaft housing, remove the 14-tooth sprocket, put the new sprocket in, torque the retainer bolts, replace housing, set correct tension to chain and torque rear wheel, and clean/wax the chain. The sprocket switch takes about an hour overall; just follow the process as outlined in the service manual. Popping the old sprocket off is a snap; putting the new one on takes a bit because the countershaft teeth are cut to very close tolerances. Cost= $15.

Bokonon at 15:54, 14 August 2009

2009-08-14T15:54:19Z

← Older revision		Revision as of 11:54, 14 August 2009
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	See the [[What replacement chain/sprockets should I consider?\|chain & sprockets page]] for information on available products.		See the [[What replacement chain/sprockets should I consider?\|chain & sprockets page]] for information on available products.

	~~[http://forums.ninja250.org/viewtopic.php?p=127340#127340 FDT: Chains & Sprockets]~~

	====Gearing for the highway====		====Gearing for the highway====

Bokonon: /* How do I change my gearing? */

2009-08-14T15:53:26Z

How do I change my gearing?

← Older revision		Revision as of 11:53, 14 August 2009
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	The first mod done by many people is replacing the front with a 15-tooth sprocket. If that doesn't drop your rpm's enough for you, you can try a 44-tooth or a 42-tooth rear.		The first mod done by many people is replacing the front with a 15-tooth sprocket. If that doesn't drop your rpm's enough for you, you can try a 44-tooth or a 42-tooth rear.

	There are a couple other options. The JT catalog lists a 16-tooth front. '''Don't Do It.''' It will cause clearance issues. It's better to step down in the rear than go any bigger than a 15 up front. You can use a 41 -tooth in the rear if you do lot of commuting and don't have to worry about going up hills. Several members on the board have a 15/41 combo, but they are shooting for gas mileage, plus they live in flat places like North Texas.		There are a couple other options. The JT catalog lists a 16-tooth front. '''Don't Do It.''' It will cause clearance issues. It's better to step down in the rear than go any bigger than a 15 up front. You can use a 41-tooth in the rear if you do a lot of commuting and don't have to worry about going up hills. Several members on the board have a 15/41 combo, but they are shooting for gas mileage, plus they live in flat places like North Texas.

	See the [[What replacement chain/sprockets should I consider?\|chain & sprockets page]] for information on available products.		See the [[What replacement chain/sprockets should I consider?\|chain & sprockets page]] for information on available products.