Larger tires and re-gearing

TheGageinator · 12-01-2014, 10:10 PM

I want to get some larger rear tires for my atv.

current specs are as follows
tire size 20inches
12 tooth front sprocket
40 tooth rear sprocket.

if my math is correct, i will need to use a 11.5tooth front sprocket with 23inch rear tires to maintain my original gearing.

since 11.5 sprockets do not exist, i would be more than happy to use 11 tooth front sprocket to gain some extra low end torque

here is the formula i came up with

F=front sprocket
R= rear sprocket
T= tire size

(F/T)T= figurative number

(12/40)20= 6.66

to find out what front sprocket i need to retain ratio/figurative number with larger 23 inch tires

(F/40)23=6.66

(F/40)=0.2895652174

F=11.5826 tooth front sprocket
rounded to 11tooth

does all this make sense?

im wanting to get these tires in 23x10x10 rear. all my riding is offroad. some mud and soft terrain. trails
http://www.itptires.com/tires/utility-atv/mud-lite-at

Weldangrind · 12-01-2014, 10:55 PM

I recommend that you stick with the 12 tooth, since anything less is hard on the chain.

Those tires look like they would also work well in sand.

TheGageinator · 12-01-2014, 11:10 PM

is the rear sprocket easy to come by in different sizes? i will have to find a larger one then. i did not think about the chain wear... the 12 tooth is quite small already.

Weldangrind · 12-01-2014, 11:18 PM

No, it's not easy to find different size rear sprockets. That said, the stock sprockets are poor, because the center hole is not properly centered.

If you had access to a lathe, you could trim the stock sprocket down and use it as a mount for a new sprocket. An offset sprocket could be made to work with a little effort.

Another option is a custom sprocket.

katoranger · 12-02-2014, 10:25 AM

Does it feel like it is geared to high currently? Staying with the 12T might be the answer. You may also want to consider using the 22" tire instead of the 23" I have 22" tires on the buggy. They do fine in most conditions. We can ride in 6 inches of snow with two on the buggy and two on a sled behind. It sp

You will likely want to install taller/more aggressive fronts also. The added grip of those rears will cause the front to push in turns. Those stock tires don't perform well at all.

Weld knows more about the sprockets. You may also think about switching the whole axle since it is bent for something more common.

TheGageinator · 12-03-2014, 05:50 PM

interesting idea about swapping the entire rear axle assembly. are there any know swaps? i can weld and such if need be

katoranger · 12-04-2014, 10:56 AM

I am not sure about a common swap, but I would look at rear axles from a honda or yamaha. Something that has sprockets available. Might even be an idea to swap the whole swingarm.

Weldangrind · 12-04-2014, 10:57 AM

I see that as the simplest way, although it will likely bring a significant challenge.

katoranger · 12-04-2014, 02:53 PM

I know that you are already planning to buy a replacement axle. I don't know if you can find an axle that is close to your current setup. Chinese tend to copy instead of design their own.

Buggy and go kart axles also. Might be able to find a sprocket here too.
http://www.bmikarts.com/Axles_c_194.html

TheGageinator · 12-06-2014, 12:33 PM

The people at KandiUSA have not been any help. I guess i may just have to take apart the axle and start taking measurements...

Dave_D · 12-07-2014, 01:33 AM

I went from 19" tires to 22" on my Gio dident touch gearing and it seems ok
Results may vary

Dave

TheGageinator · 12-10-2014, 10:20 AM

i got a response back from Kandi! the axle they have is as follows 34 is the number of splines in the middle (for the disc) 24 at both end (for the hub) Your total with shipping ($21.77) is $141.77 i need to check out my axle and make sujre it will fit. thats alot of $$ for a dumb piece of metal though...

Weldangrind · 12-10-2014, 11:28 AM

To replace the bent axle on your SunL? Maybe Humanbeing can help you find on for less on Taobao, if you're not in a hurry. After you confirm the axle specs, let us know.

TheGageinator · 12-10-2014, 05:42 PM

yes that is correct. i hate to spend that much when i only gave $400 for the whole unit.... ive been pretty busy but as soon as i am able to measure the axle ill update

Weldangrind · 12-10-2014, 11:35 PM

You don't want to try straightening it? That would be near free.

12-01-2014, 10:10 PM	#1
TheGageinator Join Date: Jun 2014 Posts: 143	Larger tires and re-gearing I want to get some larger rear tires for my atv. current specs are as follows tire size 20inches 12 tooth front sprocket 40 tooth rear sprocket. if my math is correct, i will need to use a 11.5tooth front sprocket with 23inch rear tires to maintain my original gearing. since 11.5 sprockets do not exist, i would be more than happy to use 11 tooth front sprocket to gain some extra low end torque here is the formula i came up with F=front sprocket R= rear sprocket T= tire size (F/T)T= figurative number (12/40)20= 6.66 to find out what front sprocket i need to retain ratio/figurative number with larger 23 inch tires (F/40)23=6.66 (F/40)=0.2895652174 F=11.5826 tooth front sprocket rounded to 11tooth does all this make sense? im wanting to get these tires in 23x10x10 rear. all my riding is offroad. some mud and soft terrain. trails http://www.itptires.com/tires/utility-atv/mud-lite-at
	0

12-01-2014, 10:55 PM	#2
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	I recommend that you stick with the 12 tooth, since anything less is hard on the chain. Those tires look like they would also work well in sand. __________________ 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
	0

12-01-2014, 11:18 PM	#4
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	No, it's not easy to find different size rear sprockets. That said, the stock sprockets are poor, because the center hole is not properly centered. If you had access to a lathe, you could trim the stock sprocket down and use it as a mount for a new sprocket. An offset sprocket could be made to work with a little effort. Another option is a custom sprocket. __________________ 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
	0

12-02-2014, 10:25 AM	#5
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	Does it feel like it is geared to high currently? Staying with the 12T might be the answer. You may also want to consider using the 22" tire instead of the 23" I have 22" tires on the buggy. They do fine in most conditions. We can ride in 6 inches of snow with two on the buggy and two on a sled behind. It sp You will likely want to install taller/more aggressive fronts also. The added grip of those rears will cause the front to push in turns. Those stock tires don't perform well at all. Weld knows more about the sprockets. You may also think about switching the whole axle since it is bent for something more common. __________________ You meet the nicest people on a Honda Clone.
	0

12-04-2014, 10:56 AM	#7
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	I am not sure about a common swap, but I would look at rear axles from a honda or yamaha. Something that has sprockets available. Might even be an idea to swap the whole swingarm. __________________ You meet the nicest people on a Honda Clone.
	0

12-01-2014, 11:10 PM	#3
TheGageinator Join Date: Jun 2014 Posts: 143	is the rear sprocket easy to come by in different sizes? i will have to find a larger one then. i did not think about the chain wear... the 12 tooth is quite small already.
	0

12-03-2014, 05:50 PM	#6
TheGageinator Join Date: Jun 2014 Posts: 143	interesting idea about swapping the entire rear axle assembly. are there any know swaps? i can weld and such if need be
	0

12-04-2014, 10:57 AM	#8
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	I see that as the simplest way, although it will likely bring a significant challenge. __________________ 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
	0

12-04-2014, 02:53 PM	#9
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	I know that you are already planning to buy a replacement axle. I don't know if you can find an axle that is close to your current setup. Chinese tend to copy instead of design their own. Buggy and go kart axles also. Might be able to find a sprocket here too. http://www.bmikarts.com/Axles_c_194.html __________________ You meet the nicest people on a Honda Clone.
	0

12-06-2014, 12:33 PM	#10
TheGageinator Join Date: Jun 2014 Posts: 143	The people at KandiUSA have not been any help. I guess i may just have to take apart the axle and start taking measurements...
	0

12-07-2014, 01:33 AM	#11
Dave_D Join Date: May 2014 Location: Vancouver Island BC Posts: 264	I went from 19" tires to 22" on my Gio dident touch gearing and it seems ok Results may vary Dave
	0

12-10-2014, 10:20 AM	#12
TheGageinator Join Date: Jun 2014 Posts: 143	i got a response back from Kandi! the axle they have is as follows 34 is the number of splines in the middle (for the disc) 24 at both end (for the hub) Your total with shipping ($21.77) is $141.77 i need to check out my axle and make sujre it will fit. thats alot of $$ for a dumb piece of metal though...
	0

12-10-2014, 11:28 AM	#13
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	To replace the bent axle on your SunL? Maybe Humanbeing can help you find on for less on Taobao, if you're not in a hurry. After you confirm the axle specs, let us know. __________________ 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
	0

12-10-2014, 05:42 PM	#14
TheGageinator Join Date: Jun 2014 Posts: 143	yes that is correct. i hate to spend that much when i only gave $400 for the whole unit.... ive been pretty busy but as soon as i am able to measure the axle ill update
	0

12-10-2014, 11:35 PM	#15
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	You don't want to try straightening it? That would be near free. __________________ 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
	0