sprockets again

[Andi]

Anybody know what difference there is between sprocket size front/rear combination, besides how and whether it fits on the bike?

For example my LF200GY-5 has a 17/46 set up = a ratio of 2.7

without nickel and diming a 12/32 set up would give me about the same, so would an 11/30 set up etc ...... you get my point.

I guess a larger diameter sprocket in the front maybe a little stronger and easier and smother for the chain to go around.

I would probably look to go to a 520 chain size once this is worn out. In order to then make the suitable 520 sized sprocket fit (especially in the front) I would have to reduce the amount of teeth, since the 520 sized teeth are further apart, therefore making the overall diameter bigger with the same number of teeth. The final gear ratio would then need to be adjusted by the rear sprocket.

[blimpman]

I have all the parts for the 520 chain conversion for my Lifan. I have a 35 T on the back and two sprockets available for the front .... a 12T and a 13T.

Gonna install the 12T first and see what it is like.

Original ratio 46/17 = 2.705

first new 35/13 = 2.69 ( identical in my book...)
second new 35/12 = 2.91 ( a little bit different but close )

Bruce ( EJCYCLES ) at Endless Journey Cycles found all the parts for me and if you call or PM him he can set you up with a kit. ( 2 sprockets and a good chain ) He is good at researching these things.

NOTE: I originally started with a 17T front and found out that there was not enough room for the chain and it hit the case. The sprocket was the same diameter as stock but the chain is much bigger and there was not enough room around the sprocket.

Originally Posted by Andi

Anybody know what difference there is between sprocket size front/rear combination, besides how and whether it fits on the bike?

For example my LF200GY-5 has a 17/46 set up = a ratio of 2.7

without nickel and diming a 12/32 set up would give me about the same, so would an 11/30 set up etc ...... you get my point.

I guess a larger diameter sprocket in the front maybe a little stronger and easier and smother for the chain to go around.

I would probably look to go to a 520 chain size once this is worn out. In order to then make the suitable 520 sized sprocket fit (especially in the front) I would have to reduce the amount of teeth, since the 520 sized teeth are further apart, therefore making the overall diameter bigger with the same number of teeth. The final gear ratio would then need to be adjusted by the rear sprocket.

[Andi]

So the 12 and 13 front sprocket will fit without any problems?

The 35/13 will almost equal stock performance, but the 35/12 will be more offroad torque and less top end!

I'm actually considering to reduce the ratio to get a little more top end, until I get some old on the bike. I will more use it for commuting and pleasure trips rather then off road.

I havent really looked for many sources, but browsing the "JT Sprocket" site was quite informative. They post diagrams with all the dimensions, the teeth available and the brand of bikes they will work on. Using Chinariders comparison chart, it wasn't to difficult to match up a proper conversion. Following is their link:

http://www.jtsprockets.com/

I found another handy link, an excel workseet which calculates the road speed based on the engine rpm and the sprocket sizes etc. Also provides the required chain links needed.

www.4strokes.com/tech/gearing_calc.xls

[fatboy250]

Good stuff!! If you would like to share your final findings and list it in the Parts Thread that would be great.

Jason

[blimpman]

Originally Posted by Andi

So the 12 and 13 front sprocket will fit without any problems?

Yup... either one will.

[ejcycles]

Hi All

Blimpman wrote: He is good at researching these things.

Yep and I figured wrong the first time :oops: I ordered a 15 tooth front sprocket and it was too big {diameter} with the chain on it, to fit on the countershaft and between the case. Good S.R.E. and Further research showed still quite a few sprockets that could have been close. I found a front sprocket that has a tapper/dip manufactured into it. I wanted to keep the width of the front sprocket the same as the 428 sprocket so the 520 front sprocket wouldn't wobble as much on the countershaft. {The 428 width is about 1.0mm wider than a 520.} Well I found everything needed to correctly fit the 520 chain & sprockets to these bikes. The only thing that I'm not sure of is if all of the Rear Wheel Hubs are the same. I will be posting all of the sprocket sizes, ratio's, rear sprocket hole diameter and bolt width {for A. Lifan/Lifan rear sprockets} by or sometime this weekend.

Bruce

[fatboy250]

Bruce,
Based on your and my experience with the rear spokes, I have a sneaky suspicion that the hubs are the same for the Lifan and Roketa (either disc or drum brake)

Good work on the research!! I'm sure there will be lots of interest from many to come when they finally get tired of adjusting the ever-stretching 428 chains. Dad and I usually adjust ours about every 2 weeks.

Jason

[sheadouglas]

This is the signal for me that it's time to tighten up the chain!


I'm just jokin, OK no I'm not

[madmaximum]

Looks like you may be at the end of your adjusting. Time to remove a link!

[fatboy250]

Originally Posted by madmaximum

Looks like you may be at the end of your adjusting. Time to remove a link!

That's kinda what I was thinking...WOW!

[ejcycles]

Hey Shea

Question....do you lube/oil that chain? It looks dry as can be, it helps with the stretching along with adjustment. Not knocking you I know Tom went over it with ya. The chain just looks really dry.

Bruce

[blimpman]

New sprockets installed along with the new 520 chain. I have a 12T on the front with 35T on the back. I also have a 13T that I'll try later. Took it for a spin and gearing is now better for a trail bike. Granny gear first and 5th will give 50mph tops. The drive train felt alot smoother but maybe that is my imagination...

This change is going to be perfect for trails that I am gonna ride. It should be much better on hills too. I still have to get the bike to fit me better with taller handlebars so standing on the pegs is more comfortable.

[sheadouglas]

Originally Posted by ejcycles

Hey Shea

Question....do you lube/oil that chain? It looks dry as can be, it helps with the stretching along with adjustment. Not knocking you I know Tom went over it with ya. The chain just looks really dry.

Bruce

Yeah, I do periodically. I dont do it all the time though. I just put a little motor oil on it. It just seems like everytime I hit mud, sand, water, and I come home it's dried out. Maybe I should try something else. I am not too worried about it, because when that chain wears out I'll just get something beefier along with some new sprockets.

[sheadouglas]

Originally Posted by fatboy250

That's kinda what I was thinking...WOW!

Tightens up every time! Good to go. Havent you ever had your chain pop off when you go offroad?

[mdsuave13]

hit up your local dealer and get some chain lube.. it makes a big difference..

i've had a chain pop off my old blaster, but i literally beat the #$@# out of it..