Topic: question on chain conversion

[KRONUS0100]

when converting to 530 from 630,  are we switching tooth counts or gear diameters?  idea is to maintain as close to original gear diameter is it not?
according to the following
formula.................630 32 tooth gear  32/5x6=51 tooth 530 gear
a 530 48 tooth gear is only 9.799 inches diameter, where as a 630 32 tooth gear is 7.65 inches diamter, and a 530  51 tooth is 10.15 inches.
https://www.rbracing-rsr.com/calcsprocketdiam.html    is the gear diamter calcultor im using

currently running a 14/32 630 combo on a 16 inch rear wheel with a 130/90-16 tire   (from a 120/90-18 wheel/tire that was on 18/48 530)
  according to the gear calculator, and if i undersand everything correctly..............that 32 tooth 630 becomes a 51 tooth 530 sprocket........................thats way overgeared for a 16 inch rear wheel.


should add that the current set up 14/32   that 5th gear is strictly an overdrive gear for hiway
experts please help

[Cqyqte]

How many teeth on the front 630 sprocket?  And how many teeth on the rear 630 sprocket?  Whatever numbers you get is the number of teeth you need to get in the 530 size.

[KRONUS0100]

that cant be right...............................14 tooth front and 32 tooth rear....................................................nobody runs a 530 14 tooth front sprocket on a cb750........nobody  my old 530 18 tooth is very close to same size as the 630 14 tooth.

[Cqyqte]

What bike?

[Cqyqte]

14 front 32 rear is a 2.29 ratio, which can be achieved by 17 front 39 rear, or 18 front 41 rear or 15 front 34 rear....

If I knew what bike I could tell you what's combinations are available.

[KRONUS0100]

its a 1976 cb750f1, but its sitting on 1982 kawasaki kz750 mags...............16 inch rear.......................kz runs 630 chain, so i have a f3 front 14 tooth sprocket to match the 32 tooth rear, bike is underpowered, needs more oomph  in 4th and 5th gears
would like to convert to 530, but i cant run the 48 tooth  cb sprocket on the kz wheel, bolt circles dont match, and not enough material to drill holes

[Powderman]

Am I missing something here? The difference between a 630 and a 530 chain is the width of the chain/sprockets. The chains have no bearing as far as tooth count. What ever tooth combo you ran with the 630 is the same as what you want on the 530. If you want more acceleration then go bigger on the front sprocket or smaller on the rear.

[754]

6 = 5/8 pitch between teeth
5 = 1/2 pitch

 3 refers to width  so a 530 chain would go on a 520 sprocket but not vice versa.

 Smaller front bigger rear for better acceleration.

[MCRider]

Am I missing something here? The difference between a 630 and a 530 chain is the width of the chain/sprockets. The chains have no bearing as far as tooth count. What ever tooth combo you ran with the 630 is the same as what you want on the 530. If you want more acceleration then go bigger on the front sprocket or smaller on the rear.

Error: the 6 and 5 designate distance between pins. This will definitely impact tooth count.

The 30 is the width.

http://www.amaproracing.com/rr/news/index.cfm?cid=51567

[Powderman]

Am I missing something here? The difference between a 630 and a 530 chain is the width of the chain/sprockets. The chains have no bearing as far as tooth count. What ever tooth combo you ran with the 630 is the same as what you want on the 530. If you want more acceleration then go bigger on the front sprocket or smaller on the rear.

Error: the 6 and 5 designate distance between pins. This will definitely impact tooth count.

The 30 is the width.

http://www.amaproracing.com/rr/news/index.cfm?cid=51567

I still don't see how tooth count comes into the equation. The ratio between a 630 chain with a 17/42 will be the same with a 530 with a 17/42

[andrewk]

Read this, you should then understand.   http://www.z1enterprises.com/Chain630To530.aspx

[andrewk]

Matt- FWIW, I would probably run 17 or 18t front and a 43 or 45 rear, respectively.

Also, your math is wrong.  32/5=6.4.  6.4*6 =38.4.  14/6=2.8.  2.8*6= 16.8. 

So to keep the same ratio, you'd be at 17/38.  If you're having a custom sprocket made, 43 is the custom size Cycle-X has made for 16 inch harley wheels on cb750s.

[Cqyqte]

http://www.jtsprockets.com/catalogue/model/5313

http://www.jtsprockets.com/catalogue/model/4854

Based on the numbers you gave me from the 630 gears your existing ratio was 2.29 and if you said you wanted more highway speed you need to reduce the ratio or go up on front sprocket teeth or lower on rear sprocket teeth to achieve this.  So according to the available front sprockets for a '76 CB750F1 you can choose from 15 through to 18 and if you want reduce the ratio you will need to reduce the rear sprocket teeth and you have a choice of 38 to 46 inclusively.  Use the two charts for selection possibilities and this chart http://www.jtsprockets.com/fileadmin/files/jtgearratio.pdf to select the combination that gives you a ratio less than 2.29 using the choices available.

I would try 18 front to 39 or 38 rear and see how you like the change.

[MCRider]

That may be too severe. A high ratio is an 18/45. IIRC a Daytona CR was 18/40 (OCICBW) and it took 90hp to pull redline.

An 18/38 on a stocker would limit engine revoltions and top speed, I think, drastically. Where's the fun in that?   

Personally I vote for a 17/48 for best all around performacne. A 18/45 should be a very comfortable highway gear, but would be unforgiving around town. Lots of clutch slipping in traffic.

But, to each their own.

[lucky]

The 1977 - 78 CB750's had higher 4th and 5th gear ratios.

[Dave Voss]

I still don't see how tooth count comes into the equation. The ratio between a 630 chain with a 17/42 will be the same with a 530 with a 17/42

Yes the ratio will be the same, however the diameters of 530 and 630 sprockets with the same tooth count are significantly different, so the tooth count needs to change to maintain a similar overall sprocket diameter, which may be important to keep the chain in a location that clears other components.

[Cqyqte]

If you calculate the sprocket diameters using teeth and chain pitch for both 630 and 530 chains for the front and rear then calculate the corresponding ratios between the sprocket diameters you will get the same ratios.  So if you have a 18 tooth 630 front sprocket and 38 tooth 630 rear sprocket and change them for an 18 tooth 530 front sprocket and 38 tooth 530 rear sprocket the ratio will be the same.  Chain lengths will be different but the ratio will be identical.

You are correct the chain position will be different and it is necessary to ensure that clearance to the swing-arm pivot and frame components are not compromised.  But the drive ratio remains the same, speed and gearing remain the same. 

[MCRider]

If you calculate the sprocket diameters using teeth and chain pitch for both 630 and 530 chains for the front and rear then calculate the corresponding ratios between the sprocket diameters you will get the same ratios.  So if you have a 18 tooth 630 front sprocket and 38 tooth 630 rear sprocket and change them for an 18 tooth 530 front sprocket and 38 tooth 530 rear sprocket the ratio will be the same.  Chain lengths will be different but the ratio will be identical.

You are correct the chain position will be different and it is necessary to ensure that clearance to the swing-arm pivot and frame components are not compromised.  But the drive ratio remains the same, speed and gearing remain the same.

But you can't get an 18t 630 in the space allotted. Its all relative.

[Powderman]

I think what I am reading here verifies what I said. Lets say your 630 sprockets are 50/25 (2/1), if you want a 530 chain and change to a 50/25 (2/1) 530 chain you will have both sprockets smaller in diameter. With this set up your speeds and RPM will remain the same. So all you would be looking for is a chain/ sprocket package in 530 with the same ratio you had with the 630. Doesn't matter if it's a 50/25, 48/24, 38/19,etc. Am I wrong?

[MCRider]

I think what I am reading here verifies what I said. Lets say your 630 sprockets are 50/25 (2/1), if you want a 530 chain and change to a 50/25 (2/1) 530 chain you will have both sprockets smaller in diameter. With this set up your speeds and RPM will remain the same. So all you would be looking for is a chain/ sprocket package in 530 with the same ratio you had with the 630. Doesn't matter if it's a 50/25, 48/24, 38/19,etc. Am I wrong?

Right, just do the math. Your starting point is the drive sprocket cavity size. Whatever tooth count fits in there, buy a rear to match the ratio. Or bigger or smaller to tweak it to taste.

[KRONUS0100]

going with 14 tooth front and 39 tooth rear......630.  gives me a 2.786 ratio.  will put bike back up towards the factory specified 3.0 ration using 14 and 43 in 630.  if i feel it needs more, i will get a 43 tooth rear sprocket.
factory rear tire size is 110/90-18 which is 25.8 inches tall.
my rear tire is 130/90-16 which is 25.2 inches tall...............difference of .6 inches.
never ridden a bone stock f3 wih factory gearing, so dont know what its supposed to feel like, but im fixing to find out.


in sorting this all out i found a nifty sprocket diameter calculator for 530,520, and 630 sprockets., the people who made it use JT sprockets
according to thier calculator a 39 tooth 630 equals 9.32 inches diamter and the 530 48 tooth equals 9.556 inches diamter., so im going to be close enough to factory gear sizes anyways.



here is the calculator.....................................https://www.rbracing-rsr.com/calcsprocketdiam.html

[flybox1]

I went to a 17/48 - 530 combo from my K8's heavy 630 and stock sprockets.
cant wait to try it.

[andrewk]

I think what I am reading here verifies what I said. Lets say your 630 sprockets are 50/25 (2/1), if you want a 530 chain and change to a 50/25 (2/1) 530 chain you will have both sprockets smaller in diameter. With this set up your speeds and RPM will remain the same. So all you would be looking for is a chain/ sprocket package in 530 with the same ratio you had with the 630. Doesn't matter if it's a 50/25, 48/24, 38/19,etc. Am I wrong?

It has everything to do with gear diameter and nothing to do with tooth count.  Pick the 530 sprocket that is the same diameter as the 630 you are replacing to maintain the same ratio, and forget about tooth count.

[andrewk]

going with 14 tooth front and 39 tooth rear......630.  gives me a 2.786 ratio.  will put bike back up towards the factory specified 3.0 ration using 14 and 43 in 630.  if i feel it needs more, i will get a 43 tooth rear sprocket.
factory rear tire size is 110/90-18 which is 25.8 inches tall.
my rear tire is 130/90-16 which is 25.2 inches tall...............difference of .6 inches.
never ridden a bone stock f3 wih factory gearing, so dont know what its supposed to feel like, but im fixing to find out.


in sorting this all out i found a nifty sprocket diameter calculator for 530,520, and 630 sprockets., the people who made it use JT sprockets
according to thier calculator a 39 tooth 630 equals 9.32 inches diamter and the 530 48 tooth equals 9.556 inches diamter., so im going to be close enough to factory gear sizes anyways.



here is the calculator.....................................https://www.rbracing-rsr.com/calcsprocketdiam.html

Too bad you couldn't get a 530 setup, but that 39 should correct the gearing problems you were having, and it sounds easier than having a custom sprocket made for the Kawasaki wheel.

[Cqyqte]

I think what I am reading here verifies what I said. Lets say your 630 sprockets are 50/25 (2/1), if you want a 530 chain and change to a 50/25 (2/1) 530 chain you will have both sprockets smaller in diameter. With this set up your speeds and RPM will remain the same. So all you would be looking for is a chain/ sprocket package in 530 with the same ratio you had with the 630. Doesn't matter if it's a 50/25, 48/24, 38/19,etc. Am I wrong?

It has everything to do with gear diameter and nothing to do with tooth count.  Pick the 530 sprocket that is the same diameter as the 630 you are replacing to maintain the same ratio, and forget about tooth count.

Sorry Andrew diameter and gear count is related.