Old Baldy
Pack Dog
- Joined
- Feb 15, 2010
- Messages
- 152
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- Location
- South Lyon, Michigan, USA
- Bike
- Kawasaki KLR 650
Guys
I'm copying here a post I put together on another board some time ago, for those interested in KLR650 gearing and some general info on sprockets/chain wear, if anyone's interested...
Here's a link to a simple little Gearing Calculator sheet that I built a while back. It shows the MPH at various RPM and RPM at various MPH for 2 different sprocket setups, so that you can easily compare two different setups - whether you are comparing, say the effects of a 16T/43T sprocket to the stock 15T/43T or anything else like that. Just change the sprockets in the right hand sheet, to compare to the left hand side.
GEARING CALCULATOR
motodyn.com/media/utils/ob-klr-gear-ratios.xls
SPROCKET COMBINATIONS vs WEAR.
Here's a little sheet and a write-up that I put together to show the affects on sprocket and chain WEAR of different combinations of sprockets and chain lengths, if anyone is interested....it shows the various possible sprocket combinations for the KLR, with the required chain lengths, and the simple MPH change for each combo compared to the stock gearing at 70MPH, and the sprocket "distance" for each sprocket and chain combination to make sure the combination fits the bike's chain adjusters, and the suggested best and worst WEAR combinations, above....
motodyn.com/media/utils/ob-klr-chainsprockets-wear.xls
Note#1 - GREEN combinations are good for wear; Red or Orange are not so good.
Note#2 - This is primarily for the STREET and LONG_DISTANCE highway riders, NOT so much for the dirt riders, who will wear sprockets and chains regardless of the choice of sprockets!
Before I get into the details of WHY, I'll say that there is 1 particular sprocket combo that is BAD for wear, and a few that are GOOD for wear.
Bad for wear
* 14T / 40 T (front / rear), with the 104 link chain to fit.
The GOOD wear combos are (in tall to short ratio sequence)
* 17T / 39T
* 17T / 41T
* 17T / 43T
* 15T / 39T
* 17T / 45T
* 15T / 41T
* 15T / 43T (no s---...Kawasaki know what they're doing!)
* 15T / 45T
Some key things to know
The sprocket teeth "locate" the chain laterally while it is running. Now, the chain has alternating "inner" link plates that mesh with the sides of the sprocket teeth, and alternating "outer" link plates which do not. The "inner" chain side-plate links wear on the sides of the sprocket teeth.
Each tooth on an EVEN tooth sprocket will always contact either an inside link or an outside link. Each tooth on an ODD tooth sprocket will ALTERNATE between inside and outside links and so spread the wear over the sprocket teeth better. The ODD number sprockets will show less side wear than the EVEN sprockets, but as most OE sprockets are steel, and as side wear is not normally a major issue, this is not a big deal.
Kawasaki chose the 15T (odd) front sprocket and the 43T (odd) rear sprocket to mate with the standard 106 (EVEN) link chain.
So...RULE #1, for best SIDE wear, always choose sprockets (front and back) with an ODD number of teeth, regardless of the length of chain.
Now, while the SIDE wear may be more important for softer alloy sprockets than strong steel sprockets, it gets more important to look at the teeth and roller FACE wear.
Here, it gets a bit more complicated, because there is a "hunting" gear factor involved, where one wants to ensure that the front sprocket does not "see" the same specific chain link pin on a frequent basis. (The same applies to the REAR sprocket, but we need to look at them separately)
Consider the front sprocket. If the same sprocket tooth "sees" the same chain link over and over and over again at a high frequency, then that tooth-link can cause wear to occur if there is anything not 100% in the manufacture of that specific tooth or that specific link. The one will start to wear the other.
On the other hand, if that tooth "sees" other chain links and not that one same link over and over again, then the wear is evenly spread over the whole chain, and similarly, if there is any issue with one particular link of a chain, and it does not "see" the same tooth over and over, then that wear is spread evenly over the sprocket teeth.
So, one wants to ensure that the front sprocket teeth "see" different chain links as much as possible, and the same for the rear sprocket.
To calculate this, one must take each sprocket at a time and compare it to the number of chain links. It is necessary to reduce the sprocket teeth and the chain links down into their PRIME NUMBER factors, as follows.
14T sprocket = (7x2)
where 7 and 2 are the prime number factors that multiply to 14 (as both 7 and 2 are prime numbers)
Similarly, for a 15T sprocket, the prime factors are (5x3)
and for a 16T sprocket, the prime factors are (2x2x2x2)
and for a 17T sprocket, the prime factors are (17x1)
Doing various lengths of chain the same way, we see
104L is (13x2x2x2) Note: 2 links shorter than stock for some combos
106L is (53x2) - the stock length chain
108L is (3x3x3x2x2) Note: links longer than stock for some combos
Now, we can see which front sprockets work with which chain lengths.
In order to determine the number of rotations of the chain before it sees the same sprocket tooth, and to determine the number of rotations of the sprocket to see the same chain link, one must eliminate the SIMILAR PRIME FACTORS from both the sprocket and the chain factors.
Let's look at the stock 15T and the stock 106L chain...
15T (5x3) and 106L (53x2)
Looking at the prime factors above, you see there are NO factors in common between the front sprocket and the chain, so the chain will rotate 15 times before it sees the same sprocket tooth, and the sprocket will rotate 106 times before it sees the same chain link.
This is a great combination for wear (Kawasaki know what they're doing!)
Let's look at the 14T sprocket against the stock 106L chain
14T (7x2) and 106L (53x2)
Here, you see that there is a common prime factor (2), which we eliminate from both the sprocket and chain, and this results in the situation where the chain will rotate only 7 times before it sees the same sprocket tooth, and the sprocket will rotate 53 times before it sees the same chain link.
This is much less favorable than the stock 15T, for wear.
Now, we can do the same for the REAR sprockets against the chain
40T (5x2x2x2)
41T (41x1) - a nice prime number!
42T (7x3x2)
43T (43x1) - a nice prime number!
44T (11x2x2)
45T (5x3x3)
So, let's take a look at the stock 43T with the stock 106L chain
43T (43x1) and 106L (53x2)
Again, you see that there are NO common prime factors between the 43T sprocket and the 106L chain, so the chain will rotate 43 times before it sees the same sprocket tooth rear sprocket while the sprocket will rotate 106 times before it sees the same chain link.
Again, a very good combination by Kawasaki, for wear.
Kawasaki have chosen very good combinations of front sprocket to chain and rear sprocket to chain for teeth face wear, and also chosen very good sprockets for side wear (odd teeth).
Let's look at a BAD combination, (the 14T and 40T with the necessary 104L chain to fit the bike)
14T (7x2) and 104L (13x2x2x2)
40T (5x2x2x2) and 104L (13x2x2x2)
Here, you see that for the front sprocket, the common factor (2) is eliminated and so the chain will rotate 7 times before it sees the same sprocket tooth while the front sprocket will rotate 52 times before it sees the same chain link.
The rear sprocket is bad with this combo too...
You see that the common factors are (2x2x2) which are eliminated and so the chain will rotate only 5 times before it sees the same rear sprocket tooth while the rear sprocket will rotate only 13 times before it sees the same chain link.
I'd avoid this specific combination on the KLR.
NOTE: these sprocket recommendations really are only of some significance when comparing long-term wear in a relatively "clean" environment, such as on a long distance trip/ride. Clearly, other factors such as dirt, mud, sand, general maintenance and lubrication will have a MUCH GREATER effect on chain and sprocket wear, than specific combinations of sprockets.
I'm copying here a post I put together on another board some time ago, for those interested in KLR650 gearing and some general info on sprockets/chain wear, if anyone's interested...
Here's a link to a simple little Gearing Calculator sheet that I built a while back. It shows the MPH at various RPM and RPM at various MPH for 2 different sprocket setups, so that you can easily compare two different setups - whether you are comparing, say the effects of a 16T/43T sprocket to the stock 15T/43T or anything else like that. Just change the sprockets in the right hand sheet, to compare to the left hand side.
GEARING CALCULATOR
motodyn.com/media/utils/ob-klr-gear-ratios.xls
SPROCKET COMBINATIONS vs WEAR.
Here's a little sheet and a write-up that I put together to show the affects on sprocket and chain WEAR of different combinations of sprockets and chain lengths, if anyone is interested....it shows the various possible sprocket combinations for the KLR, with the required chain lengths, and the simple MPH change for each combo compared to the stock gearing at 70MPH, and the sprocket "distance" for each sprocket and chain combination to make sure the combination fits the bike's chain adjusters, and the suggested best and worst WEAR combinations, above....
motodyn.com/media/utils/ob-klr-chainsprockets-wear.xls
Note#1 - GREEN combinations are good for wear; Red or Orange are not so good.
Note#2 - This is primarily for the STREET and LONG_DISTANCE highway riders, NOT so much for the dirt riders, who will wear sprockets and chains regardless of the choice of sprockets!
Before I get into the details of WHY, I'll say that there is 1 particular sprocket combo that is BAD for wear, and a few that are GOOD for wear.
Bad for wear
* 14T / 40 T (front / rear), with the 104 link chain to fit.
The GOOD wear combos are (in tall to short ratio sequence)
* 17T / 39T
* 17T / 41T
* 17T / 43T
* 15T / 39T
* 17T / 45T
* 15T / 41T
* 15T / 43T (no s---...Kawasaki know what they're doing!)
* 15T / 45T
Some key things to know
The sprocket teeth "locate" the chain laterally while it is running. Now, the chain has alternating "inner" link plates that mesh with the sides of the sprocket teeth, and alternating "outer" link plates which do not. The "inner" chain side-plate links wear on the sides of the sprocket teeth.
Each tooth on an EVEN tooth sprocket will always contact either an inside link or an outside link. Each tooth on an ODD tooth sprocket will ALTERNATE between inside and outside links and so spread the wear over the sprocket teeth better. The ODD number sprockets will show less side wear than the EVEN sprockets, but as most OE sprockets are steel, and as side wear is not normally a major issue, this is not a big deal.
Kawasaki chose the 15T (odd) front sprocket and the 43T (odd) rear sprocket to mate with the standard 106 (EVEN) link chain.
So...RULE #1, for best SIDE wear, always choose sprockets (front and back) with an ODD number of teeth, regardless of the length of chain.
Now, while the SIDE wear may be more important for softer alloy sprockets than strong steel sprockets, it gets more important to look at the teeth and roller FACE wear.
Here, it gets a bit more complicated, because there is a "hunting" gear factor involved, where one wants to ensure that the front sprocket does not "see" the same specific chain link pin on a frequent basis. (The same applies to the REAR sprocket, but we need to look at them separately)
Consider the front sprocket. If the same sprocket tooth "sees" the same chain link over and over and over again at a high frequency, then that tooth-link can cause wear to occur if there is anything not 100% in the manufacture of that specific tooth or that specific link. The one will start to wear the other.
On the other hand, if that tooth "sees" other chain links and not that one same link over and over again, then the wear is evenly spread over the whole chain, and similarly, if there is any issue with one particular link of a chain, and it does not "see" the same tooth over and over, then that wear is spread evenly over the sprocket teeth.
So, one wants to ensure that the front sprocket teeth "see" different chain links as much as possible, and the same for the rear sprocket.
To calculate this, one must take each sprocket at a time and compare it to the number of chain links. It is necessary to reduce the sprocket teeth and the chain links down into their PRIME NUMBER factors, as follows.
14T sprocket = (7x2)
where 7 and 2 are the prime number factors that multiply to 14 (as both 7 and 2 are prime numbers)
Similarly, for a 15T sprocket, the prime factors are (5x3)
and for a 16T sprocket, the prime factors are (2x2x2x2)
and for a 17T sprocket, the prime factors are (17x1)
Doing various lengths of chain the same way, we see
104L is (13x2x2x2) Note: 2 links shorter than stock for some combos
106L is (53x2) - the stock length chain
108L is (3x3x3x2x2) Note: links longer than stock for some combos
Now, we can see which front sprockets work with which chain lengths.
In order to determine the number of rotations of the chain before it sees the same sprocket tooth, and to determine the number of rotations of the sprocket to see the same chain link, one must eliminate the SIMILAR PRIME FACTORS from both the sprocket and the chain factors.
Let's look at the stock 15T and the stock 106L chain...
15T (5x3) and 106L (53x2)
Looking at the prime factors above, you see there are NO factors in common between the front sprocket and the chain, so the chain will rotate 15 times before it sees the same sprocket tooth, and the sprocket will rotate 106 times before it sees the same chain link.
This is a great combination for wear (Kawasaki know what they're doing!)
Let's look at the 14T sprocket against the stock 106L chain
14T (7x2) and 106L (53x2)
Here, you see that there is a common prime factor (2), which we eliminate from both the sprocket and chain, and this results in the situation where the chain will rotate only 7 times before it sees the same sprocket tooth, and the sprocket will rotate 53 times before it sees the same chain link.
This is much less favorable than the stock 15T, for wear.
Now, we can do the same for the REAR sprockets against the chain
40T (5x2x2x2)
41T (41x1) - a nice prime number!
42T (7x3x2)
43T (43x1) - a nice prime number!
44T (11x2x2)
45T (5x3x3)
So, let's take a look at the stock 43T with the stock 106L chain
43T (43x1) and 106L (53x2)
Again, you see that there are NO common prime factors between the 43T sprocket and the 106L chain, so the chain will rotate 43 times before it sees the same sprocket tooth rear sprocket while the sprocket will rotate 106 times before it sees the same chain link.
Again, a very good combination by Kawasaki, for wear.
Kawasaki have chosen very good combinations of front sprocket to chain and rear sprocket to chain for teeth face wear, and also chosen very good sprockets for side wear (odd teeth).
Let's look at a BAD combination, (the 14T and 40T with the necessary 104L chain to fit the bike)
14T (7x2) and 104L (13x2x2x2)
40T (5x2x2x2) and 104L (13x2x2x2)
Here, you see that for the front sprocket, the common factor (2) is eliminated and so the chain will rotate 7 times before it sees the same sprocket tooth while the front sprocket will rotate 52 times before it sees the same chain link.
The rear sprocket is bad with this combo too...
You see that the common factors are (2x2x2) which are eliminated and so the chain will rotate only 5 times before it sees the same rear sprocket tooth while the rear sprocket will rotate only 13 times before it sees the same chain link.
I'd avoid this specific combination on the KLR.
NOTE: these sprocket recommendations really are only of some significance when comparing long-term wear in a relatively "clean" environment, such as on a long distance trip/ride. Clearly, other factors such as dirt, mud, sand, general maintenance and lubrication will have a MUCH GREATER effect on chain and sprocket wear, than specific combinations of sprockets.
