Final drive gearing
#1
03-31-2006, 03:54 AM
Final drive gearing
I got my new chain and rear sprocket today. The rear sprocket is a 49 tooth Renthal. Chain is a 110 link 520 X-Ring. My front is still the stock 14 tooth. The 110 link chain is fine for this setup, the rear wheel chain adjusters are just at the #4 position with lots of adjustment potential to go as the chain stretches.
However, I have a question. The manual shows the chain tension with 55 to 65 mm of space between the pivot bar and the bottom of the chain. With using the 49 tooth sprocket which is quite a bit larger than the 42 tooth stock sprocket, does that measurement need to change any? Or should it still be set to between 55 and 65 mm?
I currently have it set in the range, but the chain seems tighter than before. Especially noticeable in contrast to before is that the chain does not rest on the plastic guard very much like it used to do. Any advice is appreciated.
BTW, I've not had much of a chance to ride with it - just took a quick spin around the neighborhood to make sure the bike didn't catch fire or other catastrophe. The 14f 49r gives a final drive ratio of 3.50. This is comparable to the 3.462 that folks using the 13f 45r see, or the 3.231 seen by those using the 13f with the stock 42r. The stock 14f 42r gives a final drive ratio of 3.00.
I can't wait to get it out on the trails with my new drive ratio. I've got about 95 miles on it after filling my new 3.2g tank. Still plenty of gas sloshing around in there.
However, I have a question. The manual shows the chain tension with 55 to 65 mm of space between the pivot bar and the bottom of the chain. With using the 49 tooth sprocket which is quite a bit larger than the 42 tooth stock sprocket, does that measurement need to change any? Or should it still be set to between 55 and 65 mm?
I currently have it set in the range, but the chain seems tighter than before. Especially noticeable in contrast to before is that the chain does not rest on the plastic guard very much like it used to do. Any advice is appreciated.
BTW, I've not had much of a chance to ride with it - just took a quick spin around the neighborhood to make sure the bike didn't catch fire or other catastrophe. The 14f 49r gives a final drive ratio of 3.50. This is comparable to the 3.462 that folks using the 13f 45r see, or the 3.231 seen by those using the 13f with the stock 42r. The stock 14f 42r gives a final drive ratio of 3.00.
I can't wait to get it out on the trails with my new drive ratio. I've got about 95 miles on it after filling my new 3.2g tank. Still plenty of gas sloshing around in there.
#2
03-31-2006, 04:17 AM
RE: Final drive gearing
I might try 13/48 next. I could still use a little bit shorter 1st gear for tight woods use. This woulod make 1st basically the equivalent of "low range" on a 4X4. So
on the street, I would probably then just use the bike as a 5 speed and go right to 2nd gear from a stop.
on the street, I would probably then just use the bike as a 5 speed and go right to 2nd gear from a stop.
#3
03-31-2006, 06:57 AM
RE: Final drive gearing
ORIGINAL: Nobrakes
I got my new chain and rear sprocket today. The rear sprocket is a 49 tooth Renthal. Chain is a 110 link 520 X-Ring. My front is still the stock 14 tooth. The 110 link chain is fine for this setup, the rear wheel chain adjusters are just at the #4 position with lots of adjustment potential to go as the chain stretches.
However, I have a question. The manual shows the chain tension with 55 to 65 mm of space between the pivot bar and the bottom of the chain. With using the 49 tooth sprocket which is quite a bit larger than the 42 tooth stock sprocket, does that measurement need to change any? Or should it still be set to between 55 and 65 mm?
I currently have it set in the range, but the chain seems tighter than before. Especially noticeable in contrast to before is that the chain does not rest on the plastic guard very much like it used to do. Any advice is appreciated.
BTW, I've not had much of a chance to ride with it - just took a quick spin around the neighborhood to make sure the bike didn't catch fire or other catastrophe. The 14f 49r gives a final drive ratio of 3.50. This is comparable to the 3.462 that folks using the 13f 45r see, or the 3.231 seen by those using the 13f with the stock 42r. The stock 14f 42r gives a final drive ratio of 3.00.
I can't wait to get it out on the trails with my new drive ratio. I've got about 95 miles on it after filling my new 3.2g tank. Still plenty of gas sloshing around in there.
I got my new chain and rear sprocket today. The rear sprocket is a 49 tooth Renthal. Chain is a 110 link 520 X-Ring. My front is still the stock 14 tooth. The 110 link chain is fine for this setup, the rear wheel chain adjusters are just at the #4 position with lots of adjustment potential to go as the chain stretches.
However, I have a question. The manual shows the chain tension with 55 to 65 mm of space between the pivot bar and the bottom of the chain. With using the 49 tooth sprocket which is quite a bit larger than the 42 tooth stock sprocket, does that measurement need to change any? Or should it still be set to between 55 and 65 mm?
I currently have it set in the range, but the chain seems tighter than before. Especially noticeable in contrast to before is that the chain does not rest on the plastic guard very much like it used to do. Any advice is appreciated.
BTW, I've not had much of a chance to ride with it - just took a quick spin around the neighborhood to make sure the bike didn't catch fire or other catastrophe. The 14f 49r gives a final drive ratio of 3.50. This is comparable to the 3.462 that folks using the 13f 45r see, or the 3.231 seen by those using the 13f with the stock 42r. The stock 14f 42r gives a final drive ratio of 3.00.
I can't wait to get it out on the trails with my new drive ratio. I've got about 95 miles on it after filling my new 3.2g tank. Still plenty of gas sloshing around in there.
#4
03-31-2006, 07:57 AM
RE: Final drive gearing
ORIGINAL: scat
Nobrakes, You will still need to adjust the chain to the 60 mm deflection but your index point is going to be different now. Since you now have a larger rear sprocket this raises the chain off the swing arm so my thinking is you will need to mearure it from a new point. If you were to measure it like the manual says i feel it would be to tight. Did you have any problems with the sprocket hitting the lower chain guide? I got my 49 tooth on the way should be here tomorrow. I have been running 13/45 but wanted that little lower gearing so 14/49 should do it. I am hoping it wont effect the hiway rpms to much than what i am running now.
Nobrakes, You will still need to adjust the chain to the 60 mm deflection but your index point is going to be different now. Since you now have a larger rear sprocket this raises the chain off the swing arm so my thinking is you will need to mearure it from a new point. If you were to measure it like the manual says i feel it would be to tight. Did you have any problems with the sprocket hitting the lower chain guide? I got my 49 tooth on the way should be here tomorrow. I have been running 13/45 but wanted that little lower gearing so 14/49 should do it. I am hoping it wont effect the hiway rpms to much than what i am running now.
I think you are right about the deflection. I'll loosen it up a notch tomorrow.
#5
03-31-2006, 09:07 AM
RE: Final drive gearing
Yeah if it seems tighter I'd go a little looser, try to get it about what it was before. I'm keen to hear your report on the 49 as it seems the 13 is gunna wear too quick, tho 49 is a huge difference to the 42 (3.00 - 3.50). Did you consider a 45 - 46? That would be the same as the 13 on the front, why did you go the 49 you gunna do trials riding? 
Gunna outclimb mountain goats? [sm=badbadbad.gif] [sm=feedback.gif] and dont forget the [sm=Flahssssss.gif]
[sm=ttiwwp.gif]
Gunna outclimb mountain goats? [sm=badbadbad.gif] [sm=feedback.gif] and dont forget the [sm=Flahssssss.gif] [sm=ttiwwp.gif]
#6
03-31-2006, 03:27 PM
RE: Final drive gearing
Gents, this is best way I have found to be dead nuts accurate: 1. pull one of the bolts for the suspension links. 2. Raise the swing arm so that the C/S sprocket, swing arm pivot bolt and the rear axle bolt are all in a straight line. 3. adjust the chain to the to remove most of the slack. 4. put it back together. This way you know it isn't too tight, and you can make a new baseline for the 'chain to swing arm' measurement.
#7
04-01-2006, 09:51 PM
RE: Final drive gearing
ORIGINAL: MaverickAus
Yeah if it seems tighter I'd go a little looser, try to get it about what it was before. I'm keen to hear your report on the 49 as it seems the 13 is gunna wear too quick, tho 49 is a huge difference to the 42 (3.00 - 3.50). Did you consider a 45 - 46? That would be the same as the 13 on the front, why did you go the 49 you gunna do trials riding? Gunna outclimb mountain goats?
Yeah if it seems tighter I'd go a little looser, try to get it about what it was before. I'm keen to hear your report on the 49 as it seems the 13 is gunna wear too quick, tho 49 is a huge difference to the 42 (3.00 - 3.50). Did you consider a 45 - 46? That would be the same as the 13 on the front, why did you go the 49 you gunna do trials riding?
Gunna outclimb mountain goats?
ORIGINAL: MaverickAus
[sm=badbadbad.gif] [sm=feedback.gif] and dont forget the [sm=Flahssssss.gif]
[sm=ttiwwp.gif]
[sm=badbadbad.gif] [sm=feedback.gif] and dont forget the [sm=Flahssssss.gif]
[sm=ttiwwp.gif]
This is a 49 tooth Renthal. Today was the first I've ridden it, both on the road and trails. I love it in both places - plenty of pick-up for the roads, and a good low range for technical trails.
But dangit, now I wish it had seven gears. While the pick-up is good in 6th and it accelerates fine up fairly steep hills, it take about 1000 RPM more to achieve the same speed in 6th gear as the stock gearing.
I may end up going back to the old chain and 14/42. I do have a 13 tooth front, so maybe I'll try the 13/42 combination, since I can do that at no additional expense. Decisions, decisions - I like the low-range gearing that 14/49 provides for trails. I even like the get-up it has on the roads. But the gearing seems just a little short for the road. It needs about 6000 RPM to go 50 MPH in 6th. This feels pretty high when I've been used to only using 5000 RPM to achieve the same speed.
I really do like the Renthal rear sprocket though, it's nice and light. I hate to have to put the heavy stock one back on.
EDIT: fix image link
#8
04-02-2006, 07:43 AM
RE: Final drive gearing
ORIGINAL: Nobrakes
I may end up going back to the old chain and 14/42. I do have a 13 tooth front, so maybe I'll try the 13/42 combination, since I can do that at no additional expense. Decisions, decisions - I like the low-range gearing that 14/49 provides for trails. I even like the get-up it has on the roads. But the gearing seems just a little short for the road. It needs about 6000 RPM to go 50 MPH in 6th. This feels pretty high when I've been used to only using 5000 RPM to achieve the same speed.
I really do like the Renthal rear sprocket though, it's nice and light. I hate to have to put the heavy stock one back on.
I may end up going back to the old chain and 14/42. I do have a 13 tooth front, so maybe I'll try the 13/42 combination, since I can do that at no additional expense. Decisions, decisions - I like the low-range gearing that 14/49 provides for trails. I even like the get-up it has on the roads. But the gearing seems just a little short for the road. It needs about 6000 RPM to go 50 MPH in 6th. This feels pretty high when I've been used to only using 5000 RPM to achieve the same speed.
I really do like the Renthal rear sprocket though, it's nice and light. I hate to have to put the heavy stock one back on.
#9
04-03-2006, 03:43 AM
RE: Final drive gearing
Hi,
I just got my KLX250S and find the bike is geared a bit high for the woods. I still drive country roads, but would like to investigate a new sproket for the rear.
the stock sprocket is 42 teeth, what would be a good size to use without going crazy. they are a bit expenive to just start buying without knowing.
Also, what is involved? will it just fit?
Jim
I just got my KLX250S and find the bike is geared a bit high for the woods. I still drive country roads, but would like to investigate a new sproket for the rear.
the stock sprocket is 42 teeth, what would be a good size to use without going crazy. they are a bit expenive to just start buying without knowing.
Also, what is involved? will it just fit?
Jim
#10
04-03-2006, 06:06 AM
RE: Final drive gearing
OK, so I should haver read the rest of this thread first. 14/45 is a good start?
the shop sold me a 13 front sproket that was listed for a KLX300 (they had no listing for the 2006 KLX250s sprockets), think it will fit to try the 13/42?
At first glance it looks different.
the shop sold me a 13 front sproket that was listed for a KLX300 (they had no listing for the 2006 KLX250s sprockets), think it will fit to try the 13/42?
At first glance it looks different.