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Discussion Starter · #1 ·
So I have a 415 chain conversion kit, first time ever running a smaller chain than a 520. I know the stock chain is 112 links, and sprockets are 14/43. My 415 kit is 18/56 (or 57...now I forget), which means slightly less top speed than stock. First of all, I'd like to know how many chain links would be recommended to use with the 415 chain? What would be a good number that would cover me if I use a 53-54 rear sprocket?

The other thing I'm wondering is what gear ratios are most of you racers/track day guys (or really anyone using the 415 kit) using? What have you found to be suitable for most tracks and what ratio would be needed for tracks with long straights? I haven't ridden the bike yet, so I have no idea how fast it'll get with the current ratio, but one of the tracks I'll be going to has very long straights (Road America). Two of them are long enough that most 600s would be topped out. So what gear ratio would you say works for that? Obviously there's a point at which if you overdo it the bike won't have enough power to accelerate, so I want to find that sweet spot where it's just under the rev limiter in 6th gear.

@jbluetooth, @Capitalview, @Doc-Ram, @VULGR...just tagging some of you that have more experience.
 

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I haven't ridden Road America, but I've found on tracks with lower top speed, 58 works excellent until you are near the front of the pack, then sometimes 57 works a little better. On faster tracks, 56 or 55 are excellent. I haven't need a 54 yet but one of my riders in Portland played around with it a bit, and I've sold a couple of them to guys that do run those high top speed tracks. I run a 57 at Chuckwalla and Buttonwillow, 56 at Autoclub speedway, 55 at Barber (but some guys run 58 at Barber).
 

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Discussion Starter · #3 ·
I haven't ridden Road America, but I've found on tracks with lower top speed, 58 works excellent until you are near the front of the pack, then sometimes 57 works a little better. On faster tracks, 56 or 55 are excellent. I haven't need a 54 yet but one of my riders in Portland played around with it a bit, and I've sold a couple of them to guys that do run those high top speed tracks. I run a 57 at Chuckwalla and Buttonwillow, 56 at Autoclub speedway, 55 at Barber (but some guys run 58 at Barber).
Holy ****, you made it all the way to Barber from Cali??! That's a long way! lol

So how many links do you run on your chain?
 

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Discussion Starter · #4 ·
If you know anyone that has ran this at Daytona, I imagine whatever gear ratio works well there would work well at Road America too. I just don't know enough people with R3's, let alone anyone that runs a 415 kit.

Now that I think of it, High Plains has a pretty decent straightaway on the full course. Not quite as long but close...wonder what the MRA guys run on their R3s....wonder if Jason Madama is on this forum. He would probably have a good idea.
 

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Depends on the sprocket size, 142 links for 54, 55, or 56, 144 for 58, 57, or 56. Hammer runs the same 55-58. I think Hammer even ran the 144 for the 55T, but he had the adjuster ALL the way back.
 

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I tend to keep one chain for each sprocket (luxury for sure), that way, I can have a fixed wheelbase and settings for each gear ratio. At fast flowing tracks like Thunderhill, I will go with a 55 or 56. At shorter tighter tracks like Buttonwillow or Sonoma, I'll go with 57 or 58.

Last race round @Buttonwillow, I ran with a 18F/56R and found a lack of acceleration out of a few corners. A 57R would have been the best.

Again, all of this depends on pace as well. As I'm getting faster, I seem to be carrying a lot higher revs in and out of corners. If I feel I'm running out of revs in a corner, then I go one tooth up usually. I went down to a 55 at Buttonwillow and I could never even get into 6th gear, lol. So I switched back to a 56 (although the 57 would've been the better choice). I was influenced by all the fast guys testing 56 rear on Friday, so I went with that too. No one divulged that they switched to a 57 on race day :|

For # of links, I'd like my wheelbase @598-600mm (my measurements from swingarm pivot to rear axle). I adjust # of links to reach close to that wheelbase.

If wheelbase is fixed, then only setttings to change are geometry (front high or lower). I raised rear up almost as much as my shock would allow. I just play with the front now.

Anyway, my essay is finished :lol, hope it helps
 

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Discussion Starter · #7 ·
Depends on the sprocket size, 142 links for 54, 55, or 56, 144 for 58, 57, or 56. Hammer runs the same 55-58. I think Hammer even ran the 144 for the 55T, but he had the adjuster ALL the way back.
Alright thanks. I'm gonna figure out what I want today or tomorrow, then probably get another rear sprocket from you. Maybe you can throw it in with the other stuff I ordered if it hasn't shipped yet. Is there no other size available for the front sprocket? Just the 18T?
 

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On these small capacity bikes there can be a massive difference (if you're fighting for the win) in 1 tooth difference on the rear sprocket since you are 100% throttle for a lot more percentage of the lap.
Optimal sprocket sizes will be different from someone running at the front compared to someone 10% slower. Unfortunately I don't have the option of the 415 chain so can't offer any specific advise
 

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Alright thanks. I'm gonna figure out what I want today or tomorrow, then probably get another rear sprocket from you. Maybe you can throw it in with the other stuff I ordered if it hasn't shipped yet. Is there no other size available for the front sprocket? Just the 18T?
I stock a few 17s and mostly 18s. I can get 15s and 16s also, but you only need those for really short tracks like go-cart tracks and stuff. I'm out of a few sprockets for a couple more weeks, shoot me an email about what you want to add and I'll see what I can do.
 
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