Largest reat sprocket w/o modifying chain guide?

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Old 11-09-2009 | 12:39 AM
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Default Largest reat sprocket w/o modifying chain guide?

Hi all,


Another question here. I was doing some dirtbike related net surfing, and came across mention of gearing lower to the point where second and third gear are the most used ones, while first is reserved for the most technical sections. Seemed like a good idea to me, because I would like to use second/third more around here, but they are just a bit too low to get away with (current gearing 13/42). I ride 90% dirt, and don't plan to take my bike above 65mph.

And yes, I know the smart answer is "just ride faster pvssy"

How big of a sprocket can we get away with in the rear? Without changing our stock chain guides? Looks like this guy/ is using a 49T, any other recommendations? Thanks!
 
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Old 11-09-2009 | 02:01 AM
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Not sure about the back, but you can fit a 12 tooth on the front if you want to lower your gearing. I, and a good percentage of folks on here, run a 13tooth front sprocket. Theoretically it's harder on the chain (wrapping around a smaller diameter) , but I'd say the difference negligible. Your chain gets more abuse from grinding dirt into it. 12t is about a $15 mod.
Dan
 
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Old 11-09-2009 | 02:09 AM
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I'm thinking it's probably 47. I have 14/47 gearing on mine, and I have to remove the 3 bolts on the chainguide to get the rear wheel out with a new chain. As the chain wears a tiny bit, I can tell I'll have enough slack to slip it off, but not right now. I'm running a 100/100 Kenda Trak Master DOT knobby, so it's not a huge tire. Removing the chainguide is really easy, but mine has to come off to get the wheel out. If your tire is much bigger, you'll have to consider even more room. The 47 rear sprocket just doesn't let the wheel go forward quite far enough. Leaving another link in the chain would also alleviate this. There's no clearance, rubbing, or wear issue that I can see with the 47 otherwise to cause a problem. I just ran into this because my chain and setup has the axle at a very forward location to start with.
 
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Old 11-09-2009 | 02:18 AM
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Thanks for the responses. I briefly considered a 12T, but the wear and chainwrap issues are enough for me to decide against it.

That does look like a tight fit with the 47T, what size are you running on the front? And how does the ratio feel? check out this clearance picture with the other guys 49T:

 
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Old 11-09-2009 | 04:59 AM
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From memory it was either 48 or 49. 14/48 would be approx the same as 12/42. Of course one of those combos requires a new chain (you guess which one)
 
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Old 11-09-2009 | 11:29 PM
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Default 52 sprocket

run a 52 sprocket no problems
 
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Old 11-10-2009 | 01:13 AM
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That's a beauty, twotwins. Props in my book for style (and torque)! Ever ride on the highway with it?
 
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Old 11-10-2009 | 01:33 AM
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Originally Posted by twotwins
run a 52 sprocket no problems
Nice looking setup. I notice your axle is back at max to the rear...or at least very close to clear that sprocket.
 
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Old 11-10-2009 | 01:50 AM
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Originally Posted by twotwins
run a 52 sprocket no problems
Did you mod the lower chain guard .... I ran a 49 tooth for a while, with the stock lower guard...I could not imagine going bigger with that stock guard.

Did it just rub a little and wear off some plastic?

Details on that.
 
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Old 11-10-2009 | 02:16 AM
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Default no highway

ride mostly dirt and back roads big bore kit with fcr carb
 
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