I just went from the stock 14/42 on my 09klx250s to 14/46. I like it, much better than before. I cruises down the highway at 55 and 60 just fine and I have a lot more low end like I wanted. I also ordered a 13 front but I haven't put it on yet, I'm worried it will drop it too much. Maybe I should have went with 14/47? Thoughts?

 

I ride 75% gravel roads and trails by the way...

 

How many rpm's you runnin at that speed? I need to buy some "lower gear" sprockets when I go on my riding trips. I went the opposite way in gearing. I went 15/39. I cruise the highways everyday at 70-80. 6200 rpm roughly. I can still hit the trails good too. But I wont be goin up really steep stuff. If yer doin lots of nasty trails, that gearing wouldnt be bad for ya. Goin down to 13 on the front might be puttin more strain on the chain and stuff?

 

jvessels:
you may have seen posted before that 3 teeth on the rear is like one on the front. So going from the 42 to the 47 rear is very darn close to running a 13/42. One tooth on the rear isn't enough to make much difference for most of us. I run a 49 tooth rear, and switch between 13, 14, and 15 up front depending on what I'll be doing. All three work for my chain length, and I can change it out in about 20 minutes or less.

It has usually been a 14 up front, which admittedly a 14/49 setup is darned low gearing for this bike, but I do a lot of steep slow crud so it works. And is fine around town. But not much for the highway.

And to add to that, I just put on a new rear tire, which is much smaller than the Pirelli MT-21 that I was running, and it feels like another 2 teeth on the rear sprocket. But I digress...

Bottom line...IMO you should try the 13 on the front. You may not like it, and can easily go back to the 14. No biggie. When removing the front sprocket, I'm not a fan of slamming on the tranny with an impact wrench and instead insert a large socket into the round hole on the rear sprocket and jam that against the swingarm, then use a long breaker bar on the front sprocket. Works like a charm and can even be done on the trail with hand tools if needed.

If you really want to fine-tune or see what 1 tooth on the rear does for your rpms at a given speed, check out gearingcommander.com (cool site)

 

On a related topic to swapping sprockets out regularly, I have always been a fan of clip-type master links.

I have over 150,000 trouble-free street km, plus track time, with these clips on many different bikes. I have NEVER had an issue and I have always suspected that reported instances of clips coming off were due to improper installation...until this weekend that is.

On returning from the weekend in MT on my 919 (during which I was pulling some admittedly silly speeds) I was shocked to see that I was missing the clip from my master link! Luckily the front plate had not budged from the pins, but I am now believing that the pro-rivet camp may have had it right all along.

Just something to consider if you are a fan of clip links like I was.

 

Been debating on swapping my front for a 13T, is the front nut that holds the sprocket on regular threads or reverse threads? Just want to make sure before I take a breaker bar to it

 

I have the 13/42 and love it...can still cruise the highway and got good pull in the trails

 

I posted this in another thread some time ago.

42/14 = 3 or 3 to 1. This is the stock gearing ratio. Meaning for every 3 full revolution the front makes the rear sprocket will make one full revolution.
42/13 = 3.230 or 3.230 to 1. Meaning for every 3.230 revolution the front makes the rear sprocket will make one full revolution. Or 3.230 divided by 3 (Stock Gear Ratio) = 1.076 or 7.6% gear reduction over stock. So if you are going 40 MPH at say 5000 RPM with stock gearing. With the 13 tooth front the engine will have to be running at 5380 RPM to go the same 40 MPH. 5000 RPM x 7% = 380 + 5000 = 5380 RPM.

42/14 = 3 (Stock)
45/14 = 3.21. 3.21 divided by 3 (stock) = 1.071 or 7.1% Gear Reduction.
46/14 = 3.285 = 1.095 or 9.5% Gear Reduction.
47/14 = 3.357 = 1.119 or 11.9% Gear Reduction.
48/14 = 3.428 = 1.142 or 14.2% Gear Reduction.
49/14 = 3.500 = 1.166 or 16.6% Gear Reduction.

42/13 = 3.230 = 1.076 or 7.6% Gear Reduction.
45/13 = 3.461 = 1.153 or 15.3% Gear Reduction.
46/13 = 3.538 = 1.179 or 17.9% Gear Reduction.
47/13 = 3.615 = 1.205 or 20.5% Gear Reduction.
48/13 = 3.692 = 1.230 or 23.0% Gear Reduction.
49/13 = 3.769 = 1.256 or 25.6% Gear Reduction.

So with a 46/14 (stock front) set up you are at a 9.5 % gear reduction vs a 42/13 (stock rear) set up of 7.1%. A 2.4% difference. Now if you went with the 13 tooth up front and the 46 in the rear you are going to have a 17.9%, I would say that would be too much for me.

 

Regular (right hand). CCW to loosen.

 

I've been running the 13-45 setup for 5 years, and I love it. I can do 60 and its got the perfect low end grunt for even the tightest trails.