So i just ordered a 13 tooth front sprocket then 5 mintues later read that it will limit my top end speed. I use my KLX to commute, but also will ride trails with it eventually. Should I go with a bigger 45 tooth rear instead for more top end speed or will I lose some front end power? I have an exhaust on order and I am trying to consolidate my trip to the shop for upgrades, so I am having all this done together and hopefully will have the bike going quicker either way. DACOONTZ.

 

I have the 13-45 and I can still do 60 just fine. The low end slow technical stuff really loves the new gearing, and I don't ride on the Highway all that much, just enough to get to the next trail or fire road.

 

It's stupid I know, but I like going fast on the highway, and if you ever driven in Utah then you know you have to do some shifty dodging on the interstate, so going 75 to 80 is a must. DACOONTZ.

 

going up in the back OR going small in the front is the same thing, if your only doing one.... if you wanna keep your highway speeds, get a 15 front, and a 39 rear.

 

so there's no way to increase your low end torque and increase your top speed, is there? If that is the case then maybe just leaving my sprockets as they are with the exhaust and re-jetting mods that i am going to do will be enough for now? DACOONTZ.

 

Hmmmm therein lies the dilemma, stock, the bike's power or the lack there of gets in its own way, while the bike comes with gears that should do 75 or 80, the power to gear ratio really struggles to achieve that. The more you go down in the front gear or up in the back the better the power can be utilized, but then you lose top end speed. Sounds like you need a KLR 650 as a commuter bike, and keep the KLX for shorter rides to the trails. You might try just the 13 up front and see if you are happy with the low end and top end combination, but I have a feeling that you will be disappointed in both. I have only 5 miles or less to get to riding areas in all directions, and so if all I can do is 55-60 that's plenty fast enough for me, I wouldn't ride 60 all day, but this setup works for what I need it to do. Oh and I live 2 miles from work, town and well...everywhere, so it reeeeeeeeeeeally works for me.[8D]

 

So putting a 13 tooth front sprocket on the front and then trying to keep up with 65 to 70 MPH traffic on the interstate for 25 to 30 miles each way for work is probably not a good idea, is that what you're telling me?

 

Its going to rev higher, it seems that for every 1 tooth down in the front or 3 up in the back, you increase your RPM's by about 500. You should try the exhaust and jetting first before any gear changes, maybe it will give you the power and highway speeds you are looking for with the stock gears. For the slower technical stuff off road you might be able to compensate with some tricky clutch work.

 

Smaller sprocket on the front, or larger sprocket on the rear = more torque.

Bigger sprocket on the front, smaller on the rear = more top speed. (No, you can't have both.)

Moving down one tooth on the front sprocket (14 to 13) is like moving up 3 teeth on the rear (42 to 45). Either one will "lower" your gearing by a small amount.

Personally, I was not willing to give up top speed, so I have focused on increasing the power output, and I've left my gearing alone.
Gearing is a relatively cheap mod though.

 

thanks for the info, that helps me decide. I will hold onto the 13 tooth front sprocket and see how it feels after the current wave of modifications then we'll see. So smaller in the front and larger in the back for moretrail stuff and larger in the front and smaller in the back for more top end speed or geta bigger engine. Got it, thanks again. Dacoontz.