Letter of the Week: Everything You Ever Wanted To Know About KTM Gearing - Dirt Rider Magazine

First, the KTM EXC versus XC-W (450): Besides the obvious lighting, if I re-gear the EXC to match the XC-F, will they ride the same? What else is different? KTM's website is vague.Second, wide ratio transmission versus close/ semi-close: So how is an XC-W going to ride differently from a XC-F in tight technical stuff like climbing a slow technical hill and in open desert? How is the transmission on a YZ450F going to ride versus the WR450's tranny is the same situation?Third. I don't have the resources to test these different bikes, besides the obvious differences and suspension differences that I can relate to. How come you guys never explain how these different transmissions are going to ride unless this should also be intuitive? Been a long time reader, I can't remember a time you have explained wide ratio versus close or talked about them in your bike tests.I am about to buy a new machine but want to make sure I get the right gearing/ transmission for my riding style. My current 98 YZ400 has a tall 1st and is hard to ride up slow technical hills in the mountains of Southern UT. I am looking at a XC-F/XC-W/EXC 450 or YZ/WR450.**Brad Simmons

St. George, UT**Okay, let's make sure we are all talking about the same bikes here. KTM makes a 450 EXC (street legal) and a XCW-F. Both bikes are six-speed wide-ratio. The internal gear ratios are the same. The only gearing difference is final drive. If you gear an EXC like the XCW it will feel the same. By same we mean that first gear would be significantly lower than a motocross transmission. For technical riding I frequently gear the XCW down with a one-tooth smaller countershaft sprocket. The 13-tooth counter does let the chain gnaw on the chain slider, but I prefer that to having a giant rear sprocket that gets bent on rocks. With that gearing you would almost never use first gear in normal riding. It is to save my bacon when I screw up in second gear. KTM also makes a 450 XC-F, and it uses transmission ratios much like the four-speed KTM 450 SX, but with a fifth gear added. First gear on the XC would be tall like your YZ400. If you gear the XC, your YZ400 or a newer YZ450 down to get a lower first gear, the other gears run out to quick. Not just on top, but each gear is short and too close together for efficient acceleration. When you start with an off-road transmission it is spaced farther apart, meaning the engine rpm drops more from gear to gear than the same bike with a close ratio transmission. For off-road trail riding there are very few if any drawbacks to the wide-ratio. Some very aggressive riders will feel the reluctance to pull each higher gear when traction is good, and it you gear tall for some serious top speed, the engine may be reluctant to pull the gaps between the wide gears. A WR450 has a wide-ratio transmission, and first will be lower than the YZ, but fifth is higher. The spread is shorter overall than the six-speed KTM. -Karel Kramer