Handling and turning
Posted May 07, 2016 - 06:33 PM
Last night I put my '11 WR450 back to dirt configuration (from the SM setup I've been running), and decided to keep the 14T front sprocket (instead of going back to the 13), mostly in the interest of speeding up the configuration swap. I run a 51T rear sprocket in the dirt, and with the 114 link chain, 14-51 moved the rear wheel WAY forward. Like almost all the way forward and about 20mm up from where it had been. I run my sag at about 105mm (recently measured) and my forks 5mm up in the triples. Up to this point, I feel that I've had the bike fairly dialed and for a 270 lb street-legalized tank, I really like the handling of this bike off road...or at least I'm really used to it. I steer with my rear wheel a lot, especially of course in the soft sandy trails we have here in FL, and I've come to the conclusion that that's how you have to ride this thing.
I went out today, sag and forks set as described above, and it felt like the forks were up 10mm and sag was around 80. The front end was so twitchy and unpredictable, it wasn't really fun at all. It would knife in at every opportunity, oversteer me into trees, and was exhausting to ride in the sand. I should have turned around and gone home to fix it, but was already out there so I kept going...and suffering.
So that's the lesson I learned today on the effects of wheelbase on chassis setup. Despite two annoyingly painful crashes and a couple/few dumb low speed tip-overs, I am glad I saw how bad a poor setup can screw you up, after having a decent set up for awhile.
So I will definitely be putting that 13T front sprocket back on before I ride it again, which will also get the gearing back to where I'm used to.
I would have never guessed that change to the wheelbase would make such a drastic change to the handling. Lesson learned!
Posted May 08, 2016 - 05:05 AM
Gotta push that rear axle as far back as you can for my tastes.
I run 25/105 and 5 mm on the forks, and stiff damping, and it is pretty much neutral.
All it takes is a slight lean forward or back when seated to go from over to under steering feel.
I just added an additional single link and master to my chain.
Posted May 08, 2016 - 11:25 AM
I ride a lot of long, soft sand trails with plenty of whoops, and often get lazy and just gun it when I get tired (rather than downshift). The bike has plenty of power to handle it, but the result is that the rear-end loses traction trying to keep up.
Long story short, I didn't realize the problem until I replaced the chain and sprockets and moved the rear wheel forward. It made such a drastic difference that I opted to revert back to the previous chain/sprocket combination while focused on sand riding.