Awhile ago we had a discussion on how rider weight would effect a wheelie, on the same bike. The general consensus was a tubby rider would have a harder time hoisting it up, but could wheelie at a lower balance point. A skinny rider could hoist easier, but would have a higher balance point. Or something like that.
I bring this up cuz I got in a arguement over a similar situation with one of my buddies. At the time, we both had DRZ400s. (Suzuki's kick ass dual sport bike) He has since traded his in on V-Strom, which is now totalled. But that's another story. At that time, we had the same mods on our bikes, stock motor, but geared way down for the dirt. 14/47 vs 15/43 stock.
With that gearing, I found it easier to wheelie the bike in 2nd, as 1st is too low and winds out too quick. I can bring it up in 2nd just about anywhere in the revs, with a little chop/whack on the throttle. He couldn't get his to wheelie in 2nd at all. I told him he's not doing it right, he says my weight is making it so much easier for me to wheelie. I say it's techique, and if anything, my weight hurts me. I outweigh him by approx. 80 lbs.
Sometimes I do scoot back in the seat a bit before I hoist, but to prove a point, I slid all the way forward in the seat, and could still hoist away. He then tried to say I'm leaning forward then back, using my weight to bounce the suspension. So I made sure that I didn't use any body English at all, just chop/whack on the throttle, and still no problem getting it up.
Which brings me to my question. Given that a sport bike's riding position, which by designs puts more of the riders weight over the front end, it seems logical that more weight would be better at keeping the front end down. But the ergonomics on a dirt bike are way different, with a higher center of gravity to begin with, and the rider sits upright, and further back. Is this change in riding position enough to actually give an advantage to a heavier rider? I still think not.
Keeping in mind that acceleration G's are part of the formula on on how much power it takes to make a bike wheelie under power,
(as discussed here) a heavier rider is going to require more hp to generate the same acceleration G's as a lighter rider.
Sound good? Anybody else have any different theories? I still say my buddy just isn't doing it right, and weight really has nothing to do with it. I'm not sure why he struggles with it so, as I don't even think about it much, don't get myself all pysched up, scoot back, bounce the suspension or anything like that, if I feel like a wheelie, I just snap it up. 3rd gear is another thing, I have to do it just right to get it up in 3rd, but boy can you ride em out a looong way in 3rd.
Here's a little proof of my theories in action.
