Today, I was again at Glen Helen and there were again Casey and
@Bob Casper. Yesterday, I was struggling with choppy braking and acceleration bumps, and with the front end not following the ruts well. So I asked Casey for help again. This time, he rode the bike a few times, then I rode it too a few times, and this is what we came up with:
1) The
tire pressures needed to be increased. According to Casey, and this makes a lot of sense, these bikes require much higher tire pressures because they are heavy. He found witness marks on my rear wheel showing where the
tire was rolling over and
contacting the side of the rim much more than it should have. I was under the impression that the less the pressure, the more traction, the better, as long as I don't get rim contact or a flat. What I forgot is common sense and all my automotive engineering. Low pressures might be better for deep sand and or rock crawling, but for a proper contact patch on pavement or on a hardpack track you need proper tire pressures. And so, my traction was okay, as long as I was smooth and nothing unusual was happening, but if I suddenly went more aggressive or hit some bumps, all of a sudden I was losing a lot of traction, control, and a lot of confidence! Pumping up the tires to higher pressures restored this over-the-limit traction, consistency, and confidence!
The stock Pirellis have very thin and much softer sidewalls than most Dunlops, Bridgestones, or Michelins. Stark likes them because they are very light and cheap in Europe. They need to be run at much higher pressures than 13.5 psi.
2)
Front compression 3 clicks stiffer. That made my fork ride higher in the stroke, which gave me a bit of that choppered-out feel. I do not always like this feel, but it often allows me to ride more aggressively. The ride in the choppy sections became much softer (the spring force is smaller higher in the stroke). Also, the bike started to track much better through ruts because the position of the front wheel became more consistent. The flat-turn handling suffered a little bit, but with the fork moving less the bike became more predictable. Ultimately, too much fork compression damping was bad too, so both Casey and I tried multiple settings and found a happy compromise between the rutted and the flat turns, which also happened to have given us a softer ride in choppy sections.
Here are the updated settings:
| Rider | Weight | Skill Level | Primary Riding |
| Philip | 195 w/o gear, 225 with gear | Intermediate | Motocross |
| | | |
| FRONT Suspension | Factory Default for 90/95 kg | Philip's Settings (by Casey Casper) | Delta from Factory |
| Top Clickers - Comp Low | 10 | 14/15 | +4.5 |
| Bottom Clickers - Reb Low | 12 | 14/14 | +2 |
| Fork legs above the triple clamp | 2.5mm | 5mm | +2.5mm |
| Front tire | Pirelli | Bridgestone X31 @13.5psi or higther for Pirellis | |
| REAR Suspension | | | |
| Silver - Comp Low | 12 | 16 | +4 |
| Blue - Comp High | 14 | 12 | -2 |
| Red - Reb Low | 10 | 10 | |
| Bottom - Reb High | 15 | 15 | |
| Rear Sag | 105 | 105 | |
| Rear tire | Pirelli | Bridgestone X30 @13psi or higther for Pirellis | |
Two more things that are not quite suspension-related, but still improved my control and handling since the last update:
- I rolled the stock handlebar forward to the +1.0 setting (search the forum).
- I installed a Guts Racing RJ Wing seat cover (search the forum).
