From the highest and lowest points the chain's vertical movement.

I've filmed and worked with Dave for 20 years now. He knows the technical terminology, that reducing preload does not change the spring rate, i.e. softer/stiffer spring. That said, every motorcycle comes with progressive springs, or variable rate springs, in which case changing preload does change the spring rate. Adding preload does in fact increase the spring rate to a "stiffer" rate, and reducing preload decreases the spring rate to a "softer" rate. This is verified by the effect it has on rebound damping. He uses the terms "soft" and "stiff" colloquially with riders because those are the terms THEY use and understand to describe a motorcycle with too much or too little suspension movement. A bike with all the preload cranked into the shock does not move, it "feels stiff" to the rider who will use those very terms. Dave's reply is, "We'll soften the shock and get you more comfortable." The term "stiff" and "soft" in this context refer to suspension movement, not spring rates. But, if you want to have a spring rate discussion he'll be happy to engage you. I have filmed and interviewed the best crew chiefs in the world, both WSBK and MotoGP. Dave is definitely one of them, a tuner at their level. The number of times we sat on the hot pit wall and he predicted the changes the crew were about to make on a bike are innumerable. He was never wrong, not once.

​@@MotoFeeder Thanks for your response. I am not writing this to put anybody down, but your response just proves my point, you're also misled, and you've got preload all wrong. If you sit on a bike, and you have the slightest amount of rider sag, the suspension compresses as easily no matter how much you've cranked up the preload (with the damping and rebound settings unchanged, of course)! The springs are the same, and the stiffness doesn't change with preload! Theoretically, the angles of the suspension linkage can change by a very small amount when the rear shock is extended (which is all that happens when you add preload to a shock, unless the static sag is zero), but its impact is so little that it can be ignored in this discussion. It is basic physics! It doesn't matter if you have linear or progressive springs in your forks; changing preload doesn't change the installed length of the springs (unless you have zero static sag, in which case your springs are far from suitable). It only changes the total length of the forks, i.e. the height of the front! The installed length of the spring is the same, no matter the preload (static sag not being zero)! If you add preload on a fork, the adjusters are screwed into the fork caps, but they do not compress the springs, they actually lift the fork caps and with them the triple tree, and the height of the front. It seems you are making the same mistake many others do, while also being misled by DMT. The geometry of a bike is the first thing you must set right. E.g., if you are too heavy for the bike's springs, you can't correct the problem with preload. You can change the sag and the starting point for the suspension movement, but not stiffness, at all! I take it that you have worked a lot with DMT, I am sure you've filmed many crew chiefs, but if you do not understand what I wrote above concerning preload, you are in no position to understand any technical suspension information from a crew chief. Preload is very basic, and the first thing you must understand when you set up a bike properly. Next time you talk to a professional crew chief or suspension specialist, ask him to explain preload to you. To Dave Moss too, if he's there with you. No disrespect intended. If you, or DMT, would like to discuss preload more in detail, I'd be happy to oblige, in writing or live on video. Sincerely, Nik

@@6114457 You should email Dave directly, [email protected] with your concerns and test his knowledge yourself. He WILL reply. He replies to 100% of his emails, even tho he gets 300+ per day. You wrote, "If you sit on a bike, and you have the slightest amount of rider sag, the suspension compresses as easily no matter how much you've cranked up the preload." I have hundreds of hours of video footage in direct contradiction of your assertion. Perhaps the word "easily" is the disconnect here. Sit a rider on a bike with all the preload in the shock (ducati panigales are famous for this off the showroom floor) and the shock will not compress. Remove 3 turns of preload and the shock will then compress 20mm when the rider sits on it. What's more, since the shock is in plain view on the side of the bike, you can watch the spring elongate as the preload is removed. Further more, it is easier to compress the rear suspension 20mm with 3 turns off the preload than it is to compress the suspension 20mm before the change. Dave's website and youtube channel are FILLED with video footage of these very things happening before your eyes. I understand with a straight rate spring the same amount of force applied compresses the spring the same distance no matter where in the stroke. Let's say a 200 lb rider sits on a bike with no shock preload and the shock spring is at its free length, and he compresses the rear suspension 20mm. If you add 200 lbs of force to the spring via 4 turns of shock preload, when the rider sits on the bike the rear suspension will not move. I've hundreds of hours of film documenting this very scenario. We're having some sort of nomenclature disconnect here.

this is Dave Williams, the guy sitting on the bike. You'll find Dave Moss over at his channel DaveMossTuning

Great video, of course!

It had to be done. 😂

Excellent. Yes, without suspension data loggers, the single greatest source of data is tire wear. I hope you subscribe to his website, davemosstuning.com. All the info is there to become an excellent suspension tuner. Understanding spring rates, shim stacks, blah blah is another level of course (at which Moss is excellent as well), but all the info is on the website to become great tuner. It's amazing how many people are riding poorly or untuned suspension at expert lap pace. Obviously speaks to their inherent talent level. But with a basic tune they ride even faster. I cannot tell you how many times I sat on the pitlane wall with Moss at national and world events listening to him predict the changes the team were gonna make to a bike, and then watch the team do exactly what he said.

I would suggest watching some Dave Moss Tuning videos, particularly on ergonomics.

Actually, the Yosh data guy at the time said he couldn't do much with their crude TC (called "spin control" because it did NOT use wheel speed sensors) to help Spies because he was so good with the throttle. But he could really help Mladin because he spent so much time at wide open throttle compared to Spies. DuHamel may have lost to Mladin because of "spin control" but he lost to Spies straight up.

Yes, its him.

Yes, from our OnTheThrottle.tv days.

Listing from inexpensive but good quality through to professional best quality, Vortex, Woodcraft, or Attack Performance

@@MotoFeeder thanks so much I just purchased the bike so I'm trying to make sure I replace the right stuff and get some gear to wear. Liked and subscribed

@@mikedyniin3102 You'll get the most out of your bike from watching the Dave Moss Tuning channel. Suspension is 95% of the deal, tires are 4%, and EVERYTHING else is 1%; in terms of bike performance.

this is Dave's channel. I'm sure there are answers there. kzbin.info