Motorcycle Suspension SAG Adjustment Street 

Agreed Jon ... Rod often gets crucial facts wrong, I've pointed stuff out in the past to help him correct his errors, but he seems to not accept corrections, seems he thinks he knows best ... He does put out good content but the errors spoil it for us in the know.

Thanks Nuno!🙏😁

Glad it helped! Once you do it, you'll see how easy it actually is.

That's great to hear!

Wow, thanks!

Thanks Barrett 🙏

Thanks for the feedback & the View!

Thanks Graham 👍🏍

So what you are saying is ' lose some bloody weight ' . Lol

Thank you Claudio!

Thanks for the feedback & view!

Thanks for the feedback & view!

Thanks for the view! New video out later today👍

Here is the math on MY bike; Total available front fork suspension travel, wheel off ground is 122mm which is my L1 number The sag I am looking for is between 25%-33% of L1 or 122mm on my front forks only. The 38mm sag I set is 31% of the 122mm I started with. What this means is, while I am sitting on the bike, in gear, there is 84mm of suspension travel left or the L2 number. This is covered at 03:53 of the video. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-g8cb1vUhcaA.htmlsi=3wdOxC6C3wR0mSbB As for the rear, I am only looking for that same 38mm of sag since I want the bike to ride level. If I want to get aggressive with the steering, I can decrease the rear sag (raise the back of the bike and angle it forward using more preload) but this will sacrifice ride comfort by stiffening the rear suspension feel. None of the numbers you sent for your bike mean much unless you can tell me; 1 - what is the suspension travel with no weight on your front forks, wheel off ground? This is your L1 number and the most important. 2 - what is the remaining front fork suspension travel with you wearing your gear, bike on ground no kick stand with you on it? This is the L2 Number. L1 minus L2 = S1. The Sag or S1 number should be between 25% and 33% of your L1 number for the front forks. The numbers on your bike and my bike can be completely different since different motorcycles have different suspension travel, springs, damping and riders are not all the same weight (I wish…). Just dial in the front forks to get a sag value S1 between 25% and 33% of your total available suspension. Then whatever that actual value of your fork S1 number is, in mm, match it to your rear suspension so when you sit on the bike in gear, your bike is level.

@@RodRidesWrenches I just do it a different way, I don't use the L1,L2 system as it gets too confusing for me. I've taken a Dave Moss suspension tuning course and learned from that. The only problem is I'm not good with the L1 S1 numbering so I also find percentage too confusing. I came up with the exact same number using another method which I find easier for me to understand. I can see your advice is very clear and concise but I can not do percentage as I'm number dyslexic.

Wouldn't be the most comfortable two up machine for any length of time IMO. If she's small and likes to corner on the bike though... I know I would love to tour Spain on my 1200F! 😁🏍

It's not that precise since you may want to adjust based on your speeds or road conditions and personal preference. Also the difference between 25% and 33% is like 1 cm in height on my VFR, whether your fuel tank is empty or full, whether you are in full gear like i was or jeans and a t-shirt should play a roll in your target percentage. Empty tank no gear 25%, full tank in gear 30%. But don't stress it, just get it close and your ride will dramatically improve.

@@RodRidesWrenches dont worry i just needed ball park, i dont ride a ferrari

So true!

Hello Filipe, YES you need to adjust the suspension when you add weight. Most of us would just up the preload on the rear shock but if you plan on carving some road or going the distance you may also want to up the preload on the front forks. The vague feel you are getting from the front of your bike is because the center of gravity has shifted rear so you've unloaded the front tire. When braking this weight shifts forward and you can bottom out the forks if you do not have enough preload. As far as damping, this is adjusted to match the speeds you ride and roads you are on CanyonChasers explained this well in this video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-pLFKgGuEkaY.html

Hello Thomas, when you say compression in motorcycle suspension this refers to how quickly the shock moves through its stroke as this adjustment stiffens or relaxes the hydraulic pressure against the piston and that why it is called compression dampening. Compression does not affect the shock the same way that preload does which is just on the spring. Your bike's service or owner's manual will have a factory recommended compression setting the technician would have set it to for "out of the box" PDI, from there adjust your preload to get the sag you need. The compression and rebound dampening can then be fine tuned for the roads and speed you're travelling to soak up the bumps and keep the tire on the road since they control how quickly the hydraulic part your shock moves through the stroke. You want your shock to absorb the bump but not be so soft that the hydraulics are not supporting the spring, the bike will wallow. The compressions operation inside your shock will also be affected by the speed at which the shock is moving up and down; this is why when discussing compression we often talk about two variations. - Low Speed Compression Damping Compression damping that occurs when the vertical wheel movements are slow. Such as when going through a dip or gully or on the forks during braking. - High Speed Compression Damping Compression damping that occurs when the vertical wheel movements are fast. Such as when hitting anything that has a square edge like pot holes, expansion joints, some railroad crossings, very high speed braking bumps. Again compression dampening is controlling hydraulic fluid movement during the compression of the shock only. The opposite of compression is rebound which controls how quickly the hydraulic fluid returns into the piston chamber of the shock when it expands. Here as well is a balance to move the shock back to a normal ride height once compressed otherwise the shock can become very "light" bouncy like a pogo stick, uncontrolled rebounding (not enough rebound damping), or "heavy", when the wheel extends so slowly after being compressed by a bump that it does not return to the proper ride height when the next bump is encountered. Caused by excessive Low Speed Rebound Damping. Set your sag as I mentioned above. Then make adjustments to your compression and rebound to deliver the smoothest ride you can based on the speeds and conditions you ride in. Compression and rebound are designed to be easily adjusted for a reason, as you change where you ride and how fast, the compression and rebound dampening can change to deliver best suspension performance. Preload is a more static setting for street riding and is about your own weight and the ride height of your bike. I have a motogp video that may also help explain the differences between preload and compression/rebound dampening - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-aOlDGxTN9vI.html Good Luck!

If you prefer you can use the steering yoke in the front as the measuring point but if you have inverted forks you're just using bigger numbers for the math for no good reason. At the end of the day we are only looking for percentages of 25-33% of sag from the suspension being unloaded and not supporting the bike to you in your riding gear sitting on the bike. A equal percentage of front sag to rear sag means the bike is sitting flat. Dave Moss may make it easier for you to understand. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-7Br-LcnCOWs.html The points on the rear from the axle to the seat are used because it is not possible to do the same measurements you can on the forks due to the external springs and other things obstructing access to the rear shock. Again all we are looking for is a percentage of the total amount of sag with the weight on the bike. - Good Luck!

@@RodRidesWrenches Lets say we measure from a point one metre away. And the difference between unloaded and loaded is 3cm. That is 3%. Or we measure from a point 10cm away, and the difference is 3cm. That's 30%. My point is - that arbitrary measuring datum makes a big difference if we are looking for a percentage figure. (Obviously, if we are looking for an actual number (e.g. 3 to 4cm of rider sag) then an arbitrary datum works fine.)

@@markdale1720 If the 25-33% of sag you've dialed in on the front forks is 3cm of physical distance then this is the allowable amount of sag you have to set in the rear. As long as the measuring points are between the axle and as close to vertical point that is sprung and attached to the bike, like the seat or fairing. Whatever the amount of sag that was set in the front of the bike in a physical distance is the amount you want for the rear. 3cm is 3cm doesn't matter if you have a 10 meter pole attached to the passenger pillion of you bike, as long as it is vertical you want a 3cm distance from unloaded suspension to you on your bike. In the video I thought it was quite clear that the adjustment to the rear is 38mm on my bike which was equal to the physical distance of sag in the front forks ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-g8cb1vUhcaA.html

Yes and the Pemberton Valley

How Much Fuel is in your tank when you normally ride? That's the answer, but FULL Tank has the most weight so best to use a full tank for preload settings, you can always back off a half turn at a time is you find it too harsh.

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Hello Jamie, the springs do not physically get harder or softer but from the riders perspective the suspension feels harder by adding or softer by removing preload. Adjusting preload changes which coils are engaged on the spring initially, this is more particular to the resistance of a progressive spring as apposed to a linear one but the rider perspective can be influenced by preload even with linear springs. Simon Crafar maybe has a better explanation for you, I've cued this up ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-lM5tnO9WT9k.html I felt making this distinction over what the rider feels was overkill for my message since this is what the rider interprets and unlike others I was not trying to get into bike balance aspect since my goal was a flat bike, equal preload front & back.

Here’s another theoritian b.s. statement : more preload definitely feels stiffer when you ride because it reduces compression movement

@@paolozak3014 that only applies if you run out of suspension travel. The scientific fact is that the spring rate remains exactly the same.

@@RodRidesWrenches that sounds like good sense, but the the spring rate remains exactly the same. Removing scenarios where it tops / bottoms out, when the bike hits a bump, the spring absorption of the bump is exactly the same with no preload or max preload.

Adding preloaded does make the suspension firmer. At zero preload the first 1N of force will be distributed equally along the full length of a progressive spring. However, the wider coils area is at its highest proportion of the overall length. And the resultant displacement will be governed by the overall tightness of the coils. So in simple terms, smaller forces will have more impact on resultant spring length in the non preloaded setting. With a preloaded setting, those same smaller forces will have less impact resulting in a firmer ride. This is a brilliant video that gives excellent advice and I've saved it for when I need it

Thanks New Video is out today! ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ZboWgG6R9J0.html

Adding or reducing preload absolutely makes your suspension FEEL harder or softer. Where guys like you get confused is when you read half an article or watch half a video and miss the point. The spring itself does not get stiffer or softer AND THAT IS NOT WHAT PRELOAD DOES. Adding preload compresses the spring mechanically and this makes the suspension FEEL harder preventing the shock or fork from bottoming out. Preload compensates for your bike's actual spring rate. EXAMPLE If your spring’s rate is 1kg/mm, when you compress the spring by 1mm, it will exert a force of 1kg back. When you turn the preload adjuster and add 5mm of mechanical compression or preload, the spring would exert 5kg back. To compress it further, you’d need to apply more than 5kg of force. The spring exerts more force back while under preload than when there is no preload so it FEELS harder/stiffer. Reducing preload makes the suspension FEEL softer and the shock or fork may bottom out, depending on the weight and forces on it. In this video I am using simple terms to illustrate the importance of preload adjustment for everyday riding. For the average rider when you add preload your suspension FEELS harder. For linear rate springs the actual spring rate does not change, duh, but that only means something when the spring is out of the shock or fork sitting on a bench. I’m pretty sure I addressed the impact preload has on a progressive spring in the video but for your benefit I will explain again. A progressive spring typically has two spring rates, how quickly the fork or shock transitions from one rate to the other depends on the preload settings, weight and load forces exerted on the bike, the spring rate actually changes in this case, that’s why they are “Progressive”. Please see these links to Dave Moss, obviously another rookie, ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Jlbca0SIxhw.htmlsi=2vlRGr3W6e2JBZC3&t=87 and Penske Racing, read the whole thing, especially the part about why you adjust spring preload. www.penskeshocks.com/blog/motorcycle-spring-preload-what-it-does-and-why-we-would-adjust-it#:~:text=It's%20important%20to%20point%20out,your%20shocks%20are%20fully%20extended Thanks for reminding me there is still a lot of misinformation out there!

@@RodRidesWrenches School in session!

Dude you LITERALLY said it makes the suspension stiffer on 3:27 . It doesn't make the suspension stiffer. It makes your front GOING UP OR DOWN in relation to the amount of energy introduced in the spring with the preload to keep you in a safe range of motion with enough travel left and correct geometry. That has nothing to do with FEEL. That is pure an basic SAG, and nobody talks professionally about sag in terms of "stiffness" or "softness", but in terms of milimeters / inches, because that's what is all about. You don't need to write the bible to explain me what you didn't in your video.