How To Check Motorcycle Suspension Sag | MC Garage
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- เผยแพร่เมื่อ 26 ก.ค. 2024
- Measuring and adjusting suspension sag are the first steps in setting up any bike’s suspension. An easy way to think of sag is as a measure of how much suspension travel is available to extend down into dips like potholes. Having the proper amount of sag is important for many reasons, including ride quality and handling. Do you know how to check suspension sag? In this video from the MC Garage, we’ll walk you through the process and provide tips for determining if the spring rates in your bike are right for your weight. Watch the video and then head over to MotorcyclistOnline.com for the latest features and more tech tips.
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Fantastic - Clearest most thorough explanation of sag setting Ive ever seen in years of riding! Top work and greatly appreciated guys
These garage videos are awesome.
Another great video guys. I should get my local Ducati shop to watch this 'cause I took my bike there a few months ago to get a suspension adjustment. They hadn't a clue what they were doing.
Keep these coming! You guys are awesome at these videos!
You guys are doing an amazing job!
Keep up the good work!
Loved all your videos!
Thanks!
Just stumbled upon this channel. I'm really excited about the new knowledge I have. Thanks for sharing!
0:32 1/3rd to 1/4th of total distant travel
L1, no load measurement
L2, load with rider pushed down showing upword drag
L3, load with rider pushed up showing downword drag
2:20 Sag = L1 ((L2+L3)/2)
Desired Sag = L1 * .33 to L1 * .25
.295 ( ± .075 ) * L1 = L1 ( ( L2 + L3 ) / 2 )
Just taking some notes
The mistake being made is that the total exposed slider is in no way indicative of the total travel. So all we know is that there is some amount of sag. We have no idea if the measured number is 99% of the total travel, or .0001% of total travel since we do not know where the suspension bottoms or tops out.
So this was a nice video, but it's incomplete as it does not address the 1/3rd to 1/4th portion. All we know is there is X millimeters of sag.
@@PrivateUsername That is quite right. however total (or better to say max theoretical) front / rear suspension travel is normally given in the bike's specifications
You forgot a minus between L1 and the 1st bracket, just a heads up to anyone like me who is scratching their head at the high number they got by multiplying there :D
@@PrivateUsername on the front this is not a problem because u can measure the distance left but the rear, how would u approach that?
@@PrivateUsername Yeah, with this in mind, I think this video's suggestion is actually wrong and possibly dangerously inaccurate. If you set up 25%-30% sag to the length of the shock's rod showing and especially some fictitious value gained from the backend, and not it's true available stroke, then you are setting it to something more than it should be. This is also assuming this percentage is also accurate. Front shocks don't bottom out where the rod showing is completely gone. They bottom out earlier.
Let's test this:
Shock Rod measurement (as in the video):
L1=135mm L2=87mm L3= 97mm
Sag = 135 - ((87+97)/2)
Sag = 43mm
Desired sag= 33 to 45mm
So, the sag measured was at the "bottom" of the desired sag. I'd also add some more pre-load, but someone lazy might not, saying "it's still ok".
Now, let's do it with the stroke of the front shock's cylinder (Ohlins it seems full stroke is 120mm):
L1=120mm L2=72mm L3=82mm (taking off 15mm to match values 135-120)
Sag = 120 - ((72+82)/2)
Sag = 43mm (aha, the same...!!! So, that's ok.)
However....Desired sag= 30mm to 40mm
In other words, had the dude said, "it's within the desired sag, I'll leave it", he's actually over the desired sag and might end up bottoming out the cylinder in a pinch, which could be fatally dangerous. 43mm is 36% of 120mm stroke. That might still be "ok", but as we can see the suggested method here isn't completely correct, as you've pointed out and I think I've proved. I think the measurements in the rear would be even more false. We'd need to take some geometric calculation into the equation too, i.e. the angle from the attachment point of the swingarm to the point of connection of the shock to where the measurements were taken. Not easy. I also have learned that the sag on the rear should be less than the front. I've learned, 25-30 on the front and 20-25% on the rear. I don't know if that is true or not, but reading around, every other advice suggests at least a 5%-10% less sag in the rear to the front.
Note that for 2016 and newer FGRT Ohlins forks, the manual calls for 15-30mm (front) and 10-20mm (rear) of free sag. With "rider on" (what Ohlins calls "Ride Height") the sag numbers are 25-40mm (front) and 35-50mm (front). So you can see it's a wide range and it varies between front/rear. The principles for measuring sag in this video are spot on, just check with your suspension manufacturer on sag ranges; there is no one size fits all sag number or ratio.
these "how to" videos are class! keep them coming!
Excellent intro about why setting the sag is so important. Bravo!
Really digging all the content you guys put out. Quality stuff
Awesome video ari!! Very easy to understand and do
Fantastic video, straight to the point and well explained!
Thanks for the quality info!
Excellent demonstration of how to!! Thanks
This is really good information! Thanks!
Really nice and useful, keep it up!!
I love that there are no dislikes. This channel is a godsend for motorcycle enthusiasts.
GT6SuzukaTimeTrials I dislike because he has very veiny arms
Way to jinx it 4 years ago. This is your fault
This aged well
TH-cam has gotten politically correct, I suppose, and doesn't show the thumbs down or dislikes that are entered anymore. A definite snowflake society move.
Sag is so important! Hey Ari...have you seen the Motool slacker sag setter. It's great for those of us who can't get an extra person and explain to them what to do!
I check sag more often know! Keep doing awesome vids!!
Awesome tech tip Ari! I doubt my K bike will have much for adjustment up front. My rear suspension however is aftermarket that the previous owner installed. Progressive is the manufacturer. Hopefully I can adjust it properly for a better ride.
excellent video. it was worded and presented well
The second case from 3:56 should be: "If you pulled all the preload out and you still have too little sag..." not "... too much sag..."
Caught that too.
Yep that statement doesn't make sense.... if you have no preload and too much sag you have no idea if the spring is too stiff or too soft. May be he meant to say that if you have no preload and not enough sag then the spring is too stiff, or if you have maximum preload and still too much sag then the spring is too soft?
But even that isn't necessarily true because the spring may be the correct stiffness for the rider's weight but may be under too much installed preload. I found out from another youtuber that Ohlins sell different spring clips so the installed spring length (preload) can be adjusted beyond the adjustable range.
now I understand better, I had an idea but the L1 & L2 measurements made it easy thanks
You guys are killing it with these videos. Simple, clear, to the point. Thank you so much!!!
Great video, thanks :)
fantastic info
Seeing this in 2020 .... Geat video 🔥🔥
Great video
Averaging is a nice twist of being precise I haven’t seen in other suspension how tos 👍🏼✌️
Wow no fuss and all good information! Well done with these videos and keep them coming!
May the forks be with you!
This video was EXACTLY what I was looking for. Thank you!!
Great help
If youve maxed out preload, it's a sure sign to lose some weight buddy
You can be heavy and not fat by being taller and/or muscular.
Ernesto Castellanos you can be heavy If you build a lot of muscle, and that's a healthier lifestyle than you probably.
Great info Ari, I've lowered three bikes for my wife over the years. It's difficult to do and maintain handling, safe ground clearance and reasonable travel. Would love to see your input on this topic.
lol shut up simon youve clearly never worked out a day in your life. "if you cant run a 10k, youre not healthy" WELP BAD NEWS EVERYBODY HEALTHY DIETS AND A REGULAR WORKOUT ROUTINE DONT MAKE YOU HEALTHY... MEMES DO?
Lmao damn 🥲🤣
this is just brilliant . even has a mathematical formula...eternally grateful
hey budd great vid and thanx for doing it!! just one thing u said if u take out all preload and still have to much sag" guessing what u meant was if u take all preload out and u still dont have ENUFF sag then spring is too stiff!!
your videos are great! can you make a video on Liner and Progressive suspensions?
greate vid.
wow thanks!
make suree the fork tube is lubed because a new seal can cause stiffer move ment great concise vedio!
That dude is sitting so incredibly still.... he is almost invisible
Drax said that
LIKE A STATUE HE IS VERY GOOD !
where? i cant see him!
@@Mad8vCycles He is now in Revzilla's channel
@@dainesetube still cant see him... must be really sitting still
Wow, that was very detailed. Can you tell me a quick method for knowing how much preload I need to add for riding with a pillion? I'm quite comfortable with the standard preload on my MT07, but I have no idea how much I need to adjust when riding with a pillion.
That's a nice R1 you got there
Dude I've tried your formula on my 2019 fireblade and it worked brilliantly, and without riding it again I did one turn extra and then everything was set out even after I I took the turn back on the pre load and since then I cant get my settings correct any help with be appreciated
do you have videos on rear suspensions between dual vs mono?
Dave Moss secretly hates you. All those teasers he puts out. I’m not paying for no suspension set up. Sorry Dave. Thanks MC garage. Best video ever.
could you use a front and rear stand as well to accomplish the same job as the wheel chock?
I miss these two
Hey Ari, do you have any insight on these top-out springs and how they affect sag numbers. It can completely change the results. It's a bit confusing and I don't understand
Thanks for the videos! A great help for me in getting to know my bike. I have an R1S I’ll be getting next week and I’d like to adjust the suspension for me. Is it really that necessary if I’m riding in the city and freeways or more just for track days?
It doesn't matter where or what you ride. Adjust not only your suspension, but the angle of you clutch, front brake, shifter & rear brake lever. MC's are not cars and are infinitely adjustable.
Great vid! I'm assuming that for a bike with a non-adjustable front suspension, perhaps just check the differences to see if it's a partial indicator the seals are potentially bad? Mine only has pre-load out back. Thanks.
+Ari Henning Great tip, thanks! I have a '94 Yamaha Seca II so it's pretty basic. :) Mine came in great shape from its previous owner, so that helps a lot.
I think you guys ought to host a riders' event! It'd be a good excuse to visit CA again. Or maybe you already do, in which case carry on. :D
i want this guy as my mechanic
Where do I find the tolerance figures for my bike? Great info.
Does the electronic suspension like the one you found on the Panigale S or R1M need sag adjustement or the electronic does it for you ?
Dave moss also says that forks have a bottom out point which is listed in the manual, mine is 110mm travel
Great video, your method is easy to apply. Question though, I watched a few videos by Dave Moss, and he presses down on the bike and raises it slightly, and he goes about adjusting, all without a rider. What’s the difference, is his method as accurate...is he some sort of “suspension whisperer”?
Outstanding video. At the beginning you said adjusting suspension is one of the very first things you should do to a bike. One thing I may have missed is, why is this so important? Is this specifically to determine if your springs are right for rider weight? (rake, trail, ride height are "in the right range"?) So then, in a sense, when bikes are sold with stock springs, this is to cover the masses, not a specific individual? And this rider sag measurements are critical to identify if the spring you have is right for you as the individual rider, not the masses? Sorry, suspension is very new to me.
I live in a third world country riding a 110cc underbone making 300$ a month. Why am I keep watching these?
to inspire you to do better and be better future my friend no country stay third world forever and no one stay poor forever
@@GPOLICE no you :(
150cc 13BHP here XD
@@14moldyhamsandwich in the 1st and 2nd worlds, maybe?
@@TakumisBizarreRacingAdventure 3rd world is not a rank. It's a fraction.
OK now how much L2-L3 is acceptable (stickiness)?
My owners manual says to turn the adjusters counterclockwise to add preload, and to turn it counterclockwise to decrease preload. So, as long as I turn it counterclockwise, I'm good. Thanks Kawasaki!
Installed preload front and rear must be between 8 and 15mm to achieve desired sag. If you out of that range - change springs.
You completely demystified what the hell preload even is for me, and at 4:20 on the timestamp at that.
This is a very interesting topic, congratulations on covering it thoroughly. Plus, the clarification concerning SAG and spring stiffness was well put at the end of the video. Having said that, I have some questions. In a video from D.Moss, evaluating Suzuki's DL650 suspension, he mentions that, because most of rider weight falls at the rear suspension, changing front spring preload will not have a difference in the measurements despite evaluating different weight riders. Instead, he advises on using a ziptie at the fork to evaluate suspension movement during use, so as to assess whether preload is needed or not. Does body position on the motorcycle play such a significant role in measuring SAG? Can the measurements be thrown off completely due to different bike ergonomics? Lastly, since the rear suspension seems to support most of rider's weight (in the case of the DL and other rear-heavy motorcycles), should measurements be made to the rear first and then adjust the front, considering that preloading a spring will tend to give rise to the suspension of the corresponding end?
Thanks!
Thanks Ari
I recall hearing the same thing in his videos. He isn't always the clearest. It's a bit confusing definitely
Hi! Thanks for great video! A question ; l'm 135lb and use kx250f, my sag is 65. I can't make sag higher because the spring level is on almost max. If l lose the screw of the spring more, the spring starts to moving and wiggling. What should l do to make sag higher? Thanks.
If i backpack someone frequently do i need to adjust suspension for more weight?
Will it be ok if i do my adjustments on with stands ?
Whats the recommended sag for a supermoto? Ktm 690/Husqvarna 701?
Hey Ari,
could you make a video on how to check and correct fork twist!
akshay badami: th-cam.com/video/pNEmOqY02EU/w-d-xo.html
What about pillion is carried from time to time? It will be different for one person and two people. How to get the best set up for this?
Question: after getting total distance of wheel travel with the wheel off the ground I’ve always set sag using the difference of free sag (the bike on its own weight no rider bike balanced vertically both wheels on the ground) against rider sag (the measurement with fully geared rider balanced, both wheels on the ground). So a total of 3 measurements total wheel travel, free sag, and rider sag (yes I take an average of 2 readings for each measurement so I measure 6 times total but use those 3 averages for calculations) I’ve been doing it that way for years and it’s even how it’s done on my ohlins app. That second measurement free sag wasn’t done here at all and I’m wondering why they were skipped and also how that affects the target sag numbers
Hey Ari what is preload and slag?
Great video! If the sweet spot for rider sag is 1/3 to 1/4 of total travel... how do I measure the total travel for both front & back?
What is sag figure for 1996 cbr 900rr? (919cc 128hp,sc33)
Do local dealers do this type of work or can I request to have this done during the purchase of a used bike from a dealer.
I have a 2015 r1, I'm 5'6 and weight 163lbs, how do I loosen up the rear suspension so I can 1 foot the bike better, it's a little too tall for me
If i lower only the front about 2cm will i have better cornering or isn't safe?
I get measuring the full piston exposed. But don't you have to consider what max travel would be ? Therfore having some piston area that wouldn't be considered going insider the fork when bottomed out
I have a question. How do you know the total travel in the first place? From the manufacturer’s data or the owner’s manual?
What if I change my suspension to an aftermarket product? Will the travel still be the same?
It kinda bothers me and I appreciate your answer. Thanks.
To much for my Piaggio fly. When i push down front two or three times goes to the end down, that mean front suspension is over. Thanks a lot!
Hi Blue Stig!
Can u show how to shorten a bike by adjusting suspension ?
Should of payed attention during MATH CLASS NOW IM STRUGGLING 😂
You should have also PAID attention in English class! 😉👍
To get a true reading the oil in the suspension should be up to the right temperature!
Is front fork sag adjustable without having adjustable preload? I'm having new springs installed on my bike and was wondering if the correct sag could be set during that process without the forks having adjustable preload.
My fzs rear suspension making noise ??
My bike's front showa upside down suspension goes down quickly but when doesn't come back to its first initial position. Is it normal?
hey mc garage can you guide about r15 engine roughness and decreased pick up
Hey bro plz help me i got the problem on my steering on my motorbike i replace evrything like right shock chcked the wheels tires bearing replaced and t too bt also m nt getting it right plz send me the solution
Guys,s the magical number (40mm) what you mentioned a setting for race tracks ? what would be the number i must have to ride comfortably without breaking my spine in streets which are of average grade ?
40(35-45)mm is good for street on a bike with 120mm suspension travel.
My brother and I were looking for sag percentages for cars, every search always comes up with motorcycle values. With that as the only available information, we set his car to have about twenty percent race sag. I'm surprised more information about car suspension isn't as readily available as motorcycle suspension.
+hmushmann2 In automotive terms it's called droop.
Just wanted to clarify if you pull out all the preload and you still DON’T HAVE ENOUGH sag then your springs too stiff...in the video you said if you pull out all the preload and have TOO MUCH sag you have too stiff of a spring, at that point you would just give more preload so it sags less correct?
My rear sag for some reason is equating to 4.05 as a number and my values are l1=62.6 l2=58.5 l3=58.6
Should all preload come off before doing any measurements?
You say you adjust the 43mm to the "appropriate" range. How do I know if the range is in fact appropriate? Is that in the manual as well?
how a calculation motorcycle weight and suspension
we should mention the different of spring. a progressive spring has a lot softer and that would have nothing to do with another spring rate coil down there. i have two progressive spring rear shocks they both can reach the average sag number which is 1/3 to 1/4. but the different is shown how a softer spring act when i wear full gear adding weight like 7 kgs and a softer spring will spread more rider sag number than a stronger one. of course on riding it is easier to get the feel which one is softer.
When you change your rear suspension, the pre load settings come as per factory default... While installing it, should the settings be changed or should we install the suspension directly and then make the adjustments?
Asking this for a KTM duke 390
Preload is supposed to be adjusted once u have the suspension installed in the bike.
Everybody who owns Honda there is motorcycle MD. Should check him out too.
Alternatively use a tie wrap around front fork inner assembly as a measurement tool for front adjustment...
Mountain bikers do this too but are not necessary as most forks come with a rubber o-ring to measure sag and most forks from RockShox have sag measurements written on the stantion tube. Remember to put the zip tie on backward so you can take it off without cutting it and don't leave it on because if you go through all your travel you will force the hard plastic dip tie into the seals. Or maybe motorcycle forks are different so that won't happen...
Hi. Nice vid. But what is the sag you want to achieve? I understanded how to calculate the sag, but which is the value to get to by adjusting the motorcycle? Is it in the manual?
Usually u check the manual (technical data chapter) for the max springtravel for the front and read. Then u take 30% of that number. In this video it seems like he is taking 30% of L1 as a goal.