How to Measure and Adjust Rear Preload - Adjust Motorcycle Suspension
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- čas přidán 27. 08. 2024
- One of the best ways to improve the handling of your bike is to adjust the rear preload settings of your suspension. And with most bikes, it’s something you can change using the tools that come with your toolkit. And while you can adjust your rear preload settings through trial and error, the best way to change your rear preload is to properly understand it, take some measurements and then test.
Read the full article with diagrams at therideadvice.c...
Just to clear up any confusion - adjusting rear preload in no way either stiffens or softens your rear suspension. It also does not change your spring rate. All it does is change up or down the initial position of the suspension, either when you’re sitting on it your bike or not - these terms are known as Rider Sag and Static Sag.
When you sit on your bike, you’ll note that the suspension compresses a bit. This is what you want to happen, but depending on your weight it may compress too little or too much. Ideally, you want the majority of the suspension travel to be available for actually riding - not supporting your weight. This is why it’s necessary to adjust rear preload as bike manufacturers obviously set their sag amounts on what they deem is an average person’s weight.
So how do you correctly set your rear preload? We need to take three measurements. For all three measurements you need to measure from the center of the rear axle and a fixed point above the axle.
Measurement A
Our first measurement we take is to see what the fully unloaded, or unweighted length of the rear suspension is. This measurement only ever needs to be taken once, even after you change the preload settings.
To measure it correctly, there can’t be any weight on the rear wheel. If you have a center stand the you’re in luck. If not, you’ll need to improvise. You use a paddock stand as weight will still be going through the rear swingarm where the paddock stand attaches to. In the picture above, I chocked the front wheel and used a car jack under the bike with some styrofoam to prevent any scratches. If you’ve got some strong friends, they could hold the rear of the bike up while you perform the measurement.
Measurement B
Our next measurement gives us the normal suspension length, or the length of the suspension under the bike’s own weight. Place the bike back down like you’re parking it but try to have it as upright as possible (i.e. not leaning on its side using the kickstand).
Measurement C
The final measurement we take will provide us with the fully loaded length of the rear suspension. This is the length of the rear suspension when you sit on the bike. To be as accurate as possible, it’s best to put on all your riding gear and sit on the bike just as if you were on the road. You’ll need some help here, as you won’t be able to make the measurement while sitting on the bike and also to help balance the bike while it’s off the kickstand. Make sure your feet are on the pegs and not the ground to get an accurate measurement.
Now, let’s use those measurements and convert them to our Rider Sag and Static Sag figures.
Rider Sag = A - C
Rider Sag is how much the bike ‘drops’ when you sit on it. The ideal figure for Rider Sag is between 30mm and 40mm. Some prefer to be as close to 30mm as possible, but for general street riding and the occasional track day, around 35mm should be fine.
If your Rider Sag is above 40mm then it means your rear preload is too soft and conversely, below 30mm means it’s too hard.
Static Sag = A - B
Static Sag is how much the bike’s own weight acts on the rear suspension. The ideal range here is between 5mm and 10mm. If your static sag figure is more than 10mm it means your springs are too soft whereas a figure less than 5mm then your springs are too hard for you.
Once you have your figures you’ll then know if you need to dial in more rear preload or less of it. Each bike will be different when it comes to preload settings so consult your owners manual. Cheaper bikes offer limited settings which makes it harder to get the preload right.
As mentioned before adjusting rear preload does not change the stiffness or softness of your springs. So you may very well find that even if you get the Rider Sag in the sweet spot of 35mm, your Static Sag may still be outside the ideal range. Try your best to ensure you have a bit of static sag, otherwise your suspension can top out. Therefore, you may need to increase the Rider Sag to 40mm just to get the Static Sag up to 5mm, or any other number of combinations.
Once you made the adjustments, take the bike for a ride. Don’t go on the smoothest piece of bitumen you can find as that doesn’t let the suspension go through its range. Hit the twisties and see how it feels. If you’re not happy with it, adjust it again and measure B and C and see how that goes.
The main benefit of doing this is tuning the rear suspension for the weight of the rider, which helps maintain the optimal geometry between front and back. You don't need to jack your bike up to set this. Just measure the height of the rear tail when the bike is upright with no rider on it, then have the rider sit down and measure it again. Note the difference and adjust by adding preload if it sags much more than 40 mm when you sit on it. Of course, softening it up a bit is valid too if you live somewhere with crappy roads and don't want your spine jackhammered.
Damn i had no idea you were supposed to put the preload adjusting wrench into that longer piece, I've been killing my hands all this time for nothing...
shin888 just put your glove on before you adjust it and no problems
shin888 ---> Actually, the extension handle looks like it is the wrong part/size. The wrench end should 'just' fit into the handle, as you can see from its 'flattened' state. Not only making the tool more ergonomic, but providing an 'extension' to achieve more leverage as the preload adjuster is under pressure from the spring.
@@Ducati_Dude it's like that for almost every stock motorcycle toolkit, it'll fit a lot of things (rear shock adjuster, front shock adjuster tool, a few custom flat spanners etc..) that way and give leverage ^^
And yeah it's a normal tube, that's flattened from factory, simple but it works damn well !
Hey, thanks for the tip. The "background" music is way too loud in my opinion, though. It's hard to concentrate on taking in info when there's an insanely loud pop/trance track thumping over everything. I find this is a very Australian issue, everyone seems to be a "producer" and constantly plugging their crap tunes. Hope that's not the case here. Cheers
Agreed. Very good content, but voice gets drowned out.
1:52 to 1:58. that seems like exactly the OPPOSITE of the truth. The more the sag, the SOFTER the preload tension is when sitting on the bike. The LESS the sag, the TIGHTER or STIFFER the preload tension amount is.
You are absolutly correct mate, he seems to have mixed it up in the video.
Yeah I set mine at the highest setting. ( most preload) (condensing the spring). The bike is now set up for two up fully loaded. And I do mean full.
this video by far best one that explains preload
Correct me if I'm wrong, rider sag should be 1/3 part of overall suspension travel distance. Knowing that you can adjust preload for any bike (using manual where suspension travel is noted).
Very misleading information mate. You’ve got the preload adjustment wrong.
The BIGGER the rider sag measurement, the SOFTER your suspension is. So you would need to INCREASE preload tension.
The SMALLER the rider sag measurement, the HARDER your suspension is. So you would need to DECREASE preload tension.
Contrary to popular belief preload does NOT really make the suspension harder or softer. It sets the range in which the suspension will work.
@@powermos I think imma rise mines up because of my height no cause of my weight
yeah "less than 30mm means it's too soft" that actually means it's too HARD
Artie the Swolest Man in the World mines wayyyyy to hard but I want my bike higher up
@@Fordahord1 it's your bike set it how you like. if you have way too much spring on it you can ease the rebound and compression some to compensate but I'm no expert
simple and to the point. thanks for the video. this is exactly what I was looking for.
Maybe less music so we can actually hear what you’re saying
Remember that rider sag is totally different between Street use and Track use. I think that 30mm - 40mm is good for street. I would personally choose maybe 25mm - 35mm to track. But static sag is 5mm - 10mm is both either you ride track or street
"less than 30mm and your preload is too soft, more than 40mm is too much preload".... isn´t it backwards?
francisco rios yes it is!
francisco rios I think your right there. It should be more than 30mm and your preload is too soft. Less than 40mm too much preload. When you think of it like your loading up the spring = more preload to reduce the rider sag. (Less drop). Decreasing spring pressure = more sag (increased drop). Loading up with preload reduces riders sag but gives more static sag which I think would be adjustable on the top shock absorber threaded mount. Well presented video.
Honestly, measuring static sag seems like waste of time to me if you're not going to be doing spring swaps. For a rider on most modern bikes, they should just measure how much sag they get when they sit on the bike.
That was an excellent quick tutorial that I could understand, THANK YOU.
I think it's a good idea if you have a compression adjustment to back the compression all the way out before you set sag.
Reminder: preload is only for holding tension on the spring when the wheel is off the ground. Once you are sitting on the bike you over come ANY and ALL preload tension on that spring.
Why not have the music louder to completely muffle the voice track. I mean come on!
Yea, I thought the overall presentation and intent was great, but abandoned the video part way through because I couldn’t hear your comments well enough. Perhaps dub over the sound track with better audio. Thanks.
Great video, very clear and well made
Thanks Surrey Rider, glad you enjoyed it.
man. please don't add music just to make it seem more professional. the content is very nice but the sound is not adequate for the quality of the info. please note that there are viewers who need to hear every word you are saying and they are not born english speaking so they can get it fully from a poor sound quality and most importantly a music not so low in the background. at the beginning of the video it was fine but towards the end it changed to be unpleasant. cheers mate.
Dude, you should really cut the music! I can barely recognise your voice as background for the music....
After the free sag measurement you didn't bounce the bike so as to overcome stiction.
The rider sag should be ideally 30%of the stroke length ie stroke = 90mm the rider sag should be 30mm. If you blow through this number then you are using up suspension stroke and if it is a rising rate set up then you are settling into the firmer part of the stroke. Especially true in bumpy bends where you may start to run into grip issues.
Putting a jack right underneath the exhaust.. smart guy.
+CH H My mother always said so. "You're very special son. Don't let anyone tell you otherwise" she would say as I stuck my finger into the electrical sockets. Ahh, memories.
can this also lower the saddle part of the bike? like to get your feet touch more on the
ground when you stop?
So if a-c>40mm then you adjust the spring to be stiffer in order to be between 30-40mm and if a-c
Sag setting is dependent upon your spring length from what I've read. Rider sag should be 1/3 of your spring length after you have subtracted the factory preset sag/ tension on the spring. Sag will be different dependent upon the length of your spring.
Yes.. I totally agree.
To be frank I find the video useless cause it uses absolute figures instead of percentages. Different bikes have different suspension travel lengths and different rides have different weights... Add to that, the loud music makes it sometimes hard to hear what he's saying.
@@tkiblawi1I agree. I lost my erection
good clear video
the manual also says to go harder on your spring when you're only freeway-ing
Soft suspension is not good for twisty roads, soft suspension is good for cruising comfort.
Music is too quiet l can almost hear your voice.
Rider sag varies from bike to bike there's no one size fits all option, it is usually has to be around 30% of your total travel. My adv has 220mm total travel so rider sag has to be around 66mm
Increasing preload even to ridiculous levels on a threaded adjustment seems to have no effect on the height of the rear but only makes the travel stiff and short
Preload is not a suspension tuning component, that’s a myth. Once you have bike weight on spring the preload doesn’t affect suspension
Once prelad has exactly compensated for sag, further preload won't raise th ride height but just means that more weight is needed to even begin to compress the spring.
So anyway the soft suspension is great. I increased the seat height and now it feels great very long travel
31.75 Rider Sag on my CBR, 6.35 Static. Good info. Thought the bike was a bit stiff in the rear, guess it's good.
Are these numbers work as standard for all motorcycles?
I have a dual sport motorcycle.
Beautiful video and very helpful information!
Faisal Almaiman In general, yes, the numbers still apply, though on a dual sport obviously the compromise will probably be you need to set things up for different surfaces.
How come he's using absolute figures while the calculations are relative to the suspension travel length?
Why is it so hard to find a simple explanation for this
what about Royal Enfield Classic 350 Gun Metal Gray... how to check to suspension and swingArm
Hi, could someone share whether I need to make preload 0 when I measure suspension length or max suspension travel with the rear wheel off the floor .Im a beginner trying to learn to do this on my own, so my question may sound stupid ,but still please share what your thoughts are .
New subscriber here thanks for your video...pls. Upload more
which would be a gud suspension for my ninja 400
and i even want it to raise it bit higher i.e i am looking for a longer and a good quality suspension for my ride
any such suspensions plz..
Can't seem to get the castle nut ring loose
After replaying to get over the loud shitty music i realise i DID hear that he got the preload/sag back to front, CORRECT IT FFS!!!
That was superb
I bought my bike used. No spanner. What sizer spanner do I need?
So im bottoming out on my bike... Which way do I turn what where? Honda cbr1000f. Im on preload setting 3 from 1,2 or 3.
No one seems to address this problem in a way that I understand! Help me correct my terminology to find my answer please
Stiffer, bottoming is too soft.
Turn the ring so that the spring looks to be getting more squashed. That will increase preload (which will raise the bike slightly - not make it "stiffer" - common misconception) so that when you sit on it, it will return to the proper height for you.
@@ballamoto I'm sure that will lower the bike if you compress it (things usually go down when you squash them), making it 'stiffer' due to more tension in the preload.
@@HalfdeadRider you are incorrect I'm afraid. You should look it up :)
@@ballamoto Sorry if I am wrong, but I'm not totally wrong, things that are compressed are made smaller, it's impossible to stretch something by squashing it lol
Maybe spring physics are not my strong point but it makes sense to me that more tension in a spring will make it harder to compress further (being stiffer), I will have to look it up sometime.
I also know more about car suspension than bikes, maybe they are somehow put together differently to how they look, the bikes rear suspension looks like coilovers to me, when they are adjusted for lowering/stiffer ride for better handling, they compress the shock absorber (damper) and spring as it's all one unit.
Are you supposed to take the measurements with the front wheel jacked up off of the ground? Just want mine to be as accurate as possible
Once the rear is UP off the ground the front being on the ground or up in the air doesn't change anything in the rear.
What are you saying? I thought the sag woulybe more if the preload is lesser. U saying opposite.
Is it true that more preload helps to corner the bike faster?
+Aziz Thegreat This is kind of a vague question. Preload sets how much sag the bike has when the suspension has a load on it. Every bike and riding style has an "ideal" amount of sag. For road bikes, it's generally somewhere around 30mm. A bike that has a proper amount of sag set will corner "better." Faster doesn't always mean "better." It's worth mentioning that as you increase preload, you can end up raising the rear ride high a bit. This will increase the rake, decrease trail, and make the bike turn in a bit quicker.
No
Thanks for the useful info! However this would be much better without the annoying background music.
What's with the stupid electronic noise (music?)
Hey buddy! What’s that headlight you have on the bike
The 30mm and 40mm variance... does this apply when riding two-up also?
Want to get it right for a two-up ride 487kms. Had it wound down too much on a trip half the distance, and cause problems for my passenger..
CBR1000F Kiwi MotoVlog Yes, same rule apply - except you need to do the measurement for rider sag with both you and the pillion seated. Another thing to keep in mind is that on cheaper suspension, that might not be possible - you don't want the suspension ever bottoming out so you may need to modify this to prevent this from happening.
TheRideAdvice Thanks, will do.
What kind of shoes are you sporting ?
Im sorry but the music isn't loud enough
Nightmare music - too loud over voice
when you jacked the bike up did it damage the exhaust at all? I have the exact same bike & I need to get the front wheel off the ground
Put a piece of timber between the jack and exhaust to protect it 👍🏻
good comments, thanks for sharing.
Seriously, take the music away. Just repost the vid without the music. It’s too loud, epically distracting.
The advice is shot to shit when its over powered by that sodding music
what's your weight ?
I need that gear in 2:13 to up my fourche. What is it called?? (I mean it's name) Some one help me pleaseeeeee!!!!!!!!!!!!! :(
Cool
nice shad
Mine doesn’t move
That ugly music is so distracting. This is unwatchable.
*Yeah, the bloody soundtrack gave me migraine!*
more than 40 is too much preload??! Isn’t it the opposite?
Unloaded suspension length: 585 mm
Normal Suspension Length: 580 mm
Loaded Suspension Length: 560 mm
My Ride: Fazer 2012 Model 150 CC Indian make
After more than 10 min ride, either with or without pillion, i feel my buttocks getting stiffer and even for the pillion. and the bike is very hard when travelling over bumps. i want the ride to feel softer for long travel, say like the comfort of a auto gear scooters like activa etc.. what can be done in this case? Do i loosen or tighten the suspension? If so, until what level setting like 5 or 6 like that?
How to know which is all tighten and which is all loosen? Is there any visible mark by which we can identify? Also, I do not get the tool to adjust preload. where can i get it in India?
Sure. I do agree. Just thought I could do it myself as i am a first timer in tuning preloads. Where can i get the tool in Chennai, India? Online/ Shop? Any ideas?
@@gsrajah9410 online miljayega. Nahi toh go to a nice garage and ask them to adjust preload for softness. Also make sure your tyre pressures are correct(cold)
Music is too loud. It seems like most of these types of videos do the same thing. Here's a hint, I want to listen to what you have to say. I'm not interested in your music, I have plenty of my own.
Taking measurement like this with the rear wheel off the ground is pointless. Just adjust the pre load until the sag is correct when you sit on it, just as Alpha Force says.
switch off that stupid music please!!!!
Way too much music
Hard to focus on what you’re saying with the music playing in the background.
Unprofessional.
Dislike for the add.
your motorcyle is hot!
👍👍👍
Incredible irritating music, otherwise a helpful video.
This is worse than the verge’s pc build tutorial.