Motool Slacker Digital Sag Scale

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Tested: Motool Slacker Digital Sag Scale v2

Why spend hundreds if not over a thousand dollars at your local suspension shop if you can't consistently and accurately check your sag to keep things in working order? That's where the Motool Slacker comes in...

Rating: Vital Review
Tested: Motool Slacker Digital Sag Scale v2

Update: The original Motool Slacker review was from our evaluation in early 2015. Since then, Motool has updated the product and released a version two of the Slacker, so we've evaluated the V2 and updated our review accordingly. Below you'll find our original review and in each section there will be an update on the features and our experience, each preceded with a bold "Review Update" followed by our comments in italicizedlettering, such as this part you're reading right now.

The updated look of the V2 Motool Slacker.

Before my time at Vital MX, I was lucky enough to spend quite a bit of time testing suspension and learning from one of the best in the business, Ross Maeda from KYB and Enzo. One of the most standout lessons was about how important correctly setting sag is. To put it bluntly, if your sag is incorrect it can not only affect how the bike handles, but it also affects the bike's balance and how the suspension reacts. As an example, if the shock's sag is too low, it will place more weight on the shock, thus causing it to be softer. This also takes weight off the front and would cause the forks to feel stiffer. I could go on and on about how sag affects the whole bike, but that example should give you a quick idea of how much impact it has. Dealing with customers, I very quickly found that simply setting the proper sag adjustment would either cure or reduce most complaints. This is because the riders had either never set their sag, or hadn't checked it in a long period of time. That's a problem, as our weight is ever-changing. Most riders tend to never check it because it's too much of a hassle, and they need someone who understands how to measure it to help them out. This is where Motool's Slacker Digital Sag Scale comes in, which allows a rider to set their sag completely on their own!

Slacker Digital Sag Scale Features:

  • A magnet allows the scale to be attached to any steel surface.
  • Allows user to set their sag without assistance.
  • Can be used on any size motorcycle.
  • Remote display can be mounted to bars for rider to read while on the bike.
  • Can be used to set the shock or forks sag.
  • MSRP: $149.99 (updated retail price)

First Impressions

Inside the box from Motool, you'll find the four main things needed to use the Slacker; the digital scale box, mounting clamp, remote display, and a cord to connect the scale to the remote display. The larger box is your digital scale, which has a power/rest button, LCD display, measuring cable, and a large magnent on the rear. The smaller box is a remote display, which has its own LCD display and reset button. It however doesn't have space for batteries, so the cable included feeds it power and information from the scale.


The included instructions give you all the info you need to get started, but you will need two AAA batteries. I didn't discover this until I took it to the track and decided to use it the first time, then I realized my blunder. Call it a pet peeve, but I get really annoyed when an electronic device doesn't have batteries included.

*Review Update:The newest version of Motool Slacker, V2, has a couple of updates both internally and externally. Outside, the product has the same basic look albeit a bit cleaner without the skulls and anarchy of the first version. The cable has also been updated and eliminates a little bit of a kink that our first version had developed over a year of use and the retracting feature seems to be more precise. Internally the Slacker has some software updates, the notable one being the new auto-zero mode. This feature is perfect for someone who doesn't bring a solid stand to the track or doesn't want to deal with the hassle of taking the bike on and off said stand for each measurement.

In the Shop/At the Track

Using the Slacker out at the track is fairly simple, especially when it comes to setting the rear sag. With the bike on the stand, install the digital scale to the rear axle using the magnet. Next up, latch the mounting clamp to either the rear fender or sideplate, then pull the cable from the scale and hook it to the mounting clamp. Last thing is strapping the remote display to the handlebar, then hooking the scale and remote display together using the included cable.


Once it's ready, you simply press the power/reset button on either the remote or scale so it shows a 0. Remember to only hit the reset when the bike is on the stand and the suspension is fully extended to set it to zero. If it's done when the bike is on the ground, the weight of the bike will affect the outcome of the results, as the number displayed would be starting from the static sag. Once the Slacker is zeroed out, pull the bike off the stand, climb aboard and see the results. I found that my best results happened when I placed one foot on a stand with my other on the pegs, with the goal of keeping as much of my weight as possible on the bike. Keep in mind that it's near impossible to get all your weight on the bike consistently enough for an exact readout. As an example, I looked at 102mm as if it was actually 103-104mm, once I accounted for my foot resting against the stand.


All-in-all, the product is easy to use and seems to be very accurate. I've tested the Slacker's results against the old-fashioned tape measure multiple times, and I found it to be spot on if I repeated the method with both measurements (one foot resting against the stand). Another plus with this product is how easy it is to also check your fork preload, which can be important with SFF and SFF Air forks, since they have adjustable preload. In this case, the scale is attached to the front axle, with the clamp latched to the front number plate.


Once you've set it up, it's pretty easy to repeat the process in a couple of minutes, but I do have two small digs against the product. One is the lack of batteries. My other is that the scale will only measure up to 200mm, after 200mm it goes blank. For most this doesn't matter, but I'm unable to measure the full extended length on the stand. I would like the ability to zero out the scale before attaching the cable to the clamp, thus showing me the extended length number before climbing aboard the bike.

*Review Update: The auto-zero mode was the main change to how we adjusted and measured our sag. With this feature, we were able to do our normal setup of the clamp and measurement box, albeit with the bike off the stand. Once setup, you can hold down the lcd light button for three seconds until dashes start flashing across the screen. From here you can lift up on the rear of the bike until the weight is completely removed from the rear end. Once the box senses that you've quit lifting up on the bike and the cable has quit extending it sets the scale to zero, you can then release the bike and let it settle down before swinging a leg over it. If you're able to lift the rear of the bike adequately, the rear end of the bike will settle out just like it was on the stand. 

If you decide to work with this feature I recommend lifting the bike with the auto-zero feature enabled and then throwing the bike on the stand after to see if the scale goes to zero. Basically confirming that you're lifting the rear of the bike with enough force to accurately unload the rear suspension. If you're not lifting it high enough, you'll see a number other than zero when the bike is placed on the stand. Say you see the number five, that means you still had five millimeters of travel on the rear end when you lifted it. If you see zero, it means you lifted the bike high enough to simulate placing the bike on a stand.

Motool provided video; showcasing features and recommended usage.

Overall, the Slacker is very easy to setup but there's one thing we'd like to mention about the instructions. In the setup guide, Motool recommends setting their hook to follow the angle of travel for the swingarm. This means the majority of motocross bikes would have the hook placed along the sideplate at some point. This isn't the wrong way to do it, it's just different that what the majority of the moto industry does. which is going for a more vertical travel path from the center of the rear axle, straight up the the corresponding point on the rear fender. The reason we bring this up is if you follow the Slacker instructions you will end up with a different number than measuring vertically, we've noticed it to be between six and up to ten millimeters depending upon the model of bike. For example, if you measure 105mm vertically, you may see around 98-95mm when measuring the angle of the swingarm travel. Neither of these are wrong, they're just different interpretations of measurement. 

The reason we point this out is the majority of suspension tuners and OEM manufacturers base their setup numbers off the vertical measurement (KTM and Husky even mark their fenders from the factory on their recommended point). You can choose to measure either way but if you work with a suspension tuner, we recommend asking which way they prefer to measure so you know what their recommended setting pertains to. If they tell you 105mm is your recommended starting point and they measure vertically, then you measure at the angle and set it to 105mm, you'd actually be around 112-115mm in the vertical sense. Honestly, work with your suspension guy and pick which works best for you and stick to it. Rider position on the bike, the levelness of the ground you're measuring from and how you measure can change the end result, so consistency is key to a proper setup.

Long-Term Durability

As with most tools, the durability depends on how well you treat it. Being that the Slacker has digital screens, it would be best if it was kept in its original box. The scale and remote display both are encased in fairly thick plastic casings, which will hold up to some decent abuse. My personal durability test included accidentally smashing the scale into the stand when I almost fell over, and kicking it out of the van while looking for some goggles...

*Review Update: Our original Slacker unit survived over two years of testing, Shootouts, and rattling around on the bottom of a tool box...before being passed off to one of our test riders for personal use. In that time it gained a few scratches but the workings of the scale remained unchanged, outside of receiving a new set of batteries.

The Last Word

Based on my intro, you probably figured out that I really believe the necessity of checking your sag to maintain a consistent setup. Because of this, I found this product to be extremely important, as it eliminates the main excuse that riders have when it comes to checking their sag, "I need help." Its price definitely reflects that of a specialty tool, but considering we spend upwards of $500 to have our suspension set up for us, it's well worth the price to keep this investment in check. If you're lucky enough to always have someone around that understands how to set sag, then this isn't a necessary tool. But if you're lacking the help or like to keep track of the numbers for yourself, then the Slacker could find a home in your tool box.

*Review Update: Since we received the original product in late 2014 we've used and abused it, but it remains in our toolbox to this day and gets used almost weekly. Especially around Shootout time when we're out testing amongst ourselves and need to quickly swap sag for multiple test riders, who aren't the best with the old metric tape measures. In that time, we've had multiple riders praise the product, purchase them for themselves and have yet to gain a complaint. The four star rating only reflects our wish for the Slacker to come with a rear axle insert kit or for there to be an optional set, as we've made our own for a few bikes to ensure an extra level of accuracy. Beyond that, we recommend the Slacker to about anyone. Yes it's a $150, but that's a bit cheaper than taking your suspension back to the shop just because the balance and feel of your bike has been thrown off due to improper sag.

Vital MX Rating - 4.5 Stars

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About the Test Rider

Michael Lindsay - is a born-and-raised moto freak and gearhead from the heart of motocross in Southern California. First swinging a leg over a bike at the age of five, he immediately caught the racing bug, spending nearly every weekend behind a gate…and a lot of time on the couch while injured. While swinging back and forth between moto and the off-road scene, giving him a wide range of experience on the bike. Of course, all of this led to one thing: Lindsay loves working on his bikes almost as much as he loves talking about them. When he’s not in the Vital MX forum or writing his latest product review, you can find him out at the track taking dirt naps, snapping some pictures, or drooling over the latest parts for his bike. With an outspoken personality, gearhead background, and as Vital MX’s guru for product, Michael is here to share his unbiased opinion.

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15 comments newest first

I have the V1 and love knowing my sag is correct or have the ability to make adjustments quickly and accurately. I just realized the issue with the sag utilizing the arc method vs to the fender last week when I could not get my 2016 KX450 to turn. I went to the fender with my gear on and I was actually at 113mm at the fender vs 105mm at the side plate using the arc. It required a full 2 turns of extra preload to reach 105mm at the fender and it made all the difference in the world... guess I didn’t forget how to turn a motorcycle after all these years!

Overall it’s a great product and this just proves that having the right tools to do the right job is important!

| Reply

What is the sag on the fork? It sounds like maybe the fork may be stiff and riding high in the stroke. You should have good results at 105mm to the side plate in the rear and 65mm on the forks. The SFF air forks are very tricky to get the chassis balanced by simply checking air pressure. It is very helpful to see how the bike is actually sitting by taking measurements on both ends;-)

| Reply

I have the newer version this tool and I like it. I also drilled a hole in my fender and I used the arc method as described in the sag tools manual.

My only minor complaint is that I wish it had pin locator for the axle because I am always afraid when I drop my bike down off the stand that the magnet going to move on me or I am going to bump it with my boot.

| Reply

Awesome glad you like it! I would recommend using auto zero if you have the V2. it prevents the tool from being jarred getting the bike off the stand and since the initial cable travel is outward it settles any slack in the cable and clip so it is all around even more accurate. Also, we do offer custom axle inserts for Ti and oversize axles;-)

| Reply

Yep, I am not a fan of big business myself. Don't let those guys get you down, there is plenty or room for us little guys. You just gotta keep your head up and keep on the grind!

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Actually our method of taking measurements is based directly off the manufacturers recommendations and the only exceptions are 2016 and newer KTM and Huskys where you do measure vertically to the mark they provide. We state this clearly in the video user guide. You can take a measurement anywhere but it will not give you the right number unless you measure in the right place. Say you set your sag to 105mm measuring vertically then take the measurement like it shows in your user manual- to the back of the seat bolt to account for the arc of the axle. You will see you are actually at around 95-98mm according to the manufacturers recommendation so you are running too much preload, the bike will be squirley at speed and knife in the turns. It still baffles me how so many people make this stuff up, why would you ignore the manufacturers recommendations when they are the ones that engineered the bike? Trust me, wether you use Slacker or not, measure the way the manufacturer tells you to and your world will be 100% better on the track. Your bike will be calm and do everything you ask of it guaranteed.

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So I’ve got one of these tools, can I just ask if I’m doing it correctly then because I have a 2016 ktm 250sxf and I drilled a small hole where the sag line is on the rear fender and I’m measuring it from where the manufacturer states ? I presume this is correct because I’m basically doing as I would with a tape measure ?

| Reply

HI Craig,
You are right on the money. We use the arc of the axle method for all bikes except the 2016 and newer KTM and Huskys which we do measure to the mark they provide. I think they changed it to account for so many riders measuring it vertically and running the spring a little too tight. Always feel free to hit me up if you have any questions;-)

| Reply

As we've discussed privately my comment above is based upon personal experience dealing with the OEM testing staffs from each manufacturer along with engineers from KYB, Showa, and WP...the majority of these groups measure in a more vertical sense. For instance, in our Shootouts each OEM test technician that is on hand measures in this way. As I tried to make very clear above I'm not saying one is right versus wrong, I'm making this clear that there's a difference in the end number so the user understands this when they measure. It's ultimately up to them/their suspension guy on what they run and their interpretation of what setup works for them.

| Reply

No worries Michael, you are an experienced rider and know your numbers. I just like to make sure less experienced riders and parents understand this from the start so they have a solid foundation to find their own numbers. Thanks for all the kind words, it means a lot to me that you guys use and like Slacker so much! Hope you have a great Christmas!

| Reply

I invented the UniSag sold by Motion Pro. Used a device that locked it in the axle and seat bolt. (Like the OEM Manufacturers suggest) No batteries. Couldn't get a good review from any of the Moto Mags. One said...we have never been alone enough at the track to require the use of a one person sag tool. Another said....this tool belongs in a Rocket Scientist's tool box, being made so well. Anyway, Motion Pro discontinued the UniSag and left me empty handed on several years of my contract. For those that want to hear more about Motion Pro's marketing blunders as well as late royalty payments, let me know. Thanks for listening.

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Yep, I know the tool, this is definitely a tough industry to break into. I would take it to market myself directly and build it slowly, no other company will have your vision for the product and how to present it. They will also never have your passion for the product and the benefits it presents. All I know about MP is they squash me on the teams all the time. I have had a couple team sponsorships where the tool never got promoted because MP was also a sponsor and obviously has way more money than me in the game. Factory KTM off-road buys at least 6 of these a year for the team but if I mention it on my site they make KTM call and take it down within hours. Sucks being a little fish in a big pond but you gotta start somewhere;-)

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1 member review

Best suspension tool there is

The Good:

easy to use

The Bad:

needs protective case for transport in a tool box

Overall Review:

Bought one of these six months ago because I couldn't get my wife to come out to the garage and hold up my bike with me on it AND hold a tape measure to set my sag.  

After using this thing it becomes apparent how important sag settings are, and how easily they can change from one day to the next because of constantly changing rider weight (lunch) or bike weight (mud).  

I take this and my WP preload ring wrench to the track with me every practice and race day, and for my KTM there is a significant handling and suspension difference with just 10 MM variation in sag, you can really feel how the handling and fork action changes -  plus I can do it myself in 5 minutes without having to bug someone to hold a tape measure over and over.

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1 comment newest first

I am in the process of sourcing a case for these currently, I just haven't been able to afford it. If you sign up for the email list in the bottom right corner of our site you will get a notice when we release these. I am hoping to get them sometime in the summer. Thank you for your support!

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Product Motool Slacker Digital Sag Scale
Type Tool
Features Universal Mounting: The Slacker scale works on both front and rear axles and is excellent for setting up both air forks and SFF forks. The clamp attaches to number plates or fenders offering great flexibility. Slacker even sticks to your toolbox for easy access!

Backlit LCD Display: An LCD display on both the main unit and the remote display allow you or a helper to quickly get the sag measurements you need. Backlit for night racing and poor lighting conditions.

Any Bike, Any Time: The Slacker digital sag scale works with any off-road bike 85cc or above with steel axles. This, along with the universal clip, ensures the Slacker scale works on almost every dirt bike.
Price $149.99
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