I had a old Honda rear shock handy without the spring, so I am using it to explain how to read and adjust your front shocks.
Pic 2. BASIC SHOCK COMPONENTS. This pic identifies the basic parts of the shock I will reference in this post. I have removed the spring so you can see the rubber bumper on the shock easier.
Pic 1. INITIAL INSPECTION. take a look at your shock in the front suspension. You are looking for the rubber bumper; if you are lucky, your shock will look like this pic. What you are looking for is where the rubber bumper is. It should be somewhere up at the top of the shaft. You are lucky if there is a gap above and below the rubber bumper. This tells you you are not bottoming out in the front suspension.
Pic 3. INITIAL INSPECTION. This is more likely what you will find. For my 2012 RTS (with 208lb lb rider), I found my rubber bumper jammed in at the top. The only way to get the rubber bumper up there is to bottom out the front suspension. If it is difficult to get the rubber bumper out from the top, then you can bet the bumper was wedged in there with some gusto. The only good thing about having the rubber bumper up at the top when the bike front wheel is off the ground is that you can measure the full working range of the shock. For the 2012 RTS, I found it to be 2.5".
Pic 4. BOTTOMING OUT. This shows a fully compressed shock. You can see the shock body is pushed up against the rubber bumper and there is no gap above or below the rubber bumper. At this point, the spring or damping isn't doing anything, you are momentarily riding on a fixed suspension and the only give in it is the rubber bumper and the tires. I found with the oem setup (on 3rd preload indent setting), I was effectively using half of my working range just sitting on the bike. Once you start riding and hitting pot holes, roadway irregularities, dips in the road, etc, it didn't take much to fully compress the shock. One side effect of bottoming out, is that the front of the bike dips very low to the ground. This allows you to easily scrape the front bottom of the bike. Irregular road surfaces or angled driveways are good places combined with weak springs to bottom out.
Pic 5. BASELINING, SETTING SAG. To properly adjust your suspension, you will need to raise the wheel off the ground. For the front wheel, you want to do this without raising the rear wheel as it has the park brake keeping the bike from moving while jacked up. Use wheel chocks if you have them. Once you get the bike up, push the rubber bumper back down against the shock body so there is no gap. If you are pulling it down from the wedged in position, take care not to nick the shock shaft. Then you let the bike down gently so you do not bounce the bike.
Pic 6. BASELINING, SETTING SAG. Once the bike is fully on the ground, then raised back up, examine the front shoct. You should be able to see a small gap. This gap was created by the front weight of the bike compressing the spring and moving the rubber bumper up the shaft. Try to measure this distance as accurately as you can.
Pic 7. BASELINING, SETTING SAG. Now push the rubber bumper down against the shock body, then carefully dismount the bike. Then, raise the front wheel off the ground and examine the rubber bumper location. This gap should be larger than pic 6 as the front spring was compressed by the weight of the bike and rider. You want this distance to be no more than 20 to 25% of the working range of the shock. If you find the gap is a lot more than 25%, than you need to increase the preload of the front shock. There are several ways to do this. On some oem shocks, they have adjustability indents that you can rotate to shorten the spring (adding preload) or lengthen the spring (reducing preload). On some oem models (fox or aftermarket shocks), they have a threaded portion of the shock body with 2 rings. The first ring tightens against the spring and the other ring serves as a lock ring. The easiest way to add preload is to raise the wheel again so the weight of the bike is not on the spring. The only compression in the spring is from the preload amount front installing the spring. To reduce the compression force and make it easier to add additional preload force (compressing the spring more), is to add 2 ratchet straps to the spring and compress some of the coils. I use ratchet straps as they are easiest to add to the shock while the shock is still on the bike. The straps, spaced opposite of each other, make reduce the preload compression force and make it easy to further compress the spring. Keep in mind, you need to work in equal increments on both sides of the front. For my weight on the 2012 front suspension, I found I needed all of the preload adjustment + an additional spacer (~0.75” thick) just to get the sag right. So if you are close to my weight, just dial in all of the preload indents to see how close you get to an acceptable gap. If you have fox or aftermarket threaded shocks, work in set amounts like 0.25” increments. Once you get you [1b] gaps right you have set your sag and it’s time to ride the bike to see what’s happening with riding loads on the springs..
Pic 8. BASELINING, TOP END. After riding over several miles to include [sharp] turns, [panic] stops, it’s time to reexamine the location of the rubber bumpers. If you are lucky, they will look like this pic. That is, there is a gap between the rubber bumper and the top. This tells you your suspension is now dialed in to your weight, riding style, and road conditions. If you find the rubber bumper up at the top, you are still bottoming out.
Pic 9. END OBJECTIVE. This pic depicts the range you should find your rubber bumper in. If you set your sag properly and find you are still bottoming out (no gap at the top), you can go back and reset your sag gap (gap 1B) to be a smaller distance. That might be enough to help you on the top end. But if you have reduced gap 1a to 0”, and gap 1b is 0.1” and you are still bottoming out, you need to make some changes or get used to bottoming out. There are several options to choose to help you solve this; but my thought is if you are still using the oem springs, than that probably isn’t the best solution. Of all options, new springs are the cheapest but require a little work to get them installed on the shocks. Here is a link on how I approached the problem: http://www.spyderlovers.com/forums/s...ont-Suspension
Pic 10. END OBJECTIVE. If you ride 2 up a fair amount of time, then you need to account for this in your shock setup. This means you should do all the steps above with your passenger on board. This pic shows the difference in rubber bumper movement for the 2 up vs. solo rider.
Last edited by spacetiger; 12-25-2014 at 05:01 PM.
I read through this, very good, accurate, and detailed.
If the Spacetiger doesn't mind, I wanted to add a couple details.
#1, in the photos the terms Rubber Bumper is used. Truthfully it is a rubber bumper, but in suspension tuning circles, we typically refer to it as a bottoming cushion or bottom out bumper.
#2, In regards to the procedure to measure and / or checking sag. When lowering the machine, it is best to have the suspension as free as possible. The easiest and most economical to accurate results is to place heavy plastic between the tire and concrete floor. This will allow the tires to slide to the actual position and not bind the suspension. I have used lawn debris garbage bags, Visqueen for concrete work, and most recently heavy Ziplock bags. You should use a few layers to optimize the ease of movement.
#3, Consider that the Spyder has a very basic steering design. The design suffers in that it is very prone to bump steer. If you make a change in ride height, the suspension arms will be in a new position and will possibly change the front wheel toe in / toe out.
This is a great information post. Those of you planning to purchase the new BajaRon preload adjuster should bookmark this as it is a great set of instructions on how to setup ride height / sag.
Great information! The thing is my Fox shocks have outer coil springs and adjustable rings and no bumper that I can see. The service manual specifies , for the RS rydes, that all you do is break loose the lock ring, adjust the coil ring and lock it back down again. No lifting of the bike or removing the shocks. Which is what I did. I think I'll get another 5000 miles out of them before I have to replace.
Great information! The thing is my Fox shocks have outer coil springs and adjustable rings and no bumper that I can see. The service manual specifies , for the RS rydes, that all you do is break loose the lock ring, adjust the coil ring and lock it back down again. No lifting of the bike or removing the shocks. Which is what I did. I think I'll get another 5000 miles out of them before I have to replace.
Susie
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FWIW, if you are meaning that in 5000 miles the shocks need replacement, I believe the podiums can be easily rebuilt by a Fox or a suspension tuner for a lot less than new. Assuming no major damage and simply seals and fluid.
Dialing in your [front] shocks // lots of pics
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Great Explanation !
Originally Posted by Marker
