MOTOTRAX VIBRATIONS

[Timberview01]

Increasing preload absolutely makes it stiffer. You are compressing the spring and, therefore, making it less prone to further compression.

The spring IS the suspension. The valving in the shock is simply dampening the travel of the spring.

 

[KTMDirtFace]

If you want to make it stiffer you go up in spring rates.

Pre-Load = Ride Height/Sag
Spring Rate will control the stiffness.

If I crank my pre-load on any vehicle its going to ride higher in its travel. But the same hit is going to bottom it out regardless of what the pre-load is set to.

Here found an explanation for street bikes, but the vehicle shouldn't matter: http://sonicsprings.com/catalog/preload_tech_article.php

 

[Jnorth]

If you want to make it stiffer you go up in spring rates.

Pre-Load = Ride Height/Sag
Spring Rate will control the stiffness.

If I crank my pre-load on any vehicle its going to ride higher in its travel. But the same hit is going to bottom it out regardless of what the pre-load is set to.

Here found an explanation for street bikes, but the vehicle shouldn't matter: http://sonicsprings.com/catalog/preload_tech_article.php

Yes, you have it mostly correct, but it is incorrect that the same bump will bottom out the suspension regardless of preload setting.

As you lower the preload you are bringing the suspension closer to bottomming out. To the point where you can't even use the full effective travel of the spring. So, essentially you would only be using the top 50% of the shock travel before it bottoms.

 

[KTMDirtFace]

Yes, you have it mostly correct, but it is incorrect that the same bump will bottom out the suspension regardless of preload setting.

As you lower the preload you are bringing the suspension closer to bottomming out. To the point where you can't even use the full effective travel of the spring. So, essentially you would only be using the top 50% of the shock travel before it bottoms.

Yea true but lets say for example the spring could take 500 pounds before it was fully compressed.

If I crank the pre-load down. 500 pounds is still going to fully compress it no matter what the pre-load is set to.

 

[Grr]

Yes but if the system bottoms at a low preload setting it may make contact at 450#. Whereas if the preload is upped it would require the full 500#. Only way to use the entire rated force of the spring is to reach coil bind just mm's past the stops

 

[Hawkster]

Learned this a few years ago , the snowmobile industry offers second rate compared to what the moto industry has to offer so when your looking for something for a one ski just bypass what the snow manufactures are offering when possible .

Check this bad boy out , might make setting up a bit easier http://www.ridefox.com/2016/product.php?m=moto&t=shocks&p=3341

In case I threw some one for a loop , this shock is adjustable at both ends meaning you can control the bottoming out besides proper spring setting .

 

[KTMDirtFace]

Learned this a few years ago , the snowmobile industry offers second rate compared to what the moto industry has to offer so when your looking for something for a one ski just bypass what the snow manufactures are offering when possible .

Check this bad boy out , might make setting up a bit easier http://www.ridefox.com/2016/product.php?m=moto&t=shocks&p=3341

Have something similar on the rear of my mountain bike. The bottom out chamber is awesome.

The point I was trying to make... Was you can't get more bottom out control by adding more pre-load

 

[Jnorth]

Have something similar on the rear of my mountain bike. The bottom out chamber is awesome.

The point I was trying to make... Was you can't get more bottom out control by adding more pre-load

Ya, my point was that you bottom out faster the lower your preload.

 

[KTMDirtFace]

Ya, my point was that you bottom out faster the lower your preload.

How? lets see the math.

 

[HalfBrit]

How? lets see the math.

If you take the spring adjuster off = 0 lbs preload on spring = instant bottoming out.

 

[Dam Dave]

If you take the spring adjuster off = 0 lbs preload on spring = instant bottoming out.

because you used up all the travel before you jumped with the low ride height, valving controls the speed, the only way to make it stiffer is with a spring change

that is in simple terms because there is some overlap between functions of the spring

 

[Jnorth]

How? lets see the math.

This is very simple physics. Not math. Like halfbrit said. Try taking all of the preload out of your spring. Then bounce up and down on the tunnel and watch how low in the stroke your suspension gets. Then raise the preload as much as you can and do the same thing. It won't even be close to bottoming. I can't explain it any simpler than that. I'm out

 

[007]

I agree about the spring rate is the rate and preload is for adjusting the ride height. Now if you are sitting higher in the shock stroke when it compresses you have more shock to slow the compression down. On the upgraded shock you have two different compression settings. One high speed that means when you land off a jump or hit a big bump. The other is low speed compression meaning when you come on to the ramp of a jump or softer impacts like pushing down on the tunnel.

Shock work is a fine balance!! Once you start playing with them two settings then you bring in rebound to the equation... rebound can be very tricky and can really control your sag in your suspension in riding conditions not as it sits on the shop floor. The faster the suspension can fall the better snow contact you have and you can avoid packing the suspension up and bottoming out. But if go to loose with rebound it can give you a rear kick feeling.


I'm not trying to intevien in your guys arguememt but there is way more to why you bottom than just spring rate!

 

[culater]

We are looking into the upper idler wheels a bit more. We typically see them breaking on pretty hard repetitive hits but not always. Technically the shock is supposed to bottem internally before the wheels can ever hit the swingarm but this is not always the case. That's why no physical stop was built in. We have so far successfully tested using a 10mm deeper bolt for the upper idlers, it rest more in the meat of the idler spacer and therefor is stronger. A bit more testing is needed though.

I am going to use the original shaft that came with my kits and turn it down on both sides so the idler wheels will move in 1" and then use a spacer bushing to make up the difference. Your 3 part axle fix and or longer bolt idea is just a band aid fix. You need to produce a wider moto link arm to properly fix this problem/issue. You have a good kit and once you work through a few issues it will be a reliable performer. I rode my 137 in 4 ft of snow and had a blast yesterday!

Here is a list of 6 updates I would recommend.

1 Wider motolink arm to clear idler wheels.

2 Need to address brake caliper pin attachment issues.

3 Make angle of rails adjustable for deep or low snow conditions. This is easily done on the rear link.

4 Billet or stronger ski bracket

5 Utilize two threaded spacers, the same that you use on your front wheel kit to box in the uprights making it stronger.

6 2.5" track option.

 

[Moto4Life]

I am going to use the original shaft that came with my kits and turn it down on both sides so the idler wheels will move in 1" and then use a spacer bushing to make up the difference. Your 3 part axle fix and or longer bolt idea is just a band aid fix. You need to produce a wider moto link arm to properly fix this problem/issue. You have a good kit and once you work through a few issues it will be a reliable performer. I rode my 137 in 4 ft of snow and had a blast yesterday!

Here is a list of 6 updates I would recommend.

1 Wider motolink arm to clear idler wheels.

2 Need to address brake caliper pin attachment issues.

3 Make angle of rails adjustable for deep or low snow conditions. This is easily done on the rear link.

4 Billet or stronger ski bracket

5 Utilize two threaded spacers, the same that you use on your front wheel kit to box in the uprights making it stronger.

6 2.5" track option.

Thanks for the feedback

1
I see what you are saying but I beleive that would cause me complexity that would need addressed, if the swingarm was wider than the entire front linkage would have to be much stronger to handle the additional leverage forced.

I think a internal bottom bumper in the shock and a notch out of the swingarm where the idlers would hit would be much simpler and don't have to worry about a whole host of potential failures in the linkage.


2
We have a good fix coming for this, just need to test it more


3
You thinking like a limiter strap, with the new spring on the rear I am not sure it will need to be adjustable, it seems to work really well in all conditions, perhaps preload on the spring though.


4
The race billet ski block is pretty great for this but it may be overkill for the average rider. Durability and a rubber compound that works over the long run is key, a lot of handling issues arise when the rubber wears out.


5
This one is user preference, a lot of people including me enjoy the slight flex on the trail and in crusty snow. Most of the current flex is in the bracket itself.


6
This option is actually coming for 2018, we have a custom track being made from Camso, retains the great spring snow performance of the current track with a 2.5" center paddle for bottomless powder thrust, I can tell you that a spring on the rear arm actually was a better improvement in deep snow than any 2.5" track we have used but for the ultimate deep snow performance we want to offer both.

 

[Dam Dave]

Thanks for the feedback




6
This option is actually coming for 2018, we have a custom track being made from Camso, retains the great spring snow performance of the current track with a 2.5" center paddle for bottomless powder thrust, I can tell you that a spring on the rear arm actually was a better improvement in deep snow than any 2.5" track we have used but for the ultimate deep snow performance we want to offer both.

Explain "I can tell you that a spring on the rear arm actually was a better improvement in deep snow than any 2.5" track we have used " because in Colorado deep snow I could use a 2.5 or 3.0 track

 

[Moto4Life]

Explain "I can tell you that a spring on the rear arm actually was a better improvement in deep snow than any 2.5" track we have used " because in Colorado deep snow I could use a 2.5 or 3.0 track

Basically the spring forces the rear of the kit down all the time, since our skid is designed using parallel arms it means that no matter where in the skids stroke you are at that the pressure on the rear end will be perfectly consistent causing the kit to plane on top of the snow very well. Yet if there are dips or rolls in the snow the skid will dip with them evenly instead of try and push through them which causes lost momentum.

Basically it causes the kit to act very similar to a snowboard from a stand still to high speed, currently it is only acting like a snowboard at high speed.

With that being said the deeper paddle will help in very deep snow, but you will notice more of the difference with the spring alone, than the track alone.

 

[Seekins]

I've got enough time with the 2" track to know that in anything but wet heavy snow it just spins, even on the flats. The 2.5 track hooks up and you get momentum. You can feel it pulling instead of just rev.
Your spring helped the attack angle but there's going to be other issues because of it. Hammering on that bolt is going to drive it out of the aluminum threads that hold that rear slider together.

I modified Eric's kit so has a few things done to make the kit work as good as it's ever going to., removes stress off of some areas and actually helps it get around in deep snow. Someone should listen to him. - Glen in Lewiston

 

[dooman92]

Wheel contact or not?

Finally got an opportunity to do some testing on my 120 enduro kit. Initially I thought the upper idler shaft was broken by contact with the motolink arm. I no longer believe that was the cause. I removed all shock preload and spring retainer and completely compressed the suspension so that the rubber bumper in the shock was compressed about a 1/2", essential bottomed out. At that point I still had nearly a 1/2" clearance between upper wheel and the motolink. I have photos but can't post? Additionally, there was no indication on the arm that there was ever any contact. In my case I believe other forces caused the shaft to break and we may be looking in the wrong area for a fix. When the suspension leans that puts stress on that shaft also, when stuck in a hole the only thing keeping the rails from staying in the hole while the bike is maneuver out is the rear slide joint and that upper shaft. Pulling the bike sideways out of a hole puts considerable stress on that shaft and rear joint. Of those that have had a shaft break can you see any evidence that the motolink hit the wheels?

 

[dooman92]

Additional ref spring preload

Preloading the spring will help with bottoming. If that is even the cause of shaft break? See above. Reference the preload issue in looking at the shock/ spring noticed the following. Uncompressed the spring is about 9" long. The shock compresses about 4". So with no preload at bottoming the spring is compressed to a length of 5". If one compresses the spring with 1/2" of preload and the shock bottoms, now the length of the compressed spring is 4.5". So the spring is compressed an additional 1/2" with the preload. If the spring is a 200lb per inch then we increased bottoming resistance by 100lbs as the spring was compressed to a shorter length with the preload.