K Mod and Holz and Timbersled Challenge

[Mtn. Muncher]

Good point by Winter Brew. It seems that most people compare these skids at their max abilities and adjustments and miss the boat on how they are actually tuned and used out in the mountains. Seldom ever do we see our skids run at their max coupling capabilities. They are mostly used on stock sleds and can provide a great improvement to your deep snow performance and ride quality. Snowmobile skids are one of the most complex suspensions on any motorized machine in the world. So it is a little hard to explain all the differences and their benefits.<O</O
I do not have a comparison video but I can explain it to help understand the coupling differences between the Timbersled Mtn. Tamer and the Kmod Gen-2. There are advantages and disadvantages to both in my opinion. Kevin please come on here and correct me if I am wrong on any of this.

<O</OFacts about these skids at full coupling adjustment capability:<O</O
1. Both skids will mechanically pull the front arm up the same amount.
<O</O
2. Timbersled Mtn. Tamer will have 2” of movement at the back bumper before it couples then will pull the front arm up at a slightly faster rate than the Kmod Gen-2.
<O</O
3. Kmod Gen-2 will start to pull the front arm up as soon as the back moves and will pull the front arm up at a slightly slow rate then the Timbersled Mtn. Tamer.
<O</O
4. At mid stroke of the suspension travel both skids will have coupled the front arm up the same amount.
<O</O
5. On both skids the coupling is seamless (meaning you cannot feel a clunk when it touches the coupling adjuster) and you only feel the skis wanting to stay low to the ground.<O</O

Keep in mind that these facts are at full coupling and that both of these skids are adjustable to anything in-between.<O</O
Also know that coupling only happens when the back arm is being compressed like when climbing a hill or when the skis try to come off the ground. If the front arm at any time is pushed up farther than the back arm by the snow or a bump the suspension will uncouple for that short moment of time.

<O</OAllen from Timbersled<O</O

 

[KMOD]

Good point by Winter Brew. It seems that most people compare these skids at their max abilities and adjustments and miss the boat on how they are actually tunes and are used out in the mountains. Seldom ever do we see our skids run at their max coupling capabilities. They are mostly used on stock sleds and can provide a great improvement to your deep snow performance and ride quality. Snowmobile skids are one of the most complex suspensions on any motorized machine in the world. So they are a little hard to explain all the differences and there benefits.<O</O
I do not have a comparison video but I can explain it to help understand the coupling differences between the Timbersled Mtn. Tamer and the Kmod Gen-2. There are advantages and disadvantages to both in my opinion. Kevin please come on here and correct me if I am wrong on any of this.

<O</OFacts about these skids at full coupling adjustment capability:<O</O
1. Both skids will mechanically pull the front arm up the same amount.
<O</O
2. Timbersled Mtn. Tamer will have 2” of movement at the back bumper before it couples then will pull the front arm up at a slightly faster rate than the Kmod Gen-2.
<O</O
3. Kmod Gen-2 will start to pull the front arm up as soon as the back moves and will pull the front arm up at a slightly slow rate then the Timbersled Mtn. Tamer.
<O</O
4. At mid stroke of the suspension travel both skids will have coupled the front arm up the same amount.
<O</O
5. On both skids the coupling is seamless (meaning you cannot feel a clunk when it touches the coupling adjuster) and you only feel the skis wanting to stay low to the ground.<O</O

Keep in mind that these facts are at full coupling and that both of these skids are adjustable to anything in-between.<O</O
Also know that coupling only happens when the back arm is being compressed like when climbing a hill or when the skis try to come off the ground. If the front arm at any time is pushed up farther than the back arm by the snow or a bump the suspension will uncouple for that short moment of time.

<O</OAllen from Timbersled<O</O

This is a good post and the customer has many options on two very good skids.

Allen is right with the fact that coupling skids pull up the front of the rails, I think the main difference of the two different designs are at what ratio we pull the rails up compared to the rear arm. At K MOD we call it a parallel swing arc. If the ratio isn’t the same front to rear then the swing arc cannot stay flat through the travel. Staying flat can also have a positive effect on track tensioning.

Mid stroke front arm coupling could be different if the ratios are different, also it depends on how the straps are set and how aggressive your coupling is.

Allen is right when he stated the coupling only happens when the rear arm is compressed, unless we stop the rear arm from moving back forward then you have reverse coupling which will pull the back of the rails up, this is possible but makes for a harsh ride.

With the new 4 position billet quick adjust coupler we have a new milder position at number 1 which gives us about 1.5’’ of travel before it contacts the coupling block.

Winter Brew commented on the adjustability of these skids, we at K MOD have tested many days to come up with a package that is very adjustable for all types of riders and abilities that will bring them to a higher level of performance , for them and their sled. If it handles better they have more confidence and can ride harder.
We have a premium shock package with dual Raptor 20 position compression clicker shocks with triple rate front track spring and a dual rate rear track spring, with this combo we can dial in any vehicle and rider from 120 lbs. to 250 lbs. with or without boost all in preload and clicker adjustment along with coupling.

All in all we call it coupling and have our own way getting it done, both skids are good designs but a little different. Competition is good; it drives the companies to better products that ultimately are good for the consumer and industry.
Thanks, Kevin

 

[philsummers21]

I have to say. Seeing two posts side x side from competitors like you two is absolutely amazing. No bashing, just solid facts. Alot of companies could learn from you two on how to run a business in a formal and correct manner. Let your products speak for themselves. Ive personaly never tried or been around a kmod but kmod and timbersled are 2 suspensions id definitly spend my money on. Props to both of you.

 

[byeatts]

I have to say. Seeing two posts side x side from competitors like you two is absolutely amazing. No bashing, just solid facts. Alot of companies could learn from you two on how to run a business in a formal and correct manner. Let your products speak for themselves. Ive personaly never tried or been around a kmod but kmod and timbersled are 2 suspensions id definitly spend my money on. Props to both of you.

X2.Good job guys, No bashing. A few things to note is a falling spring rate skid in the last few inches of travel will just collapse , meaning there is little shock resistance due to the lay down angle and leverage applied to the shock and renders the last bit of travel pretty useless.. Both these skids are similar in coupling .As for K mod what is the range from 1-4 adjustment in inches for coupling?Also Timbersled also allows ride height adjustment.I have altered my timbersled a bit and had the slide mechanism chromed and custom bushings made so I dont need to grease it. It runs dry with no mess.

 

[likkerpig]

I'd like to understand what the differences are in terms of ride quality as it relates to the front arm moving. What does moving at a faster rate vs. a slower rate mean for me relative to what I'm going to see and feel while riding?

 

[Mtn. Muncher]

Thanks guys for the complements. My passion is working with suspensions; if I did not make my living building them I think I would own a suspension outlet store and sell all that is available in the industry.<O</O


It’s hard to explain without going in to great detail and writing a book but I will give it my best shot and try to keep it simple.
<O</O

Geometry of a coupling suspension design is what we have work so hard on for years and have defiantly made huge improvements to our Mtn. Tamer design. The falling rate problem that a lot of skids have is amplified on a coupling suspension. We have worked these issues entirely out of our skid design. It all has to do with push points and angles that have massive load pressures between them. As of last year the new Mtn Tamer now has an evenly progressive rate similar to a dirt bike suspension and then has a adjustable bottom out system that has a jounce bumper in the shock with a adjustable bottom out pad on the arm where the arm hits the rubber pad on the rail (this adjustment is preset from the factory depending on what shock option you go with). This allows use to use max compression of the jounce bumper for max bottom out force the last 1.5” of travel (this adds 1000lbs of bottom out force). With this new geometry we can monitor the stiffness more accurately with spring rate and or air on the Fox shock with much lower spring rates or air psi. For example I am 220 lbs and I run 110 psi in the back Fox shock or a 300lbs. rate spring with very little to no preload. This makes the skid much softer the first couple inches of stroke. Evan at this the skid will still rebound all the way to the top when you get off the sled. The pre load should be adjusted with the rider on it not with rider off like on the stock suspension (they normally sit there with a few inches of sag with no added weight stacked on the sled).
<O</O

The ride height adjustment on the Mtn. Tamer is one of the most commonly used adjustments that the skid offers (it is a shim system that can be added to make the back of the sled as low or high as you desire). On coupling skids with vertically mounted shocks they attend to put more weight onto the skis when slow riding (when coupled or uncoupled, ether way) because they do not slouch/sag in the back like the stock skids do; this makes the stock sled feel more friendly to the average rider and is one of the main reasons they do not go to a skid design like the Timbersled Mtn. Tamer or Kmod Gen-2 but have copied more what Holz has done with their Alfa-X with better geometry like the longer front arm and coil over shocks. For us on the Mtn. Tamer we use the rear arm ride height adjustment to offset the feeling of heavy ski weight at slow speeds without jeopardizing the coupling or deep snow performance (simply put the sled sags or squats anyway when you hit the throttle and weight transfers).
<O</O

Any won that is interested in buying any aftermarket skid needs to be willing to fine tune it to your liking, if so I can guaranty that you will have a better than average riding experience.
<O</O

Allen from Timbersled<O</O

 

[Mtn. Muncher]

I'd like to understand what the differences are in terms of ride quality as it relates to the front arm moving. What does moving at a faster rate vs. a slower rate mean for me relative to what I'm going to see and feel while riding?

I think I understand your question. You are referring to how fast the front arm is pulled up when the skid couples and what you are feeling in the ride of the sled. Is that correct?

<O</OLike I said in my facts above on the Mtn. Tamer the back bumper will move 2” before it couples when adjusted to max coupling then will draw up the front arm slightly faster than on the Kmod Gen-2. Is what this means to you and what you will feel is that when you are going up a hill or on flat ground the sled will have a slight chance to transfer some weight for added traction and maneuverability before forcing the skis to the ground and keeping the skid parallel to the ground angle you are on. As for the stiffness of the skid you will not feel that it is firmer but will feel that it is actually smooth when hill climbing because it bridges the bumps and dips in the hill and will carry more speed of a result of it.

<O</OI am sure Kevin will have some more valuable info to add to this. When the skid has no independent movement in the rear when fully couple it will more likely shoot straighter when you are on and off the throttle on a steep hill with lots of HP but will be les maneuverable on flatter train.

<O</OAgain keep in mind that these 2 skids are adjust on the fly so you do not have to ride them all the time like this. It is mostly for extreme hill maneuvers and comfort of having some advantages over your buddies when trying to get up some tuff spots on the mountain.

<O</OAllen from Timbersled<O</O

 

[byeatts]

I think I understand your question. You are referring to how fast the front arm is pulled up when the skid couples and what you are feeling in the ride of the sled. Is that correct?

<O</OLike I said in my facts above on the Mtn. Tamer the back bumper will move 2” before it couples when adjusted to max coupling then will draw up the front arm slightly faster than on the Kmod Gen-2. Is what this means to you and what you will feel is that when you are going up a hill or on flat ground the sled will have a slight chance to transfer some weight for added traction and maneuverability before forcing the skis to the ground and keeping the skid parallel to the ground angle you are on. As for the stiffness of the skid you will not feel that it is firmer but will feel that it is actually smooth when hill climbing because it bridges the bumps and dips in the hill and will carry more speed of a result of it.

<O</OI am sure Kevin will have some more valuable info to add to this. When the skid has no independent movement in the rear when fully couple it will more likely shoot straighter when you are on and off the throttle on a steep hill with lots of HP but will be les maneuverable on flatter train.

<O</OAgain keep in mind that these 2 skids are adjust on the fly so you do not have to ride them all the time like this. It is mostly for extreme hill maneuvers and comfort of having some advantages over your buddies when trying to get up some tuff spots on the mountain.

<O</OAllen from Timbersled<O</O

Allen I purchased the first Ski Doo skid you had available in 07/08. Still running it with the rear arm upgrades. I was also dealing with the falling spring Rate and had Tom,s build me a custom Evol-R rear shock which fixed those issues completely.It totally change the behavior of the skid with plushness up top, complete rebound and nice bottom resistance. you've made some nice changes since then.Ive also added an additional air tube to the front shock which took the harshness out of the initial hit,Since then you offer better shock upgrades.I,ve been very happy with the way the skid handles.

 

[likkerpig]

Thanks Allen that's exactly what I was asking for!

 

[mfatty]

price

How come no one has talked about getting what you pay for, suppose all the products are going on the same sled what would each one cost ? I think that has alot to do with the value of the the skid everyone would purchase...imo why hasnt holtz chimed in yet ? maybe there product isnt up to your standard ?

 

[likkerpig]

I hear what you're saying but as we all know different parts sources can all have different pricing which may or may not be controlled by the manufacturer. Msrp is one gauge but may not be the actual price one would actually pay...

 

[Aussie Niko]

Great video Allan, make total sense seeing it in action.

 

[KMOD]

Coupling

A few more thought on coupliing and how we like to do it.

Coupling: All coupling skids be it K MOD, Timbersled, M10, Racers Edge, CR Racing are all falling rate designs. What this means is; as the front or rear arm move through their travel, the shock lays down and becomes less effective to the point of what we call over centering. Over centering happens at the point where the rear arm is compressed to horizontal, on some designs this can actually lock the suspension down. Now as bad as this sounds there are ways to overcome this issue in most cases. The easiest way to do this is by reducing the amount of travel. To Allen’s credit this is what he has done by welding (bottom out pads) standoffs on his rear arm to eliminate the over centering that his coupled suspensions had at full compression (jounce). Also they have made what would seem an easy way to limit the travel at full rebound (ride height) by simply adding spacers. Some have commented how nice of a feature this is and I agree it’s important for this design.

We at K MOD do this in a completely different way. First you NEVER EVER reduce the amount of travel on a snowmobile. The draw backs to limiting travel are a much shorter duration of shock movement by the shaft piston assembly in the shock. With more duration (stroke) we can control dampening to help absorb bumps with lighter spring rates.
One of the reasons our suspension works so well is our equal length arms front and rear. The way that we mount our arms in relationship to one another (geometry) and how we mount the skid in the tunnel allows for more rear axle travel then others that we have measured! Now that’s a big deal, anytime you have that much duration to absorb a bump or a drop or whatever.
How we deal with ride height is simple. We adjust spring preload up and down to achieve the ride height that we are looking for. Doesn’t get any easier than that and it’s a percentage of overall travel, and you have to have ride in, sag, droop call it what you will, it’s very important. Off-road trucks use about 50% of their travel in ride in, that’s huge. K MOD uses about 20% to 25% in ride in.


On the Timbersled suspension it is more important to adjust with spacers because of the single rate springs (or air). The total duration of the shock is less after the ride height is adjusted (you must compress the rear shock and arm to put a spacer in) plus it makes the coupling start sooner (you just moved the arm closer to the coupling adjuster) there by eliminating some of the 2’’ of free travel. Also spring preload just went up the same amount of the spacer that was installed (firmer ride).

On the K MOD skid we use Raptors triple rate springs (TRS) along with progressive valving and a corrugated jounce bumper that gives you 1500 pounds of load at the last part of the travel where you need it the most.
With the amount of travel that the K MOD skid gives you it allows for a smoother ride over the small stuff but still has great bottom out capabilities with exceptional durability.
Thanks, Kevin

 

[byeatts]

A few more thought on coupliing and how we like to do it.

Coupling: All coupling skids be it K MOD, Timbersled, M10, Racers Edge, CR Racing are all falling rate designs. What this means is; as the front or rear arm move through their travel, the shock lays down and becomes less effective to the point of what we call over centering. Over centering happens at the point where the rear arm is compressed to horizontal, on some designs this can actually lock the suspension down. Now as bad as this sounds there are ways to overcome this issue in most cases. The easiest way to do this is by reducing the amount of travel. To Allen’s credit this is what he has done by welding (bottom out pads) standoffs on his rear arm to eliminate the over centering that his coupled suspensions had at full compression (jounce). Also they have made what would seem an easy way to limit the travel at full rebound (ride height) by simply adding spacers. Some have commented how nice of a feature this is and I agree it’s important for this design.without this a 162 length only has the same as a 144 lenght of track on the ground when fully compressed

We at K MOD do this in a completely different way. First you NEVER EVER reduce the amount of travel on a snowmobile. The draw backs to limiting travel are a much shorter duration of shock movement by the shaft piston assembly in the shock. With more duration (stroke) we can control dampening to help absorb bumps with lighter spring rates.
One of the reasons our suspension works so well is our equal length arms front and rear. The way that we mount our arms in relationship to one another (geometry) and how we mount the skid in the tunnel allows for more rear axle travel then others that we have measured! Now that’s a big deal, anytime you have that much duration to absorb a bump or a drop or whatever.
How we deal with ride height is simple. We adjust spring preload up and down to achieve the ride height that we are looking for. Doesn’t get any easier than that and it’s a percentage of overall travel, and you have to have ride in, sag, droop call it what you will, it’s very important. Off-road trucks use about 50% of their travel in ride in, that’s huge. K MOD uses about 20% to 25% in ride in.


On the Timbersled suspension it is more important to adjust with spacers because of the single rate springs (or air). The total duration of the shock is less after the ride height is adjusted (you must compress the rear shock and arm to put a spacer in) plus it makes the coupling start sooner (you just moved the arm closer to the coupling adjuster) there by eliminating some of the 2’’ of free travel. Also spring preload just went up the same amount of the spacer that was installed (firmer ride).

On the K MOD skid we use Raptors triple rate springs (TRS) along with progressive valving and a corrugated jounce bumper that gives you 1500 pounds of load at the last part of the travel where you need it the most.
With the amount of travel that the K MOD skid gives you it allows for a smoother ride over the small stuff but still has great bottom out capabilities with exceptional durability.
Thanks, Kevin

Couple of thoughts, as far as Timbersled having a single spring rate.I dont no all whats offered now but I run a dual air chamber Evol -R which has adjustable rates for initial settings and separate adjustable rate for bottom resistance, Thats something a dual rate spring wont do since there's only one spring adjustment without changing springs.,Also when sucking the skid all the way up there is no track contacting the snow for about 15 inches back from the drivers,that part of the track is raised up in the tunnel and therefore I also made bottom bumpers which were higher then stock setup to stop at a point where I still have all the track pulling.There is a portion of the travel that hinders performance since when fully compressed a 162 has about the same amount of track pulling as a144 for a short period. Again if all will post the suspension pics of the travel when mounted in a sled these issues can be seen.for those who are in deep powder and you fully compress you can feel the sled lose its forward momentum , feels like hitting the brakes as the chassis drags through the snow, this was minimized by altering the bottom rubber stop.JMO

 

[Matte Murder]

Byeatts could you post a pic of that?

 

[KMOD]

Couple of thoughts, as far as Timbersled having a single spring rate.I dont no all whats offered now but I run a dual air chamber Evol -R which has adjustable rates for initial settings and separate adjustable rate for bottom resistance, Thats something a dual rate spring wont do since there's only one spring adjustment without changing springs.,Also when sucking the skid all the way up there is no track contacting the snow for about 15 inches back from the drivers,that part of the track is raised up in the tunnel and therefore I also made bottom bumpers which were higher then stock setup to stop at a point where I still have all the track pulling.There is a portion of the travel that hinders performance since when fully compressed a 162 has about the same amount of track pulling as a144 for a short period. Again if all will post the suspension pics of the travel when mounted in a sled these issues can be seen.for those who are in deep powder and you fully compress you can feel the sled lose its forward momentum , feels like hitting the brakes as the chassis drags through the snow, this was minimized by altering the bottom rubber stop.JMO

Byeatts
Excellent comments

You are right on the fact that the Evol shock has dual air chamber adjustability and bottom out resistance plus the fact that there is a rebound clicker also, all in all it’s a great shock especially over the STD float. We started the Gen II in 2009 with the Evol shock std on the rear and still offer that combination. But when I got into the Raptors it really raised the bar on performance and adjustability, between the basic preload adjustment and the 20 position clicker tied with the quick change coupler we are able to fine tune the skid for a much broader range of riders and performance. The point to the dual rate coil over was to have a compliant ride for part of the travel and then ramp up for the big hits; this is something a single rate can’t do.

If I understand correctly you made the jounce bumpers taller on the front of the rail to keep the front of the rails from pulling up too high in the tunnel? From what you’re describing the front of the track is too far in the tunnel not keeping enough contact in the snow? Which can cause drag with the skis and tunnel?
There are a few things that could cause this, but I don’t know about your sled in particular. Just some thoughts or questions, are the drivers stock or smaller? What is the preload (air preasure) on the front track shock? What length of front arm are you running? If I remember right the Rev had a 14.5’’ front arm?
What you quoted on the 163 having the same amount of track in the snow as a 144 is exactly what most stock sleds do without a coupling skid. The front arm releases and extents while the rear arm compresses, the front end comes up and you’re trenching with the front portion of the track in the air with little or no contact on the snow. Remember the difference of track in the snow between a 144 and 162 is only 9’’. But what a huge difference 9’’ can do for a sled in deep snow.
You are 100% right in the fact that if the entire track isn’t in the snow the sled is not efficient enough to get up on the snow as quick and will slow down. One of the benefits of a coupling skid is to keep more of the track in the snow more of the time.
I like the fact that you’re not afraid to try different things to get the performance that you need in your conditions.
Thanks, Kevin

 

[sledsrock]

Byeatts skid pics

Byeatts could you post a pic of that?

Here's a couple......

 

[sledsrock]

Another pic of Byeatts Beast

Full sled pic.

 

[madmini660]

Here's a couple......

what is done to the front float in this picture would like to do this to my'n

 

[byeatts]

what is done to the front float in this picture would like to do this to my'n

Thats an air tube for additional volume and is sold by fox. Without it the initial hit is harsh and with it its very supple, In fact its a tad too much air and i will shorten the tube one inch for next season.It turns the standard float to an extra volume shock just like the newer shock comes with.that shock is 4 years old.