Stiff ride after track extension on apex

[evil eagle]

I'm not sure why but not the sled seems to be a stiff ride and rough ride since I stetched it out to a 136. I was expecting the opposite with it bottoming out more without getting a heavier spring.

 

[blade072]

I'm not sure why but not the sled seems to be a stiff ride and rough ride since I stetched it out to a 136. I was expecting the opposite with it bottoming out more without getting a heavier spring.

My friend and I have found the same. He stretched his Polaris and I stretched my Blade to 136. Both of these suspensions are M-10s. The suspension became a lot stiffer. We played with shock valving etc. but could never get it to soften. We finally put a softer rear spring in the suspension and it softened the suspension to where it is fun to ride.
We cannot figure out what caused this to happen. Maybe some suspension experts can chime in and give a detailed reason for this.
Jim

 

[Grimm]

Are you positive that you installed the suspension correctly? Sometimes, it can be quite easy to use the wrong bolt hole when bolting in the rear swing arm.

Did you do anything else to the suspension.

 

[KevinS]

Not the first time I have read this on TY. If you look at a 136 from an Apex LTX or an Attak you can see that the rear arm on the skids are completely different. On a 121" the upper idler wheels are on the rear arm. On a 136" the upper idlers are on a separate shaft.

 

[TJRTX]

I think most of the problem is from the coupling. When you increase the amount of rail behind the rear mount point,it's that much more rail trying to be forced up when rear to front coupling is in effect. The change in geometry also has to have some effect. Try putting a dolly under the front of skid only and I would bet you'll find a soft compression.the farther you move the dolly back the harder it will become. I stretched a 128 inch cat f series rear to 136 on my apex and found by trail and error that by lowering the front of skid mounting point lower in tunnell it coupled much smoother and softer . Which made the ride much softer. At least in my application I believe the front of skid mounting bolt should be lower than rear for best ride .

 

[basic700]

Does it have to do anything with the track getting tighter as the suspension compresses??

 

[TJRTX]

Yes, I agree I forgot to mention that. I run my track as loose as possible. It deffenitly affects stiffness. I'm able to run my softer than stock because of the cat torque sensing link on rear arm ,which keeps a more constant track tension throughout the suspension travel

 

[evil eagle]

I did'nt really think the coupleing would be effected by this change. I don't see any warnings from the sellers of these kits of the side effects.
I did read how the track will tighten as it compresses. I did'nt tighten the track as much as I did when it was a 121. I played with it in the garage with tightening the track and very loose. I can with my body weight laying on the tunnel ext and pulling on the track can make it almost bottom out. with it tightened alot, and it was harder to make it compress somewhat but not as much as I thought it would.
So I guess I will have to live with the stiffness.
That and the ext being I think a bit too short, I have the adjusters driven all the way in all but the last 1/4 inch of adjustment just to have the brand new track as tight as I have it.

 

[Malmlof]

Does it have to do anything with the track getting tighter as the suspension compresses??

Basic nailed it on this one, you need a set back upper Wheel axle as on the Attak. For correct geometry of the track.
The set back axle should be offset as far as you lenghten the rails.

Otherwise the tightening of the track will affect the driveshaft and skid with very high loads on bump impact and landings.

Hope it helps, before something brakes.