• We are no longer supporting TapaTalk as a mobile app for our sites. The TapaTalk App has many issues with speed on our server as well as security holes that leave us vulnerable to attacks and spammers.

Rear Torsion Spring Mod

we have been working on a friends 14 ltx se with the rear springs off the rear sags to the point that the front to rear coupler engages then the front spring will hold the rear up, drops about 4 in I dont think its the shock. we had the rear shock revalved removed the rear blocks drilled a new hole for the lower spring mount above the through bolt that holds the rear shock front mount. this shortend the long side of the spring which should increase the rate but the lower inital preload allows some sag. I go 230 dressed and and rode 175 mi yesterday spent `1/2 the day on that sled and 1/2 on my stock rtx base. the ltx rode way better. much better traction and transfer and had a nice progressive feel. in a drag we have always been dead even yesterday he pulled by 2 to 3 lengths all day. might be something to try.
 

Do you have photos and measurements of your work? If I read correctly you shortened the long leg(working leg) of the spring and relocated the blocks? I have the same sled, LTX, and am trying to get some "plushness" in this skid. Good work.
 
sorry cant post pics but we moved it directly above the bolt that goes through the skid and holds the wheels and shock mount. front of rear shock.
 
Cannondale, I for one, like your "Innovative" idea's and sharing them on TY.

Just a though; is that Axis rear shock a high pressure unit? I totally get what you're saying about a shock being able to add suspension "spring", especially if it is a high pressure deal. I just serviced my suspension and was actually able to collapse the rear arm for installation, and it would almost stay collapsed. It had very little rebound pressure.
 
ViperBill said:
we have been working on a friends 14 ltx se with the rear springs off the rear sags to the point that the front to rear coupler engages then the front spring will hold the rear up, drops about 4 in I dont think its the shock. we had the rear shock revalved removed the rear blocks drilled a new hole for the lower spring mount above the through bolt that holds the rear shock front mount. this shortend the long side of the spring which should increase the rate but the lower inital preload allows some sag. I go 230 dressed and and rode 175 mi yesterday spent `1/2 the day on that sled and 1/2 on my stock rtx base. the ltx rode way better. much better traction and transfer and had a nice progressive feel. in a drag we have always been dead even yesterday he pulled by 2 to 3 lengths all day. might be something to try.
Click to expand...
Right its not the shock but the geometry. They moved the rear scissors 1 inch forward(129") this makes the rear less progressive. Thats easily fixed with shock but is no way to change the sag other than spring since 1 inch forward on my rails is a cutaway for wieght.
 
DT said:
Cannondale, I for one, like your "Innovative" idea's and sharing them on TY.

Just a though; is that Axis rear shock a high pressure unit? I totally get what you're saying about a shock being able to add suspension "spring", especially if it is a high pressure deal. I just serviced my suspension and was actually able to collapse the rear arm for installation, and it would almost stay collapsed. It had very little rebound pressure.
Click to expand...

No 200psi in Axis. Same as the stocker. Dont forget skid has to be in sled or top skid mounts connected to react the same as in sled. Guys I am not saying the bending didnt help. It did but if I bend the springs on a RR skid like I did it would be slammed to the ground with me on it. Actually did that last week guy is both racing and trailriding his and he didnt want to mess with spacers in shocks for Ice XC Races. I only weigh 145 so am nowhere near couplers. Last year I did change nitrogen pressure in rear shock and I did get a little more sag but still not enough to be happy. Please understand I am probably not being clear on this. I know it is the geometry of the skid that causes the sled to be on the Top Out stops with no weight on it. But the problem is I cant change geometry and cant change the shock PSI. That leaves the spring. What I find is any spring even a bent and lighter rate than stock does not give me enough sag to be on the couplers or even close to them. Maybe on a 137 it does. 129 it does not.
 
145, wow, that was a few cheeze burgers ago, heck even a couple marriages ago. I'm around 200 and my '15, even with spring block on low, sits near the top of it's travel. Probably not optimal for speed runs like what you were doing. Never heard of spring bending. Do you think there will be any long term issues with it?
 
DT said:
145, wow, that was a few cheeze burgers ago, heck even a couple marriages ago. I'm around 200 and my '15, even with spring block on low, sits near the top of it's travel. Probably not optimal for speed runs like what you were doing. Never heard of spring bending. Do you think there will be any long term issues with it?
Click to expand...
I would put a more gradual bend in like we did for that RR. With a torch to soften. But yes like mine is I am sure it would crack if ridden hard. Did it with a press. Dont own a Oxy Acetelyne torch. The springs on there that I bent are TWO steps lighter than stockers also. RR has exact same springs as RTX and LTX stock. So the bend and lighter spring really should have been drastic. Guys my Phazer has a good 6-8inches of sag with me on it. Works awesome! ZPS is the way to go for handling,traction and still take the bumps. Look at the Trophy trucks they are lower than a stock truck. Even back in day the fast street drag cars were lower in rear not jacked up like some did to clear tires.
 
Just measured. With me on sled and standing in middle of boards I have about 2 inches of sag measured here. Thats pathetic.
Static sag
IMG_1178.JPG

Rider Sag
IMG_1179.JPG

Static(no rider) coupler gap.
IMG_1180.JPG
 
Need to apologize for being so testy. This sag issue has been bothering me since I got sled. Working on Daughters boyfriends 97 670 Doo roach, Her headlight plugs on car corroded and had to replace them and fighting with skid my Knuckles and hands are just shot. Have to put it all back for Muni Giveaway Ride. Been busy. Will relax and have fun! Sorry.
 
With softer torsions and shocks revalved on my Ltx se I have 3 1/2 to 4 inches of sag when I sit on the sled, I'm around 250 lbs. when I'm trying for speed runs I lock my feet as tight in the footwells as I can and hang off the back as far as I can to get it to squat more yet still be somewhat aerodynamic...and I'm not an aerodynamic guy lol. I've had several guys on my sled ranging from 150 lbs up to me at 250 and it's always the fastest with me on it. Getting that rear to sag and the front up the skid right up in the tunnel it has almost no angle at all where the track approaches the ground at the front of the skid, that approach angle is also a big factor.
 
this skid sucks top end in its original setup BAD. i am looking into getting a plusher ride and some sag. cannondale you probably will get my shocks for a revalve soon, i was running across lake wissota last night, and would run 105 on snow, just seems to hit a wall at 100. have it pinned doing 100 and hit some ice it spins to 125-128 so i know the clutching is there. and the power should be! but cruising at those speeds and on the throttle the sled has virtually no sag. watch a doo on the throttle and there bumper is almost dragging!
 
Sorry for the poor quality photo, it's just a screen shot of a poor quality video but you can tell how much the rear end is squatting on my Ltx se. This is low speed launching but even at higher speeds I can get it to stay squatted right down, maybe us fat guys finally have an advantage!
 

Attachments

  • image.png
    image.png
    123.5 KB · Views: 109
You must log in or register to reply here.


Back
Top