Suspension Modification and Set up

[86Rrider]

OK, I just finished reading the 14 pages of 400EXrider707's thread on suspension theory over in the general mechanical section of the forum, as well as the links to GT Thunder's site info and others. I now have questions that I want to direct right at you other 250R owners (since I can't find it searching in here);

Can someone explain to me exactly what the advantage is on swapping in a rear swing arm from a 88-89 R into a 86? I've read that the 88-89 swinger is 1" shorter and made of aluminum, vs. the 86 made of steel and 1" longer. But other than the weight savings, what is the handling advantage of this swap?

I am asking this, for over in 400EXrider707's thread, it is pointed out many times that switching to after-market front A-arms with a +1 forward creates more steering issues than it's worth. But the point of if +1 A-arms are added to a quad, a +1 swing arm should also be added. So, does the 86R benifit from the +1 A-arms because of the swing arm being longer?

Background- I have a 86 R that I have been riding in it's stock configuration for the last 13 years. Prior to that I had nothing but stock 3-wheelers. Now at age 40, I am finally undertaking modifying the suspension on my R to try and get a smoother trail ride out of it.

Thanks for any "light" you guys can shed on this subject for me!

[deathman53]

I'll explain it for you. With your 3 wheelers, did you ever have a extended swingarm? On my atc250r, I had a stock length swingarm(85-87 length). I had to get a +1 because my new motor makes so much more power, it was un-rideable. First thing I noticed with the longer swingarm was a bigger turning radiaus and it took more effort to turn, being a by-product it was more stable in turns and I could ride it harder and longer with out the front end rising too much. Now I ride my 86 200x, it has a real short swingarm, it turns on a dime and gets awesome traction, but I have to do alot of counter-steering to keep it from going 180 when powersliding in corners, almost doing like the classic "full lock slide" that you seen 3 wheeler racers doing in corners.

Now how does this apply to quads? you ask? Same principle, a shorter swingarm gets better traction at a compromise to stability and needing for counter-steering correction. This is where the +1 forward a-arms come in, it puts more weigh on the rear, resulting in more traction, but slower turning. Due to kinda like more rake on the front end of the trike does, I noticed this when changing from a 85 250r frame to 86 250r frame(more rake). The 85 would turn sharper, faster and would require correction, where the 86 feels more planted and doesn't need as much correction. The 86 also felt far more stable.

I have a lsr framed quad with 88/89 length swingarm and +3 +1 a-arms, I also have stock framed with 89 swingarm and +3 +0 t-pin. The spindles are leaning back almost the same and camber is nearly the same. The lsr framed it turns slower and more stable, not needing much correction at all. Now comes the stock framed, it turns on a dime and tends to need correction, especially with fast turns. The difference is the +1 forward. I rode a bone stock 86 and holy cow, did it need correction in fast turns. I rode a stock 88 and it wasn't so bad, way more traction, but wasn't as stable in rough stuff.

Its a fine line between stability, traction and weight placement. Too much of any of it isn't good and could make bad results. You know how short bed and short body pickups tends to spin wheels and spin out. Then you have long bed and short front pickups that do also. My 2 tricks are great examples of this, first nission frontier, short body and 6' bed. It tends to spin out in rain and spin the tires in it also, not good stability. Other, f-350, crew cab and 9' bed. Its planted to the ground, can't get it spin out, the rear wheels only spin in mud and soft dirt(mainly due to the very street like tires and it being a dually). A truck where I used to work, it was a chevy 2500, regular cab and 8' bed. It spun out, didn't get good traction in wet stuff and for it to move in snow/mud/ice, it had to be in 4 wheel drive. It would do a mean burn-out in the dry street. It got no traction to the rear. There are other factors, if you have the ride height in the front too low and/or rear too high, it will act like it needs alot of correction and less stability. There should be 3/4"(with the rear being lower) difference between the under the frame-ground in front of the motor and frame-ground under the footpegs. For most, a 88/89 length swingarm and +1 forward a-arms is the ticket. I ride it like a trike, using the rear to turn and the front to countersteer, so its more obvious to me. I'm sure somebody else will have a different opinion.

[86Rrider]

Thanks for the input deathman!

To answer a couple of your questions; No, all the 3-wheelers I had were bone stock - '84 -185S, '83 -200M, '84- 200X, '85 - 250R and currently '83 - 250R. The closest I came to a suspension mod was I stuffed a rear shock from a '86 ATC250R in the back of my 200X. The result was a big rake to the bike, but I'm 6'2" and at the time 220 lbs. so when I got on the bike it set level. Never noticed a handling issue with it. Both of the ATC 250R's are a hand full, always needing to ride up on the tank and steer with the throttle - counter steer with the front tire, and yes, I hang-off the side of the machine in hard cornering.

Now, my '86 TRX 250R I have never really noticed much steering correction needed. But, I ride this machine on a MX track about once a year. The rest of the time it is trail ridden. When it comes to tignt turns, I usually lean-out, stab the throttle to bring the rear around and just point the front wheels where I want it to be out of the corner. I never really have had any complaints on the steering, which is why I posed this question.

As of now, I have bought a set of Laeger +2+1 A-arms, the longer tie rods, brake lines and a set of Elka tripple spring shocks- remotes, compression adj. no rebound. I have it all installed on my quad and I am still in the process of adjusting the front settings (toe and camber, no caster adj.). So, upon reading the posts I mentioned, I started to fear that with the +1 forward on the A-arms, I am now going to be experiencing steering issues. Therefore, I wanted a 250R owner's opinion and experience with what affect the +1 would have.

So in reality, the whole thing comes down to weight transfer and the placement of the tires in relation to that. Using your example: the 9' box F-250 basically has the tires out at the far corners. So it has the weight distributed very evenly, so traction is excellent, but you need a farm field to turn the thing around. To make an example of the 88-89 swing arm and +1 A-arms you are in a sense doing what Chrysler and Ford did back in the early 60's with the altered-wheel base cars. Move the front tires forward to almost under the front bumper, then move the rear axle forward about 16" and now the car has awsome hook at the start line! Yet, in reality, the actual wheel base of the car remained the same. So I will end up with the F-250 charactoristics, where if I get ahold of a -1" swing arm (88-89) I would keep my handling charactoristics plus increase my traction.

Sorry for the long post, but I got to type-thinking.

[CorvetteZ06]

try and find a 88-89 swinger in good condition, it will give you better traction, and its lighter. plus, since you have the +1 forward a arms, it will bring your 86 R to the 88-89 geomatry specs.

[deathman53]

keep in mind, you need a 86/87 style 88/89 length. If you get a stock 88/89, you need to weld 2 tabs to the bottom rail for the rear motor mount.

[86Rrider]

Thanks again for the input guys!

So if I keep my eyes out for a stock 88-89 swing arm, the swap will eleminate the rear engine mount? So I should look for a aftermarket 88-89 swing arm that was meant to go on a 86-87 frame? I've seen chromoly arms from the big names, but did anyone make an aluminum one that would fit right?