New to LT, Caster Adj, Is is darting?

[Pepto_Bismol]

Me again,

I finally put my entire quad back together with some Herrmann LT and Elka Elite Quad Rate up front, same in the rear (Herrmann +1.5 SA and Elka Elite).

I have great photo installs and will write up a review soon.

But on to my question:

On my previous 400EX, I bought Elaka triple rate, but used stock A-Arms.

Now, I have the Herrmann LT on my new 450R. I set up everything as best I could using angle finder. Here is what I have:

Chamber 5 degrees negative
Caster (as best as I can tell) 5 Degrees Positive
Toe 1/4 in/ front

One thing I can say, is that having spherical bearings top and bottom makes it difficult to find the center line for the vertical adjustment for caster. I used the angle finder at center line marks (measuring approximately where the middle of the king pins go thorugh the spindle) on the outside of the top and bottom to obtain caster reading (see pics below). Any alternative suggestions?

So I took it for a quick test ride, and I am suprised at how sharp it turns (very easy).

Going down a straight (top speed), it seems to hold the line well, no twitching (unlike the twitching experienced with stock setup at high speed), but the steering if VERY sensative. Like, just the slightest touch will move me one way or the other (at high speeds, that might not be a good thing, but I didn't seem to have any real control issues during the test ride) Seems almost too sensative, but again, I have never had LT setup before.

So my question is, does this seem normal, or perhaps I have improper readings on the caster, and need to adjust more positive.

My type of riding, Mostly Desert, with 1/4 time MX track.

Comments?

Pepto:cool:

[Pepto_Bismol]

Here is the setup:

http://members.cox.net/peptob/herrmann.jpg

[Pepto_Bismol]

Here is the Caster Adjust:

http://members.cox.net/peptob/close.jpg

Pepto:cool:

[R3Concepts]

For one get a stabalizer if you dont have one..next 5 degrees negative camber is a little much, try around 3 or 4..And caster, the more caster you have the quicker it will turn..Id also adjust that down to 3 or 4 but caster is ++, like you already know.

[Pepto_Bismol]

R3,

Thanks for the reply. I am suprised (well, not really...) at how "mute" the community is when it comes down to such a focused question. Many views, but no response.

Anyway, the chamber is actually reading 4.5, but the tolerance on the angle finder is +/- 1 degree, so I just said 5. I will probably bring that in a tad too though.

One question, wouldn't reducing the amount of positive chamber make it even more sensative to turn? I thought the more negative (or in this case, the less positve) the caster, the quad would be less stable at high speed, and easier to turn?

I am under the impression that I do not have a good read on the caster. I spoke with Brad from Herrmann and he stated that the design of the LT A-Arms (when the upper heims are seated in all the way, or basically turned out an even number both front and back) was close to the caster of stock.

It's just tough to get a read on the angle in such a tight spot with the dual sphericals.


One last thing, obviously you ride some desert, any suggestion about type / quality of a stabilizer?

Of course GPR or Precision would be my first choice, but I have depleted my "excess" cash (excess, yah right!), and don't have the $450 bones to pony up at the moment. Any thoughts?

Thanks!

Pepto:cool:

[BLACKeR]

im not a long travel guy, so i dont know how mush different it is than standard travel. but from the picture your "toe" looks to be going out. i believe the prefered "toe"is 3 degrees in, yours looks to be going out. also your camber looks real steep to me. i would bring the top of your tires out a bit. but i know with long travel thats can be different. i would sugest making adjustments, to it and trying them out. to be honest its difficult to recomend the right set up from pictures and what you say its at. i have found that things like this are best left up to personal prefrence. as for dampners, i think the denton dampner works just fine, and it only costs i think $120

[TBD]

Here is my suggestion.
Camber: 2-3 degrees negative(top of tire leaned in toward frame)
Caster: 5.5 degrees for MX, 6 degrees for trails and desert
Toe: 1/8- 1/4" toe in
Stock TRX caster is 6.0 degrees positive. Just remember to set your caster with someone(someone of equal wieght) on the quad in a riding position. Too little of positive caster will make the quad twitchy and too much will make the steering slow and tend to give the steering a little push in the frontend.

[Pepto_Bismol]

Hey,

Thanks for the replies.

BLACKeR,

To answer you question, the camera that was used to take the picture was close to the quad, so it appears that I have the toe out (it's actually 1/4 in dead on), and since the camera was on the ground, the chamber "looks" extremetly negative too. It is only 5 degrees. But I will probably bring that in some.

TBD,

Thanks for the info too. I did't realize that stock was at 6 degrees (that explains alot, including the feel of the ride). I am resetting everything over thanksgiving weekend. I will let you all know the results.

One thing, what do you mean exactly when you say that too much positive caster will give the steering a little push in the front end?

Can you explain what that is so that I can tell what I am looking for (how does the quad react when "pushed").

Thanks!

Pepto:cool:

[TBD]

Push is also refered to as under steer. When you go into a corner and try to turn the quad through the corner the frontend will slide in a forward direction instead of turning. That is push. Too much caster will lay the tires back when turning so it will have a tendencie to slide instead of turning. Too little caster will make the quad steering very twitchy.

[400exrider707]

This explains EVERYTHING! Its in adobe so if you dont have it download it.....
http://www.lsracing.com/img/Guide_21.pdf

[Pepto_Bismol]

TBD,

Gotcha, Thanks for the clarification.

400exrider707,

Thanks for the link, but I have already seen that information (and I have that document).

Although it is good information, the specific instruction are for LSR A-Arms.

The Jig that Herrmann uses is different than the jig LRS uses, and there is a significant difference in how to properly align the type of A-Arms I have (fixed spherical heims) as opposed to LSR (Ball joint with adjustability).

What I'm asking is more or less from people with specific experiences they have had setting up thier front ends which generally cannot be found in a more generic document. But hey, thanks anyway!

Pepto:cool: