ruts off cambers and such

[sr5bidder]

Hey I finally got the blaster out on some trails ( Doc Hilts Trails) in Alabama and noticed when running down the trails the blaster would dart off one way or another and was really a handfull keeping it straight, I have my wheels about zero toe in or out (straight ahead).

when the trails where flat I had no problems but when one side was sightly beveled higher or just generaly bumpy with ruts would dart or pull badly.

My fronts are flipped wider and rears are 22x12x8 super swampers.

Is there a fix for this in the toe adjustments?

in rc cars setting toe out more slowed the steering down if you where have problems with looping out in the turns....or maybe it was the toe in ....too many beers ago....

I do have a certain amount of slop in the a-arms and wheel bearings that needs attention nothing major

 

[xjma]

Not much you can do in those situations, it's just straight up geometry that is making your bike turn itself in the ruts. It's both the rear tires and the front tires doing it.

IMO, the best fix is to realize how/why the bike is turning in the ruts so you can do your best to reduce it from happening, or atleast be ready for when it does so you can correct instantly and it won't be a problem.

Imma try to explain, no guarantees, though, so bear with me.

Lets think about just the rear wheels for a minute. You have a solid rear axle, both tires spin at the same speed, no matter what. If they're both inflated to the same pressure, they should be the same height. On a flat surface, they spin and go straight. On the same flat surface, when you turn, one of those wheels has to go faster than the other one (so one is losing traction). If the tire pressure is significantly different on one side vs. the other side, the effective radius of the tires are not the same, and so with the axle spinning on a flat surface, it's going to want to steer you to the side with less air pressure. Make sense??

OK, now lets consider a rutted surface. Again, just the rear tires, and inflated the same. AT first you're on a flat surface going straight, everything is fine, then one tire drops into a rut, while the other tire stays on a flat surface. Two things are happening here 1) the tire in the rut is traveling further than the tire up on the flat surface and 2) even with the same tire pressure, depending on the Xsection of the tire, you may have a different effective radius since the tire in the rut may be riding on the side of a curved tire Xsection while the tire up on the flat surface is still riding pretty much in the center of the Xsection.

Loose bearings are only going to increase these issues. I have to get back to work but you get the idea, hopefully. It's the nature of ruts.

 

[stephen12091985]

check ur air pressure in your tires

 

[sr5bidder]

well I'm just going to finish up the rear hydro's and try to unload it, the blaster takes up to much space and my kdx can do everything the blaster can 10x better and 100x smoother...except those awsome power slides

maybee i can get what I paid for it...maybee I can sell just the engine what do you all think a nicely rebuilt engine should bring?

I'd like to get an automatic wheeler for the wife, but for me I think I'm going to stick with 2 wheels

 

[UniRacing]

I would keep it.

and roost the kdx

 

[phragle]

with the previous mentioned geometry, you need to consider the kingpin angle of inclination. draw an imaginary line thru the center of the upper and lower balljoint, where that line hits the ground, should be the center of the tires contac patch. fliiping the front wheels changes that so every rut you hit works like a lever pulling the tire/wheel. a good steering stable helps, but that is a band aid not a cure.

 

[quadboy22p]

if you are runnning stock a-arms you will not have all the adjustment needed to accomplish great handeling. the camber and castor can play a big role in steering and the toe should always be straight. if it is toed out your quad will more likely jerk 1 direction or the other. and toed in will decrease steering capabilities.

 

[xjma]

with the previous mentioned geometry, you need to consider the kingpin angle of inclination. draw an imaginary line thru the center of the upper and lower balljoint, where that line hits the ground, should be the center of the tires contac patch. fliiping the front wheels changes that so every rut you hit works like a lever pulling the tire/wheel. a good steering stable helps, but that is a band aid not a cure.

I think you're referring to the scrub radius....way too much geometry for an ATV!!