Bump Steer

[DESERT RACER]

Is anybody familiar with bump steer? I have long a-arms on my banshee and when I take the shocks off and lift the tires as far up as they go, I get about 2 inches of toe-in on each wheel. I think I can eliminate it by re-posistioning the tie rods, does any one have experience with this or have some suggestions? Thanks

[crazyracer]

well, usually when the a-arm is in the stand posistion with you body on it, the tires should be completely parallel. Once you extend then further or lower the quad, the geometry gets all screwed up. Predators have Zero bump-steer, but i'm not sure if you can eliminate it completely.

[DESERT RACER]

The wheels are fine with my weight on it but when the shocks are compressed from hitting a bump or something it gets really bad toe in. I know it can be fixed, its just going to take a lot of trial and error

[TAL]

I don't know yet either. I recently acquired a 2000 'she and it has +2 a-arms on it. I noticed the toe is all screwed up also. I imagine the only way to fix it is going to be replacing with special spindles that will put the tie-rod geometry back into the correct position, but I really don't know yet, as I really haven't started researching it yet.

May I recommend asking questions to the various a-arm builders out there? IE: Lonestar, and others.... They are bound to have an answer to our problem. YEAH, it's probably going to cost more $money$. Heck what doesn't these days?!?! A proper fix will be well worth the cost though.

Let me know if you guys hear anything worth knowing about!

~TAL

avagianos@rochester.rr.com

[Banshee]

Something seems screwed up with your tie-rods. Check to make sure your ball joints are functioning in all directions. Are you sure your tierods are the proper length for your setup? My tires on my banshee stay straight when compressed.

[TAL]

Well, I really don't have the same problem that Desert Racer has. I think my tie rods are just out of adjustment, but I don't know, haven't really looked too hard at it. Personally, I think my Banshee is a product of a MORON that assembled it, but like I said, I just acquired it and haven't gotten into fixing it yet.


I know that if you make the a-arms too long without the right length shock, that can cause issues.

I also know that if you put too long of a shock in with stock a-arms you will get really adverse affects also.


I had a 1998 Yamaha SRX 700 snowmobile that had a serious bump steer problem. I know, because I caused it.
What I did was I put in shocks that were 4" longer than the stockers, without changing the length of the a-arms.
I added the longer shocks to increase travel and to lift the front end up to match a lifted high-travel M-10 rear suspension that I installed.

Only one reasonable way to fix the bump-steer problem I created on the SRX. (Without just returning to stock shocks.)
Increase the length of the a-arms, and if needed, increase the height of the spindle arms, which would make less of an angular drop for the tie-rods, thus fixing the bump steer issue. The key is keeping the tie-rods close as parallel to the ground as possible. Steep steering angles are detrimental to steering with high travel suspension.

I never made the change on the SRX, though I know that would have fixed it. I sold it to some poor dingus about a month ago. I did tell him about it and he didn't seem too concerned. Either he has money or is just dumb, because it really needed to be fixed to make it ride as it should. Oh well...

Perhaps I just answered Desert Racer's question for him and didn't realize it??
I dunno...

~TAL

[DESERT RACER]

TAL, you hit the nail on the head-- the angle of the tie rods compared to the a-arms. A stock bike's tie rods are almost parellel to the a-arms, my tie rods are angled much steeper than the a-arms. You also mentioned a raised spindel, that would be hard to find in my case due to the arms not being built by a major company, but I have been playing with adding brackets onto my stockers to change the angle of the tie rods, specifically to raise them higher. You are one of the first people that actually has knowledge about this problem, it I ever get my bike dialed in I'll let you know what I did to it.

[TAL]

This is likely going to be a longggggg thread...

Boy, it sure is good to know I get something right once in a while. LOL!!

The thing is, I like to experiment here and there from time to time with home-made "upgrade" mods. Fabrication is fun, but can become time consuming and expensive, especially if you have to make a lot of prototypes until you get it right. That comes from not doing, or not knowing how to do the math or figure it all out on paper before you start fabricating. Truth is, some of the best designs of things happen by trial-and-error, or by accident!

With me, sometimes my fabrications work out, and sometimes they get put back to the stock design, mostly because I don't feel like going through the engineering headaches of making an idea work and would rather spend my time using the thing that I'm modifying, rather than work on it all the time!
(In this case I'm obviously referring to getting out and riding the quad rather than work on it all the time!)

One thing's for sure, if you spend enough time, effort, and reasearch at anything, sooner or later you will figure it out! (I still wonder why I didn't get more into the mechanical test engineering field. I'd likely be good at it, and certainly enjoy it.)


Let me suggest that once you get your quad all dialed in, you may actually want to patent your 3+ suspension idea! Yeah, no kidding! Why? Well, because some joker will copycat it in no time flat and they'll market it and get the royalties from the idea and not you! You may as well get something for all the hard work and mindless hours you spent racking your brain and searching for an answer to your problems for your improved design! I couldn't do it with my mod, because it was merely using factory parts from one machine on another to achieve the height lift and suspension travel increase. Now if I'd made custom spindles, or any other custom item, I'd have patented it and tried to market the idea. I mean hey, why not?!




On your tie rod angle topic... May I suggest, if possible (and I don't know if it is or not)... You may be able to lengthen your steering shaft and lower the tie-rod ends closer to the frame/ground to lessen the severe angle. Again, I don't know if it is a feasible idea or not, as I don't have your quad in front of me to look at.


Another thought, and now I'm getting kinda out there in the thought process...

Again, using "snowmobile technology" or actually even John Deere farm tractor technology, you could put/weld a pivot shaft and add a bellcrank wherever you need it to be on the frame to accomodate the correct tie rod angles you are looking for. Then, you would run a drag link back from the bell crank to the steering shaft to complete your newly designed steering system.

Yeah, it would be a seriously time consuming, mind racking, money eating mod, but how very awesome if it worked!


One last thing. Although it will not fix the problem, to minimize bump steer and just plain 'ol bumps, you may want to add a steering stabilizer / dampner. I believe PEP makes one. They do seem to help somewhat, although they are kinda pricey and sometimes I wonder if they are really worth the expense or not. I suppose it depends on the type of riding that you do and the machine you are putting it on. Also, like everything these days... how deep are your pockets?

LOL!

As for my issue with my Banshee, well the tie rods are in fact definitely mis-adjusted. To compound the problem, the +2 a-arms on my quad make the front wheels have a lot of camber. I think it is called negative camber when the top of the wheel leans in towards the bike.
(I could be exactly backwards on that, it may be positive camber. I always get the two mixed up because it isn't something I concern myself with often enough. Heck, why would you, unless there was a problem anyhow?!)

At any rate, with the tie rods misadjusted for too much toe-in and the varying camber through the suspension travel, I was getting some annoying bump steer. I also found that I need to re-bush the a-arms, as the bushings are hosed. I've found a lot of wear issues like that on my quad in recent days. Hmmm.... Maybe that's what I get for buying my Banshee on eBay! Sight unseen, always a risky way to buy! Oh well, for what I saved, I can afford to pour money and time into it! Besides, it's fun!

Take 'er easy...
~TAL

[370banshee]

guys.... there is something you have to look at... the movement of the a arms are in a radial pattern.... not a straight up and down movment... your gonna get wierd camber when compressed or extended.... thats just the way it works... look at your a arms... they are attacked to the frame at one end and each other at the other end... the only way they can move is radial.... the upper arm is nothign but a LOCATOR... as it just holds the spindle in place... the lower arms do the grunt work..... i see what your saying about tie rod angle.. and it;s effects but..... anything you do the to tie rods will not stop the radial movement of the arms themselves.... honda did have a rather good fix for this on teh 250R.... instead of a parallel front frame section (to ground) they built the 250R with a raked form frame section.... the nose of the frame was higher than the footpegs... this in turn put the entire front suspension angled backward... now hitting a bump didnt; move the suspension UP like on a banshee but rather UP AND BACK... threrfore removing alot of bumsteep problems... and making the quad handle very very nice

[DESERT RACER]

I thought I did alot of thinking about this, but those are some long responses. It would be cool to fabricate a fix for bump steer and market it. It would be nice to finally make money off the banshee instead of spending money on it.