Just for the sake of discussion, seeing as how at least one person up here has either seen or actually built almost everything one could think of, I am surprised there hasn't been a discussion about adjustable wheel base ideas. I am not saying this would be some killer mod, just perhaps some minor to moderate enhancement if you could work out the bugs (and I am sure there would be many at first.)

What I had in mind was this. Let's start with a picture of a rig recently posted here that has rear axle links that are easily viewable: http://www.brownsfabrication.com./main_img/pa2.jpg

Now picture if the rear axle link bar mounts at the frame were all located at the same vertical plane just over/under each other, mounted inside a "box" located at the inside of the frame rail. That box could then be fitted with grooves lined with say a 1/4" teflon sheath that rides on the track (pinnable I suppose via sheathed holes in the frame rails for street use lets suppose) and these teflon tracks ride in some type of arrangement (use your imagination) on the inside of the frame rails. Now at the front of that box that holds the upper mounts for the rear axle link bars it would be a reasonably simple affair to add some type of hydraulic ram that would control the front-to-back position of that box and it's mounts. Control the ram however you wish.

It does't seem that complex. Just wondering why no one has done it. Unreliable? Not enough benefit (seems like you could get rams that would give you say a foot or more of wheel base adjustment...)? Too much cost/too much work (like that has ever stopped folks on this board) :D Anyway, interested in folks thoughts on it. I realize that it wouldn't work with such link configs as double a-frames, but with the one in the pic it would seem simple enough.

I don't see why it wouldn't work with a double A-frame? Make the crossmember that the A-arms attach to slide for and aft instead of each control arm and bingo:D You would need a drive shaft with an ungodly amount of travel though:eek: I"m not sure how you would mount shocks either? It's interesting and I saw it on a buggy on the net one time, but I don't know if it would be any real use:rasta:

Originally posted by desertCJ
I don't see why it wouldn't work with a double A-frame? Make the crossmember that the A-arms attach to slide for and aft instead of each control arm and bingo:D You would need a drive shaft with an ungodly amount of travel though:eek: I"m not sure how you would mount shocks either? It's interesting and I saw it on a buggy on the net one time, but I don't know if it would be any real use:rasta:

The reason I was thinking the double a-frame wouldn't be practical is that the cross member for the links mounted towards the center is often lower than the frame rail (drops down) and that would create a lot of torque on the sliding mount when the axle wrapped... but hey, just about anything could be done with enough time/money/ingenuity.

On the drive line I doubt that would be a problem as many link setups only use an inch or so of drive line travel and a foot travel is NOTHING for Jess@ HighAngle, he's the man!:D

I thought about it on my buggy. It'd be easy with coilovers, I would just need another set of links and a long slip driveline....

This was discussed a long time ago here on POR, but I can't find the thread. It has been done on a Scorpion, I think it was. He had a hydraulic ram that would move his rear frame back. I'm not sure as to the technical specifications of it. Of course, it wasn't legal for any RC comp since they all outlaw adjustable wheelbases.

J. J.

personally I think its just one more thing that may break at the wrong moment, I prefer to build my rig as simple as possible, less parts = less things to break right?

Originally posted by mytzlflick
personally I think its just one more thing that may break at the wrong moment, I prefer to build my rig as simple as possible, less parts = less things to break right?


Can I get an AMEN!!!

the blue tube buggy with a cobra sticker on it and a 9 inch in the rear has an adjustable subframe rear which lets it have an adjustable wheelbase. ( i think thats the guy ) its been around for a couple of years, and i guess it works just fine. its obviously not the end all mod, but the guy still uses it i guess. personally, i would rather have less moving parts, less hassle.

SO it's kinda like a novelty:rolleyes: Who cares though? So is rear stear but we are seeing that a lot more often now. I'd like to see one of the bulletin board guys set one up and play with it. It might be fun. Can you imagine.....your rig is sittin there spinning all four tires on a big ledge.....no problem dude, throw that lever and stretch the wheel base a foot or two:D

I can see the value of rear steer in competition but not in normal usage, could have used it to clear a few trees this weekend and maybe saved a little cab damage but that would make the trail less challenging and what fun is that.
if you had an all out competition buggy it might be interesting but in the real world if I am stuck on a ledge and the go pedal won't cure it then the winch will.

Originally posted by mytzlflick
if you had an all out competition buggy it might be interesting

Assuming you chose to ignore the fact that it is stated in the rules that it is not allowed.

I wasn't really thinking of an on the fly adjustment but it's be handy to have that be a possible adjustment from competition to competition, like a nascar with different springs and chassis for different tracks....

This thing is adjustable from 104-114

I think that Campbell Ent. built one a couple years ago. It was called the Iron Pig or something. It adjusted it's wheelbase by adding lift height with hydraulics. The higher he lifted the rams the shorter the wheelbase got. The guy with the rock garden in his backyard was the owner. I think he rolled it in his first, and only ARCA comp(it was the first season, before the current set of rules), on the first obsticle.

Yep that blue buggy was the one I was talking about:D Got wheelbase:smokin:

We'd thought about it after seeing the trend of longer verticle obstacles in RRCA the year before last... Rulebook states you must have a "fixed wheelbase" though, so we said screw it... Like someone else said, I like to keep my trail-rig as simple and trouble free as possible. :)

Originally posted by mytzlflick
I can see the value of rear steer in competition but not in normal usage, could have used it to clear a few trees this weekend and maybe saved a little cab damage but that would make the trail less challenging and what fun is that.


That is EXACTLY one of the reasons I thought it would be interesting: shorter wheel base means better turning radius and in place like up here in the NW we have lots and lots of trees and lots and lots of sane enviromentalist (including many of us wheelers) and lots of environazis (like the Sierra club, PETA, PAWS, etc.) So I hate to see tree damage that can be avoided! That's exactly why I think this has use in the real world even if it is not allowed in competition. Also, think of this: rear axle stuck on a rock section, just line lock your front brakes, engage only the rear wheel drive, give it some mild gas and shorten the wheel base and as long as your assembly is built beefy you have a decent chance at being able to pull your rear axel up over whatever it was hung up on before when you were stuck. Just a couple more thoughts to throw into the mix.

On the one by Campbell I believe it was called Big Iron and yes he rolled it but his method of shortening the wheel base like you said was to raise his rig which trashes your center of gravity/roll center and so it was totally a no brainer he'd roll it doing it that way. Just dumb. Sliding mounts that change neither of those 2 wouldn't have that problem though.

OK, admittedly I am throwing this out there not just because I suspect it would be a useful mod in some situations if well thought out and implemented strongly, but also because I am trying to bait someone else into doing it as I am out of money! LOL! :D

Originally posted by BornInAJeep
I think that Campbell Ent. built one a couple years ago. It was called the Iron Pig or something. It adjusted it's wheelbase by adding lift height with hydraulics. The higher he lifted the rams the shorter the wheelbase got. The guy with the rock garden in his backyard was the owner. I think he rolled it in his first, and only ARCA comp(it was the first season, before the current set of rules), on the first obsticle.

That was Big Iron(y). It was owned by Dave Hickman, and built by Troy Vickory. I think after some attempts at reworking it by Cambell, it was finally scrapped. Last I heard, a new one was being built as the old one was too heavy and complicated.

Yeah, Big Iron, it sounded like a rolling hydraulic pump, he got to the first obstacle, hit the wrong hydraulic lever and caused himself to flop. I laugh my ass off every time I watch that million dollar piece of shit on tape:flipoff2:

My buddy and I were thinking of doing this on his jeep.Our idea was to mount the front of the rear springs to a subframe underneath the stock frame.This would be on some type of sliders.Then using a ram be able to adjust the wheelbase.Our idea behind this was if you were stretched out with say your rocker on a rock you could suck the rear tire into the rock and force the rig up it easier.We decided not to do it though.Could be interesting.Blazin:rasta: