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rear anti roll bars
tony-devon - 7/9/11 at 04:11 PM

just wondering if anyone has any good links to information regarding rear ARB fitment/design etc

Im interested in possibly fitting one on the back of my custom build but know nothing about them.

I get the body roll, but stiffening the shocks, or fitting stiffer springs does nothing good for the ride, so I was hoping that a roll bar would be at least a partial solution


spiderman - 7/9/11 at 04:59 PM

Live axle or IRS?


Sam_68 - 7/9/11 at 05:35 PM

This isn't the Kawasaki engined trike listed on your profile, is it? If it is, you're onto a bit of a loser...

Bear in mind that on low-slung cars like Locaterfields, the main job of ARB's is to balance the handling by influencing diagonal weight transfer... and fitting a rear ARB will promote oversteer, unless you make other adjustments to compensate, so its a fast way of screwing up your car's handling if you don't know what you're doing.

Stiffening the springs often isn't as bad for the ride as you expect, provided it is matched with properly-specced dampers.

Stiffening the dampers won't work in isolation as a means of limiting roll - it slows down the rate at which the car rolls when it enters a corner, but the ultimate roll angle (assuming the corner is long enough) will remain the same, and the stiffer dampers will screw your ride up much worse than stiffening the springs.

Try reading Allan Staniforth's 'Competition Car Suspension' to gain an understanding of the design calculations involved.

Actual implementation is usually pretty striaghtforward: they work just like a front ARB... a bit of steel bent into a broad U-shape as the ARB itself, running through bearing blocks mounted on the chassis and linked to the wishbones/axle using rose-jointed drop-links.


britishtrident - 7/9/11 at 06:43 PM

A all I would suggest is suck it and see you could probably adapt an ARB from a road car, just start with a fairly soft bar.

3 wheeler suspension design is another country, you can ignore 80% of the stuff in books for cars, the big snag is all the roll stiffness has to come from one end, and the roll centre of the single wheel has to be at ground level. The alternative to adding an anti-roll bar or stiffening the springs would be to raise the roll centre on the rear end to try and increase the roll resistance -- but I would be careful high rear roll centres can have unpredictable consequences.


Sam_68 - 7/9/11 at 07:59 PM

quote:
Originally posted by britishtrident3 wheeler suspension design is another country, you can ignore 80% of the stuff in books for cars, the big snag is all the roll stiffness has to come from one end, and the roll centre of the single wheel has to be at ground level...


Is the OP building a single front wheel trike, then?

Sorry, my comment was tongue-in-cheek on the assumption that most people build reverse trikes (twin wheels at the front) these days... and obviously you can't fit an ARB at the back of a reverse trike.


tony-devon - 8/9/11 at 08:23 AM

Hi, thanks guys, yes my trike is one at the front, using a design sort of borrowed from the locost at the rear end, decided not to try and reinvent something thats proven already, also was good practice as I plan to build a BEC next

will maybe try even stiffer springs first before looking at ARB, the shocks are AVO adjustable, but dont know any further info as they were purchased 2nd hand

I wanted some ride comfirt hence the IRS back end on the trike as opposed to the common hardtail frames, but it has brought with it the whole new world of suspension and handling, think stiffer springs will be a good start.

thanks for advice

built 2 wheels many times, quite a few 3 wheeled, next stop 4 wheels gradually Im getting there LOL


britishtrident - 8/9/11 at 09:55 AM

If the rear is Sierra width then Mondeo rear anti-roll bar might be a worth investigating.