I know wieght will be a factor as My car has a Mini Shell strapped to it and the target wieght will be 580 Kgs, what is the average wieght of a Locost ? and what kind a roll bars have been fitted ?

Cheers

Clive

[Edited on 30/4/04 by F1 Mini]

I think I may have worded this wrong. What I meant was Anti roll bars, for the suspension. Not roll over bars, sorry for the confusion there.
Any pic's of them etc.

Clive,

Here's a thread with some pics:

http://www.locostbuilders.co.uk/viewthread.php?tid=6859

The norm is to have one only in the front, but I'm thinking that with IRS (lower roll center), one in the back might be helpful as well.

Pete

I am going to try mine and if it needs a bar on the front or back then it will get one. Did this with my grasser, hence why the bar on the back never got painted properly!! Doh! (see photo archive and all will be clear!!)

[Edited on 30/4/04 by NS Dev]

Fitted ARB on my MK. See some pics on archive.

Very nice, zetec!

Did you get it from MK?

quote:

---

Originally posted by zetec
Fitted ARB on my MK. See some pics on archive.

---

A nice use of those Stauff hydraulic pipe clamps there Zetec, they are very handy (and nice and cheap!) for that job aren't they!!

Yep got it from MK. Martin has started fitting on some turnkey cars. I think it is 19mm tube. Wouldn't be tricky to make if you can get the right tube and bend it. For what they were asking I thought not worth me making taking into account the mounts and rod ends. I think it makes a difference and suspect they back will get one next. See caterham and Westfield fit them, love or hate them they normally research these things.

quote:

---

Originally posted by zetec
I think it is 19mm tube. Wouldn't be tricky to make if you can get the right tube and bend it.

---

In theory I agree Mark, but in practice you will find different.

Having had no advice and nothing to lose I made the rear anti roll bar on my grasser (see my photo archive though forgive the state of it, it had been raced for a year!!) from cold drawn 19mm OD 3mm Wall mild steel tube. I heated it and bent it bit by bit in a vice and it is fine.

It works great, have run with it connected and disconnected and with trailing arm rear suspension (no built-in anti-roll) it is very noticeable in effect!

The steel does not twist far enough to reach it's yield point (even though this is quite low) and so does not get permanently twisted, and that is with 10 inches of suspension travel!!!!

I think in higher mileage applications, the mild steel would fatigue fracture after a while, but I suppose you could just replace it as it is cheap and easy to make

Again, as long as it is not welded it seems to be ok (well to fairly high mileage anyway) I know of a very high profile kit car that uses mild steel anti roll bars, and the kits that you can buy from Rally Design etc use mild steel.

I always woundered what material is used, but have never found out exactly what grade of steel. I have seen a straight tube with flat bar welded at either end at 90 degrees, on a few race cars so welding can't be that bad.

[Edited on 3/5/04 by F1 Mini]

I did 3 laps of donington in an extremely reputable (and expensive) kit car with an experimental welded blade-adjustable anti-roll bar and it snapped on the heat affected zone right in the middle of Redgate......I made sure I didn't weld mine!!!!!!!

Oops, I bet that was fun...

Hmmmm, well I didn't crash but to put it technically (which wasn't how I put it at the time!!) the car did change attitude mid-corner quite dramatically!

Just another thought though, it was tube welded on at about 110 degrees in this case and it was the adjuster tube (the "blade" tube) that broke, not the main torsion tube, and it broke in bending at the weld, not torsion, so maybe not quite as clear cut as I made out!

Gosh I am posting lots here!! Just to go back to Mark Allanson's point about the mild steel fatigue failing, this is possible, but it is also possible with high grade alloy steel as well. It is just the stress level that the fatigue occurs at that is different.

I cannot remember the exact details, but the "cycles to failure" vs "stress applied" graph is an exponential curve, so up to a certain applied stress, the cycles to failure is infinite. As long as the anti-roll assembly is working within this stress range for the material used (including welds and their "de-rating" factors) then there will be no problem whatever material used.

I agree with NS Dev. As long as the fatigue limit isn't exceeded, you should be golden. As far as welding goes, if you want to splurge a few bucks on having the whole assembly (bars and arms if welded on) annealed (ie stress relieved) than you can probably even get by with a fabrication (good welds, no major pin holes or porosity). Thats a lot of qualifiers, but adds an option.