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Trailing Arm IRS?
Jermyn - 2/2/05 at 04:23 PM

Has anyone set up a Trailing Arm Type IRS such as what is found on Triumph TR6s?

I have access to multiple aluminum rear trailing arms from TR6s. Since they are readily available to me I figured I'd ask.


britishtrident - 2/2/05 at 05:07 PM

Not a good idea


mangogrooveworkshop - 2/2/05 at 06:36 PM

quote:

I have access to multiple aluminum rear trailing arms from TR6s




Sell them on

and use the money to buy some bones and uprights from gts...........thats the way forward


Peteff - 2/2/05 at 06:44 PM

Postage might be a bit of a stinger


MikeRJ - 2/2/05 at 06:48 PM

I suppose a semi-trailing system as used by the Sierra and BMW wouldn't be so bad (is this what the TR6 has?), but a fully trailing system on the driven wheels would make for "interesting" handling due to the large camber change.

That said, a tried and tested solution such as a Live axle, De-dion axle or proven IRS from e.g. MK would save a lot of grief.

[Edited on 2/2/05 by MikeRJ]


Jermyn - 2/2/05 at 08:36 PM

I don't really know the difference between the 2. check out the pics and you tell me. Rescued attachment TRS-035.gif
Rescued attachment TRS-035.gif


Jermyn - 2/2/05 at 08:37 PM

Heres another pic. Rescued attachment chassis_build2-8.jpg
Rescued attachment chassis_build2-8.jpg


JoelP - 2/2/05 at 09:07 PM

good wheel poise in bumps, but as the car body rolls, the wheel will gain (or lose, depending on the side) camber. hence reduced grip on corners.

this setup is much like the sierra setup. which i used...

edit - unless you set it up with static camber (pos or neg, cant remember which, but leant in at the top!) and accept poor tyre wear.

[Edited on 2/2/05 by JoelP]


The Shootist - 2/2/05 at 09:29 PM

Simple, easy to fabricate, and fits with almost no change to the book or any other live axle plans. All the unsprung weight advantages you get with IRS, but without the fancy geometry requirements + if you really must fiddle, the link angles can be played with to give anti dive responses.


britishtrident - 2/2/05 at 09:33 PM

Camber change in roll is fine if the angle of the pivots in plan view is about 21 to 25 degrees real problem is it goes to toe out on both roll and bump.
They can be set up to work quite well in the dry but on a get or greasy surface woop outs goes the tail -- not so bad on a car like the old Tr that have a high polar moment of inertia are nose heavy and want to understeer so it no big deal ---- but on a Locost you will be into the bushes or worse in the blink of an eye.



[Edited on 2/2/05 by britishtrident]

[Edited on 2/2/05 by britishtrident]


Jermyn - 3/2/05 at 02:50 PM

Point taken. My real motivation in asking about this kind of setup was to take the stresses off the B-post from the typical trailing arm type setup.

I thought maybe this way I could reduce the section by the driver/passenger enough to make a 6" triangulated sill so I could have a full size door. I'd pretty much have to re-engineer the whole chassis and move toward a mix of ladder-space frame to make it work.

Maybe at that point I'd be better with a solid rear axle?

Or.....From what I understand, doors are a pain in the arse anyway. Besides, do I really want to compromise the handling just because I have to climb in and out of the car?

Nevermind my rambling here... I'll probably just stick with De dion and forego the doors


britishtrident - 3/2/05 at 04:54 PM

In any event semi-trailling arms won't reduce the loads on the chassis ---indeed following the Triumph set with regard to spring location would put much greater loads on the pivots and spring abuttments.

What you have to pay attention to when designing a chassis is torssional stiffness something that a ladder chassis even one as massive as the TRs severely lacks.