Quote:
Originally Posted by Cobra4B
Thanks Kel & Dan - FWIW Panoz says I should just spread the upper chassis and that it's not an issue at all. They said they do it to cars all the time. Also, said they moved away from the heim-jointed adjustable bars because they would get some inward sag from the upper chassis over time.
Others have also said that you want to "jack" in some preload to that upper part of the chassis to account for the loading of the suspension etc.
I've decided to buy a new tubular bar from Coleman, but go one size larger than the original one that came on the car. This way I can bolt it up, then turn the bar a couple of turns to expand it (LH and RH threaded heims like the trailing arms etc.) and slightly load the chassis. IMO it's the best overall option.
I can then remove tension for easy removal of the bar vs. having to break out the scissor jack and a metal bar every time I want to remove/install it.
Kel - Did you measure the lower part of your chassis to see if it matched the upper? Curious if yours is spread out at all with the bar installed.
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Brian, measured bottom and pretty much the same as the top. May be 1mm in it. The bolt centers in the removeable member I have appear to be around 30.75".
I mentioned I like the GTS brace because it is stiffer, I meant in compression and bending. Tension is not the issue between the heim jointed item and the GTS item but the 2 other load scenarios are.
I am not a fan of preloading the chassis unless this is a must for fitment and cannot be remedied easily. If the GTS bar is used and is a good fit, once it is torqued in at 90ftlbs any movement due to suspension deflection will be due to other load path factors or member deflection.
My time with aircraft engineering taught me that preloading normally leads to stress cracking once a dynamic load is applied (i.e. where the direction of load may not be in the same plane as the preload force, unlike torqueing a fastener, where the preload is in the same plane as the force experienced by the fastener).
Just one mans opinion of course!!
Kel.