Monday, March 28, 2011

Tri-Point Engineering front swaybar

I'd been trying to figure out what swaybars to run on the car for awhile.  On my old CSP MX-5, I ran a Mazdaspeed RX-8 front bar along with the stock rear bar.  However, most of the time, I ran with the rear bar disconnected. 

In working with my friend Jason Saini, he told me that Tri-Point Engineering had a speedway style front bar for the car.  For those unfamiliar with this style of bar, it's used primarily on Nextel Cup, Craftsman Truck, and Busch GN cars.  The advantage is that the middle section of the bar is separate from the ends, so it's possible to easily change rates by just changing the middle.  This middle section has splines at both ends which the "arms" attach to.  In the case of the Tri-Point bar, the arms are made of aluminum and have five adjustment holes per side, which gives a lot of adjustment.  It also came with adjustable endlinds that can be adjusted on the car.  According to Tri-Point, the softest setting is 55% stiffer than the stock MX-5 bar.

Obviously I'll still need to figure out what to do with the rear bar, but I'm going to start with the stock bar and tune from there.


The install was pretty easy.  Since the middle section can easily be pushed into place from one side.  I used a little white-out to mark the arm and the bar for reassembly.  After that, it was pretty much the same as any other swaybar.  The only other thing that needed to be done was to grind down the bushing brackets a little to allow the remounting of the ABS sensor bracket that can be seen in one of the pictures.

4 comments:

  1. Ron, thanks for the interesting blog. Those of us running NCs in STR look on your build with amazement.

    Tri-Point specifies the wall thickness of the different bars they offer, but they don't give the outside diameter. That's crucial information for calculating the bar's spring rate, the roll stiffness on the front, and the front roll couple. Did you happen to measure the OD? Will you share that information? I've e-mailed Tri-Point but haven't heard anything back.

    Thanks.

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  2. It's dark and cold, so assuming I put the micrometer on the right part of the bar, the OD is 1.25"

    Thanks for the kind words. It's been a labor of love!

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  3. Ron. Thanks for getting back to me. Sounds like the thinner wall (0.188 in) would give me about the right roll stiffness.

    Thanks again.

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  4. I called Tri-Point, and they confirmed the OD is 1.25 inches. They also now have a bar with 0.125 wall thickness, which sounds like a good fit for my needs.

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