Does anyone currently have Polyurethane Bushes fitted to their front tension Rods?

[Danbob]

Hello All,

Does anyone currently have Polyurethane Bushes fitted to their front tension Rods?

I have a pair of castor adjustable items I was due to fit this week, but when I’ve thought about it, I’m not sure that a poly-bush here is a wise idea.

My concern is that looking at the layout of the front suspension links, the tension rod is required to move around two axes of rotation. It needs to rotate up and down axially as normal, but as the arc of the lower control arm pulls the outboard end of the tension rod inboard and outboard, the bush also needs to allow the rod to rotate laterally also. The OE original rubber bush is compliant enough to allow this without putting a high bending moment in to the tension rod. A spherical bearing would allow the same.

The polyurethane bush is significantly stiffer then the rubber bush and is a step closer towards being a pinned joint with only one axis of rotation. My question is does a Poly-bush have enough compliance to allow suspension travel without putting too much bending stress on the Tension rod.

A quick google search on this subject shows that some owners of other cars (300ZX and S13/14) with a similar setup have had some problems in this area. Has anyone had a bad experience in an MR2? Bent Tension Rod? Tension rod – Control arm bolts shearing, Tension rod weld failure etc??



I am hoping that there are quite a few of you using a polybush here and have had no problems!! Then I can fit the bushes with some confidence that all will be OK. I did consider rose jointed adjustable rods, but they are a lot of cash, and I didn’t fancy every Fore/Aft wheel input being transmitted straight into the chassis with no damping.


Cheers

Dan

[snowtigger]

I have rose jointed ends on my rods and they clunk horrendously if not greased, but the idea of bushings that are too stiff could be worse as it needs to move .

[terryo]

i have used poly bushes with different offsets, to fix caster problems in stock cars. these bushes are very common on modern cars, not just Toyotas. depends on the design of the bush. i've had our local poly bush company specially make some for the MR-S which work a treat.

[fab4mr2]

I've used them for decades. First found out about them from a local shop owner in San Diego who raced a MKI in regional events. But make sure only to use the cone shaped bushes, as they will allow the movement necessary. The clam shaped bushes that twosrus sells limit the movement excessively and are not recommended. I tried them once, just to see, and they really restricted the movement of the strut rod, and thus the rest of the suspension.

Here is a link to the Energy Suspension type that I have used. Haven't actually seen others of this shape. You will tend to find them listed as fitting the Celica, I believe, but they are the same dimension as for the MKI. They will fit both the front and back strut rods. I torque mine down until they won't turn any more (lol), and they work perfectly (the metal tube spacer stops the nut from turning more, though it can be shaved to add additional castor). These are much better than even new oem ones. Oh, and make sure to save the original oem metal clam-shell type washers as they are a bit bigger than the newer oem replacements. The new oem ones are so small that the poly bushings will start to flare over the edges of them as they are clamped down tight. The original ones will contain them perfectly, even when torqued down hard.
http://www.energysuspensionparts.com...FecbQgodyF7Ruw

[Honey]

Unscrew fork caps and let forks collapse. See how much room you have between seal and lower triple and that will tell you how much you can lower it.
What is shock length?

[jimi]

Unscrew fork caps and let forks collapse. See how much room you have between seal and lower triple and that will tell you how much you can lower it.
What is shock length?

??
fork caps on an MR2 ?

[thomp1983]

he's talking about front motorbike suspension for some reason

[jimi]

That's what I thought, can't see the connection though

[Grenade]

That's what I thought, can't see the connection though

I had to read that twice. Not sure what they mean by that.