Rear toe change with load
 

Not sure if anyone else has taken video of their rear wheels and the movement but I was trying to get an idea of wheel life with my current setup and found this instead.

Seems the wheel is flexing in (Toe-in) but I can figure out the source of the movement. I have RT trailing arms and OEM bushings in the rest of the rear joints.

When I put a ratchet strap on the rear wheel at the bottom and put a lot of load in it, I dont measure anything more than a couple thou of deflection at the OEM bushing locations which makes me think either I dont have enough load or thats not the issue.

A couple things I do know,
-Bearings dont have any play in them
-Nothing in the system has slop in it, everything comes back to normal after the loading (no alignment changing)
-Wheels are Enkei PF01 18x10.5 but I dont thing flex would show up as toe-in

Any thoughts here? Anyone else try the same test or want to go out and try it as well? Id love if their was an easy answer here I'm missing but at this point I'm just going to replace a few more bushings and see if it gets better.

And heres the full run. Try slowing it down around a spot you find to be most damning.

Holy **** that's a lot. Only way to tell would be to try to film the suspension. Hard to say if is wheel flex or not.

Do you have any video from under the car, pointing to toward the inside of the wheel?

It's difficult to visually separate the tire flex from the wheel angle change in those outside videos.

Its definitely more movement than I had expected but has been this way for YEARS! Ive just never put a camera on it to check it though now Im going to be putting a camera on everything.

I really cant figure out where the flex is coming from but it looks like the bottom pushes in more than the top pulls out which would make you think toe out change. But instead we get toe-in change. So I have whiteline bushings for upper arm and the bumpsteer bushing for toe-arm on order. One thing I just thought of but havent checked, is the subframe rigidly mounted or are there rubber bushings in it? I know the diff bushings are all swapped but I havent looked at the subframe ever.

I put a dial indicator at the base of each bushing and used a ratchet strap between the bottom of each wheel, but maybe I need to try pulling against the chassis and try to move the subframe to isolate one side.

Dallas

Would have thought you were running your lower arms already?

Are you running this WL Kit here?

https://cimg2.ibsrv.net/gimg/www.evo...154a85356e.gif

I haven't changed that bushing yet. I thought I had one in a box at home but cant seem to find it. So just ordered it with the upper arm bushings to at least reduce those variables. Once I get those in I'll try to record at different angles to see if its improved or still the same.

Anyone else want to strap a camera to their car and see if they have similar movements?

I thought those RT arms were CrMo? Wonder if those, flexing under load, would cause that Toe movement?

Still curious why they are still on your EvO vs the SSB's?

The subframes are hardmounted to the chassis, no bushings.

subframe is rigidly mounted and quite sturdy, but the toe link is not mounted to the sub-frame but rather to the body. Maybe there is flex in that mount.. The inner bush is rubber, and is quite stiff, but who knows how it is getting on with age.. I run a custom toe arm now with sphericals on both ends...
If you had movement on the lower arm you would get toe out..

Did you check the wheel bearing?

the original video shows movement even better... just had a look.. Did you ever measure the bump steer on rear suspension... as it looks to me like built in bump steer... but sure does look like a lot..

Those arms should only effect the wheel moving fore/aft but I suppose that is a possible area things could move. If that flexed the wheel would move forward. Maybe i'll try disconnecting it and checking the effects of it moving. And I don't have the SSB arms on yet because I wanted to stick with as much consistent (with the exception of this terrible movement) as I could before nats. But I may just say screw it and finish another prototype to run.

I'll just have to bring the old ones as backup because my luck is if something stupid can happen, it will.

In for info.

Tire deflection and camera angle. I don't think the wheel itself is moving that much.

Have you tried slowing the video and just watching the lip? Certainly looks like its moving quite a bit to me but will get a better angle after I get these bushings replaced.