RTA bushed OEM vs Harder placements.?!


KieranEG6

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To start I will say I found this over on the DC2 forum but its really good information. And I dont think I have seen it covered on here before.

I am about to rebush my EG6 so thought I would do some research first.

Here is a great explanation to why it is best to stay with the OEM rubber Rear trailing arm bush.

"The rear suspension on the DC2 (and a lot of other Honda's) is quite special.

The trailing arm bush is designed so the wheel can move backward or forward - that's why there's so much play in it.

The trailing arm is controlled by 3 arms. Simplifying slightly:

The lower control arm takes the main side loads.
The upper control arm controls camber.
The front control arm controls toe.

The special bit comes in when you brake. When you're braking, the tyre as it grips wants to move slower than the car currently is. That pulls the wheel backwards compared to the car.

Now, the trailing arm bush is specifically designed to allow the wheel to move back like this under braking. You're probably thinking that's useless and bonkers. Not so. Look at the lower control arm, and the front control arm. When the trailing arm moves back, it's held by both of those arms which limit where it can move. The front control arm is a lot shorter than the lower control arm. So when the trailing arm moves backward under the braking load, the front arm will angle more than the lower arm simply because it's shorter. That means the front of the trailing arm has to move inwards. Adding toe in.

To put it simpler, the trailing arm bush is designed to be soft so that the arm moves back under braking, causing the front control arm to pull the front of the trailing arm in, adding toe in, stabalising the back end under braking.

Even more clever is the way the amount of toe it added is purely related to how far back the wheel is pulled, which is related to how hard you're breaking and how much grip that wheel has. So if one wheel loses grip compared to the other, the toe of the two wheels will differ, helping stabalise the rear end. Really cool, and clever.

Honda has several patents on it.

If you put a much harder bushing in place of the standard trailing arm bush, you stop the backward movement under braking which stops the toe change under braking.""

For those who understand suspention movements and geometry will see the value in this description.

Integra DC2 • Login

Plenty more pages of discussion on the thread. :nice:
 



noodels

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Honda rta an intresting set up, would increase rear toe if using hardrace, if not oem rta.
 


thunderboy

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Looking at replacing my RTAs after my road trip to stelvio pass. Reviving this thread as it seems a good bit of info!
 


type-r-dunk

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VERY interesting point this. When they developed suspension set up for the Type R they used harder bushings in places, I'm sure they would have looked into this if it was necessary.
Dunx
 


lloyd

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Very interesting, so all these poly and pillow ball type rta bushings are maybe more of a hindrance than help,
 


elchunk

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I rebushed everything in my car with uprated bushes apart from the RTA bushes. they are designed to move and it helps keep the car stable on heavy braking.
 


thunderboy

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Has anyone got the part number for the OEM RTA from ek9?

And if theres a picture rich how-to on the best way to switch them somewhere I'd love to read it.

When I changed them on my old EG for energy suspension poly, I set fire to the old using white spirits and melted them out... Guessing I shouldn't do this if replacing to OEM
 



jesse888

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I used a hammer, hammer in and out.
 




jesse888

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They look very similar to the hard race item.
 


David vti-s

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I can vouch for how much easier this job is with a proper rta tool. They should fit really tight dunno if I'd trust one just hammered in.
 


KieranEG6

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Just done mine on the MB6. Hammered straight out and hammered back in. Was on a 108k+ milage Original bushes aswell (well bush casings lol no rubber left). Best to soak each side with WD40 for a while before you start.
 


type-r-dunk

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I fitted some Blue Print RTA's a few weeks ago and hammered in easy due to the tapered edge. Fitted some OEM bushes a few days ago and what a pain in the ass due to no tapering and really tight fit.
Dunx
 


jesse888

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I got my oem ones from Honda, complete with tapered edge.
Where did you get your "OEM" ones from?
 


dozzy1989

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Reviving this thread as I'm about to start building an EK9 track car and I'm considering what to do with the suspesnsion setup, I had been swaying toward the idea of a complete hardrace pillow ball setup incorporating adjustable camber and toe arms to make the most balls out hardcore setup I can, allowing a precise geometry setup and adjustability.. Then I read this thread! Would the toe in effect you get under braking with OEM RTA bushes be as beneficial on an EK9 with significant downforce? I'm thinking downforce would increase braking stability quite a lot in itself and could mean this toe in effect is less beneficial/necessary?

Can anyone with track car experience comment?
 

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Murray

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Reviving this thread as I'm about to start building an EK9 track car and I'm considering what to do with the suspesnsion setup, I had been swaying toward the idea of a complete hardrace pillow ball setup incorporating adjustable camber and toe arms to make the most balls out hardcore setup I can, allowing a precise geometry setup and adjustability.. Then I read this thread! Would the toe in effect you get under braking with OEM RTA bushes be as beneficial on an EK9 with significant downforce? I'm thinking downforce would increase braking stability quite a lot in itself and could mean this toe in effect is less beneficial/necessary?

Can anyone with track car experience comment?

I had poly bushes in the RTA in my sprint/hillclimb CRX and the rear end was stable with no ill effects. Had it around Knockhill as well and still it was ok.
 


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