JDM Rear Sway Bar 19mm or 20mm?

I was at a JDM importer today as they had a JDM rear sway bar for the 05-09 legacy.

 

Measured it there and it was 19mm. I couldn't find much info on why it was 19mm and if that made any sense as everyone talks about the 20mm JDM sway bar.

 

Only thing I found was this

Found some more info here

And a bit more here

 

All threads have some saying 20 mm other saying 19 mm and one statement of there being both 19 mm and 20 mm, with each coming from different revisions.

Iirc they are 19mm.

Anyone have anymore info on this? Has anyone actually measured a rear JDM bar at 20mm?

 

I believe you m spranks but would like some more input if possible. If all JDM bar are in fact 19mm I can go ahead and buy this bar.

Does it really matter? Whats the significance of a jdm part? Its a sway bar. If using the OEM front bar 19mm pairs well. If you really want to decrease body roll 24-25mm front and 22mm rear. For track you could go 27mm rear or no bar and a spring north of 6k. Depends on the track. For me no bar and uber stiff springs worked better on the Roval.

Does it really matter? Whats the significance of a jdm part? Its a sway bar. If using the OEM front bar 19mm pairs well. If you really want to decrease body roll 24-25mm front and 22mm rear. For track you could go 27mm rear or no bar and a spring north of 6k. Depends on the track. For me no bar and uber stiff springs worked better on the Roval.

 

Does anyone still make (or still stock discontinued) RSB over 21mm? Would love to know if that's the case.

Does it really matter? Whats the significance of a jdm part? Its a sway bar. If using the OEM front bar 19mm pairs well. If you really want to decrease body roll 24-25mm front and 22mm rear. For track you could go 27mm rear or no bar and a spring north of 6k. Depends on the track. For me no bar and uber stiff springs worked better on the Roval.

 

Yes, it matters for a few reasons.

 

1) I have a 3.0R so my only front bar option is a Tribeca. Which is 25mm.

2) So a bar closer to that size would be better so I may have to go aftermarket. But availability and price are a factor.

3) I don't care if it's JDM but JDM parts like this are easy for me to get locally and cheap. So it's a much better option then aftermarket in my case.

4) If there are 2 versions then depending on the finally outcome it would be better to pair the 20mm rear with the 25mm front. It's not ideal as the rear should be bigger but as said before price and availability. I have no issues searching/waiting for a different size bar if they do in fact exist.

5) I do agree the 19mm bar would pair well with the stock front bar.

 

Lastly I like knowing and having correct information out there.

 

I'm not tracking the car nor do I plan on increasing spring rates. Would just like to decrease a bit of body roll and make the car a bit more neutral. It's a DD so lower spring rates but a larger bar is a better combination for the street as far as I'm concerned.

 

Of course pairing the 19mm rear bar with the stock front bar will make the car more neutral. Though technically a 20mm would be even closer to neutral. But I agree the 21mm front and 19mm rear is a good combination.

 

But if I want to decrease front roll also then I'll have to go to the 25mm bar. Having a 19mm rear would then bring me back to about the same difference front to rear as stock. Having a 20mm would help make the difference not as large though it would still be far off the neutral handling I am interested in. And therefore a aftermarket rear bar would likely make more sense in this case.

Aftermarket bar stiffness is normally higher than OEM, even in the same diameter. If using a 25mm front even a 20mm rear will not neutralize the steering. Subaru intentionally made the car plow.

 

Whiteline used to have a chart showing the rate of stiffness of their bars. But not everything is the same anymore.

I'm pretty sure the one I installed on my '06 about 11 years ago was/is 20mm.