I finally am behind the wheel of my new JCW 2dr hardtop. Awesome!

I am contemplating going with the 19mm H-sport rear sway bar.
For comparison purposes, would anyone know the diameter of the stock bar?
I think it is the same for the "S" and the JCW or the diameter of the rsb when the "sport suspension" option (ot the JCW suspension option) is chosen, which is how my JCW was delivered?

This would help me decide if I should I go with a larger 22mm bar available and not the 19mm or stand pat with what I have.

I really want to go from understeer to neutral, not oversteer.

Many thanks,
Ballyrick

 

stock 17 mm
sport 18 mm
jcw suspension 18.5 mm

22 mm is generally too large for many people as it introduces a good amount of oversteer

 

Hi Slinger 688,

Thanks so much for your response and your input. You confirmed my concerns that 22mm was too large.

At the same time I did not realize the "sport" and JCW bars were that close in diameter to 19mm. Do you believe the upgrade from "sport" (18mm) to the H-Sport 19mm bar is really justifiable considering the cost and increased possibility of ongoing squealing and the need to relube?

 

You really need to check the diameter of your current bar, I'd say 99% of the bars we have taken off have been 17mm, even if they had SS.

 

I think there will be a positive difference by going to 19mm. You do not have to increase size much to increase stiffness by quite a bit. Also the adjustability helps.

Many if us wrap the bar at the point of the bushings with Teflon tape and lube it. It generally will help reduce squeaks and the ability to lube with the h-sport bar is a plus.

 

At least for the Mini bars (that are solid), remember its not really the diameter, but rather the cross sectional area (pi x r2) that matters--stiffness goes up non-linearly with diameter. If it's a tubular bar, then you have to get more specific stats on on torsional resistance to make general comparisons.

 

To Way's interesting earlier post about frequent smaller bars being found on the cars they handle, I mic'ed mine just now--2010 S with the factory sport suspension. Came in at 18mm (a little more actually--0.713 in more or less), just getting at one accessible straight area past the bends as best I could under the car. Assuming the steel stock they use is consistent diameter along its length, at least mine meets what it was spec'ed to have for that suspension. Not doubting what you find in the field; mine at least does pass muster. Could be too many owners think S = sport suspension automatically, which of course it doesn't.

 

I've never needed to wrap an Hsport bar in teflon tape. As for other brands we have done all kinds of crazy things to get them not to squeak, thats why I only recommend the Hsport sway bars, they are by far the best.

 

 

Measured mine after Way's comments because it is easy to measure as it is sitting in my closet. My sports suspension does have an rsb of 18 mm. Guess they got mine right.