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      12-14-2007, 03:42 PM   #1
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Arrow Review - Hartge Antiroll (sway) Bars on 335i

So after a few weeks waiting, I've finally got the Hartge antiroll bars installed by the guys at Birds. No pics of the install I'm afraid, as I forgot to charge the camera Although in saying that, there's bugger all to see really!

Hartge Antiroll Bars
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As standard, all 3 series cars use largely the same antiroll bars, regardless of spec or model. 26.5mm diameter at the front, 13mm at the back. BMW have deliberately setup the rear to be quite loose, so that the car has a natural tendancy to understeer when close to the limit. Having the back setup like this also helps the DTC/DSC system to maintain traction, given the lack of a limited slip diff. The MSport bars have a slightly different design to take into account the lower suspension setup, and as such might be a tad stiffer than the SE versions.

The Hartge antiroll bars are appreciably more substantial - 28mm on the front (approx) and 20mm on the rear. Installation took just over three hours - the installation of the rear bar requires the subframe and exhaust to be lowered slightly to provide access. Fortunately dropping the rear subframe doesn't alter the geometry of the rear wheels, so the alignment of the wheels is unaffected. The front is considerably easier, although the skid plate underneath takes ages to remove as there are so many little bolts.

The Hartge bars come with new polyurethene bushes and mount to the existing points, and are therefore undetectable to the eye unless a technician is specifically looking to see if they've been changed.

So what are the results of the installation? Well firstly, driving down the high street in Uxbridge there was absolutely no change detectable in the way the car was riding. It had the same compliancy, the same secondary ride, and even deliberately driving with one wheel on the ruts and bumps and the other on clearer road didn't show any undue stiffness in suspension.

Then I hit the A roads heading towards the motorway, and that's when I noticed that there was a massive difference in the lack of roll now experienced. The front-end bite is hugely increased, to the point where I initially thought I had cornered too hard too early. The sensation is a little odd and requires a bit of time to readjust, but now that I've driven about 300 miles since the installation, I can safely say that the cornering is so much more precise, with more control, absolutely zero push-on understeer, and it breeds much more confidence. The car feels completely alive, and I really do 'drive' my car now as opposed to the car driving me. It responds to every single steering input, and the previously 'dead' straight-ahead feel through the steering wheel has gone. It's not so alive that it's annoying though - the antiroll bars (along with the LSD) have transformed the car into a proper driving machine, without being twitchy and tiring.

However, like the LSD there is a BUT. Because the car rolls less, there is less subjective feel as to when the car is approaching its limits of adhesion. You have to be driving stupidly to breach the limits, but when you do you really see the benefits of the LSD and traction control! It's masses of fun now though, and once I've fully understood how the car now behaves, I'm sure I'll be able to monster windy country B-roads like never before.

It's a great upgrade and now only leaves me to upgrade the brakes to AP 6 pots (early next year I think). It's not too expensive either - about 800 fitted inc VAT (the antiroll bars, not the brakes!)

Out of the two upgrades though, I think it would be imperative to do the LSD first, before the antiroll bars, as the extra traction is needed to balance the increase in lattitudinal stiffness of the new bars. If I had the funds to do only one upgrade, it would be the LSD every time as it adds so much more driveability. The rollbars are really the icing on the cake for me.

Roll on the 'Ring next year!!!

Last edited by E92Fan; 12-14-2007 at 06:54 PM.