Project S4: Wheel Alignment/Suspension Geometry Set-up

I try to practice what I preach. But I have to hold my hands up on this one. Confession time! Father… it’s been two years since I fitted the amazing Bilstein B16 coilover kit to Project S4 and I have since fitted superb Dunlop Sport Maxx TT rubber, phenomenal Whiteline rear anti-roll bar & links and the inertia-busting Powerflex poly bushes. All these subtle, simple suspension modifications have combined to transform the S4’s handling: It’s sharp, accurate, fresh and fabulous and still rides really well. But I’ve known for way too long that a decent wheel alignment would make it all so, so much better… yet have not made time to do it. I confess! Guilty as charged!

I’ve been banging on and on about the importance of the right wheel alignment/suspension geometry set-up for decades as a car hack, with various project cars and features. It’s absolutely vital for whatever you use your car for – road, track, drag, rally or race – making the most of the suspension and tyre package you have and setting it up for your car’s specific type of use. The right set-up – done by the right, talented operative – can literally transform how your car drives and is possibly the best £100-£150 you can spend on handling tuning for your car. You can dial out handling characteristics you hate (understeer) and dial in handling characteristics you like (neutrality, and a bit of oversteer!), not to mention saving you money on incorrect tyre wear. It’s a total no brainer.

A correct four-wheel alignment (to specification, not just within tolerances) is especially critical to the S4’s Quattro handling. Alignment experts say that correct adjustment requires an alignment ramp on which all movements can be fully relaxed and an optical measuring rig. And whilst a laser rig has no particular advantage over a cross-hair mirror rig – the critical factors are the skill and dedication of the operator – it does make life easier, and we’ve chosen a brand new Hunter laser alignment machine for the job. That said, the task can be done by a real expert using fishing line and simple measuring equipment, though this is time-consuming and not really recommended.

So, I finally got my ass into gear and booked a session with my local STS Tyre Pro centre, who have a state-of-the-art Hunter Pro Align laser wheel alignment machine in a fabulous ex-MOT bay (the alignment is more commercially successful than the MOTs) and (crucially) a first rate, experienced operator – perfect for the Project S4. The STS Tyre Pro centre is a great place to go for this service, tyres and batteries (as I recently had fitted to Project S4 here) – the lads pride themselves on speedy, efficient, professional service and their smiley customer service and (transparent) waiting room facilities are the best in the business, in my view, especially at my local Wymondham branch in Norfolk, under Kieron’s superb management. They make everything easy, fun, relaxed and do a great job, at a great price. What more can you ask for?

We got on the lift ramp and strapped Project S4 to the Hunter laser alignment machine, programmed in the factory settings (code 1BD for the S4 and RS4 Quattro) and then re-programmed in the desired alignment settings we were after – dialling in more negative camber all round, and getting the toe virtually parallel, with a lean towards toe in, especially at the rear.

Picking the right settings is important. Naturally, STS have a list of all the factory settings, but I wanted something less safe and middle-of-the-road and a tad more bespoke and aggressive. Not bonkers, full-on track settings, but focused fast road settings. So, I gave my old pal and ex-WRC spannerman, the talented Mr Richard Bulmer at Tracktive Solutions a bell. Richard & I go way back. He built me an unbelievably good sprint Type RA Impreza a few years back, which won some trophies and I still miss today. It was utterly amazing. And it had the best suspension set-up I’ve ever had the privilege of driving. Perfection.

Richard suggested dialing in some negative camber all round, to sharpen turn-in and steering accuracy: 1.5 degrees on the front and 1.25 on rear (if you want to be more aggressive for track use, then 2.0 on the front 1.5 on the rear), and suggested running the toe virtually parallel on the front (just slight toe in) and 0.3mm per side toe in on the rear (or 1.0mm per side if the back end is a bit loose). FYI: Positive toe, or toe in, is the front of the wheel pointing in towards the centreline of the vehicle. Negative toe, or toe out, is the front of the wheel pointing away from the centreline of the vehicle. It’s all a balancing act between straight line stability and turning accuracy and ability. And wheel alignment is a very different beast for FWD, RWD or 4WD cars, which is why it’s best to get specialist advise with this sort of job. Get it wrong, and your car will be awful to drive – or even dangerous. You should always also take time to get used to any new set-up and its handling characteristics.

The job took just over one hour and STS Tyre Pro charge at £25 per adjustment, bringing me in c£100. Bargain. So, what’s the S4 feel like post-alignment?

God, I wish I’d done this when I should have, months ago! I’ve been missing out. I was lucky I set up the Bilsteins so straight and true initially and the handling has been far better than standard ever since, only getting better since adding the Whiteline and Powerflex goodies and Dunlop rubber. At least giving it the amount of time I have before the alignment has certainly given everything time to settle in (way to long in fact!). But I knew a good alignment would bring it all together, and maximise the benefits of all the suspension tuning to date – and it has, and some.

Turn-in, adjustability mid-bend and steering generally all feel noticeably more accurate. And the polar moments of inertia between steering angle and directional changes are a lot shorter and less noticeable now. Overall, the S4 feels a lot more nimble – most noticeably at the rear end, which is now a lot more active, stable, accurate and best of all, playful. You can really get the tail wagging now with a sharp mid-bend lift, or a boot full of gas – even in the dry, where it was much more passive prior to the alignment. I can’t wait for it to rain now, or the bloody snow and ice to come again, and we can get some proper four wheel Quattro classic drifts going on – at the track, naturally! The front end is also now less prone to wash out, with initial push-on understeer – something it always used to have a capacity to do, before the Bilstein’s, Powerflex bushes and Whiteline ARB were fitted anyhow. The alignment has all but eliminated this. Bravo: Sharper front, more active rear and greater control all-round. Sorted.

With the Bilsteins, Powerflex bushes, Whiteline ant-roll bar/links and the Dunlop Sport Maxx TT rubber, I really feel like I’ve got a cracking fast road, occasional track tool suspension and tyre package on the S4 now (and the Tarox brakes are fab too). And the STS Tyre Pro wheel alignment (with Richard Bulmer’s Tracktive Solutions settings) are the final piece of the jigsaw; long overdue, but well worth the wait. Highly, highly recommended stuff.

Want my advise? No? Well, you’re getting it anyhow… get your car an STS Tyre Pro alignment this weekend. You will not believe the difference it makes. And it’s all win, win, as the alignment will save on tyre wear as well as making the S4 a whole heap better to drive, road and track.

S4 suspension – “done.”

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Thanks to:

Kieron and his team at STS Tyre Pros for the excellent wheel alignment (& battery replacement) service (www.tyrepros.co.uk)

Richard Bulmer at Tracktive Solutions, for the wheel alignment recommendations (www.tracktive.co.uk)