Project TTS/SF: Wheels & Tires
by, 10-22-2010 at 04:15 PM (21198 Views)
Words: Jason Crouch, Photography by Cole Kelly & Jason Crouch
In our previous installment we traveled from California to Alabama to visit the guys at APR and get the car pushed up to the 400hp mark. They accomplished this using their excellent Stage 3 turbo kit developed for the TTS, which utilizes a GT2871 turbo. And with much higher levels of power, it seemed a fitting time to improve our car’s ability to claw at the pavement with a new set of tires shod on lighter wheels that would allow us to drop some unsprung weight from the equation.
It’s probably safe to say that most people following this series understand how vital a choice the right set of wheels can be, not only for performance but also for setting your car off properly from an aesthetic perspective. The wrong setup can take a car with a set of OEM rims and make it look worse with a poor choice in aftermarket wheels. It’s also a safe assumption that if you know what’s going on with the aftermarket wheel world, you know that HRE Wheels is one of the best wheels that money can buy.
So I started looking at their website, and following them on Facebook and it became immediately apparent that their stance on the whole aftermarket wheel world is very much in line with mine, as a modded car nut. I started to get the sense that they may be willing to open their doors to Project TTS/SF and much like the letter I sent the guys from APR last month, I sent HRE a proposal that detailed my idea to go behind closed doors at their factory and actually watch/film my wheels being made. Dave and Guy of HRE both got back to me with an interest in offering “Fourtitude forum members” an exclusive inside view.
As a rule of thumb, I believe that part of living a unique full life starts by choosing a slightly different path. Like many of you reading this, I like exclusivity and that’s what HRE is known for. Every time a customer places an order with them, the wheel is cut specifically for the vehicle as a one-off set. Instead of stocking towering shelving units with pre-built wheels, they keep the raw aluminum face slugs and barrel halves in stock and custom build every order, every time. The advantage is that you get custom offsets, lip-depth and obviously control over the height and width of the set up. So if you are after a custom fitment, check out HRE for yourself.
As stated earlier, a bad choice in aftermarket wheel can destroy the original lines of a car. Doing something like using a very angular geometric wheel on a car with those nice curvaceous lines like the MK2 TT wouldn’t exactly gel. I’m a dyed in the wool “wheel whore” so I probably spent two weeks p-chopping the TTS with different HREs that I liked before finally deciding that the comp series c93 was the right choice. The staggered lip stance always held appeal to me and since this was going to be a ground up custom order, I ran with a 2” front lip with BBK clearance and a 3” rear lip which ended up helping the TTS look menacing and purposeful.
Once I got down to HRE headquarters in Vista near San Diego, I met with vice president of HRE Wheels, Alan Peltier and got a great lesson in the science behind rotational inertia and un-sprung mass.* When a wheel is properly engineered, with the aforementioned concepts in mind, your car will react more favorably to quicker acceleration and improved stopping distance. The major advantages of running a lightweight 3-piece wheel such as the comp series is that you shed unwanted pounds off the car. The stock TTS split-5 spoke wheels in 19”x9”weighed in at 30.6 lbs and the HRE comp series c93 wheel in 19”x9.5” weighed nearly 9 lbs less at 21.8 lbs per corner! So the car lost 36 total lbs, reduced its un-sprung mass and gained a half an inch of width all around. It may not be horsepower, but it is using the cars power more efficiently and that’s really the hallmark of this build.
The second half of this new rolling stock equation is the rubber. There are so many variables when it comes to determining which tire will be the best option. Going back to my front wheel drive A3, the stock tires were less than adequate. Once I piped a bit more power through that car, I was chirping it at every light with terrible wheel hop due to the lack of stickiness that a good set of high end tires can bring to the table. I put on a set of Goodyear Eagle F1s and suddenly the car’s power met the road. Tire hop became a thing of the past and I became a huge fan of this grippy compound. If it ain’t broke, don’t fix it was my mentality for selecting my tires for Project TTS/SF. Goodyear makes great products, they have the sizes that I was after and a shoulder profile that will tuck under the fender during compression on hard cornering so a set of 245/55/35 Eagle F1’s were ordered. Fortunately, they made it to HRE Headquarters the day before my wheels were finished so that I could keep my schedule and make it to WUSTE 2010 on time.
You may be asking yourself, why did he go from a 255 down to a 245 section width of tire? The way it works is every tire manufacturer has different shoulder profiles. Some are more square than others and end up running a full size wider once on the wheel. The Goodyear line runs a bit squarer which strengthens the corner in the shoulder section of the tire. That is hugely advantageous when you run a moderately lowered car, but Project TTS/SF is sitting nice and low, so I went with a narrower section width to get a beveled sidewall/shoulder profile. The contact patch is almost identical to the OEM tires, but now the stance is dialed properly, the tires grip like no tomorrow through the corners of my favorite canyon runs and the grip during the wet months will be dramatically increased.
Special thanks for the help in this installment to:
Troy and the boys at Group 5 Motorsports (http://www.group5motorsport.com/)
Martin and everyone at All German Auto (http://www.allgermanauto.com/)
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