Dexter@tirerack

Bridgestone/Praxis engineers were recently here testing the new adjustable suspension system on our track. Upon closer inspection, I found this system to be quite awesome, considering it seems to be the answer to what all of us are looking for: the ability to lower suspension up to two inches at a moment's notice for sporty driving while spring rate automatically adjusts itself for the ride height. This is only the short of it, as the complexity of the system is pure genius.

The quick points:

* Only available for WRX upon release
* Automatic corner weighting
* Entire system adds about 30lbs. to the car

The system will include:
· 3-way adjustable struts (4)
· Air springs (4)
· Remote reservoirs (4)
· Spring-rate control valves (4)
· Air compressor
· Air dryer
· Trunk mounted, auxiliary air reservoir
· Valve block
· ECU
· Height sensors (4)
· Wiring harness (pre-assembled with fuses and relays)
· Cockpit control module
· Brackets for remote reservoirs, compressor, ECU, valve block, and height sensors
· Air plumbing
· Installation hardware
· Detailed instructions with video support

There is a press release scheduled next week - at that time I can be more specific. We're able to take orders now if you wish to get in line for a system - priced at $3450. They are expected to be available the beginning of August. Give me a call if you're interested.

Take a quick look here at the interactive demo to see what it's all about.

I'll be able to drive on the system early next month, upon which I'll give a full report.

Dexter
877-522-8473
Ext. 207

dropkick_muppet

iTrader: (4)

i'm going to be really interested in reading a review of the Bridgestone/Praxxis system when it finally gets released to the general public. the idea of being able to effectively change spring/damping rates and ride height from inside the car is very appealing. if the system works effectively and smoothly, it might provide a realistic alternative to coilovers.

the drawbacks looking at the system are it's cost and it's complexity. coilovers have the advantage of being a) cheaper and b) easier to install. plumbing the air lines, mounting the compressor, tanks and all the related hardware required by the B/P system would take quite a bit of time, thought and energy. depening on the size of some of the hardware, trunk space could be an issue. before buying the system, i'd really want to know the dimensions and electrical requirements of some of the components. from just the description, it doesn't look like something that Joe WRX Owner would tackle on his own in their garage -- which only adds to the cost.

in any case, i'm definitely interested in hearing about how it drives once you've had a chance to drive on it.

Dexter@tirerack

Great thoughts (and a great user name). When comparing to coilovers, the biggest difference is the spring rate change. Coilovers, even progressive ones, rely on the same spring rate whatever your ride height. This is because you're just changing what is essentially the perch for them to rest on. Manufactures have to make ride comfort as well as performance concessions to get a rate that is acceptable for the highest and lowest perch settings.

The Praxis system adjusts the spring rate as the height changes. That, in my opinion, is the reason this will be widely (if not wildly) popular.

Another point is the automatic corner weighting. The system actually weights the springs as necessary to compensate for changes in weights on any corner of the car. This means no matter who or what you're carrying, the car will corner the same - right to left. There is no easy "sure fire" way to get the coilover adjustments exact.

Installation won't be bad either - only one hole to be drilled. If you can do coilovers, you would likely be able to do this. They estimated 8-10 hours for the standard workshop warrier.

Finally, the ability to make this change instantaneously is quite attractive.

dropkick_muppet

iTrader: (4)

thanks.

you're spot on that any coilover system is going to have to rely on the same spring rate no matter what the ride height is set at, and that the only thing you can really adjust is the spring perch which provides preload adjustment. the fact that the Praxis system allows you to actually adjust the rate of the springs is a huge improvement over a simple preload adjustment. if people pick up on this, and appreciate it, i'm sure that the system will have a very wide audience. Autocrossers and track day folks who drive their car to and from the office every day would probably appreciate it, and benefit from it the most.

again, a great improvement over coilovers.

my biggest concern with a system like this would be it's reliability. anytime you're dealing with a complex system of air lines and bags versus a simple shock/spring setup, there is always so much more to go wrong. it'll be interesting to see how this implementation stands up to daily driving, and how Bridgestone/Praxis addres some of the safety issues (what happens if a bag deflates, or a line leaks?). i don't suppose this will be on display at any sort of car show in the SF Bay Area anytime soon, will it? i'd love to see on both in parts at a booth, and installed in a demo car.

Dexter@tirerack

They're warranting the air-strut units for two years and the rest of the system for one - which includes use in sanctioned, amateur motorsports events. That, to me, says a lot. I'll give more details after I learn them.

As far as the press release - it's a closed event. I know it is taking place at a racetrack out West, but that's all I've got.

DarriiffftaaHuy

iTrader: (1)

sounds sweet, i've noticed many cars coming out with this adjustment stock... well two or three that i can name. VW, PORSCHE, and VOLVO are the few I can think of with this adjustability... however, this is the SUV/ WAGON Crossover models.

im interested to see how reliable this will be, as it would be perfect for me, as I enjoy track and off road. if only it allows you to lift the car over stock... then it'd be perfect.

Dexter@tirerack

The "rally mode" is stiill a bit under wraps. I can tell you there's an option for about a 1/2" lift over stock, and with the adjustability of the shocks (just like Koni Sports or KYB AGX) you could infer that it's a good possibility that the car can easily be set up for rallyx.

dropkick_muppet

iTrader: (4)

Volvo teamed up with Ohlins to build the adjustable system on (i'm pretty sure) the new S60R. most people in the car world have probably never heard of Ohlins, but they're *the* name in motorcycle suspension, and they know their business.

you're right, that does say quite a bit about their confidence in their product. i'm assuming that they'll include local level auto-x events and track days into their warranty coverage if they say they'll cover sanctioned motorsports events.

Dexter@tirerack

I'm assuming the same. I'll learn more soon, but SCCA events would likely be considered "sanctioned motorsports events."

Dexter@tirerack

The Praxis people are here today installing a system on a WRX sedan. I've been down checking it out and have been quite impressed. The installation is involved, but anyone who can install a car stereo and speakers/subwoofer should be able to do it. They estimate about 10 good hours for installation and I would agree with that.

The compressor mounts in the driver's front wheel well - under the battery. There's plenty of room there if you've ever had the fender out you could see. The tank and valve block mount in the trunk. The tank has about the dimensions of a 6 1/2" bazooka subwoofer. The switch for the ride height looks like standard Subaru size - similar to cruise/foglight switch.

I asked how the system was initially calibrated, and it turns out the user programs the three ride heights with the car up on three jacks and measuring from the ground to the fenders on a flat surface. The recommended touring ride height would be OE, and the sport mode should be set at 25mm lower and then race mode should be set at 50mm lower.

The wiring harness is large but well labeled and the instructions, though still in development, will be very well detailed - better than any I've seen.

I'm heading back down in a bit to check on progress with installation. I'll post again with anything new.

Dexter@tirerack

I was able to drive the "Bridgestone/Praxis equipped" WRX sedan home last night to get initial impressions of the system. Though this is a prototype system on this car, it's functionality is spot on. The car is essentially a stock '02 with 17" SSR Competitions and Bridgestone S-03 tires. Here are the quick points that should be made:

I left the parking lot in "touring" mode, with the car at stock ride height. The first thing I noticed was the increased responsiveness over stock because of the quality of the dampers used. (I use the same wheels on my car with same sized Sumitomo HTR+ so the difference is more than just the tires/wheels)

Once I hit the highway, moved it into "sport" mode. Yes - you can change modes while driving in a straight line and not accel/decelerating (the system has an accelerometer incorporated). The change happens quickly - in just a few seconds the front drops and then the rear. It goes this way so your lights don't shine up in oncoming traffic. In sport mode, the responsiveness increased even more and the ride was still acceptable, though a bit rougher. I think this is the mode I would spend most of my time in.

After a few miles of this, I had to try the "track mode," which drops the car about 2" from OE. The same front/rear drop occurred and the ride got another step rougher. Driving was fine in this mode until I started onto a rough section of the highway and I realized why they call this "track" mode. As I hit the offramp I noticed huge differences in handling compared to my stock suspension - most notably in terms of responsiveness and less sway.

The only thing I wasn't able to test, because of my late departure from work last night and my early arrival today, was the different damping levels of the struts. A **** on the bottom of each strut adjusts both compression and rebound of each unit simultaneously. There are recommended settings for each mode of the system, and I was running "touring" damping with all three modes of the height/spring rate adjustment. I will test the different levels tonight and this weekend, as they've been quite generous with allowing me the use of the car.

These are my brief driving impressions, I'll list bullet pointed considerations/observations in a subsequent post. Bottom line though, this system is the "real deal," and it does what it's supposed to with delightful precision.

Dexter@tirerack

As I compose the list of considerations/observations, BRING ON THE QUESTIONS. I have spend a lot of time with the engineers and installers and I'm gaining a great understanding of the system.

Dexter@tirerack

The compression/rebound of the dampers is not adjustable from inside - only on the bottom of the struts. The ride height/spring rate is what is adjusted while in the car.

The computer can be switched off after putting the car in "track" mode and everything will remain as it was. The computer disconnection/removal - not sure - I'll test it tonight. The valves rest in closed position, so I I expect it will be fine. The engineer I spoke with is a past president of his SCCA club and he will gladly compose a letter to the authorities explaining "non functionality" of the active components of the system when in the "off" position.