Bridgestone/Praxis Suspension System
08-12-2003, 01:21 PM
#48
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Join Date: Mar 2003
Location: Warsaw, Indiana
Posts: 681
Car Info: 02 WRX Wagon White
Alex,
For this to be released on the Legacy, there's going to have to be a lot of surveys completed for Legacy owners dying to buy it. I'd guess their marketing research will lead them toward the Evo, RSX, Civic, and Eclipse crowd before the Legacy. I'll do my best though!
Jan,
Turns out Bridgestone/Praxis aren't immune to the normal delays in releasing a new product. The latest ETA is last week of August. I'm giving them a bit of slack on this because I understand how the smallest of things cause an unexpected delay.
For this to be released on the Legacy, there's going to have to be a lot of surveys completed for Legacy owners dying to buy it. I'd guess their marketing research will lead them toward the Evo, RSX, Civic, and Eclipse crowd before the Legacy. I'll do my best though!
Jan,
Turns out Bridgestone/Praxis aren't immune to the normal delays in releasing a new product. The latest ETA is last week of August. I'm giving them a bit of slack on this because I understand how the smallest of things cause an unexpected delay.
Last edited by Dexter@tirerack; 08-12-2003 at 01:37 PM.
08-14-2003, 06:22 PM
#49
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Join Date: Apr 2003
Location: Maui, Hawaii
Posts: 128
Car Info: 2004 WRX STi
Any word yet on how the final product will play with the USDM STi?
I had read somewhere a while back that the 'Sport' mode would be the same as the Stock settings and that 'Touring' would actually raise the car from it OE settings.
Have you guys gotten a chance to drive the STi, and if so, how would you say it compairs to the Praxis system on 'Track' setting?
I had read somewhere a while back that the 'Sport' mode would be the same as the Stock settings and that 'Touring' would actually raise the car from it OE settings.
Have you guys gotten a chance to drive the STi, and if so, how would you say it compairs to the Praxis system on 'Track' setting?
08-15-2003, 01:02 PM
#50
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Location: Warsaw, Indiana
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Car Info: 02 WRX Wagon White
Maui,
The system is calibrated by the user. On the STi, one might set one index at above stock ride height for rally use, then one at stock height for normal driving, and one with a 1-2" drop for autocross/road race use. It's set using a ruler and three jacks on a flat surface and can be changed at any time to suit your needs.
The system is calibrated by the user. On the STi, one might set one index at above stock ride height for rally use, then one at stock height for normal driving, and one with a 1-2" drop for autocross/road race use. It's set using a ruler and three jacks on a flat surface and can be changed at any time to suit your needs.
08-16-2003, 06:59 PM
#51
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Join Date: Aug 2003
Posts: 7
Car Info: 04 Forester XT
Any word on whether this system might work on a Forester? Specifically the new 2004 XT's. I know other already made WRX coilovers will work on this car.
The new Forester XT seems like a car that a system like the Praxis could apeal to buyer by being adjustable up and down for utility and sportiness. It would seem pretty easy to redesign for this vehicle since it too is based on an Impreza platform that is just taller.
If you build it, they will come. At least I will.
Regards,
Justin
The new Forester XT seems like a car that a system like the Praxis could apeal to buyer by being adjustable up and down for utility and sportiness. It would seem pretty easy to redesign for this vehicle since it too is based on an Impreza platform that is just taller.
If you build it, they will come. At least I will.
Regards,
Justin
09-02-2003, 09:30 AM
#54
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Location: Warsaw, Indiana
Posts: 681
Car Info: 02 WRX Wagon White
The system is expected to arrive here today or tomorrow (they have shipped from Praxis). There are a few going to I-Club members, so you should be able to hear some others' feedback soon.
09-02-2003, 12:23 PM
#55
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Posts: n/a
I'm interested in the durability of the bladders. I regularly drive on dirt/gravel roads and I'm a little concerned that a rock might be able to penetrate them.
This sounds like an nearly ideal setup for me on my 04 wagon. I really like the appeal of the track mode for serious tarmac driving, sport mode for daily driving and stock mode for offroad.
Mike
This sounds like an nearly ideal setup for me on my 04 wagon. I really like the appeal of the track mode for serious tarmac driving, sport mode for daily driving and stock mode for offroad.
Mike
09-03-2003, 07:54 AM
#56
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That's a good question. I spoke to the engineer about the same thing when he was here. He said that it would be extremely difficult to pop the air bags with a screw driver if you tried. They are made of the same rubber materials as the ones used on semi trucks. They will not be harmed by normal road/rally stones that bounce about the wheel wells.
09-08-2003, 11:03 AM
#58
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To address the "crispness" question: This observation is likely because the spring rate on a coilover is generally higher than that of most air suspension systems.
The difference in the Praxis is that the spring rate changes exponentially as ride height changes because of volumetric changes inside the air chamber. The shape of the cylinder that the the spring bladder rides on is oddly shaped to achieve this spring rate change.
Also, in contrast to other air spring systems, the air bladder rolls over the cylinder unstead of being compressed between two flat surfaces or perches. Picture it as compressing a balloon between your two flat hands compared to pushing your fist into the balloon. The larger your fist, the more the balloon will resist the compression. If you forced a cone shaped object into the balloon, the resistance to compression would increase in a non-linear fashion - which is most similar to the Praxis system.
So, in sumary, the Praxis would likely be less responsive at stock or raised height than a coilover. At the 2" drop however, the Praxis would be similar or stiffer than a coilover.
As far as transitions also, the Praxis system's valves are fully closed after adjustments. The transition effect would be the same as any metal spring at the same rate.
That is the real benefit of the Praxis. Smooth when you need and stiff when you need it - all at the press of a button. You're not riding on the same spring rate regardless of ride height - as with coilovers.
Do I have an STi? No. If everyone on this board buys a Praxis from me? Likely.
The difference in the Praxis is that the spring rate changes exponentially as ride height changes because of volumetric changes inside the air chamber. The shape of the cylinder that the the spring bladder rides on is oddly shaped to achieve this spring rate change.
Also, in contrast to other air spring systems, the air bladder rolls over the cylinder unstead of being compressed between two flat surfaces or perches. Picture it as compressing a balloon between your two flat hands compared to pushing your fist into the balloon. The larger your fist, the more the balloon will resist the compression. If you forced a cone shaped object into the balloon, the resistance to compression would increase in a non-linear fashion - which is most similar to the Praxis system.
So, in sumary, the Praxis would likely be less responsive at stock or raised height than a coilover. At the 2" drop however, the Praxis would be similar or stiffer than a coilover.
As far as transitions also, the Praxis system's valves are fully closed after adjustments. The transition effect would be the same as any metal spring at the same rate.
That is the real benefit of the Praxis. Smooth when you need and stiff when you need it - all at the press of a button. You're not riding on the same spring rate regardless of ride height - as with coilovers.
Do I have an STi? No. If everyone on this board buys a Praxis from me? Likely.
09-10-2003, 01:44 PM
#59
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Join Date: Mar 2003
Location: Warsaw, Indiana
Posts: 681
Car Info: 02 WRX Wagon White
Take a look in the new Sport Compact Car- page 153 - they do a nice Praxis review in there.
November issue, that is.
November issue, that is.
Last edited by Dexter@tirerack; 09-11-2003 at 10:13 AM.
09-12-2003, 08:09 PM
#60
Praxis system is in ...
Dexter, you told me to go ahead air in public any more install experiences.
After 3 days install time it is all in. Alignment took a little longer than usual >1.5 hr; I will get more from the alignment mechanic next week as we were ready to go this eve ... ~7PM.
Drove home from the shop & felt like I was riding on a hay wagon. This is supposed to be set at the "touring" ride so I am guessing that the Praxis engineering clockwise might have a perspective from the other end of the struts (for ride adjustment) OR another possibility is an air line plumbing error.
The air line plumbing error is a definite possibility as there are some conflicts in the instructions.
... damn editor just wiped out an hour's worth of typing ... tomorrow
After 3 days install time it is all in. Alignment took a little longer than usual >1.5 hr; I will get more from the alignment mechanic next week as we were ready to go this eve ... ~7PM.
Drove home from the shop & felt like I was riding on a hay wagon. This is supposed to be set at the "touring" ride so I am guessing that the Praxis engineering clockwise might have a perspective from the other end of the struts (for ride adjustment) OR another possibility is an air line plumbing error.
The air line plumbing error is a definite possibility as there are some conflicts in the instructions.
... damn editor just wiped out an hour's worth of typing ... tomorrow
Last edited by PsiStar; 09-13-2003 at 06:32 PM.