[Flycaster]

Originally Posted by Thejoyofdriving

...And what better street tires can i get than the RE070?...the options are endless.....Nitto's, Bridge stone RE-01R's, Falken RT-615's, falken FK452's, etc. ...

I think MGizzle is talking in terms of pure grip, and there isn't a tire on that list that comes even close to the 070's. Personally, I hate the damn things, but they have as much grip as most pure racing rubber I've used - they are also the noisiest tire on the whole frigging planet (a function of their concrete sidewalls). To each his own.

[Thejoyofdriving]

Originally Posted by idrivearocket

Do ABS systems really wait until tires are sliding before the system kicks in???

I have driven many cars that felt like the ABS was kicking in way before the tires were going to slip. How many times have you done the ABS clickidy click all the way to the red light when you were sure your own pedal feel could have stopped the car faster...

Few times, i hear no abs you stop faster as long as you do it right(thats why race cars dont have abs), but i would take abs any day for daily driving, much safer, the natural human instinct is to slam on the brakes when a dangerous situation is encountered, with out abs.......bye bye...

[Thejoyofdriving]

Originally Posted by Flycaster

I think MGizzle is talking in terms of pure grip, and there isn't a tire on that list that comes even close to the 070's. Personally, I hate the damn things, but they have as much grip as most pure racing rubber I've used - they are also the noisiest tire on the whole frigging planet (a function of their concrete sidewalls). To each his own.

hmmmmm, in terms of pure grip i bet all the ones i mentioned would do better, even the tire rack surveys(take them with a grain of salt) say so.

[Flycaster]

That's a bet you'd loose, amigo. The tire rack surveys are worthless. Go read Scott Siegle's track and set-up summaries, with actual lap times. The only other "common" street tire that comes close is the Advan on the EVO...and those are only $260 apiece. If your car isn't handling right, the problem is not the rubber.

[nautique196]

Originally Posted by MGizzle

No point in putting on better tires if you don't have enough friction or brake output to lock them up or provide "ideal" slip.

controls.

agreed. this post made a lot more sense than your first. putting on the better tires will allow you to upgrade the pads/rotors to be able to lock them up. tire issue is everyone's own opinion/preference.

[MGizzle]

Ok. Let me give this another shot. Take a look at a tire slip curve (not lateral one but its similar). It gives you friction force vs. slip %. You will notice that the peak grip of any tire is around 15-30% slip. Before and after that it drops of significantly. This doesn't mean the tire is "slipping" entirely. Your ABS unit is calibrated for this. Hence, if you slap better tires, or worst tires on it, the ABS unit will still use the values it was calibrated for with the stock tires. Now try to imagine how this can go wrong. here is an example. The ABS unit uses speed sensors to determine percent slip. Now if you slap a better tire on it will use the same speed differences BUT your new tire needs to slip more or less to achieve better grip (depending on tire slip curve). Hence, the ABS unit will not allow it to go to that ideal slip % and will release it sooner or later. That is bad and will reduce your distance. Look at it this way. When you put a bigger turbo on your engine you need to TUNE IT, calibrate it for the new turbos specs. It is simple as that. Same thing with tires.

Your pads and rotors will not mess this calibration up and if so insignificantly. Now, what about calipers??? Hmmmm.....listen up. Bigger calipers are OK if and only if the P-V (pressure vs. volume) curves of those calipers match the stock ones pretty good or close enough. What is this in english? The caliper fluid volume has to be same or similar to the stock ones because this is what the ABS unit is calibrated for AND MECHANICALLY ENGINEERED FOR. Hence, if you get bigger calipers with bigger pistons you will need more fluid to generate the same force/pressure and your ABS unit WILL take longer to do this, hence your time to lock up etc. is longer and effected. This can throw off your distance some. Hence why companies that know what they are doing design their calipers bigger but with smaller piston sizes etc. to try and match the stock P-V curves.

Brake lines: SS lines can reduce your ID under pressure hence you can get fluid to the rotors quicker achieving lock up sooner. This is not bad but insignificant in my opinion. You can hardly tell a difference and you get more change in the ABS unit itself that can cause bigger difference than the lines.

Vehicle Mass/Sprung: This will effect your dynamics a bit and going lighter might not improve it. Your car will lift, changing your suspension geometry and your weight distribution on all four corners (statically too). Hence, you need to drop some significant money and time to get this right. Without Coilovers or ballast I don't know how you can do it. You are putting less weight on the tires so you might effect the transient time to reach peak grip, hence lock up. With handling it is different. You don't have an ABS unit lateraly. Yes, 2008 has VDC and losing weight on it can mess with this system depending on how it reads from the sensors.

Vehicle Mass/Unsprung: heavier tires, rotors, wheels etc. will kill your inertia and this will effect your brake output alone killing your distance. However, the ABS unit will hurt too because it is trying to release the tire at a time where the system still has enough inertia to roll the tire forward after it is released. I am telling you, we had issues with this when calibrating some heavier cars and you have to make sure you release with enough inertia left to spin the tire forward after you release.

Guys, the STi is a very properly designed machine. I see that some of you are new to the forum so you need to take a lot of things with a grain of salt in the aftermarket. For example your tire comment. I hope you understand that you are very wrong about the RE070's. As an example you should take a look at the new GT-R and see what tires it runs in Japan and what tires it used to kill everything at the Ring. Also, ask your self how come that Bridgestone released these tires for the STi only (hmmm.all wheel drive, center diff, big brakes etc.) and then 2-3 years later slapped it on the most talked about car in quiet a while, the GT-R (all wheel drive, torque distribution front to rear, big brakes etc.).

Hence, unless the person starting this thread is not street driving his STi I doubt that he can find significantly better tires on the market. Oh, and when he does, he will need the pads and maybe rotors.

My advice, get SS lines (cheap), get a MC brace (cheap), get pads (not too expensive) and maybe some nice rotors (I would recommend slotted to keep those pads clean).

[MGizzle]

Originally Posted by Thejoyofdriving

Now, i am just in high school physics, but, isnt the force of static friction 20% or so higher than the force of kinetic friction? If so, it would be better to not allow the tires to go in to kinetic friction (i.e. slipping) and hold them right before the limit of adhesion to take advantage of the higher coefficient of static friction? And what better street tires can i get than the RE070? I dont mean to make fun of you, but...the options are endless.....Nitto's, Bridge stone RE-01R's, Falken RT-615's, falken FK452's, etc. the list goes on forever.

This is exactly why I mention the 15-30% slip. This means you are not slipping, only 15-30% there. You explained it with the static friction.

Again, your options are not endless on tires. If you ask me they are zero. Read my above comment. Pretty funny though that you think they are.

[chaos311clarity]

tires and pads.

[Thejoyofdriving]

Originally Posted by MGizzle

I hope you understand that you are very wrong about the RE070's. As an example you should take a look at the new GT-R and see what tires it runs in Japan and what tires it used to kill everything at the Ring. Also, ask your self how come that Bridgestone released these tires for the STi only (hmmm.all wheel drive, center diff, big brakes etc.) and then 2-3 years later slapped it on the most talked about car in quiet a while, the GT-R (all wheel drive, torque distribution front to rear, big brakes etc.).

Hmmm, the way I look at it is that car manufactures do the best they can on a budget. The OE tires may very well be the best tires to put on the STI in the price range that the manufacturer has in mind. I think there are much much better tires out there, but, the reason that they didnt use these better tires is, either that they have too much road noise for the common consumer, their tread wear is too fast or the ride comfort may be too poor . Think about it. They wouldnt put the best grippiest tires on the car stock because it would A) cost to much or B) the consumer might not be willing to trade grip for tread wear or discomfort. For me, i really dont care how loud the tires are or how bad the ride is. I am a die hard grip/handling guy, unlike the average consumer i am willing to trade tread life, ride comfort, and noise for some more grip. So the RE50's may very well diliver the best grip with out being too loud, uncomfortable, and tread life good enough so that there will still be tires left on the car when you drive the car home from the dealer

[Thejoyofdriving]

oh and, Mgizzel, you are no doubt an expert, and i value your posts, they are very informative, next time i want to get a tire/wheel/brake upgrade you will be the guy ill talk to

I am having trouble understanding the 10-15% slip thing.
i understand that the tires are not total locked up.