Xenonk Posted January 7, 2007 Share Posted January 7, 2007 sidewall flex has some slack too.. not to mention that just because you are on the binders doesnt mean the sidewalls and the rest of the tire stop spinning.. Keefe Link to comment Share on other sites More sharing options...
NSFW Posted January 7, 2007 Share Posted January 7, 2007 I can see how slidewall slack would delay the onset of braking (by a fraction of a wheel revolution), but not how that would affect pedal feel. If nothing is compressing in the set of components between the pedal and the brake disc, the pedal should be solid, regardless of what the tire does. If I'm reading that right, joecool should make chalk marks his tire and wheel, drive around a bit, and see if the marks still line up? How often is this really a problem? Anyway, my guess is squishy pads (and perhaps a proper bleeding) will have the highest probability of solving his pedal feel problem, for the least money. It worked for me (different car, but same principles). Link to comment Share on other sites More sharing options...
NSFW Posted January 7, 2007 Share Posted January 7, 2007 And BTW, thanks for humoring all of my questions. I learn a lot here, even when I ask dumb questions (see above!). Link to comment Share on other sites More sharing options...
turbo2nr Posted January 7, 2007 Share Posted January 7, 2007 sidewall flex has some slack too.. not to mention that just because you are on the binders doesnt mean the sidewalls and the rest of the tire stop spinning.. Brakes can only hold around 300 HP on my Buick....I launch at 15PSI and run 30PSI making 800HP eventually. I have never spun a tire on a rim. I seriously doubt any of you have brakes strong enough to spin a tire.....just not gunna happen. Even with race slicks! I pick up the front end, on a 3500lb car with foot wide slicks...no spin. I now run wheel rim screws as my program is getting pretty serious recently, and I don't want trouble. I also think tires have nothing to do with my poor brake feel. The pedal feels like it sinks, and I have to apply excess pressure. No lines or tires are gunna help that. I'm sure we all know when the tires are to blame. ABS gets triggered, squealing tires, etc. Link to comment Share on other sites More sharing options...
pdw Posted January 7, 2007 Share Posted January 7, 2007 Brakes can only hold around 300 HP on my Buick....I launch at 15PSI and run 30PSI making 800HP eventually. I have never spun a tire on a rim. I seriously doubt any of you have brakes strong enough to spin a tire.....just not gunna happen. Even with race slicks! I pick up the front end, on a 3500lb car with foot wide slicks...no spin. I now run wheel rim screws as my program is getting pretty serious recently, and I don't want trouble. I also think tires have nothing to do with my poor brake feel. The pedal feels like it sinks, and I have to apply excess pressure. No lines or tires are gunna help that. I'm sure we all know when the tires are to blame. ABS gets triggered, squealing tires, etc. He's talking about the whole wheel/tire combination spinning, as in rolling. Link to comment Share on other sites More sharing options...
Xenonk Posted January 7, 2007 Share Posted January 7, 2007 Brakes can only hold around 300 HP on my Buick....I launch at 15PSI and run 30PSI making 800HP eventually. I have never spun a tire on a rim. I seriously doubt any of you have brakes strong enough to spin a tire.....just not gunna happen. Even with race slicks! I pick up the front end, on a 3500lb car with foot wide slicks...no spin. I now run wheel rim screws as my program is getting pretty serious recently, and I don't want trouble. I also think tires have nothing to do with my poor brake feel. The pedal feels like it sinks, and I have to apply excess pressure. No lines or tires are gunna help that. I'm sure we all know when the tires are to blame. ABS gets triggered, squealing tires, etc. I wasnt talking about the tire spinning on the rim, Im just talking about the wrinkle wall effect. Easiest job to maybe fix this "squishy" brake problem is to just re-bleed the lines and put in better brake fluid. I think at the 2nd day of owning the car, I swapped out the silly stock fluid and ran on ATE super blue and Motul. I never had any complaints with the car because they stop fine and they are very predictable. I think this is just one of those car-to-car differences that people just need to learn how to deal with. Heck just the other day when I jumped into driving with a car with an automatic, I instinctively kept looking for the clutch pedal. My mind is programmed to look for the clutch. I think it's just the drivers that need to spend time with the car and learn the differences and make their own fine driving adjustments. Keefe Link to comment Share on other sites More sharing options...
pdw Posted January 7, 2007 Share Posted January 7, 2007 I wasnt talking about the tire spinning on the rim, Im just talking about the wrinkle wall effect. Easiest job to maybe fix this "squishy" brake problem is to just re-bleed the lines and put in better brake fluid. I think at the 2nd day of owning the car, I swapped out the silly stock fluid and ran on ATE super blue and Motul. I never had any complaints with the car because they stop fine and they are very predictable. I think this is just one of those car-to-car differences that people just need to learn how to deal with. Heck just the other day when I jumped into driving with a car with an automatic, I instinctively kept looking for the clutch pedal. My mind is programmed to look for the clutch. I think it's just the drivers that need to spend time with the car and learn the differences and make their own fine driving adjustments. I agree with you about bleeding the brakes but fluid will make zero difference in how the brakes feel assuming you're comparing brand new fluid. Better fluid gets you a better boiling point and maybe better longevity. Think about it. The fluid doesn't compress and therefore one fluid won't feel better than the other. Link to comment Share on other sites More sharing options...
xjoecool85x Posted January 9, 2007 Author Share Posted January 9, 2007 ooo ok i'll have to get that checked out and also try to figure out why my car isn't starting... damn battery prolly need to replace it:( and it's brand NEW..anyways if i bleed the brake lines and get new fluid will it work better and still keep the stock bridgestones Link to comment Share on other sites More sharing options...
Xenonk Posted January 9, 2007 Share Posted January 9, 2007 I agree with you about bleeding the brakes but fluid will make zero difference in how the brakes feel assuming you're comparing brand new fluid. Better fluid gets you a better boiling point and maybe better longevity. Think about it. The fluid doesn't compress and therefore one fluid won't feel better than the other. I gotta find that book that I was reading on hydraulics that "some" fluids are compressable as it can go through a physical change. http://www.newton.dep.anl.gov/askasci/chem00/chem00936.htm http://www.physlink.com/Education/AskExperts/ae15.cfm Keefe Link to comment Share on other sites More sharing options...
NSFW Posted January 9, 2007 Share Posted January 9, 2007 Far as I can tell, compressibility figures aren't disclosed by the manufacturers, nor are they a DOT standard, however DOT 5 (silicone) is widely held to be more compressible than DOT 3, 4, or 5.1 (glycol). Given that they're not disclused, I'm guessing they're all very, very close. Otherwise they'd give numbers (look how much better we are!) instead of just using weasel words like "low compressibility." (Lower than what?) If you switch fluids and get better response, that might be because the new fluid is better, or it might be because the old fluid has been contaminated by air and/or water. Unless you have compressibility figures for each, you'd pretty much need to compare two fluids back-to-back on the same car to minimize the variables. (I've heard people say of the same kind of thing about spark plugs - new plugs = better mileage, yay these plugs kick ass. But it's not because the new plugs are better, it's because the old plugs were turning to crap.) Link to comment Share on other sites More sharing options...
pdw Posted January 9, 2007 Share Posted January 9, 2007 Far as I can tell, compressibility figures aren't disclosed by the manufacturers, nor are they a DOT standard, however DOT 5 (silicone) is widely held to be more compressible than DOT 3, 4, or 5.1 (glycol). Given that they're not disclused, I'm guessing they're all very, very close. Otherwise they'd give numbers (look how much better we are!) instead of just using weasel words like "low compressibility." (Lower than what?) If you switch fluids and get better response, that might be because the new fluid is better, or it might be because the old fluid has been contaminated by air and/or water. Unless you have compressibility figures for each, you'd pretty much need to compare two fluids back-to-back on the same car to minimize the variables. (I've heard people say of the same kind of thing about spark plugs - new plugs = better mileage, yay these plugs kick ass. But it's not because the new plugs are better, it's because the old plugs were turning to crap.) Yeah, to determine if one fluid is truly better than another for braking feel, you need to compare in the same system that is both perfectly bled and use new fluid. Like I said, for braking feel, I seriously doubt Motul or whatever is any better than generic DOT4 bought at Autozone. If I were racing, I'd worry about the brand of brake fluid I used. For street use, pretty much any DOT4 is fine. Link to comment Share on other sites More sharing options...
f1anatic Posted January 9, 2007 Share Posted January 9, 2007 Tires and pads first. +1 on this recommendation Link to comment Share on other sites More sharing options...
Vimy101 Posted January 9, 2007 Share Posted January 9, 2007 I had a few misgivings about the stock brakes when I first got my Spec. because they didn't feel like my Infiniti's. However after about 15k of driving, I now think the stock set up is actually very good. I mentioned in some other thread that LGT brakes are like the clutch: they're great once you get used to them. Link to comment Share on other sites More sharing options...
sandwood Posted January 9, 2007 Share Posted January 9, 2007 I've had: stock brakes; stock brakes with ss lines and fluid; stock brakes with different pads, ss lines, and fluid; bbk with different pads, ss lines and fluid. fair number of combos. all these combos in both winter and summer rubber. imo, ss lines do not make as big a difference in braking FEEL as the pads. the pads make the biggest difference in feel, as some have said. tires don't make much if any difference in feel, although they change the feel of driving generally and of stopping distances in particular. I also was a bit disappointed that lines didn't make that much of a difference to the sponginess, but nonetheless you cd tell the difference. in fact, right now (briefly) i have 2 legacy gt's and one has stock brakes but ss lines, while the other is 100% stock. I slightly prefer the feel of the ss lines and it is a mod I wd do again. but pads first. getting out of the legacy game Link to comment Share on other sites More sharing options...
edmundu Posted January 9, 2007 Share Posted January 9, 2007 I agree with Sandwood on the SS lines. They are better, but not the 1st choice to improve the pedal/braking feel. I had the stock rubber lines on the Brembo's, and after adding SS lines, there was only a slight improvement, the lion's share of the improvement obviously, came from the caliper/pads. Which at the time were oem Sti pads. When fitted with Ferodo ds2500, the braking action was simply awesome! Link to comment Share on other sites More sharing options...
bdisco Posted January 9, 2007 Share Posted January 9, 2007 +1 SS Lines & Pads should be in the top 3 for Mods. Link to comment Share on other sites More sharing options...
praedet Posted January 9, 2007 Share Posted January 9, 2007 Air in the lines is probably about 60% of the sponginess, than about 30% the pads, and lastly about 10% the rubber lines... Motul RBF600 is "spongier" in feel than Prospeed. I have changed from one to the other in two different cars and that is just the truth. Fluid CAN effect feel. Ted Link to comment Share on other sites More sharing options...
pdw Posted January 9, 2007 Share Posted January 9, 2007 Air in the lines is probably about 60% of the sponginess, than about 30% the pads, and lastly about 10% the rubber lines... Motul RBF600 is "spongier" in feel than Prospeed. I have changed from one to the other in two different cars and that is just the truth. Fluid CAN effect feel. Ted You sure you properly bled it with the Motul in there? It's not like the glycol from one brand to another is THAT different and compressability would imply substantially different chemistries. Link to comment Share on other sites More sharing options...
praedet Posted January 9, 2007 Share Posted January 9, 2007 ^^^Yep I have put in the Motul RBF600 3 times in 1 car and 2 in the other. I ALWAYS bleed the system VERY well. The car that has had it 3 times doesn't even have ABS, so the ABS system can't be the culprit. The Motul RBF600 is a slightly different feel... Ted Link to comment Share on other sites More sharing options...
robinlsb Posted January 9, 2007 Share Posted January 9, 2007 ^^^Yep I have put in the Motul RBF600 3 times in 1 car and 2 in the other. I ALWAYS bleed the system VERY well. The car that has had it 3 times doesn't even have ABS, so the ABS system can't be the culprit. The Motul RBF600 is a slightly different feel... Ted Ted knows what he is talking about. I concur with his diagnosis:) "Belief does not make truth. Evidence makes truth. And belief does not make evidence." Link to comment Share on other sites More sharing options...
praedet Posted January 9, 2007 Share Posted January 9, 2007 Thanks Link to comment Share on other sites More sharing options...
NSFW Posted January 10, 2007 Share Posted January 10, 2007 Thanks, Ted. It's such a welcome change, to read first-hand experience with changing one variable at a time. Link to comment Share on other sites More sharing options...
praedet Posted January 10, 2007 Share Posted January 10, 2007 Your welcome Link to comment Share on other sites More sharing options...
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