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12-08-2012, 07:24 PM | #501 |
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12-14-2012, 12:19 AM | #502 |
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Hi, I haven't been on here a lot in a couple years and just stumbled on this thread.
Great write-up, curious to see some of the posts in the 21 or so pages. I agree with the 1st post, 100%. For street use, most brake systems are perfectly fine UNLESS you really don't know how to use them. Yes, tires (and proper inflation....) make a bigger difference. Not carrying around lots of extra weight also helps....all other things being equal. I run basically stock brakes (rotors were replaced at one point, nothing special) with SS lines and nice semi-metallic pads. Yes, I can get brake fade. Usually that is either: -Running in the hills -Driving waaayyyyyy too fast on public roads The pads I run have a consistent feel. The SS lines improve the SYSTEM a bit since the 1998 ABS systems had a strange pulse that rubber lines aggravated. The SS lines changed the pulse frequency which helped. I learned to drive in a 1968 Plymouth Fury III with a small V-8, bias ply tires and 4 wheel drum brakes. You LEARNED to manage brakes to help fight fade. I like others that run some BBK's. They added rotational mass (hurts performance) and weight on the wrong end of the springs (which hurts handling). It helps even out the performance. LOL. |
12-16-2012, 02:55 PM | #503 |
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Thank you for the post! It seems to be such a common misconception. Brembos sure look nice thought!
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12-22-2012, 12:30 AM | #504 |
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Best source of info I've found so far : ) Thanks!
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12-22-2012, 05:56 PM | #505 |
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Vehicle:2013 WRX Hatchback Dark Grey |
I Know a little about brakes
I didn't read anything in the otherwise brilliant post about ABS brakes. We aren't talking about systems that lock up so there might still be something to the increased surface areas of larger rotors.
But, with that said, I once made a full pass in an 11 second Chevy II with original drum brakes on all 4 corners. Very Scary and dodgy but I didn't die! |
12-23-2012, 12:25 AM | #506 | |
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Quote:
The system that we are discussing doesn't include the tire and road interface. The brakes locking are an ideal condition for a system where an idealized rotational mass is being studied. In this situation the important forces involved are between the disk and the brake pad. The force equations here are actually less dependent on brake pad contact area than they are on brake pad material. Which would indicate that as long as the stock brakes are using a sufficient material they should do the same job (on the first stop) as the more expensive brakes. They will be much less fade resistant than better brakes because of the geometry of the brake interface, but that is another story. There are just too many variables to account for if you look at the whole system while simply comparing brake capability. ABS actually plays an important role in stopping the car, but it doesn't factor into the comparison of actual brakes. |
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12-25-2012, 01:07 PM | #507 |
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good post
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01-11-2013, 03:51 PM | #508 | |
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well said
well said but lines pads rotors are very important
Quote:
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01-11-2013, 05:13 PM | #509 |
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I'm just going to keep quoting this line since it makes me laugh my ass off no matter how many times I read it:
"BUT MY BUDDY PUT BREMBOS ON HIS WRX WITH WTFBBQ ALLOY PADS, SUPERBUTTSEKS INCREDITAINIUM LINES AND CHUCK NORRIS BRAND FLUID AND IT STOPS WAY HARDER." |
01-16-2013, 10:51 AM | #510 |
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Great post (even though I'm commenting years later), I just picked up an 06 WRX wagon so I've been going through all the stickys; I've owned many vehicles in my 29 years (mostly Fords, it's OK though I'm wearing my Flame-Proof suit); example vehicles and brake "upgrades"
1966 Mustang - 4 wheel drum, went to front disc to reduce fade (also the springs inside the drum fell apart a lot) - this car is under the knife again, I want to turn it into an open track vehicle, so thats a whole other ball of wax. 1992 Mustang 5.0 - disc/drum - swapped SN95 rotors & calipers in front because the fade was evident on the stock brakes in normal driving conditions (well normal teenager driving conditions) also I ran wider tires that were quite sticky. 1993 Impreza - disc/drum, 1.8L FWD Auto - it had 14" rims so you can imagine how small the factory discs were, I replaced front axles more often than I replaced front brakes, great little car minus the axle chewing issue, used the cheapest brakes I could find, fade was never evident (no upgrade). 2003 SVT Focus - disc/disc brakes were massive, went to centric "premium rotos" because the rim/hub conact points were anodized and I ran a summer & winter set so I swapped wheels a lot, I should note I did front brakes at 75k and rears at 98k; that car was easy on brakes 2002 Honda CBR F4i - EBC HH pads and stainless lines adjustable levers - pads were for track days, lines were for better lever feel (bike had really long rubber lines) adjustable levers were because the stock brake lever was uncomfortable 2007 Toyota Yaris (my wifes car) disc/drum - centric "premium" rotors - she has a winter set and a summer set, the anodized contact points make it easier to swap wheels. I only did her fronts at 60k miles, and the pads had plenty of life, that car is easy on brakes too, I pulled the drums apart and the shoes look brand new still I've owned an 88 and a 93 F-150 (disc/drum) , 2002 Explorer (disc/disc), 88 Buick regal (dont even know what it had for brakes) all of them have had enough braking power and I never noticed fade, even when I over-loaded my 93 F-150 to the point of blocking the rear suspension to keep the wheel wells off the rear tires. With the exception of the mustangs (sub-standard brakes) and the motorcycle (intended track use) I have found no reason to upgrade brakes, with the WRX, since its my DD, I will most likely stick with stock pads and fluid, maybe do centric rotors for the anodized surface, but I don't think these brakes for DD use will need an upgrade. Unrelated but related - "AWD is soo much better in the snow" FALSE! AWD gets you moving in the snow but doesnt do dimp to help you stop or handle; its your freaking TIRES! |
01-25-2013, 02:27 PM | #511 |
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thanks for the help, blowing through these stickies is helping a ***** ton
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02-01-2013, 03:15 PM | #512 |
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Good post OP, but....
"Well, as we have established, the grip of the tire on the road is the ultimate determining factor, so you want wider and or stickier tires. Preferably, both"
Stickier tires yes indeed, but as far as stopping distance goes width is not a factor AT ALL (goes for surface area in a braking system as well), unless you were talking fade, which you clearly were not. With regards to stopping distance and friction force there are two different coefficients of friction, static and dynamic. Static friction is when there is no slippage between the two friction surfaces (tire and road in this case). Dynamic friction is when there is slippage between surfaces (i.e., lockup situation). With any two friction surfaces being the same, the coefficient of static friction is always greater than the coefficient of dynamic friction. That is why ABS is so good. It keeps the road and tire in a state of static friction, rather than dynamic. Think of putting a piece of wood (or anything else for that matter) on a flat surface and slowly raising one end of it to create an angle. You will be able to get that angle pretty steep before the wood begins to slide. Once it starts to slide you will have to decrease the angle dramatically to get the wood to stop moving. That is the static/dynamic coefficients of friction at work in a physical application that anyone can test themselves. It is always the case no matter what two friction surfaces you are talking about. Always. The equation for friction force is: (friction force)=(coefficient of friction) times (normal "vertical" force) That is it. Notice there is no variable for surface area anywhere in that equation because the surface area does not matter. Sticky tires just increase that coefficient of static/dynamic friction. Ever wonder how a locomotive can pull such huge loads on knife edges that are the steel wheels and tracks? The coefficients of friction are poor with steel on steel, but the normal force is massive. Other than this slight oversight, your OP is spot on regarding everything else. I am happy to be able to clear this up and add to a wonderful discussion. Signed, Old egg-headed engineer that loves him some good physics talk Last edited by Hoon Goon; 02-01-2013 at 03:23 PM. Reason: Didn't do the quote thing right, but oh well. |
02-01-2013, 05:40 PM | #513 |
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So if stopping a vehicle is negative acceleration, and width of tires don't matter when it comes to negatively accelerating, then why does a wider contact patch matter so much during positive acceleration?
I am not trying to be rude or argue...I am just curious why in drag racing, road racing, etc., wider and stickier is better than skinnier and stickier. I feel that if you were correct, then every race car out there would be buying 165 width slicks instead of tires twice that width because the extra width is only gaining them weight instead of grip. It just seems to me that you are missing a variable in your equation somewhere... |
02-01-2013, 10:44 PM | #514 |
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Tires are a somewhat special case in the frictional force world. Here is an interesting article that explains why a wider tire (and therefore surface area) is better for stopping:
http://www.physics.sc.edu/~rjones/ph...efriction.html The basic premise is that the tire road surface is not an idealized coefficient situation. The tire has the ability to shear at the contact point with the road and therefore the wider the tire the more shear resistance is available. There are also deformation issues based on road conditions. If the road was extremely flat and the tire shear issue was solved then surface area wouldn't affect the situation as much (or at all). |
02-06-2013, 09:33 PM | #515 |
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Op is saying all we need for a brake upgrade it this,
http://www.ebay.com/itm/3D-SILVER-BR...item2a28c58eaf |
02-06-2013, 10:08 PM | #516 |
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nice point so i guess the only point upgrading your brakes is by going faster than the factory top speed but who goes faster than that on a daily basis anyway so i guess upgrading your brakes is till useless
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02-10-2013, 09:32 PM | #517 | ||
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Quote:
Quote:
****NOTE FELLOW NASIOCers: A GUY JUST ADMITTED HE WAS WRONG***** I am a hydraulics/hydrology guy, but I still love the cars and thinking about this stuff! |
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02-14-2013, 01:30 PM | #518 |
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Awesome article and great refresher as I'm getting back into the hobby (been driving a Yaris for 2 years now, shoot me! - waiting on a new STI now)
I'm surprised how many people don't realize this though! 18x10s here we come! :-D |
02-28-2013, 06:21 PM | #519 | |
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Quote:
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03-14-2013, 11:29 PM | #520 | |
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help please
2013 New Impreza sport 5 speed noises
Ok, So Id like some advise. Dealer changed factory oil at 1k miles per their recommendation to remove break in metal etc deposits they billed me and serviced the vehicle with 0w20 oil synthetic subaru oil. The car had a moderate engine clacking noise, but now after the oil change its significantly louder, to the point i can hear it under acceleration even with the radio on, and on decel its loud as heck too. This is my first Roo, and need advise. I truly love everything else about this functional and fun car, but none of my previous 16 cars have ever had these noises (not that can be heard like this) and they have all been used. Thanks. Quote:
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03-22-2013, 05:22 PM | #521 | |
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Seriously?
Quote:
Dafuq does this have to do with the original post? |
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03-22-2013, 05:42 PM | #522 |
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^^not to mention he quoted the entire original post... it's wrong in so many ways
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03-22-2013, 06:53 PM | #523 |
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Haha, right! I'm scrolling and scrolling, aaaand scrolling down expecting to read another argument for why big brakes are absolutely necessary for street cars and instead -he's got a ticking noise...?!? WTF?
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03-26-2013, 06:28 AM | #524 |
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Excellent write up
Very informative . |
04-30-2013, 01:19 AM | #525 |
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agreed
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