Big Brake Kit Discovery

[wildcard]

This thread haz revolutions...

[yaris2010RS]

Originally Posted by Lil Abner

Actually, no. You are correct about the tires rotating different per mile depending on the diameter. But that doesn't apply to the rotors. The rotors will ALWAYS rotate at the same revolutions per mile as the tires!!! This is because the rotors are attached to the wheels. The wheels to the ground.

kinda true. the rotor center will spin at the same revolutions per mile as the tire but the speed of the rotor outer edge (the part that the pad hits) in relation to the pads themselves would be spining at a different speed then stock.

objects on the same shaft will have the same angular velocity but if they are different size they will have different linear velocity.

this is a tough subject seeing as the speed of the wheel is controlled by the shaft and the wheel on the road controls the speed (miles) at which the car is travelling.

you cannot use revolutions per mile to compare, my school website is down so i cant get to my notes or i would be able to tell you exactly what the linear velocity in relation to the brake pads would be.

[Lil Abner]

Yeah, that's what I posted earlier about the angular velocity compared to the linear at the rotor edge.

I'm sure the OP is wondering what happened to his thread. :-)

[yaris2010RS]

Originally Posted by Lil Abner

Yeah, that's what I posted earlier about the angular velocity compared to the linear at the rotor edge.

I'm sure the OP is wondering what happened to his thread. :-)

lol, atleast it didnt turn into an oil thread.... lol. everyone on YW kept themselves in check.

im excited to see how the new disks work out. maybe even some pics of them mounted. i would be very interested in a set as my rims look naked inside.

[Henry G.]

Seems like 10" discs brakes front AND back would fix the 2200 lb Yaris nicely...and kit for that?

[cdydjded]

Originally Posted by Lil Abner

Actually, no. You are correct about the tires rotating different per mile depending on the diameter. But that doesn't apply to the rotors. The rotors will ALWAYS rotate at the same revolutions per mile as the tires!!! This is because the rotors are attached to the wheels. The wheels to the ground.

You did not understand what I put. Obviously the tire & the rotor rotate the same revolutions. My point in using the tire calculator is cause you can use a taller tire or shorter tire which would apply to a rotor with a 12" diameter (taller) or 10" diameter (shorter). My point is no mater what it is a tire, a rotor anything with a circumference, the bigger it is the slower it rotates, the smaller it is the faster it rotates.

[Lil Abner]

Originally Posted by cdydjded

You did not understand what I put. Obviously the tire & the rotor rotate the same revolutions. My point in using the tire calculator is cause you can use a taller tire or shorter tire which would apply to a rotor with a 12" diameter (taller) or 10" diameter (shorter). My point is no mater what it is a tire, a rotor anything with a circumference, the bigger it is the slower it rotates, the smaller it is the faster it rotates.

I get what you're saying, I just think you're using the wrong terminology. No offense, so don't take this as me being a d**k. When you say "rotates faster" or "rotates slower" you're referring to angular velocity, or the RPM's.

Look at it like what a previous poster said. If something has a set angular velocity (let's say 2,000 rpm), then you can determine the linear velocity at different points away from the center. The linear velocity at a point away from the center is (omega) * (r). (Omega) is the angular velocity, (r) is the radius. Looking at that basic equation, the larger diameter has a larger linear velocity than the smaller diameter since (omega) remains constant.

Tires and the rolling diameter is a different can of peanuts because they are driven from the center and the outer diameter.

Again, I'm just trying to help confusion, and not be a blankity-blank.

[ilikerice]

after reading this post, i think i have just been mind raped...

[cdydjded]

Originally Posted by Lil Abner

I get what you're saying, I just think you're using the wrong terminology. No offense, so don't take this as me being a d**k. Again, I'm just trying to help confusion, and not be a blankity-blank.

I take no offence whats so ever with what you are saying. Im not like some people here that cant have civilize conversations without getting pissed. Its hard for me to explain what Im trying to say, and maybe Im am using the wrong teminology. My basic argument is that the larger the rotor the slower it spins. Think of this, on a supercharger, if you want more boost, you need to spin the S/C more & that is done with a smaller pulley. If you want less boost you run a larger pulley.

[Lil Abner]

Originally Posted by cdydjded

I take no offence whats so ever with what you are saying. Im not like some people here that cant have civilize conversations without getting pissed. Its hard for me to explain what Im trying to say, and maybe Im am using the wrong teminology. My basic argument is that the larger the rotor the slower it spins. Think of this, on a supercharger, if you want more boost, you need to spin the S/C more & that is done with a smaller pulley. If you want less boost you run a larger pulley.

I get what you are saying and thinking about. But you're thinking it the wrong way still. See, tires and pulleys have a relationship between the outer diameter and the inner shaft. A large tire/pulley having a linear speed of 15 feet/sec will have a slow angular velocity (revolutions per minute). A small tire/pulley with the same 15 feet/sec will have a LARGER angular velocity. So yes, you are 100% correct with all of that.

However, a rotor is totally different. It's not driven by the outer diameter, and the outer diameter doesn't DO anything to the system like a pulley (belt driven) or tire (road driven).

Umm, do you have a ceiling fan at home? If so, try this. Turn the fan on low so you can see the blades spinning. Lay on your back, and look up. Point your finger at the inner tip of the blades. Move your finger to follow the blades as you watch it with your eye (sorry, close one eye). Notice how your finger/hand is moving slowly to keep up. Now follow a point on the outer tip of the blade. If you're doing it right, your hand should be moving a lot faster to keep your finger on that point.

Another way to try it is a merry-go-round. Standing close to the center, you can notice you don't feel like you're spinning very fast. But when you go to the outer edge, you can tell you are spinning a lot faster.

I can understand the confusion, I honestly can. When I took classes on this stuff, I could see people getting confused until they ran some numbers or played with toys or something. I'm an engineer with over 3 years experience designing transmissions. Hopefully I've helped some. I agree, I hate people on forums who get pissed and yell. So I appreciate you not yelling at me.

[seth_man]

Originally Posted by Lil Abner

Yeah, that's what I posted earlier about the angular velocity compared to the linear at the rotor edge.

I'm sure the OP is wondering what happened to his thread. :-)

lol, no not really, its good conversation and some valid points. i know not everyone understands the math behind angular and linear velocity so carry on.

yes i am also glad it hasnt turned into an oil thread yet

i know the hub bores are not the same size and i measured the play in the stud holes and the rotor can only move .003 in any direction and .oo3 off center doesnt bother me.

its been raining here for a few days but ill try to get some more pics tomorrow, they do fill the wheel up nicely.


as for brake function at slower speeds just cruising around town they feel stock, but at higher speeds and pedal effort it stops, it stops very well. i cannot really quantify it or anything but i can say it stops alot faster when you need to, i will still have to see how the next track day goes but as of right now i have to say best upgrade thus far

[yaris2010RS]

how much was the kit? and i am more worried about the wheel feeling off balance because of the .003 (inch) give of play

[mazilla]

TAG

[seth_man]

Originally Posted by yaris2010RS

how much was the kit? and i am more worried about the wheel feeling off balance because of the .003 (inch) give of play

ive had it sitting around, took it off a ctr that we put stock brakes back onto to run smaller wheels, owner didnt want them back.

i was looking around and ive seen used kits for sale on honda forums for $100-$200.

ive already had it on the highway and various speeds up to 90 and no vibrations. so balance doesnt seem to be an issue

[bobolinko]

If the Calipers mount at the same points or at the same distance from the Axle Center, there is no difference in the braking at all, so nothing changes except the size of the rotors.... That'd be absolutely pointless... Hope the Caliper mounts are away from stock, and SECURE. Just my 2cents...

[PHXDEMON]

So what gen civic was the BBK off of?

[Viperoni]

The extra rotor diameter will at least give you more mass to absorb heat and more surface area to sink it away. Useful in racing.

[mazilla]

Where's the OP with a final review, how are things holding up so far?