Big Brake Kit Discovery - Toyota Yaris Forums

seth_man · 04-22-2011, 07:25 PM

well i had some extra time at the shop and decided to try something out just for s&g's. i discovered that the AEM big brake kit for civics BOLTS ON to the yaris. NO Cutting, Drilling, Cursing or Modifying to bolt them on. 12" rotors and they fit under my 16" wheels. i did have to clearance the front top of my caliper .010" or so to have a little clearance for my stick on wheel weights.

What you will need:

1. 7mm Spacer to go between Stock Yaris caliper bracket and caliper extension bracket that comes with the brake kit

2. Longer Bolts I used 12mmx1.25mmx50mm bolts instead of the stock caliper bracket bolts

3. Nothing else

wildmongoose26 · 04-22-2011, 07:41 PM

What all is included in said kit? The bracket for the caliper and the rotor and thats it?

Brent

seth_man · 04-22-2011, 07:45 PM

yeah, rotor, bracket, a few bolts

Flipper_1938 · 04-22-2011, 10:48 PM

So, how much better is the braking with a bigger rotor and stock caliper?

cali yaris · 04-22-2011, 11:08 PM

^ good question. You have the same caliper/pad operating on a rotor that is now spinning faster. Braking might be worse, not better. It will definitely be hotter.

Overall though, very neat idea.

yaris2010RS · 04-22-2011, 11:48 PM

very nice...... this seems like a less expensive way to get a bigger brake look on aftermarket rims....

if only have a rear disk kit with less work....

krusty · 04-23-2011, 12:38 AM

Quote:

Originally Posted by cali yaris

^ good question. You have the same caliper/pad operating on a rotor that is now spinning faster. Braking might be worse, not better. It will definitely be hotter.

Overall though, very neat idea.

How would the rotor be turning faster with a bigger diameter rotor?

cali yaris · 04-23-2011, 02:04 AM

If you think about it, at the perimeter, a larger diameter "circle" has to travel faster to achieve one revolution as a smaller circle. The outside of a larger rotor is where the pad contacts it. I'm armchair discussing here, but I do know the friction would be greater to slow the velocity, causing more heat.

And all of that might not make a huge difference. Let's hear the OP's review!

Spahrticus · 04-23-2011, 05:44 AM

I just see stock pads being chewed up...

seth_man · 04-23-2011, 07:45 AM

Quote:

Originally Posted by cali yaris

^ good question. You have the same caliper/pad operating on a rotor that is now spinning faster. Braking might be worse, not better. It will definitely be hotter.

Overall though, very neat idea.

well first track day will be next sunday so i will find out. feels pretty good driving around town though.

Quote:

Originally Posted by Spahrticus

I just see stock pads being chewed up...

some hawk pads are on the way

eTiMaGo · 04-23-2011, 08:11 AM

Quote:

Originally Posted by cali yaris

If you think about it, at the perimeter, a larger diameter "circle" has to travel faster to achieve one revolution as a smaller circle. The outside of a larger rotor is where the pad contacts it. I'm armchair discussing here, but I do know the friction would be greater to slow the velocity, causing more heat.

And all of that might not make a huge difference. Let's hear the OP's review!

That's true, but it's my understanding that the main advantage of larger rotors is to have more mass and surface area to dissipate heat from braking, so the temperature increase you mentioned may be canceled out.... food for thought! (and google searches

)

Lil Abner · 04-23-2011, 09:58 AM

You will still have the same angular velocity (rpms), but the tangential velocity at the outer diameter IS bigger (faster). However, you need to look at the main benefit of this system. The larger diameter of the rotor, and the pad being further away from the center INCREASES the torque the brakes can apply. Torque equals F X D (force times distance). So you should notice an improvement. As far as heat, I don't see that as a problem. Sure, aftermarket pads will help, but the stocks should work for now (unless you track the car).

Kongo-Otto · 04-23-2011, 10:18 AM

Centering the disc should be done by the hub not by bolts. And of course i would never modifiy a brake caliper this way.

Atleast in Europe that kind of engineering is strictly forbidden.

Lil Abner · 04-23-2011, 10:21 AM

Quote:

Originally Posted by Kongo-Otto

Centering the disc should be done by the hub not by bolts.

That's a good point. I didn't see that when I first looked. Some rings to center the rotor might be a smart thing to do.

cfeng · 04-23-2011, 01:35 PM

Quote:

Originally Posted by cali yaris

If you think about it, at the perimeter, a larger diameter "circle" has to travel faster to achieve one revolution as a smaller circle. The outside of a larger rotor is where the pad contacts it. I'm armchair discussing here, but I do know the friction would be greater to slow the velocity, causing more heat.

And all of that might not make a huge difference. Let's hear the OP's review!

There are considerations necessary for matching a brake pad to a rotor. Usually, the inner diameter of the surface that the pad touches is 58% of the outer diameter, in order to achieve greatest braking torque.

RedRide · 04-23-2011, 06:24 PM

Consided a caliper brake on a bicycle.
You need relatively little caliper pressure on the rim as compared to the pressure you would need if it was close to the hub.
It's just basic physics.

cdydjded · 04-23-2011, 10:06 PM

Quote:

Originally Posted by cali yaris

^ good question. You have the same caliper/pad operating on a rotor that is now spinning faster. Braking might be worse, not better. It will definitely be hotter.

Overall though, very neat idea.

I think you might be confused on this one. The larger the rotor the less it rotates per mile, the smaller the more it rotates per mile. Think of tire sizes. A 205/40/17 has a diameter of 23.46" & rotates 859.80 per mile. A 205/50/17 has a diameter 25.07" & rotates 804.44 per mile. as you can see the taller tire has less revolutions. Here is a link: http://www.gtsparkplugs.com/TireCalculator.html

Lil Abner · 04-23-2011, 10:09 PM

Quote:

Originally Posted by cdydjded

I think you might be confused on this one. The larger the rotor the less it rotates per mile, the smaller the more it rotates per mile. Think of tire sizes. A 205/40/17 has a diameter of 23.46" & rotates 859.80 per mile. A 205/50/17 has a diameter 25.07" & rotates 804.44 per mile. as you can see the taller tire has less revolutions. Here is a link: http://www.gtsparkplugs.com/TireCalculator.html

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.

04-22-2011, 07:25 PM	#1
seth_man View User's Garage Drives: 08 Liftback Join Date: Oct 2008 Location: Thompson, CT Posts: 159	Big Brake Kit Discovery well i had some extra time at the shop and decided to try something out just for s&g's. i discovered that the AEM big brake kit for civics BOLTS ON to the yaris. NO Cutting, Drilling, Cursing or Modifying to bolt them on. 12" rotors and they fit under my 16" wheels. i did have to clearance the front top of my caliper .010" or so to have a little clearance for my stick on wheel weights. What you will need: 1. 7mm Spacer to go between Stock Yaris caliper bracket and caliper extension bracket that comes with the brake kit 2. Longer Bolts I used 12mmx1.25mmx50mm bolts instead of the stock caliper bracket bolts 3. Nothing else

04-22-2011, 11:08 PM	#5
cali yaris ULTIMATE View User's Garage Drives: 07 Yaris Turbo Join Date: May 2007 Location: Canoga Park, CA Posts: 14,859	^ good question. You have the same caliper/pad operating on a rotor that is now spinning faster. Braking might be worse, not better. It will definitely be hotter. Overall though, very neat idea. __________________ Micro Image forums, online store and shop are now closed. It was a great eight year run, but it was time to focus on other things. I'm still selling parts on eBay under micro*image seller ID and customers can still make requests for anything specific.

04-22-2011, 11:48 PM	#6
yaris2010RS View User's Garage Drives: no-longer-boosted '10 Yaris Join Date: Nov 2009 Location: Angus, Ontario Posts: 1,891	very nice...... this seems like a less expensive way to get a bigger brake look on aftermarket rims.... if only have a rear disk kit with less work.... __________________ If it has boobs or wheels sooner or later your gonna have problems with it

04-23-2011, 02:04 AM	#8
cali yaris ULTIMATE View User's Garage Drives: 07 Yaris Turbo Join Date: May 2007 Location: Canoga Park, CA Posts: 14,859	If you think about it, at the perimeter, a larger diameter "circle" has to travel faster to achieve one revolution as a smaller circle. The outside of a larger rotor is where the pad contacts it. I'm armchair discussing here, but I do know the friction would be greater to slow the velocity, causing more heat. And all of that might not make a huge difference. Let's hear the OP's review! __________________ Micro Image forums, online store and shop are now closed. It was a great eight year run, but it was time to focus on other things. I'm still selling parts on eBay under micro*image seller ID and customers can still make requests for anything specific.

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04-22-2011, 07:41 PM	#2
wildmongoose26 Drives: 09 5dr Yaris Join Date: Mar 2009 Location: Dallas, TX Posts: 443	What all is included in said kit? The bracket for the caliper and the rotor and thats it? Brent

04-22-2011, 07:45 PM	#3
seth_man View User's Garage Drives: 08 Liftback Join Date: Oct 2008 Location: Thompson, CT Posts: 159	yeah, rotor, bracket, a few bolts

04-22-2011, 10:48 PM	#4
Flipper_1938 Drives: 2010 Yaris Sedan Join Date: Oct 2010 Location: Kentucky Posts: 529	So, how much better is the braking with a bigger rotor and stock caliper?

04-23-2011, 05:44 AM	#9
Spahrticus Drives: ///M3, Yaris Join Date: Dec 2010 Location: Chehalis Posts: 22	I just see stock pads being chewed up...

04-23-2011, 09:58 AM	#12
Lil Abner Drives: 2009 3dr LB Manual Join Date: Mar 2010 Location: Dublin, Ohio Posts: 412	You will still have the same angular velocity (rpms), but the tangential velocity at the outer diameter IS bigger (faster). However, you need to look at the main benefit of this system. The larger diameter of the rotor, and the pad being further away from the center INCREASES the torque the brakes can apply. Torque equals F X D (force times distance). So you should notice an improvement. As far as heat, I don't see that as a problem. Sure, aftermarket pads will help, but the stocks should work for now (unless you track the car).

04-23-2011, 10:18 AM	#13
Kongo-Otto Drives: '09 Yaris & '10 Auris Join Date: Apr 2009 Location: Germany Posts: 268	Centering the disc should be done by the hub not by bolts. And of course i would never modifiy a brake caliper this way. Atleast in Europe that kind of engineering is strictly forbidden.

04-23-2011, 06:24 PM	#16
RedRide Drives: '09 Yaris carmine red 2d HB Join Date: Jun 2009 Location: Middletown, NY Posts: 1,501	Consided a caliper brake on a bicycle. You need relatively little caliper pressure on the rim as compared to the pressure you would need if it was close to the hub. It's just basic physics.