# geek question!!! brake angle



## SR20dee (May 1, 2002)

sorry if this is a repost for any one

I was wonder what the affects of seting up brake calipers at different particular axis's of the rotor does. 

i note that alot of larger cars use the same calipers but at a different orientation. 


such as a l31 altima and a b15 sentra.. 


does this affect force.... thoughts.. nerdyness.. engineers?

im curious as hell. id usually ask sarah but she said not to  LOL


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## Greg200SE-R (Feb 5, 2003)

SR20DEe said:


> sorry if this is a repost for any one
> 
> I was wonder what the affects of seting up brake calipers at different particular axis's of the rotor does.
> 
> ...


The pistons should provide the same force whether the calipers were centered at 10 o'clock, 2 o'clock or even at the bottom. 

I would think that caliper size and clearance (between the brakes and suspension components for example) and things like brake line routing or mounting strength would influence caliper positions more.

Soundsl like Sarah has good brakes too.


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## SR20dee (May 1, 2002)

I will note one difference i note from being an experianced B15 owner.. the RTR world challenge car has the brake caliper between the 180 and 20 axxis.. why bother changing the the axis from its 90-180 axis postion??


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## SR20dee (May 1, 2002)

BUMP! damn memorial day weekend


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## ReVerm (Jan 13, 2003)

SR20DEe said:


> I will note one difference i note from being an experianced B15 owner.. the RTR world challenge car has the brake caliper between the 180 and 20 axxis.. why bother changing the the axis from its 90-180 axis postion??


Why not ask them?

The reasons that come to mind would be packaging (space constraints) and cooling. Depending on the car, it's easier to control the airflow over, under, and through the brakes when the caliper is positioned a certain way.


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## SR20dee (May 1, 2002)

ReVerm said:


> Why not ask them?
> 
> The reasons that come to mind would be packaging (space constraints) and cooling. Depending on the car, it's easier to control the airflow over, under, and through the brakes when the caliper is positioned a certain way.


I did... the pit guy's answer was lower center of gravity and its just alot easier to install that way  LOL



I do like the notion you brought up about air flow.


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## ReVerm (Jan 13, 2003)

SR20DEe said:


> I did... the pit guy's answer was lower center of gravity and its just alot easier to install that way  LOL


Haha. Hey, it all makes sense though, especially considering how much calipers weigh and the importance of ease of install/removal/replacement at the track.


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## SR20dee (May 1, 2002)

ReVerm said:


> Haha. Hey, it all makes sense though, especially considering how much calipers weigh and the importance of ease of install/removal/replacement at the track.


yeah but the comment about lower center of gravity was ammusing simply becuase they are brembo calipers.. and should allready be light weight 

but easier to get at in a jam is correct. from the looks of the lowering job.. it looks like it would be alot easier to get at from the bottom. 


I still think there is something more to the angles on brake calipers.. SUVs usually have them on the back side or bottom. some cars have them on top. 

thanks for your inputs man


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## SR20dee (May 1, 2002)

bump happy tuesday


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## SR20dee (May 1, 2002)

bump 1 week later.. is there any one worth a damn on this site?


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## chimmike (Oct 17, 2002)

SR20DEe said:


> bump 1 week later.. is there any one worth a damn on this site?



If b15sentra.net was so good, you'd be asking there, no?


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## SHigSpeed (Apr 30, 2002)

SR20DEe said:


> bump 1 week later.. is there any one worth a damn on this site?


No need to bump-bump! :^) 

From a purely braking efficacy standpoint (not including heat dissipation concerns), the orientation of the caliper has no effect. However, for purposes such as center of gravity which has been mentioned as well as bleeding issues, it does make a difference. The bleed port has to be the highest part of the caliper or else there'd be no way to get all the air out hence most calipers (especially multi-piston jobbers) end up vertical either leading or trailing. 

-SHig


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## morepower2 (Apr 19, 2002)

SR20DEe said:


> sorry if this is a repost for any one
> 
> I was wonder what the affects of seting up brake calipers at different particular axis's of the rotor does.
> 
> ...


There is some advantage to them being behind the steering axis on the front wheels, it slightly helps the centering torque but the effect is very small on a car.

The main thing is that the bleeder screws be perfectly upright so the calipers can be bled effectivly, or to insure that the bleeder is at the highest part of the caliper.

Mike


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## SHigSpeed (Apr 30, 2002)

morepower2 said:


> There is some advantage to them being behind the steering axis on the front wheels, it slightly helps the centering torque but the effect is very small on a car.
> Mike


Mike,

How does the orientation of the caliper about the axis of the rotor affect steering centering torque? The caliper is essentially solid with the upright so I'm having a hard time visualizing how the location of the force path affects anything...

Thanks!

-SHig


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## SR20dee (May 1, 2002)

now this is more like it


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## morepower2 (Apr 19, 2002)

SHigSpeed said:


> Mike,
> 
> How does the orientation of the caliper about the axis of the rotor affect steering centering torque? The caliper is essentially solid with the upright so I'm having a hard time visualizing how the location of the force path affects anything...
> 
> ...


Because it hangs under the caster line.

Mike


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## SHigSpeed (Apr 30, 2002)

morepower2 said:


> Because it hangs under the caster line.
> 
> Mike


I guess I still can't visualize. I can see why outside forces under the caster line (such as road inputs on the tire) will add to centering torque, but the forces that the caliper exerts on the rotor is completely internal to the system.

Here's an experiment that might bear this out? Take a car and put it on jackstands and crank the wheel full lock. Put it in gear and get the wheels spinning. Are you saying that by applying the brakes the steering should center (assuming a trailing caliper)?

Later,

-Scott


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## morepower2 (Apr 19, 2002)

SHigSpeed said:


> I guess I still can't visualize. I can see why outside forces under the caster line (such as road inputs on the tire) will add to centering torque, but the forces that the caliper exerts on the rotor is completely internal to the system.
> 
> Here's an experiment that might bear this out? Take a car and put it on jackstands and crank the wheel full lock. Put it in gear and get the wheels spinning. Are you saying that by applying the brakes the steering should center (assuming a trailing caliper)?
> 
> ...


No its the torque of the mass of the caliper sitting there, the same reason why they often locate motorcycle calipers there. Hardly makes any difference on a car.


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## James (Apr 29, 2002)

I don't really understand the geometry yet but you're saying that the weight of the caliper under the castor line creates a slight (SLIGHT) moment about the ball joint so in a hard turn where the pneumatic trail would approach zero the moment of the caliper would help increase the self-centering torque and not let the tire break away correct?


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## SHigSpeed (Apr 30, 2002)

morepower2 said:


> No its the torque of the mass of the caliper sitting there, the same reason why they often locate motorcycle calipers there. Hardly makes any difference on a car.


Oh MAN! That makes sense, but yeah, like you said, hardly makes a difference (unless you have 50 lb calipers and 45 degrees of positive caster).

Thanks for clearing that up.

-SHig


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## SR20dee (May 1, 2002)

nice nice !! thanks alot guys


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