# Difference between front and rear brake calipers



## BillWeg (Dec 4, 2006)

Forgive me if this seems obvious, but my bike has mechanical brakes and I have no experience with the hydraulics. I've noticed that the hydro calipers are usually sold as Front or Rear. Is there a difference between them? 

I ask because I run my brake levers reversed (front brake to right lever). This is not a problem with my mechs, but with a hydro caliper I dont know if i will encounter problems. what will happen if I attach the "rear" hydro caliper in the front?


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## dru (Sep 4, 2006)

I think it is usually because of the hose length. Also the adapters for the standard mounts are different in some cases. I have a set of Deore 555's and they are identical except for hose length. The 555's are direct fit to the iso standard mounts and use shims for fine tuning their positioning.

Drew


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## anotherbrian (Mar 18, 2005)

BillWeg said:


> Forgive me if this seems obvious, but my bike has mechanical brakes and I have no experience with the hydraulics. I've noticed that the hydro calipers are usually sold as Front or Rear. Is there a difference between them?
> 
> I ask because I run my brake levers reversed (front brake to right lever). This is not a problem with my mechs, but with a hydro caliper I dont know if i will encounter problems. what will happen if I attach the "rear" hydro caliper in the front?


The position of the disc tabs, relative to the wheel axis, is different front to rear. A disc caliper that fits a 160mm rotor on the rear, will fit a larger (180mm?) rotor if mounted in the front.

Hope sells their brakes with a reversed lever option ("UK" models on some online sites).

You could always swap the hydro hoses yourself. Some systems are easier than others, and if you can't do the work yourself I'm sure a shop could.


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## BillWeg (Dec 4, 2006)

anotherbrian said:


> The position of the disc tabs, relative to the wheel axis, is different front to rear. A disc caliper that fits a 160mm rotor on the rear, will fit a larger (180mm?) rotor if mounted in the front.
> 
> Hope sells their brakes with a reversed lever option ("UK" models on some online sites).
> 
> You could always swap the hydro hoses yourself. Some systems are easier than others, and if you can't do the work yourself I'm sure a shop could.


But if I am planning to run 160mm on both wheels, would the "front" and "rear" calipers matter? Or can I just pick any one caliper at random and put it in front?

Also, I have a set of XT hydro brakes here, but I have no way of telling which one is "rear" and which one is "front". They look exactly the same, and are not labled as "front" or "rear". How can I find out which one is the "rear"?

Thanks!


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## Speedub.Nate (Dec 31, 2003)

anotherbrian said:


> A disc caliper that fits a 160mm rotor on the rear, will fit a larger (180mm?) rotor if mounted in the front.





BillWeg said:


> But if I am planning to run 160mm on both wheels, would the "front" and "rear" calipers matter? Or can I just pick any one caliper at random and put it in front?
> 
> Also, I have a set of XT hydro brakes here, but I have no way of telling which one is "rear"...


Bill, what Brian was saying is that if you remove a caliper + adapter from a rear 160mm application and bolt it to the fork, it's going to fit a 180mm rotor.

Most manufacturers make one interchangable caliper, and a handful of adapters to make the caliper fit various front and rear applications and rotor sizes. Your XT caliper is fine either front or rear; you just need to make sure you've got the right combination of adapter and rotor diameter to make it work where you want it to.


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## BillWeg (Dec 4, 2006)

Thanks Speedub and everyone else! I now have the conception sorted out! So essentially, the calipers are the same, just the adapters are different.


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## anotherbrian (Mar 18, 2005)

Generally (and apparently in your case), that is true.

Hope hydraulic brakes have not used adapters in the past though, instead having a range of caliper sizes to which the appropriate (based on it being used front or back) rotor is matched.


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## oldskoolbiker (Jun 2, 2005)

Bill,

Yes the calipers are the same, but the adapters are different. However that is really a non issue for you. You stated you like to have your brakes moto style (i.e., reversed). If you buy a new set of brakes you will need to do one of the following.

1) Buy hayes brakes. Their levers can be "flip floped" (i.e., mounted on either side).

2) If the brand you buy can't be flip flopped you will need to swap the levers so that the left lever is mounted to the longer brake line, and the right lever mounted to the shorter brake line. This will require bleeding the brakes. Unless you're really mechanically inclined, you'll probably want to get a good shop to do that for you.


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## BillWeg (Dec 4, 2006)

Yep, but I already have a set of XT hydraulic calipers lying around, just need to put the levers and hoses together. Although I have never bled brakes before, I went thru the instructions, and they seemed to be pretty straightforward, and I am confident that I can get the job done (when else is my mechanical engineering degree gonna come in?) .

Do you still think that its safer to get an lbs to bleed them? my lbs is going to charge me 40 bucks for that, and its something I am not willing to pay.... but if its that risky, I just might..


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## oldskoolbiker (Jun 2, 2005)

You can do it yourself. You'll have to buy a bottle of mineral oil. You'll also need a rubber tube to catch the excess fluid coming out. One thing with bleeding brakes is not to take any shortcuts. You need to follow the directions exactly. You absolutely need to get all the air out of the lines.


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