180 Rotor On Rear.

HowardSteele said:

I have shimano 160 rotar rear and have a spare 180 rotor.Question being, is it worth the trouble to switch to the 180 ,obviouslly adjusting the caliper hight.
I see it is becoming common for most bikes to run a 180 front and a 160 rear.
Why arn't they drunning 180 on front and rear?.

FWIW. At one time, it seems as though having the two different size rotors was common -- in part, it was a matter of frame clearance as much as lack of need BECAUSE the rear brake just doesn't do as much work and therefore it isn't going to need to dissipate as much heat ...

Don't forget, at one time (i.e., shortly after the turn-of-the-Century), many riders only had a disc brake on the fork & a V-brake for the rear.

From the bike seller's point of view, if I were the bicycle marque or the retailer, then I think I would rather build with or stock only one size; and, that is probably why 180mm rotors were being used front-and-rear for a few years (including, 2009) PLUS with the trickle-down to less expensive bikes it was probably too much of a nuisance to explain to the newbie why there were two different size rotors.

Since I'm not as attentive to the MTB market as I probably should be, I had to look at several different bikes & I see that Gary Fisher has at least one bike with two different rotor sizes (so, I presume there is at least one TREK with two different size rotors, too) ... I don't know if it is actually qualifies as a trend -- WHAT'S OLD IS NEW, AGAIN!?!

[left]Regardless, I wouldn't bother unless you plan to ride someplace where you anticipate encountering a lot of STEEP & WET riding conditions ... [/left]

[center]Why carry the extra weight if you don't need to? [/center]

The one question is: do you feel the need for more braking power?

I am assuming, of course, that you already have a 180 on the FRONT.