Mark42

A few years ago was the proud owner of a 29'er Mongoose full suspension alloy frame bike. It was heavy, it was geared probably too low, but it would go where ever I pointed it. Had a Rock Shock fork, and an Italian oil rear spring shock with preload and compression/expansion adjustment. Had removed the rear triangle and drilled the pivot point and installed a grease nipple. All in all, it was an OK bike, just too darn heavy.

Anyway..... The disc brakes were 160 mm front and rear. And they kind of sucked. So a 203 mm front disc and adapter was ordered and installed. The crappy Zoom caliper (3 ball bearings) suddenly went from totally sucky to stand on your nose full blown stoppie. I could ride a stoppie for about 5 feet. With the OEM organic pads.

I often get advice to upgrade the calipers on my bikes for better braking. Until they ride the bike and hit the brake with the 203 disc and practically sends them over the bars.

I wonder why bigger diameter disc is not standard. The increased leverage from the longer disc radius is obviously what is turning sucky brakes into amazing brakes. And no changes to brake shoes or calipers were done.

I have a pic of me in full stoppie on that bike from a few years ago. But I won't post it because that is when I was fat. LOL!

dabac

There's more to brakes than ultimate stopping power.
Your observation ignores things like modulation and lever feel.

dsaul

I feel like this is the third time you've posted the same thread. What response are you looking for?

JonathanGennick 

Bigger diameter disks are standard, in many cases. Airborne Bicycles' Griffin ships with 180/160 front and rear. Specialized's Enduro Comp 29er ships with 200/180 front and rear. So it depends upon the bike and the intended riding conditions. My Priority Bicycles Continuum ships with 160/160, which is fine for pavement riding. Whereas the mountain-bike world has seen a move toward larger rotors since 29ers started to become common.

JanMM

Why is an easy stoppie a good thing?

Mark42

Modulation and lever feel is what lets you ride a stoppie.

Mark42

Because its fun as all ****.

Mark42

Funny, I was going to say the same thing about your post.

ColonelSanders

It is the first time I have seen it.

Interesting that larger calipers can make such a difference.

I've been toying with the idea of both getting a higher up the food chain set of disc brakes, as well as larger rotors and I didn't realise that larger rotors alone could make such a difference.

So if I hadn't read this thread and gone ahead with the double upgrade, I would probably be attributing all the performance improvement to the brake calipers alone.

dabac

Larger rotors, not calipers.

And how much it does is open for debate.
I like to run one size larger on the front, so I've both switched to bigger fronts or a smaller rear to achieve that.
While there definitely is a difference, I've never noticed such a big difference.
My "good" discs do well on both 160 and 180. My cheap Tektros, well, they're still underwhelming even with 180 mm rotors.