On Saturday, October 21, 2017 at 5:19:43 PM UTC-7, Frank Krygowski wrote:
On 10/21/2017 4:07 PM, wrote:
On Saturday, October 21, 2017 at 7:12:03 AM UTC-7, Joerg wrote:
When researching upgrades to larger rotors I read that there may be
limits for frames and forks. Why?

Explanations were usually scant and contradictory, with some saying it
doesn't matter and some saying it does. After all, when increasing the
rotor diameter by a couple of inches the brake force on the caliper goes
down by about 30% and then due to it being positioned farther out this
should cantilever back into the same +30% into the frame or fork bosses
as before. The maximum deceleration achievable on each wheel remains the
same, until it is very close to locking up. So it should be a wash,
shouldn't it?

Now THAT is something that Frank should be able to answer. I don't believe that leverage forces are linear are they?

Give me a photo and I'll see what I can do.

A photo? The forces on a disk have to do with the diameter of the disk going from 160 mm to 206 mm should be all the information you need don't you think?