[ohiogsp]

When looking at forks why does it say max disc? How does the fork restrict the disc diameter?

 

[Flamingtaco]

It's about how much force the fork can take under hard braking conditions.

 

[ohiogsp]

oh ok that would be really important when going downhill!! lol thanks

 

[ohiogsp]

so I am running a 203mm disc and shimano slx hyd brakes. I was looking at a Suntour XCR
LO-R-29-AIR it says 185 max disc. How bad would that be? lol

 

[CannondaleF9]

so I am running a 203mm disc and shimano slx hyd brakes. I was looking at a Suntour XCR
LO-R-29-AIR it says 185 max disc. How bad would that be? lol

That would be too much of a difference. It will at least loosen the quick release so the wheel falls off, but in more extreme cases, it can snap the brake caliper off due to twisting forces of the large rotor.
I am running a 203mm rotor on a fork that has a 200mm limit. Mine is OK but is nearing the limit of rotor size larger than max rotor size.
Look at RockShox forks. They generally have larger max rotor size.

 

[EddyKilowatt]

How bad would that be? lol

Well two obvious bads would be 1) brake torque rips the caliper off the fork (lowers are made of soft alloy) jamming the wheel and sending you over the bars onto the rocks or 2) brake torque through the caliper buckles the fork lower sending you over the bars onto the rocks. But if you always ride on soft sand or grass, it shouldn't be a problem. Be sure to wear a GoPro so we can lol with you.

 

[ohiogsp]

ya ok I will step up then. lol I was looking at a rockshox reba solo air. Think that would be a better fit? I know it says 200mm also?

 

[Bimmer74]

It's about how much force the fork can take under hard braking conditions.

Yes, this is true, but it's just a guideline.

If you're a heavy guy riding aggressively on grippy tires, then you should pay close attention to the maximum disc size.

If you're a lighter guy or you ride less aggressively or you're on less grippy tires, then you'll be putting a lot less stress on the fork...

BTW, I'm putting a 203mm on a RockShox XC-28 that I doubt is rated for a 200mm disc. I'm not worried about it.