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Not a moto guy but commuted on a street bike for a while. One key difference might be intensity of use. If you’re riding steeps on an MTB you’re on the brakes in some fashion nearly constantly for the whole track (5min?). Gravity is our throttle and it’s always WIDE OPEN.

I conceed. You are spot on here. I enjoy making things more complicated! But I like my bike simpler. I believe having the best rotors and pads with the least unsprung, rotating weight is a worthy balance to strive for. Mostly everyone likes sensitive suspension and any unsprung weight reduction will help that. Some of these thicker rotors are brutally heavy on top of the additional spacers and bolts required to mount them. Older calipers also might not be compatible. I am also mullet, so my 180 rotor has more leverage on my little wheel than a 29er so I...

Im heavy at 6’4 250lbs and typically run TRP brakes with their 2.3mm 223mm rotors with good results. I tried the 246mm 2.3mm Galfer rotors and it was a big fail. Halfway down a descent they would warp wildly from the heat - like 10mm out of true. I realize I’m an outlier size wise but there is DEFINITELY something to the rotor size vs. thickness ratio. I think at 223mm we are probably at the limit for 2.3mm thickness.

It didn't come off dickish but it also isn't productive to attempt to broadly squash a point of view simply because it runs counter to popular belief or your own opinions. Shirking the "bigger is better" rotor mentality works for an apparent minority of people. And I am fairly certain I don't have freakishly strong index fingers. Your point 5 seems to imply that I am suggesting some razor-thin margin where vertical feet of a descent is part of an equation to establish what braking setup you need for that particular descent. That is nowhere my posts. I stated that...

To summarize: The heavier (you + bike), faster (you) or steeper terrain- You benefit from larger and thicker rotors. If you are lighter,ride flatter terrain- You can get away with smaller and thinner rotors.

Added point, the same sized rotor is less effective on a 29 inch wheel compared to smaller wheels. Look at the rotor size in relative terms to the wheel diameter instead of absolute sizes of 180, 200, etc. mm. @jeff.brines considering you're also a moto guy, how is braking done on a moto? One finger or two finger? What are pad clearances like on motor bikes? Etc.

Mentioning Codes specifically, R feels like garbage to me, RSC works. I'd rather have 180 mm rotors on RSC brakes than 220 mm rotors on R brakes. Because of feel alone.

This is a little off topic, but how do people feel about more powerful braking system vs larger rotors. Both weigh more and deliver more braking force, but which is best? In the past I've stuck with whatever cheap calipers my bike came with e.g. codes, and bumped the rotor up from 200mm to 220mm. That's an easy win of 10% more braking force (ignoring heat issues which might give more or less advantage depending on whether your brakes were too hot/cold to start with). For me this has always been a simple upgrade path: buy a couple of rotors...

I’ve definitely been doing some experimentation on my 120/140 bike (REEB SST). Having spoken with the man who designed the bike, he is a low stack enjoyer and rides a medium (so the FC/RC ratio is more like 1.78 vs my Large’s 1.83). I’ve run everything from a 40-50mm stem and 20mm to 50mm rise bars, and I’ve settled on a 50mm stem and 35mm riser bars with 15mm of spacers as being the best combination between feeling “safe” on the bike and getting good front end grip without going out of my way to ride the front. A low...

I feel like I'm reading a Seb Stott/Henry Quinney article get created before my eyes. Y'all've seen two basic principles gt raised here. Here are a couple visual aids I made to help show the relationships I see people using to help solve the OP's question. The stars show the particular contrast being made: a brake system near it's optimum temperature giving some level of performance greater than a brake noticeably below that optimum temp. The blue dots are just some ways we might fill in the relationship for other temps. Note that this is a relationship (as the posters...

On a moto- single finger is plenty to do a stoppie. Pad clearance is about zero- wheel rotates a few times when spun off the ground… Not acceptable for a bicycle.

Certainly not Martin Maes or Troy Brosnan level of rider here, and most likely not near @jeff.brines either, but here's what I have found in 26 years as a bike mechanic, 30+ years of riding offroad. If you're primarily riding in terrain that has short descents or very short braking zones, 180mm rotors are probably big enough. Larger rotors might take you too long to heat up enough to get the full power out of them. On the other hand, if like me you live in a mountainous area with 5-10+ minute descents being the norm, and weigh more than...

There is a big difference between the surface slightly bluing on a carbon steel rotor (on a car) during bedding in and turning an entire rotor dark blue on a MTB. A similar bedded in look on a MTB rotor (let's call it light blue) is not cause for concern, similar to cars. Deep bluing could be. MTB rotors being much thinner and stainless (most rotors on cars are carbon steel, I don't know about motorcycle rotors) are much less durable. My experience with changing heat treatment is from my day job, firearms manufacturing. If you turn stainless steel deep...

I have the stevo in s4 and put an xl seat stay on it to give it a 10mm longer CS measurement (I think that was the difference...) The improvement was night and day.

I am curious how much the hunch over is from proportions on those bikes of people you list and then the upright folks having better bike proportions, higher stack, and the ability to weight the front a lot more naturally all while being more upright still. I mean look at all the changes that Minnaar was trying to do to his old XL SC to have a better fit. Mega stack, +10 custom chainstays, higher bars. I think Jackons bike came out to 1.79 at the time and Minnaars was something like 1.86. BIG difference in ride characteristics between the...