veganbikes

What would you do? I am generally maxed out at 160 rotor anyway on the frame and fork but I am probably going to run some variant of the Magura 2 piston MT4s and just not sure if I want to go with flat mount or just get the adaptor and run post mount like three other disc brake bikes in the fleet? I guess I could also run MT5s which I am considering as I do want really good braking power. It is a Vado SL 5.0 if y'all wanted to know and aesthetics aren't really the major concern and I don't mind running flat mounts either so it is really not a I really dislike flat mounts reasoning. I would love to run 180s which would make the post mounts maybe the better route but in talking with my old Specialized technical adviser he suggested against it and I don't want to void any warranties or have any issues like that plus I want him on my side still because I might be able to get diagnostic tools and such from him even though I am no longer at a Spesh dealer but still in the industry.

FBinNY 

You probably don't really need help, but FWIW, I'm a believer in KISS. So I avoid adapting or "make do" when there's a straightforward alternative.

Also, while there's an advantage to larger rotors, the potential loss of rigidity MAY degrade performance (or may not).

So. without a specific reason to adapt for a larger rotor, I'd stick with the direct mount.

cpach

I'd keep it all flat mount, personally. The Magura MT4 solution sounds pretty good, possibly coupled with premium pads/rotors. A higher powered option might be Hope RX4's with Shimano MTB levers.

veganbikes

Ehhh I did ask the question, normally don't really need the help more just needed to hear some other opinions and think about it more. I don't want to live in my own echo chamber on this one as I really haven't played with flat mounts enough to really decide much.

In the end I think I am sticking with 160s so I would have adaptors anyway (and I think flat mount is generally using adaptors even at 140 for some of it). Since the frame and fork is 140 native but I don't want to go that low. I am probably using Magura MDR-C rotors which are pretty rigid so I don't worry too much there. I wish I could do the MDR-Ps but those only go down to 180mm : (

Though KISS is always a sensible solution.

Yeah I thought about the RX4s initially I am still on the fence though my initial hang up was resolved with a new rear light from Supernova so maybe I will put them back on the radar but I do have Magura MT4s on another bike so it will help with parts on hand. I would want 2-3 finger levers though the really short ones I have on my MTB are fine for that but I generally like a little longer lever and finding the XT trekking stuff in the U.S. has generally been tough. Though Alfine might still be an option.

I probably should just stick with FM and stop worrying I just saw the FM to PM adaptors and said well hey that could be neat.

Thanks all for the help both of y'all : )

FBinNY 

No need to explain or justify.

My comment about you not needing help wasn't a challenge. It was an acknowledgement of respect based on your many posts here. I also inferred that you were simply doing reality check and replied accordingly.

Polaris OBark

I found there wasn't enough room for a flat to post adaptor plus post-mount caliper in the rear triangle of my wife's frame, so I wound up having to purchase separate calipers. It was worth it. If the adaptor had worked (as it did with the fork), it would still look terrible.

tyrion

Having owned only 2 disc brake bikes I'm hardly an expert but I like exceeding the recommended max rotor size (modern steel bike, cable pull disc brakes).

If you want to stay with 160mm rotors I'd say try 4 piston disc brakes - the larger brake pads do apply more stopping energy and beefier caliper housings provide better heat dissipation. I saw a video of a Magura spokesman who said ideally you want a big rotor to dissipate the heat, but if you can't get that big pads and big caliper bodies will help manage heat.

mpetry912 

First make sure everything is clean, calipers are aligned, pads are broken in, etc. Do the easy stuff first.

I'm in agreement with FBinNY about not using adapters if you don't have to. Adapters just add more hysteresis and flex in the brake load path which affects braking "feel" and possibly performance.

if you want more braking authority, then experiment with pads or possibly 4 piston calipers.

if you are riding mega downhills and need more heat dissipation then maybe a larger rotor, but then you get into "adapters" that will cause other problems, come loose, etc.

one other change you might consider is going to a front hub with centerlock disk attachment as opposed to ISO. I made this change on the ebike and it made a noticeable difference.

Truly it is hard for me to imagine that a properly rigged disk brake setup on a bike would not provide more than adequate braking authority for almost any type of riding. A recent braking experiment that I did with 2 bottles of wine in the panniers, 55 lb Ebike, going down the Big Hill here on the island, resulted in in braking temps in the mid 200 degrees F measured on my Fluke infrared pyrometer May not be true for all bikes and riders, but my conclusion is that, at least for the riding I do, disk brakes are more than adequate.

/markp

veganbikes

This would all be brand new stuff entirely nothing to clean or anything it would be set up properly as well. I was just not sure if I wanted to get a flat or post mount brake (with adaptor) on my new set up. Basically right now on my other e-bike I am running a 203mm rotor at the front and a 180 rear but that weighs quite a bit more than the new bike but I still like the good stopping power so I may go 4 piston. When I built up my MTB I went with 4 pistons but the rotors are a bit smaller than I want but that was parts availability mainly and not having the wheels I was going to run on it.

I think I am sticking with flat mount and thanks again to all for your help : )