Flat mount discs - worth the wait and cost?

The spirit of Grav-lo-cross. No but seriously, cyclocross and gravel go here!

Moderator: Moderator Team

greentimgreen
Posts: 224
Joined: Thu Jul 24, 2014 8:36 am

by greentimgreen

I'm in the process of deciding on a gravel bike, my front runners being the Parlee Chebacco and Open U.P.

Both of the current versions do not have flat mount disc brakes, and because of this I understand that Parlee frames might be going on sale soon. So the question is, should I buy now, potentially for less money, or wait for new models with flat mount compatibility? Is it much better? I'm new to this disc brake game!!
2014 Parlee Z-Zero DADi2 & ENVE (6.2kg)
2015 Colnago C60 RSWH Campag Chorus & Mavic SLR (c.7kg)

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com



AlphaDogCycling
Posts: 55
Joined: Fri Feb 15, 2013 6:57 pm

by AlphaDogCycling

On the Chebacco the updated version is switching to flat mount. I have a deposit down on one, so I'm hopefully near the front of the line


Sent from my iPhone using Tapatalk

greentimgreen
Posts: 224
Joined: Thu Jul 24, 2014 8:36 am

by greentimgreen

What made you choose the new version? Just the flat mount? Is it that much better?
2014 Parlee Z-Zero DADi2 & ENVE (6.2kg)
2015 Colnago C60 RSWH Campag Chorus & Mavic SLR (c.7kg)

fordred
Posts: 86
Joined: Sun Sep 13, 2009 4:22 pm

by fordred

I took the discount and got a post mount fork and IS frame.
Reason being flat mounts are designed for 140mm but I'm 180 pounds and plan to use 160mm,which negates the flat mount advantage if I were to use an adapter.
Figured I probably won't be upgrading the brake calipers or I can use mtb's version if I really want to.
The big discount on current frames are too nice to resist,espexially when the frames ride the same.

AlphaDogCycling
Posts: 55
Joined: Fri Feb 15, 2013 6:57 pm

by AlphaDogCycling

greentimgreen wrote:What made you choose the new version? Just the flat mount? Is it that much better?


Actually I'm waiting for either Dura Ace 9170 or eTAP HRD to come out, so waiting for the flat mount update wasn't a problem


Sent from my iPhone using Tapatalk

User avatar
ms6073
Posts: 4290
Joined: Fri Jul 23, 2004 8:24 pm
Location: Houston, Texas

by ms6073

fordred wrote:Reason being flat mounts are designed for 140mm but I'm 180 pounds and plan to use 160mm

With Shimano BR-S805, the front mounting plate is reversible, allowing the use of either 140 or 160mm rotors simply by flipping the mounting plate. I am 180 lbs (~81 kg) and running 140 mm Shimano Freeza rotors front and rear on a KTM Revelator Sky road bike and braking is very good (1-finger modulation). A friend of mine who at 6'6' (198 cm), is close to 200 lbs., and he just started riding a 2017 BMC Road Machine 01 with Di2 hydraulic and it came stock with 160 front, 140 rear and he has told me he has no issues with braking whether on flat roads or fast descents. To run 160 mm rotors in the rear simply requires the addition of the Shimano SM-MA-R160 adapter plate under the caliper.

Image
- Michael
"People should stop expecting normal from me... seriously, we all know it's never going to happen"

fordred
Posts: 86
Joined: Sun Sep 13, 2009 4:22 pm

by fordred

ms6073 wrote:
fordred wrote:Reason being flat mounts are designed for 140mm but I'm 180 pounds and plan to use 160mm

With Shimano BR-S805, the front mounting plate is reversible, allowing the use of either 140 or 160mm rotors simply by flipping the mounting plate. I am 180 lbs (~81 kg) and running 140 mm Shimano Freeza rotors front and rear on a KTM Revelator Sky road bike and braking is very good (1-finger modulation). A friend of mine who at 6'6' (198 cm), is close to 200 lbs., and he just started riding a 2017 BMC Road Machine 01 with Di2 hydraulic and it came stock with 160 front, 140 rear and he has told me he has no issues with braking whether on flat roads or fast descents. To run 160 mm rotors in the rear simply requires the addition of the Shimano SM-MA-R160 adapter plate under the caliper.

Image


Ar, now i know...
I guess i got the impression when most the forks for flat mounts state that it's for 140mm. Didn't really read up Shimano specs.
:thumbup:

User avatar
wheelsONfire
Posts: 6283
Joined: Mon Jul 07, 2014 8:15 am
Location: NorthEU

by wheelsONfire

I wouldn't consider 140mm rotors for a gravel bike.
Bikes:

Ax Lightness Vial EVO Race (2019.01.03)
Open *UP* (2016.04.14)
Paduano Racing Fidia (kind of shelved)


Ex bike; Vial EVO D, Vial EVO Ultra, Scott Foil, Paduano ti bike.

ooo
Posts: 1590
Joined: Sat May 21, 2016 12:59 pm

by ooo

cyclocross worldcup 2016/2017 bikes are equipped with 140mm rotors
'

User avatar
wheelsONfire
Posts: 6283
Joined: Mon Jul 07, 2014 8:15 am
Location: NorthEU

by wheelsONfire

Maybe they are, but 160mm Rotors are offering better/ faster braking.
Bikes:

Ax Lightness Vial EVO Race (2019.01.03)
Open *UP* (2016.04.14)
Paduano Racing Fidia (kind of shelved)


Ex bike; Vial EVO D, Vial EVO Ultra, Scott Foil, Paduano ti bike.

User avatar
Mr.Gib
Posts: 5577
Joined: Fri Mar 18, 2005 4:12 pm
Location: eh?

by Mr.Gib

Just to chime in on the 160 vs 140 rotor question, it makes total sense that for cross or riding mostly flats or if you are light weight, that 140 mm rotors are adequate. However at 180 pounds (80 kg), a 140 mm rotor is totally inadequate when trying to stop from 50 km/h plus on a steep hill. I have tried a variety of different set ups and they all fail. Stopping distances are dramatically shorter with the 160 mm rotors. I know having to bring your bike to a near halt from top speed on a 10% to 20% slope is not a regular occurrence for most of us, but if it applies to you, I highly recommend 160 mm rotors.
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

deanet
Posts: 11
Joined: Wed Nov 05, 2014 2:33 am

by deanet

i did tried 160f/140r by red 22 hydro, but found it's to hard to handle the power of the rear,
and finally turn back to 160/160 at the end, with the shimano adapter above.

petepeterson
Posts: 1402
Joined: Fri Jan 07, 2011 6:58 am
Location: 604

by petepeterson

I have the new shimano flat mount calipers. They look super clean on a frame with flat mounts which is nice. Other than that there is no difference.

wpccrunner
in the industry
Posts: 429
Joined: Fri Dec 07, 2012 8:34 pm
Location: CO

by wpccrunner

so besides all the rotor size debate, what are peoples thoughts now on flat mount vs post mount? Are there any benefits to going flat mount, besides aesthetics? I am in the market for a new cross bike and have narrowed down to a few options with my biggest decision being whether to go flat or post mount.

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com



ooo
Posts: 1590
Joined: Sat May 21, 2016 12:59 pm

by ooo

you can use post mount caliper on flat mount
flat mount usually 12x100, post mount usually 15x100
'

Post Reply