What size rotors do you recommend?

Discuss light weight issues concerning road bikes & parts.
icantaffordcycling
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by icantaffordcycling

I went from 160/160s on my last bike to 160/140 on my current bike and now 140/140. I noticed absolutely no difference.

kode54
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by kode54

same here. has been a great combo.
joejack951 wrote:
Fri Dec 06, 2019 6:55 pm
Similar weight here. I went with 160F/140R and can't see how I'd benefit from a larger rear disc. I could probably get away with 140F/R but that's uncommon enough that I decided to not bother.
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by Weenie


bm0p700f
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by bm0p700f

A bigger rotor is a bigger heat sink so bigger rear is better. You can drag that brake more without overheating.

While 140mm rotors maybe adequate, saving 20g should never be that important as to go for the smaller rotor.

RedbullFiXX
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by RedbullFiXX

bm0p700f wrote:
Fri Dec 06, 2019 10:56 pm
A bigger rotor is a bigger heat sink so bigger rear is better. You can drag that brake more without overheating.

While 140mm rotors maybe adequate, saving 20g should never be that important as to go for the smaller rotor.
I wouldn't be so sure about that
Spending less to save weight
Folks here on WW spend absurd amounts to shave 20g :lol:

At the end of the day, build your kit as it suits you
Cyclocross, in general, is about riding the wrong bike for the conditions.

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Noctiluxx
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by Noctiluxx

RedbullFiXX wrote:
Fri Dec 06, 2019 11:27 pm
bm0p700f wrote:
Fri Dec 06, 2019 10:56 pm
A bigger rotor is a bigger heat sink so bigger rear is better. You can drag that brake more without overheating.

While 140mm rotors maybe adequate, saving 20g should never be that important as to go for the smaller rotor.
I wouldn't be so sure about that
Spending less to save weight
Folks here on WW spend absurd amounts to shave 20g :lol:

At the end of the day, build your kit as it suits you
Screw this, I'm going back to rim brakes! :lol:
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LeDuke
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by LeDuke

I just went 160/160 so I can swap wheels between my road, wife’s gravel and my MTBs in a pinch. If I break a wheel, I can adapt any of my current front wheels, with the exception of one “Boost” 15x110mm front, to fit all of our bikes.


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TobinHatesYou
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by TobinHatesYou

I tried 160/140 for a while and went back to 160/160. It's a microscopic change in system weight and a massive change in braking power on steep/technical stuff.

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Lewn777
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by Lewn777

I wouldn't run a 140 as it could get too hot. Usually I don't use the rear brake on smooth roads desecending up to 10% gradients but I drag a bit of rear brake in situations like cornering with dusty/wet/gravel or other similar circumstances or descending rough or steep stuff. This puts a huge amount of heat through the rear brake, for an extra 20g, I know what I'd prefer. 180s on MTBs are far better than 160s, more power, better modulation and better able to handle the heat. Definately switch to a floating/2 piece rotor if you don't have one already as that helps in heat dissipation and seems to help prevent warping too.

bas
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by bas

I have a propel with 140/140 and a revolt gravel bike with 160/160. The bigger rotors feel noticeably stronger. Both bikes with ultegra brakes. I tried to fit a 160 to the front of the propel but it doesn't seem like they make an adaptor to do it

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TobinHatesYou
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by TobinHatesYou

bas wrote:
Sat Dec 07, 2019 8:45 am
I have a propel with 140/140 and a revolt gravel bike with 160/160. The bigger rotors feel noticeably stronger. Both bikes with ultegra brakes. I tried to fit a 160 to the front of the propel but it doesn't seem like they make an adaptor to do it

Does a standard 160mm front flat-mount adapter not work with the Propel fork?

ruklaw
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by ruklaw

Yeah, should just be a case of mounting the existing adapter the other way up.

I upgraded my 140mm rear disc on my first road disc bike to 160mm and definitely felt the improvement - rear braking had seemed pretty puny on that bike - and have stuck with them ever since, but I am a very heavy rider, I would have thought small riders would be fine with 140mm all round (certainly I've never felt the need to go any bigger...)

Thomson
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by Thomson

Bike came with 160mm f/r I will just keep it the same. :-)

bas
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by bas

TobinHatesYou wrote:
bas wrote:
Sat Dec 07, 2019 8:45 am
I have a propel with 140/140 and a revolt gravel bike with 160/160. The bigger rotors feel noticeably stronger. Both bikes with ultegra brakes. I tried to fit a 160 to the front of the propel but it doesn't seem like they make an adaptor to do it

Does a standard 160mm front flat-mount adapter not work with the Propel fork?
No, they don't use a standard mount for the fork. If anyone has done it love to hear, giant in Australia says they can't get a 160 adaptor

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joejack951
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by joejack951

bas wrote:
Sat Dec 07, 2019 10:15 pm
No, they don't use a standard mount for the fork. If anyone has done it love to hear, giant in Australia says they can't get a 160 adaptor
Can you post a pic of the fork/caliper/adapter? I am sure something could be made to adapt it to take a 160mm rotor.

by Weenie


andreas
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by andreas

140mm rear was almost useless for my riding (85kg, hilly/mountainous), overheated and bent so easily that constant truing was needed. Much more stable setup with 160mm. My disc brakes are still more hassle to maintain and a lot harder to setup and keep perfect than my rim brakes, though...

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