Disc Rotor Dilemma

[Mart]

I’m going to standardise both my bike wheels in terms of rotor size to 180 front and160 rear and wondering what other folks use

Does anyone go lightweight on their rotors? If so which ones/brand ??
or is it a case of beefing up as bike will be heavier so needs more robust rotors (like a Shimano Ice Tech)

I just can’t decide which way to go - Help!

[Zippy]

FWIW
I'm 180 front, 160 rear, shimano ice tech rotors where possible. All my bikes use the same brake pads too.

[Chew]

Think for simplicity I just use the same on the front and rear of the bike.

Can remember what size off hand, but I'd be going for robust rather than light weight. 10 grams is worthless if they were to break in the middle of nowhere.

I have the Shimano ICE ones on my bikes because a) they were cheaper than the standard ones, b)with the plastic middles they seem to warp less than the rotors which are made from once piece of metal

[substandard]

I have two very light xc race bike builds

One is an 8kg Scott scale and that has 180 160 quaxar ultralight rotors on it, used it for bb200 and no issues with overheating, running Sram xo brakes on that.

Second is a 10.5kg salsa beargrease fatbike which I’ve run quaxar and hope floating 180 140 rotors on, had a few issues with the 140 ultralight rotor overheating in steep races but swapping to hopes they take an absolute pasting. Running xtm8000 brakes on that one with ice tech pads. On a loaded bike an ultralight solid 140mm rotor is probably marginal, 160 I’d happily run though

[jameso]

180s front and rear here on the bike that does most loaded off-road miles. Why bother with 160 rear, 180 is only an ounce or so more? Lightweight rotors, no chance, personally - the whole purpose of a rotor is to turn your speed/momentum (KE) into heat so the less surface area the main rotor part has, the less effective it is. Weenie-ism gone mad .. : ) Light brakes would be fine for some rides but I use cable discs and the bike goes abroad here and there.

tbh I'd put a 203 front on the bike if I had one to hand but the 180 F+R combo works fine - I'm not that heavy though.

[Bearbonesnorm]

Just to cause some upset ... I only ever use 160mm on the rear as I find 180mm complete overkill. Sometimes, I only use 160mm on the front too. It's only let me down on two occasions but both times I was able to avoid near certain death. You'd think I'd have learnt something from the first experience

[ScotRoutes]

160/160 on everything except the big bouncy bike. Never needed or wanted anything else.

[ianfitz]

160/160 on everything except the big bouncy bike. Never needed or wanted anything else.

Same for me. Apart from not owning a big bike.

Keeps it simple in terms of spares etc. Same brakes too, although at 2-3 years old the Shimano slx and xt are becoming unreliable and will be replaced with Magura with their five year, no questions warranty

[fatbikephil]

I go large with discs as more is always more....but regarding durability I've been using shimano ice techs on the fat bike for 3 years now - no warpage and no detectable wear. Hope semi floating rotors on the alloy carriers are also warp resistant and wear well. I find solid stainless discs warp after a few months although this doesn't affect performance just gives a bit of brake rub.

[whitestone]

180 front, 160 rear on both bikes. Solid steel rotors on the Solaris, Hope floating rotors on the fat bike.

Only advantage of same size front and rear is if the front rotor breaks or becomes very warped then you can swap the rear to the front without needing to adjust the mount. Not known of anyone having to do this.

[ericrobo]

Ian

I used to use Magura but I’ve got Shimano on all 4 bikes, a mixture of SLX (very good - the fluid and hoses seems to last for ages, very positive feel to the brakes), and on my Scale 900 Shimano XTR, faultless

And ice tech rotors on the two Scales I have.

What I really like about the Shimano brakes is the really very easy 2 minute job of getting air out of the system (if you buy the little plastic thingy with its plunger)

Compared to Magura - which was difficult and a real PITA, and I always ended up with fluid everywhere. Back brake being especially difficult if you only have two hands...
Unless they’ve latched on and copied a leaf from Shimano

[Mart]

Cheers Guys - I hadn’t really thought about same size front and back before but you’ve helped loads.

[Alpinum]

I live in the Swiss Alps and the steeper the ride, the happier I am. I also like to ride Long downhills non stop.
Some of which have more vert loss than the height of highest summit in the UK.
My weight bounces between 80-86 kg.

180/180 on the fatbike. Only sees snow and cold. Overheating very unlikely. Organic pads. Sram discs.
200/180 on my long travel trail bike. Overheating is a big issue. The stuff I ride kills organic pads after about 10 min. This happens regularly. Sintered here mostly. Sram discs.
180/160 on my ssp rigid bike. Everyday bike, travel and rarely some trail biking in the flatter areas of Switzerland. Organic pads. If it wasn't for the trail Biking, I'd probably go 160/160. also to swap discs if bodged. Hope and no name discs. Both with Al-spider
180/160 on my short travel trail bike. It's quite new so I'm just running the OEM Brakes. Killed the original organic Shimano compound on the rear just yesterday. Glazed, squeek, not much performance left. This was on the rear. The rear pad has fins... will change to swissstop pads and larger discs.

My former short travel bike had 200/180. Never had an issue here. Superstar discs with Al-spider.

I did lot's of bikepacking in the UK with 180/180 discs which were absolutely fine with any type of compound and disc.

If I did most of my biking in the UK, I'd probably be on 180/160 discs.

I really liked the Hope saw discs. Never tried the newest gen, but they must be really good.
Why? They stay true when other discs go all crooked and seemed to help manage the temperatures better.
And, they used to be some of the lighter options, despite thicker steel than many other discs.

[redefined_cycles]

Generally the Avid ones I use... lighter ones are good but middle priced ones are easier to pay for. Never gone wrong with them

[jameso]

Killed the original organic Shimano compound on the rear just yesterday. Glazed, squeek, not much performance left. This was on the rear.

Stop dragging the brakes maybe?


(joke / ducks .. ha)

[GregMay]

180/160 on all MTB
160/140 on cx/gravel/buzzword bikes

SRAM rotors mostly, but expensive Ice-Tech for racing 24s.

[dlovett]

Shimano IT 180’s front and rear on HT/Susser and fat rear. 203 on fat front.

Camino has silly little 160 Avids on front and rear. Hoping to beef them up a bit when they wear out as they are fine for road and cox stuff, but not dh.

[danielgroves]

160/160 on both bikes.

Salsa has Avid G2s or whatever they're called because that's what it came with.
On one has the Shimano floating ones that aren't ice tech

[Alpinum]

Killed the original organic Shimano compound on the rear just yesterday. Glazed, squeek, not much performance left. This was on the rear.

Stop dragging the brakes maybe?


(joke / ducks .. ha)

Guilty as charged


A typical profile from my last multiday trip may explain why some need big discs

[Bearbonesnorm]

Camino has silly little 160 Avids on front and rear. Hoping to beef them up a bit when they wear out as they are fine for road and cox stuff, but not dh.

You probably don't want to be fitting anything larger than 160mm to that Duncan.

[slarge]

160 front and rear, alligator lightweight ones from XC Racer. Work well, never cooked them, but in my view brakes are overrated - they slow you down!!

[ZeroDarkBivi]

will be replaced with Magura with their five year, no questions warranty

Compared to Magura - which was difficult and a real PITA, and I always ended up with fluid everywhere.

I used Magura for a while, 5-6 year ago, but they where a PITA to bleed and two brakes went back under warranty. Hopefully they are a bit better now...

[Justchris]

I’m going to standardise both my bike wheels in terms of rotor size to 180 front and160 rear and wondering what other folks

Be careful. My newest bike came with a warning of a voided warranty if you changed size of rotor.

Cheer

C

[Pete-G]

160mm front and back on the Sequoia, 180mm front, 160mm rear on the Stooge, and 200mm front 180mm rear on the White T129 which is what I use on the steep stuff so want the best control and modulation I can get. I've used Alligator rotors in the past and found them to be next to useless. Current Shimano rotors seem to do the job perfectly.