MTB Rotor Size Comparison! Do Bigger Rotors Stop Better?

MTB Rotor Size Comparison! Do Bigger Rotors Stop Better?
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[@FATTY1990]

Larger Rotors do make a difference i tested this myself on a cheap store bought bike and had the rotors laying around for a new build and it may be a small difference but it could be the differcence between life or death

[@KNGER1988]

I have a heavy ebike and I'm over 200lbs myself. Thank you for this video you talked me into it

[@iangustafsson]

Neat comparison Kyle; another amazing video!

[@CobraKyle]

Appreciate that Ian!

[@harrygrimley4352]

This was a good informative video. Thank you. I wondered.

[@CobraKyle]

Thank you Harry!

[@dmapp899]

Thanks for the video. Could you please make another similar video but using 4 piston brake caliper? Thank you in advance! Cheers!

[@serpadu]

What about a cheap (RT54) vs intermediate (RT70) vs expensive (RT905) test? Same bike, same calipers, same diameter. Ideally on a long paved descent, to see how they handle the heat, if the cheapest warps... I've used randomly in different bikes various rotor levels, but can't really judge if there's a braking performance difference between a slx and a xtr rotor. It is probably very difficult to differentiate them in a blind test even agains the cheaper ones, like RT26.

[@fishrideandski4910]

i was thinking about getting new bigger rotors so this should be useful

[@CobraKyle]

I was pretty happy with the results. I guess it was worth the money!

[@how2ssipp793]

Thanks! Love the vids

[@jasonbrown467]

i skipped to the results so i didnt watch the whole thing but from a leverage stand point, it should most definitely give you more stopping power. honestly i always thought this was more about dealing with heat dissipation, but that may be an added benefit?

[@KillerArcadeGames]

That E-Bike is far too much fun! Its actually perfect if you want someone to help film, I didn't complain once about frequently going up and down a parking garage...I also didn't pedal! haha. Cobra Kyle now has 10,000 subs!! Congratulations!

[@dreadsanddirt5966]

I run gigantic rotors (220/203) and the hand effort required to control speed is DRASTICALLY less. I play guitar for a living so anything I can do to alleviate sore hands from riding is a welcome change.

[@VoodooJeff]

@SlaveLaboringKid well, I had my first bmx race in 1984, been on a mtn since 1997. I've ridden some of the biggest, steepest, most beautiful places on earth over the years and at one point thought I'd be really cool and get my pro card so I suppose I know my way around a bicycle. Not to mention I weigh 220lbs so having a bit of extra brakes goes a long way. I've been over my bars plenty of times in the 40 years I've ridden and I can't say any of them was due to having too much brake power :-)

[@cunning-stunt]

@slavelaboringkid7597 Only if you are a complete novice. More likely that you will roll an endo down the slope. I ride steep loose rocky and steep dirt trails, if you are going over the bars then you have your CG in the wrong place on the bike. Larger rotors dissipate heat better and offer greater brake modulation which means less brake fade and more traction control.

[@jamesdiamond1582]

I put 203mm rotors front and rear on my lectric e bike with tektro aries calipers metallic pads gotta say it did the trick I am Towing a 95lb black lab in a trailer 😂😅🤘👍🎥

[@dynamitedanny3531]

You're telling me this free content was performed by a guy without a PHD in Physics outside of a multi million dollar laboratory? CLICKBAIT

[@CobraKyle]

You MONSTER!

[@bradley3549]

I have 220 front and rear on 27.5 and honestly, I think I'm going to downsize to 200. I'm fairly lightweight and I feel like I have better modulation with smaller rotors.

[@harrygrimley4352]

Don't forget, if you ate or drank anything during the test you change the weight and thus momentum. Peeing will change it also.

[@CobraKyle]

Oddly enough I had to pee the whole time while filming this. Probably why I made that first mistake lol. There were no bathrooms there and I didn't want to skew the results. I'm committed to my craft!

[@harrygrimley4352]

@@CobraKyle clearly. Part of why we like you

[@thepro08]

what about if he farts during braking? lool

[@JaredRMorgan]

Time to see if I know what I'm talking about or if I'm full of garbage! LMAO. Legit excited for the result.

[@CobraKyle]

Turns out you're full of garbage, and science proved it! lol

[@MikeBMW]

Nice vid, Kyle, thanks! However, you should be wearing a Cobra Kyle T-Shirt just as I'm doing at this moment. :)

[@CobraKyle]

Thanks Michael! I really should be wearing that shirt at all times lol. I appreciate you wearing yours!

[@billr5756]

What happens when you put metallic pads on resin-only disks? Seems like this would be the cheapest upgrade.

[@CobraKyle]

Great question! I researched it a little and it's something you probably wouldn't want to do. Those rotors aren't designed to handle the heat/friction that metal pads generate, so it will most likely be very loud, not stop as well, and I saw some reports of it actually warping the rotor.

[@jecanvlogs1090]

Hello...can you help me?floating 160mm rotor and regular 160mm rotor same size diameter??no need to put adapter when you install it in your bike?

[@durk541]

No need

[@ramainvicta]

I have a hybrid commuter bike that I use everyday to work. Do you think it's a good idea to replace 160mm to 203mm. I really like the look of bigger rotor.

[@danielyusupov1447]

I think 180 would be better because jump from 160 to 200 is too big for adapter.

[@adeverel]

@@danielyusupov1447 I just put 203s on a stock 140 so it can be done.

[@Faceless009]

I have fornt 180 and rear 160 and I have the old 180 disc rotor that is in solid condition and i would probably swap rear so then i will have 180 in front and 180 in back, is that a good idea?

[@fraserthomson5766]

I would bin the 160 and run the 180 on back, 203mm on front. Failing that, add 4 piston caliper on front, 2 piston on rear.

[@phil5073]

Just a newbie in mtbiking. Let's say he has only 180 and 203... How should should you modulate brakes in steep rocky corners and what rotor setup shoud you use? A) 180F/203R - front modulation B) 203F/180R - front modulation C) 180F/203R - rear modulation D) 203F/180R - rear modulation

[@TheWrigle]

Pretty much always run the bigger rotor up front as it does like 70% of the braking. As you brake, your weight shifts forward making it very easy to skid the rear brake. Having a more powerful rear won't do much if you don't have a more powerful front to match as your back with just brake traction while you are trying to brake the front end.

[@Semprefi]

I’d be interested to see the results of a test with the 180/160 rotors and metallic pads so we could know which alteration was responsible for the better braking results the pads or bigger rotors or both

[@zap...]

Are you properly bedding in the rotors and pads before testing?

[@CobraKyle]

Yeah I did...just didn't film that part

[@markjwoodford1931]

Those metal pads take a lot of bedding in!

[@komoonkh]

Imagine those metallic pads when they are bedded in. Hah.

[@CobraKyle]

Very true! The results could have been even more drastic!

[@shawnalove5050]

I didn't watch till the end because it seemed flawed, in that he didn't mention bedding any of the new brake pads. Unless of course it was s test to see how brand new, unbedded pads and discs stop compared to each other.

[@trevorschnedler4472]

Does anyone in mtb worry about hitting their rotors on rocks? I've never seen it, so I figure it's rare but I guess it could be a downside to bigger rotors.

[@CobraKyle]

You raise a good question! I've never had any issues with this, but definitely a larger area for rocks to strike.

[@Skippy-id9yt]

More likely to smash the frame first (for my forks or rear triangle ) ,perhaps dropping Ng down in not them is possible off rocks etc though ?

[@cunning-stunt]

Derailleurs hang far lower and stick out side ways more than any rotor. A 10-52 tooth rear cassette is the same diameter as a 200mm rotor. Never managed to hit the cassette with a rock.

[@galaxyfit5666]

It's like 26 inch and 27.5 inch

[@familyandfriendsadventures5782]

Not all heroes wear capes! Now if I could just find some 203 RT86's in stock anywhere...

[@BawlzOfuzz]

Why do you have a smaller rotor on the back? Surely you want more stopping with the back brake?

[@stefhirsch6922]

You want the bigger rotor on the front. When you slow down your weight shifts forward. Thus 80% of your stopping power is your front brake whereas only 20% is your back.

[@FightFilms]

To maximize efficiency, you'd probably want the bigger rotor on the brake you engage the most/longest.

[@1911Zoey]

I'd want a bigger one on the back too for modulation and better heat spread (bigger surface area).

[@TrailFeatures]

Excuse me, but you failed to take into account the weight of the moon's shadow in these test. if you were taking this _seriously_ you would have accounted for such a basic variable. *TEST INVALID.*

[@CobraKyle]

"You're telling me this free content was performed by a guy without a PHD in Physics outside of a multi million dollar laboratory? CLICKBAIT". I'm looking forward to these comments lol

[@_lucifer_gaming_]

@@CobraKyle 🤣

[@MTBRadDad]

🤣

[@warlockboyburns]

I'm using $40 4 piston ztto hydraulic brakes with 203mm rotors and they are too powerful. The wheels skid rather than slow down.

[@benjaminbotelho336]

this test is flawed because you're using brand new brakes without bedding them in.

[@EvoX180]

They have been bedded in

[@Semprefi]

Yes but none of the combinations were bedded so while the stopping distance may have changed with bedding all combos had the same handicap

[@kshaffer1964]

Not a very scientific test... the slightest difference in the pressure placed on the brake levers will affect the outcome. Without consistency and measurable input, the output is flawed.

[@navykip]

I like the new bike 🚲.

[@CobraKyle]

Thanks! I really like it too!

[@Covid-mq9cp]

you need to bed new rotors,

[@GoodTrails]

SCIENCE!!!!!

[@CobraKyle]

Welcome to "Cobra Kyle's Fun with Science Super Extravaganza Power Hour"

[@Sanwizard1]

Should have added metallic pads on small rotors first. Then ceramic pads. My little banana seat schwinn with pedal brakes in 1970 worked better than both those setups. It should lock up the wheels.

[@CobraKyle]

Did you even watch the video? lol. I addressed everything you mention in the video. The smaller rotors are only compatible with resin pads, so didn't feel like using incompatible brake pads on them would prove anything. You can easily lock up these brakes, but felt it would be easier to be consistent feathering them to a stop.

[@popoypoop]

Riding on the streets wont make that big of a deal. If u ride mtb out in the trail and steep terrain hot weather the big rotor will make a big difference

[@caperider1160]

It is so obvious from simple logic. Not even worth an experiment. More kinetic energy can be burned as heat for the same angular displacement, assuming equal frictional coefficient & braking force. Besides, much better thermal management. Heat reduces frictional coefficient for the same braking force.