Video: Syndicate Pit Gibberish - Why Would You Run a Smaller Rear Rotor?

Mar 5, 2019 at 3:23
by Steel City Media  

bigquotesThis week on 'Pit Gibberish', Jason Marsh sparks the debate over 'Why would we run a smaller rotor on the rear?' Does he know? Do we know? Do you know? Answers on a postcard below...The Syndicate



127 Comments

  • 112 0
 I like big rotors and I can not lie
  • 93 0
 Other calipers can't deny
  • 44 1
 When i see a little Tiny brake, u can Kiss my thoughts goodbye.
  • 3 32
flag deadmeat25 (Mar 5, 2019 at 7:32) (Below Threshold)
 @Vudu74:..
  • 41 1
 With a round thing in your face means your sprung, cause you pulled the brakes too tough, and your friends noticed your butt getting stuffed. A rip in the jeans your wearing, everyone's laughing and cant stop staring.
  • 28 0
 'Cause I'm slack, and I'm long And I'm down to get the friction on
  • 29 0
 Baby Got BraAap
  • 5 0
 It's mechanical advantage, it's hard to dispute. Squeeze it less if it's too much for you.
  • 7 11
flag RollinFoSho (Mar 5, 2019 at 20:40) (Below Threshold)
 Why, because most people are trying not to skid around corners and wreck the trails.
  • 2 0
 ain't no breaking when pads are wore
  • 1 1
 @RollinFoSho: @RollinFoSho: actualy not most... but "kind ones" which are maybe those who time to time build or repair some trail...
Big back rotor is advantage in supersteep grippy conditions, which are almost never ocours, so for the most of the times, 185mm back rotor is totaly fine (for trailbike)
I had 203mm on my enduro/trailbike for my Xmass Vacation in Finale Ligure, because u can find there 1km vertical downhills, i was there 14days and NEVER changed my back brake pads, because of the big - good cooling - rotor... and when i came back home, i swith it back to 185 to save some backwheel clearence in tight trails...

DH bike is another thing, u need maximum stopping power anytime and if you are riding DH trails for whole at once, big rotor on the back is way better in cooling -> less eating the pads -> braking more instantly but of course than your back tyre will last just few days...
  • 3 0
 Officially the best thread in pinkbike history.
  • 61 5
 Personally. I like the smaller rear because I dont want to break traction on the rear if possible. When I squeeze the levers equally, on a downhill, my front wheel has more weight in it and so less likely to skid with that force. The rear with less weight will skid with less force. So a smaller rotary equalizes the braking. Plus the steeper the terrain the more you rely on the front brake anyway. Try skidding to a stop in steep terrain it just doesnt work. That's me anyway. But I've run 200/180 and 180/180 and If your brakes are strong enough you'll be fine.

Maybe it's a cop out for when they spec shit brakes? They aren't downsizing the rear but up sizing the front?
  • 12 1
 This makes sense:

@JacksonTM "They aren't downsizing the rear but up sizing the front"
  • 1 0
 Yep, I think that way of thinking answers a lot.

If you want to increase the braking power of the bike as a whole making the front rotor bigger, rather than the rear is the way to do it (if you are going to upsize one only) as your weight is behind the front rotor.

Plus it is hard to get big rotors in most rear triangles.

If thinking of keeping the weight down and going full weenies then you downsize your rear rotor before the front too.
  • 13 0
 I think Marshy may be looking at this from a different lens than most of us. He's looking at heat and how that impact braking performance and he sees a DH bike at the end of each run. He may be seeing similiar heat between the front and rear and therefore is concerned about that heat impacting feel/performance over the course of a run.

WC braking points are a lot different than your everyday riding and making sure the brakes are very consistent for very precise braking is probably his top priority. Versus the subtly in riding styles the rest of use with more last minute and random braking.
  • 2 0
 @dhx42: Agreed, we definitely need to remember that he's talking about braking performance at the World Cup downhill level and these ponderings honestly don't apply to most of us. Long story short: if you're having braking problems, address them. If you're not, keep on keepin' on.
  • 6 1
 The enemy of brakes is overheating - if you ride a park or trails with more than 700m vertical downhill then you should be running 200mm or higher rotors as the heat will dissipate quicker during prolonged usage which will result in a consistent brake lever feel from top to bottom. I ran 180mm for a month at Angel Fire and blued 2 180mm rotors, 1 200mm lasted 2 months with no blue. If you have blue on your rotor it has been compromised - the heat treatment has been weakened. The other factor no one mentioned since physics is a big part of braking - rider weight - 210lbs for me so 200mm is a no-brainer, under 150lbs a 180mm rotor would probably be more than enough.
  • 4 0
 I generally run the largest rotors possible front and back, the key to a bike that doesn't pull skids automatically is a brake that modulates well in my opinion. now 180 is really fine for nearly any application but I wouldn't ever run 160 for fear of the rotors simply getting too hot, people don't realize how hot mountain bike brakes get after a good hard run, take it from someone who has a sizable permanent scar on their shin from one- they get very very hot.
  • 2 3
 The true answer is in the history of DH brakes. They used to be total crap and 203mm rotors were needed not just for heat but for a larger lever to bring down a bike with crappy powered brakes and give sense of "modulation".
203mm is further away from the center of mass and has better leverage, more heat dissipation for crappy old school underpowered DH brakes.

But here is the PRACTICAL reason to run a smaller rear rotor now that brakes are more powerful and you can sneak a 180mm on the bike.

It's for clearance for Amateurs and park rats to not destroy the bigger rotor and/or bend it so the rotor will last more than a few weekends on the back. We all place the front wheel and then rudder with the rear, lean it against a pole, etc.

203mm rotors on the back of my DH bike are a BUTCH to keep from bending all the time.
  • 2 0
 Seems to me you just need to work on your braking skills. Top level brakes give enough adjustment that I can see no reason to lessen the brakes ability. The smaller brake rotor will fatigue your hand/fingers more than it will ever actually help you.
  • 1 0
 @bizutch: When using 180mm or 203mm rotors, I use rotors with a spider. Indeed fearing that they'd otherwise bend from crashes, abuse etc.
  • 2 0
 or you could just run 200 front and back and learn how to control your pointer finger a bit better lol
  • 1 0
 @nismo325: Exactly, brakes have never been so good.
Why would you want less.
I assure you some joey on 180 rotors is using them a lot more than a WC DH racer on 203
  • 1 0
 @bizutch: so try leaning yur rig on the driveside
  • 1 0
 @shedsidechuck: that would be some not so smartness. Smile
  • 1 0
 I fully agree with Marshy's take. Since he's specifically referring to a 180mm rear rotor, that definitely seems inadequate for heat dissipation on a pro DH bike. For sure, you want more power in the front, if anywhere, but brakes are way more commonly feathered and dragged on the rear, and that's what will build up heat over the course of a run. I use my rear brake WAY more than my front, just because of the control aspect through corners and loose/slippery terrain. I don't lock it up, but I probably use the rear 75/25 compared to the front. And yeah, I run 180 on both ends of my trail bikes (dualy and HT), and only the rear rotors get black'n'blue.
  • 1 0
 Yep so you can brake hard and late into corners without you back brake locking up. I don’t drag the back brake much anyway so it’s not a problem overheating.
  • 1 0
 @thenotoriousmic: pick up the paceWink
  • 7 0
 I tacoed my rear wheel once and ended up doing a 15 mile DH with about 25% of my rear brake functional (rim brakes), and it wasn't at all that bad. That day I learned how much more work the front brake does in comparison to the rear.
  • 14 4
 I believe the word they are looking for is "Modulation". Something Shimano brake owners have not seen in a long time... Wink
  • 6 0
 I use a Digitus Secundus Manus to modulate my Shimano brakes. They work really well. Try amazon/ebay.
  • 9 2
 Why wouldn't you?
Honestly, if you're pointed downhill 80% of your weight will be on the front contact patch, meaning the rear will skid out with very little input.
Same reason some motorcycles have dual front discs, but a smaller rear one.
  • 6 0
 I wanted a big disc on the back for instantaneous reaction, not more power, just a quicker response. I did a lot of back wheel steering. But I also smashed a few rotors on rocks, so sometimes I would go smaller if the track needed/allowed for it.
  • 5 0
 Same reasons as with motorcyles and cars - weight transfer and forces needed to brake before traction breaks dictate the size of the brakes. I have never seen a car with the same size brakes front and rear, even on a front wheel drive car where engine braking wouldn't add to rear braking power. IMO smaller rotors cause less mass (especially unsprung mass), less rotational inertia, and more clearance for less impacts with objects - rocks, tree stumps, etc.

That being said, 203 rotors in back would perform better, like anything else, it's a trade-off.
  • 9 5
 I think they do it because it takes effort to engineer rotor clearance on the back of the bike. Realistically, it is probably difficult for a bike with 6" or less travel to take advantage of a 203 in the back, due to weight and traction shifting forward under braking.

That said big rotors all the way!
  • 28 1
 It has to do with physics. Your body is in front of the rear wheel, so the your mass will just drag the rear brake. The front brake has a lot more work to do. Your body is behind is behind the front brake/wheel, so it actually has to stop your body mass from moving forward. That puts the front brake under much more load, so a larger rotor helps provide the extra force (and heat dissipation) needed.
This isn't an argument in support of a smaller rear rotor. It's just an explanation of why a front rotor can benefit from greater size.
Experiment: Pedal to the top of a hill, then fly down at top speed and fully grab your rear brake. You'll skid for ages and eventually slow down. Now, pedal back up, fly down at top speed and then fully grab your front brake -- let me know if you notice a difference in outcomes. Wink
  • 15 0
 @DRomy: this comment needs a disclaimer
  • 6 2
 @DRomy: What you said. FFS, this is known by pretty much anyone who's ever paid attention to their bike.

Smaller rear is for better modulation and the fact that you need much more power on the front before the wheel locks. Weight shifting forward creates more grip on front.

I'm giving Marshy the benefit of the doubt here, but he's coming across as clueless. Sure at WC DH speeds, skidding and modulation might not be an issue, and roasting the rear brake surely is a problem. But riding wet slimy tech, trail riding, not blowing up your local trails, modulation makes a difference. He should know this.
  • 3 1
 @DRomy: exactly, same reason why the brakes and on any car are bigger in the front.
  • 1 0
 @DRomy: good explanation. Plus, a stronger front brake makes stoppies easier for showing off to crowds :-)
  • 2 0
 @westeast: Only in America...;-)
  • 2 0
 @sino428: the big difference is that bikes ain’t cars, you can shift your weight around and use all kind of techniques to generate more grip on the rear end cars can’t, the rear just gets used that much more i maybe change 1 pair of brake pads on the front of my race bike and 5-10 on the rear end and the track i ride the most is 1700m long and has an altitude change of 1000m to put in perspective how steep it is.
  • 1 0
 @satansdog: bikes are different than cars, but the physics is still the same. Just because you use the rear brake more (I’m the same way) doesn’t mean that it doesn’t take more power to stop the front wheel than the back. There will always be more load on the front brakes when you use them. I personally run the big rotors front and back on my DH and park bikes, but that’s preference. I could of course size the back down and be fine.
  • 9 1
 Weight transfer.
  • 3 1
 Agreed. Two factors on rotor size are braking force and heat dissipation. Braking force requirement on the front is way higher than the rear due to the weight transfer (CG height / wheelbase). However, people tend the drag the rear brake 3x longer than the front so it generates about as much heat or more. Therefore you end up with about the same size rotors.
  • 9 2
 I run one pad on the rear.
  • 4 1
 I run the largest rotors my bike will fit, so 200 front 200 rear. I agree there is no point in running smaller rotors unless you're trying to save weight, and the weight difference is pretty minuscule. Assuming that you can exert enough force on the brakes to lock up the rear wheel with the smaller rotors, which should be a given with modern hydro brakes, the only difference is the amount of force you have to exert at the lever with your fingers. Smaller rotor, higher force pulling on the brake lever.
  • 3 0
 Front to Stop, rear to slow down.

Combination of the two. Usually more front than back in any ratio.

Experimenting with contrast exercises will reinforce the first statement.

For the same amount of lever pressure I get a bit more front than back. I would use the same size on a DH bike due to dragging the rear more often (durability and heat dissipation)
  • 3 1
 I started out with a V-brakes front and rear. After too many crashes I upgraded my front brake do a hydraulic disc brake but stuck with the V-brake in the rear simply because my frame wouldn't accept a disc brake. So that's how my riding developed over the years. Relying on front brake and front suspension and basically ignoring the rear. Even though after years I got both front and rear disc brakes (190mm front, 160mm in the rear) I never really started using the rear brake much. I had a few rides with 160mm in the front. That brake rotor turned blue within a single ride. I'm this is riding down overgrown landfills turned recreation area type trails in The Netherlands! Steep, twisty maybe, but definitely short. After that, I never have ridden smaller than 180mm in the front. Actually it is since May last year that I got brake and fork without IS brake tabs that I had to move from 190/140 (f/r) to 180/160. But I never had trouble with that 140mm in the rear.

Yes of course you can't apply the front brake in corners. It just never made me use the rear brake instead. I just learned the hard way to brake hard before the corner if I need to and then just let it roll. If I want more oversteer I shift more weight to the front wheel and at some point the rear wheel loses traction. That slows me down too. Now of course despite what Jason says, I'm probably still slower than him Wink .
  • 8 0
 Burning discs in Holland??? Where?? I need to go there!!
  • 1 0
 @WECustomizeBikes: Haha, you are from the The Hague area, aren't you? It was in Rijswijk, Elzenburgerbos if I recall correctly. Either it was in the section where the A4 trails are, or across the A4 highway. If im riding the latter, it is typically the section where those wooden stairs (with the switchback on the opposite descend). I've got to admit again that especially back then I relied on the front brake exclusively. And I rarely drag the brake. I pick my spots and brake short and hard. The brake in question was a Magura Marta brake. I think I initially bedded those pads in with a 180mm or 190mm rotor and just as an experiment I tried it with the small Marta rotor (with the narrow brake track). So maybe it would have held up better if I had bedded in that rotor too.

I just checked my bike and noticed that the anodizing of the front brake lever has faded whereas except for some scratches, the rear brake lever is still proper black. These are 2006 Louise brakes so yeah, they've seen some use.
  • 2 0
 Personally I like hard biting 200mm rotors, however I only use a little finesse to control them. For me, this keeps arm pump down and lets my old ass finish a big run. I kind of see Marshy's motorbike analogy, but seems like it only applies to downhill tech terrain on a dirtbike. On open race tracks, you don't have time for engine braking to make a difference.
  • 5 0
 Those that ride very steep sustained terrain will appreciate a large rear rotor.
  • 2 0
 My bike came with 180s on the rear but I now run 203 front and back (later on I also changed from double pot XTs to Zees, and that was a transformative upgrade to my bike). I still go through rear brake pads and rotors about twice as quickly as the front.

I weigh a lot and often ride in steep terrain. I'm also probably a hack rider.

Also I find it much easier to modulate a more powerful brake.
  • 5 0
 the biggest brakes you can possibly get all the time every time ...........next
  • 1 0
 Hahaha, yeah, I'm like fifty pounds heavier than when I was young, and my hands are weak.
  • 5 0
 What about brake jack? Dose it make a difference on braking bumps?
  • 4 0
 Rotor size will not make a difference to brake jack/anti rise assuming with the smaller rotor you can still lock up the rear wheel. You're exerting the same amount of braking force regardless of rotor size, just inputting more/less force at the lever.
  • 1 0
 Ummm that's what I was thinking, assuming your 'real world' riding is not locking up the rear end like your filming a edit for PB but applying a more controlled squeeze of the rear brake to maintain speed and control. the reduced braking power 'might' mean a more active rear end. but you could have the same effect with big rotors and just riding death grip!
  • 2 1
 The 180 rotor on the back of my Demo lines up perfectly with the Horst link pivot, so I'm guessing it does have an affect on braking in relationship to the chain stay pivot on 4 bar bikes.
  • 1 1
 @bigburd: It does not matter where it is located, all that matters is what it is mounted to. For example on Trek's ABP design, the caliper is mounted to the seatstay rather than the chainstay to help isolate braking forces and reduce brake jack. This is also why, floating brake calipers that actually mounted to the frame were used in the 90's.
  • 1 0
 @tgent:
So you are telling that there is difference where they are installing brakes in car? Some of the cars have at the “front” some at the “back”.
If it would be issue everybody should install in the same position.
In tbe end the forve is the same bc brakes are working on the same radius no matter if it is above hub or below...
  • 2 0
 And here I am with a 160 on the rear for the reason of not having a large rotor that may hit stuff and bend when playing on trials stuff and plus helps keep me from skidding but on long DH runs it turns blue.
  • 2 1
 I dont see any disadvantage of running a bigger rotor front and back aside from weight, the front brake is used less but has alot more stress put on it when it is used than the rear which equals more heat I prefer two 200mm because i dont care a whole lot about weight but if i had one 180mm and one 200mm i would definitley put the 180 on the rear
  • 3 0
 Larger rotor brakes are snappy. snappy brakes keep hands fresh.fresh hands and nice to have. would like to try some of the 220 rotors on the 27.5 keep it extra snappy
  • 2 1
 To flip the argument around, why are bikes spec'ed with small front rotors?

Many 'enduro' bikes come with f&r 180mm rotors. 180 is fine for most riders in the rear as there is only so much grip to be had with a rear brake, but ride down a sustained rock slab for instance and it's nice to have the extra bite and heat management from a bigger rotor up front. 200 / 203 for both is fine but it means upgrading two sets of rotors / adapters so I normally just go with upgrading the front rotor.
  • 7 3
 Frame clearance, ground clearance, less weight, less locking up, less need for high braking forces. Pick one or all.
  • 1 0
 Just bought myself a 180 rotor today, so I know why people do so - or at least, why I did. The only reason was, that I found it incredibly cheap, and paid for 180 rotor 1/3 of what I would have to pay for exactly the same rotor with 203 mm diameter.

And I regret it already - although the difference was like 3x, it was still less than 20 GBP.
  • 1 0
 Even though I brake equally with front an rear at the lever... Front an rear brakes have different jobs in that the majority of slowing down is done by the front brake as the weight is behind it, the rear controlls the balance an handelling of the bike under under braking as the wieght is in front of it

Think of it as the difference in front an rear wheel drive on a car

Ive recently down sized all my rotors to save around 5-6oz on all my bike but the DH rig. That will allways be 200 F & R because i'm a coward Big Grin
  • 1 0
 At 43 years old with a life of pulling brake lever (most of it from the days of rim brakes) I will always take the biggest and strongest brakes I can have. That way its as easy on my hands as possible as I get deeper into a long run. It does take skill to use a strong brake properly.
  • 1 0
 I have ridden with old crappy brakes from back in canti days, to v brakes, to disc brakes... This made me laugh because I just slapped some 203's on my bike front and rear, which was an sb6 yeti with 180 front and rear....

I rode a devinci at whistler, true downhill rig for the first time and was like 'holy cow'... this thing brakes so easily.... so why not put them on my yeti. I have to say, they are touchy, super touchy if you just XC ride, but I like it... I guess I"m a bad rider, but I like to slide like I"m 11 years old and have a good time, so on/off works for me.

Anything is better than canti rim brakes Smile
  • 1 0
 203 front ,183 back ,for my capabilities it’s more then enough cause for the speeds I get and the ability I have i need more the front brake in that steep hills than someone that can make cornering look easy on steep stuff,but yes I see the point in the real pros using a bigger rotor on the back and with that 29’s why the hell not ?and how about twin rotors
  • 1 0
 In motor industry it is made like that bc rear is generating just about 30% of braking force so putting brakes from front at the rear wouldnt change a lot. At the bike it works the same way. Ofc you can compensate it with weight distribution but still the back will loose the grip easier. Static friction force(blocked wheel) is smaller than dynamic force (rotating wheel) so you will stop later with blocked wheels than with rotating wheels.
Less force at the back give less chance to block wheel. It is just physic during braking you and your bike, car whatever os trying to rotate around the front wheel so the back is going up.
Friction force on tire is F=N*f. N is force of your weight. f is constatnt of friction depends of rubber and what is ground made of.
So when you brake fork dives, back is trying to go up N force is getting smaler so the F is smaller too, than you are loosing grip and it is getting even more smaller. So you dont need so much force to block rear wheel and to avoid that you use less powerfull brakes at the back.
  • 2 0
 Some weight weiner probably wanted to save 4 grams in the early 2000s and the trend just stuck as people tried to justify their reason for copying someone they thought was cool.
  • 1 0
 Im surprised Marshy and the comment section isn't discussion brake modulation. The smaller the rotor, the more force it takes to stop it, and therefore the better the modulation. Better modulation because the more force required, the more room you have to slow instead of stop before braking traction. Minimal for sure, but worthy of being a part of the discussion if weight savings from a 180 to 203 is being considered.
  • 1 0
 Fabien Barel went down to 160 rotors for his world champ bike. Tried it and it worked really well...less chance to hit something also. I think better riders use the front brake more often...when changing to 29er wheels braking changed noticeable - more grip on one hand but also feeling to fast entering some turns/sections. 200/180 is not an extreme take, you should try and switch back to 200/200 if it doesn't work for you...
  • 1 0
 I have been messing around with this particular topic since my very first disc brakes on an mtb; Hope C2. I use my front brake much more than the rear on bike and moto. On DH I have the same size rotor front and back for the very reason he mentions in the final 1/3 of the video. I don't have a gear box and an engine I can use to brake as well and the speed, heat dissipation requirements and I once had a bike with Hope 6ti up front and the 4 pot out back. That was great in the UK but after 2 weeks in the summer in Portes Soleil I cooked the caliper and it was leaking. Same happened in Portugal later that year (note: Hope Service is next to none; sent in direct for £75 and fully rebuilt caliper and new pads both times). However on my trail/enduro or whatever you want to call it this and next season, the rear rotor is smaller. I save weight, I catch it less on rocks on narrow passages, I have yet to blue one, the speeds are not full on as in DH, and yes vanity it looks better imho. Size matters. Even when you do not understand the basics of physics, when a stick wacks you around the head it hurts. All about energy.
  • 1 0
 It's simple. Your discs are blue or black: run bigger discs. You ride in the Alps or in any bigger mountains with long descends: run 200 mm > discs read and front.

I'm riding 180mm in the back of in my bike right now in the Alps. With 82kg and aggressive riding, it's not enough.
  • 1 0
 I reduced my stock 203mm rear to a 180, the lack of weight over the back wheel on steep stuff, combined with a big ol' brake meant it locked up as soon as you looked at it.

would I get less brake jack (its a single pivot) if I could get away with a 160mm, even if it just kept me off the back brake a bit.
  • 1 0
 Love the comments up top, Sir mix-lot would be proud.. Most bike brakes are crap, if they really wanted to make a brake that is durable and reliable it’s easy.. but would add a tiny bit of weight therefore we are left with squealing crap that goes thru pads like a kid thru candy! That’s what they want apparently? We have only been using disc brakes since the mid 90’s what do you expect? Simple brake problems fixed in your lifetime? Haha. Bigger pads with the proper compounds to run thicker rotors and more fluid capacity and bam...problems mostly solved. But why do that? when we can be bleeding brakes after every hard use and buying brake pads like crazy and rotors that squeal like a pig. It’s all about the brake companies making money!
  • 1 0
 ive never understood this trend, my only guess as to why most bikes come with it is because a lot of trail and enduro bikes only have room for a 180mm max rotor, which is kind of annoying. my cotic bfe only has room for a 160mm max rotor in the back which is really annoying. heard some bikeshop bs that its for better modulating or something like that, if I had the choice too its 203 front and rear with the most powerful brakes I can get, brakes are not something to worry about weight or cheap out on, its the most important safety feature on your bike,
  • 1 0
 If you want to under power the back brake (smaller rotor) so that it doesn't lock up when you pull both brake levers evenly then you should learn to modulate your brakes independently. A bigger rotor has more modulation and most of the time your aren't modulating the front and rear brakes evenly. The bigger the better as long as it fits and you don't care about the extra weight.
  • 2 0
 That’s what she said
  • 1 0
 only reason I can think of having bigger brakes on the front is when you go onto the brakes, the weight of the rider transfers forward therefore needing more surface area to displace the heat, similar to cheaper car (including my own) having disks on the front and drums at the back as most of the braking force and heat is generated at the front.
  • 1 0
 200mm Avid in the front 185mm Hope in the rear cause that’s what came on the bike when I bought it. I’m also running Avid Elixcer CR’s which I think most everyone hates but they work for me. Got two sets of Trucker Co pads but haven’t put them on yet so no clue how they work.....
  • 1 0
 Bigger isn't always better. Keep in mind this is at the highest level of racing as well. On my DH bikes i have run 200 mm front 180 rear. On my trail bikes 180 front 160 rear. HT 160 fr 140 rear. Modulation is key for control. And control trumps sheer power any day for me.
  • 6 2
 Once you go 200/200 you never go back
  • 1 1
 Let's put a camera in front of this idiot and see what happens.. Wink You don't need the same amount of power for the rear. I run a 183, 4 piston front and a 160 2 piston rear. No issues. If I want to skid, cuz idiots need to skid to change direction, I would put a 4 pot or a 183 rotor on the rear. But I'm not an idiot. So I wouldn't do that.. Just sayin..
  • 3 0
 ever been to Morzine´s hidden tracks?... check your rear rotor after a couple laps...^^
  • 1 2
 Wouldn't imagine that motorcycle engineers would take into account engine breaking when sizing brakes. Its not out of the possibility to be in neutral. CG of a bicycle or motorcycle are quite high compared to their wheel base so the weight transfer in turn is more.
  • 3 2
 or on a two stroke, so no engine braking anyway.
  • 3 1
 @woofer2609: There is engine braking on a two-stroke.
  • 2 1
 @willsoffe: true, but very minimal to almost none existent in my experience. Depends on the bike.
  • 2 1
 @woofer2609: with a Recluse on a 2 stoke it is like a free coasting moto. I couldn't get used to it. I like the 4 stroke engine braking more.
  • 3 0
 in 2 stroke 125 cc race bikes (and smaller one´s)the guys used to grab the clutch during the braking till mid corner when they start to put some gas and release it. So no engine brake for many reasons,main one it is very easy for the piston to be stuck while hard engine braking due lack of lube and just simply by the extreme angle in the corners, can do the same,grab the piston and boom you are flying...In 4 stroke new bikes you have a system in the clutch to modulate the engine brake so the rear wheel is always turning,no locks,no high-side flip in to the air...There is engine braking on a 2stroke, but it is not very useful and not very healthy for the engine.
  • 3 0
 The title is misspelled or I don’t get the joke
  • 1 0
 Agree 100%- maybe clearance, but really a 10mm (top and bottom) difference, giving up added heat dissipation and power. Make all your brakes Trump sized- huuuuuuuge.
  • 2 0
 Front slows you down,back is for control-therefore can be smaller.
If you don’t know get out of the pits.
  • 2 1
 I currently run a 180/180 set up, and the only reason I would run a 200/180 is because 1 new rotor is cheaper than 2.
  • 2 0
 Funny tio ear the bike industries talking about the bike industries
  • 2 0
 223Front 203Rear or 203 both nothing less!
  • 2 0
 Fox tech guys, using RockShox digital shock pump. Funny.
  • 2 0
 At the end of the day, probably Fox nor SRAM make their own shock pumps. It is typical catalog material.
  • 1 0
 @vinay: Definitely.
  • 2 0
 I'm a clyde....the bigger the better for me....both ends!
  • 2 0
 I'm mostly 100% sure Jason's trolling the pits, and us.
  • 2 1
 The guys got a good point
  • 2 0
 Cuz it’s moto
  • 2 0
 Who even uses brakes?
  • 3 0
 coward levers
  • 1 0
 So everybody will be laughing at my 140mm rotor on my Rocky?
  • 1 0
 Maybe I'm just running a bigger front rotor. Ever think of that?
  • 1 0
 why do you need to even brake in the first place
  • 4 5
 Brakes only slow you down. Smaller real rotor looks cooler and less likely the be bashed on stuff.
  • 1 0
 Works for Rossi.
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