Rotor Size Article - Larger Rear Rotor?
- Thread starter djjohnr
- Start date
Yeah, 203mm was the "big" rotor size for a long time because it's (almost) 8''. Then SRAM (correctly) decided that was dumb because it made adapters more complicated and went to 200mm, but most other brands didn't follow their lead to it turned into that XKCD comic about standards, and then when 220/223mm rotors started to be a thing nobody bothered to fix it so now we have both of those too.
2 stoke hard enduro would be closest i suppose pretty low engine braking....
2 stoke road racers high grip surface but if you go fast enough anything is a low grip surface....
203mm are 8" from merica
200mm are metrics
223 hell if I know? Maybe just to use a 180 to 200mm adapter or 160 to 180 adapter to get from 203 to 223
Don't forget 225 hopes and old formulas
I think the old Redravens were 235mm.
so none then!
I'm of the opinion that comically large rear rotors will be in fashion in a few years. Heat dissipation is a problem with bike rotors.
Also, the mopeds bike stores are currently selling will require larger rotors anyway, and that will probably drive the trend.
Also, the mopeds bike stores are currently selling will require larger rotors anyway, and that will probably drive the trend.
I hear plenty of 2stroke trail dirtbikers complaining about overheated rear brakes, none about the front. There's this assumption that moto has it all figured out from so many years of racing but those guys sure don't know dick about downhilling and brake use. Enter a dirtbike race and be prepared to dominate everyone when the trail turns down. In fact, other than a very small group of trials trained riders I'd say dirtbikers are shit on techy trails. It's the blind leading the blind when talking about gear and technique. All those guys on 240lb bikes, sitting the whole time, and crawling through tight trails. It's funny to see how much better it can be done on a 110lb Surron with some MTB style. Dirtbikers are as driven by tradition as roadie/XCers. No ability to think outside the box, try new things, or figure things out for themselves.
I don't know too many dirtbikers but a good percentage of the ones I have met I have had to wonder if they were missing major structures in their cortex.
That's true for the majority of amateur class off-road racers. In the Expert/A class events where there are major downhills in the desert races, there is still significant opportunity for passes and gapping on the downhill sections/technical sections.
In the AA class and Pro class though, those racers are VERY competent descenders. To the point where I'd say they have a lot more finesse than most mountain bikers especially on really messed up terrain with high consequences. Many have trials backgrounds, but many do not, or get into it later in their riding careers. All of them are mountain bikers however (varying levels).
The variance in speeds in those classes though is really wide compared to DH/Enduro times. It makes DH racing even more mind-boggling.
Motocross track riders aren't real likely to think outside the box on gear and setups and usually stick to tradition. With off-road riders you'll find some seriously wacky setups though. Some have merit, some are just the result of a series of rabbit holes. And other things are just tradition for the sake of tradition and never seem to get questioned no matter the group.
The good old days of running the biggest rotors you can find on Magura Gustavs
Also weren't those Gustav discs completely flat, with no cuts or holes? They must have been really fun to ride in the wet...
Sorta related, I just realized what your profile picture is, hahaha!
I saw it in a forum a few days ago when looking up brake stuff.
Ah, I see you're taking the thread derailing path moar seriously my young Padawan.
Lead you through it I can. But commit to it you should.
Gustavs had so much power this was never an issue. I used them for 3-4 years and I never had any issues with them. Earlier models had weak lever bodies but later ones were perfect outside of weight.
I stand corrected sir! Which Magura model had those thick, not cut rotors then?
I think it was Sachs disc brake, steel and AL rotors, one for dry, other for wet wetther. It was terrible
Also Gustav but earlier model years. I remembering using it on my first dh bike
Wow, that's closer to the 220 Magura that I have, with the expansion design. This is what I think of when I think of old Gustavs: https://www.retrobike.co.uk/threads/magura-gustav-m-front-brake-with-rotor.398684/
The floating caliper design was interesting. I don't know if other dirt bikes use it, but cars definitely do.
Yeah all the dirt bikes use pistons only on one side and the caliper slides.
When they went away from magnesium their brakes worked amazingly. Just not their XC brakes but in those days no xc brakes worked.
I will say that the modulation with a 6" rotor was still the best of any brake I have had, but they would get hot in one good stop and the lever would come to the bar.
The original Magura brake hose or whatever it's called expanded like crazy too, I had Goodridge hoses with both sets, it made a world of difference for that one stop before they overheated.
That's the same setup I use on my 105lb Surron, where they have plenty of power for 1 finger stoppies and skids while heat capacity has never been a problem. Should be plenty of brake for any MTB scenario.
All dirt bike rear rotors are solid and all dirt bike calipers (front and rear) are floating. Kind of 50/50 split on floating rotors vs solid rotors on the front though. I don't think there's even room for the rear rotor to have rivets. The hubs are larger in diameter than the front and the rotors are smaller.
Also switched to goodridge. Hell I'm tempted to do it on my current bike. I hate the feeling of expanding brake line
Probably a Julie that broke. Back in my shop monkey days we sold Julie’s on all our budget builds because they were cheap as hell. We bought OEM cases of them for like $25/pair. They were a goofy ultra low pressure system that used cheap plastic lines and even cheaper plastic fittings, they did work well when they weren’t broken.
Louis, at least the 2nd Gen forward, we’re phenomenal. There’s still a set on my ‘05 yeti that have never been bleed. Still feel better than most new brakes and they had gobs of power, if it weren’t for being 51mm IS I’d probably still have my other pair on a bike.
Magura also used Galfer rotors that were thicker than standard and had far fewer holes back then, I think that helped their performance a lot. I’ve never had a rotor last as long, stay as true and refuse to heat up quite like those early Galfer/Maguras.
Still have Louise BAT's (2010ish?) with Venti rotors still in service on one bike.
They are still strong and well modulating - just a good feeling brake, well at least on the 26'r they are on. The rotors are about done as they are now pretty worn at 1.7mm (2.0 when new) but still running true. I had really good luck with these rotors having a few sets. Just wished the adjustment knobs on the brakes were alloy and not plastic.
They are still strong and well modulating - just a good feeling brake, well at least on the 26'r they are on. The rotors are about done as they are now pretty worn at 1.7mm (2.0 when new) but still running true. I had really good luck with these rotors having a few sets. Just wished the adjustment knobs on the brakes were alloy and not plastic.
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Those rotors were sold quite late after 2010 I'm sure since I found them new at quite a few shops around 2013. They were amazing. If I was on the market for a new rotor I'd seriously consider hunting those.
Also this topic really makes me want to visit my father only to dig through the old parts cellar