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Discussion Starter #1
Seems like there has been a lot of talk about brakes lately and it got me wondering - When did disc brakes first appear on a production dirt bike? I know I, and probably a lot others here remember when it was said that disk breaks could not work on a dirt bike. My 1977 YZ 250 had drum breaks as well as the bikes I raced against. When did we all finally decide that disk breaks are superior in the dirt too?
 

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I thought disc brakes were considered better than drums on dirt bikes was in 1982 when discs came out on the KXs. Are you being serious? Theres no way you can compare brakes on.a 1977 YZ to brakes on a 2018 YZ
 

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Discussion Starter #3 (Edited)
I thought disc brakes were considered better than drums on dirt bikes was in 1982 when discs came out on the KXs. Are you being serious? Theres no way you can compare brakes on.a 1977 YZ to brakes on a 2018 YZ
I think you are totally misunderstanding me. I have no doubt about the superiority of disk brakes and have made no statement claiming otherwise. i'm just asking a question:confused:

Do I need to be more specific? OK. When was the first production dirt bike with disk brakes introduced?
 

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No wonder my wife hates me. Sorry Sibyrnes.
Of all the advancements to.dirt bikes I feel discs are the biggest improvement. I.can deal with cooling fins or even twin shocks
Id love to own 77 YZ250 for VMX
 

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I saw a guy ride a 2-wd Rokon up into the bed of a pickup!
I'd forgotten the crazy things had discs.
 

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I'm not sure about other brands, Kawasaki's KX motocross bikes got front discs as standard for 1982, they kept drums in the rear for another few years, but by the mid-80's those were replaced with discs also. As with most things, racing spurs development and of course racing-oriented bikes are the first to get the new tech, with it slowly trickling down to more pedestrian models over the years.

Obviously drums lived on in the trail/dual sport market for much longer. The early disc brakes were not a tremendous improvement as far as actual braking, but the chief complaint was rider fatigue and arm pump from having to four-finger death grip the brake lever constantly throughout a race. Hydraulic discs required less effort from the rider.

I'm not sure why hydraulic drums never caught on with motorcycles. They were extremely prevalent in cars, hell, some cheap economy cars now still come with drum brakes in the rear, of course hydraulic. Motorcycles seemed to skip that step, replacing mechanical cable pull drums straight to hydraulic discs. Likewise, moto's never really got mechanical discs either, although these are extremely common in run of the mill bicycles these days. (with hydro discs being found mostly on higher end bikes)
 

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Discussion Starter #9 (Edited)
Thanks, RaZed, good info. Back in the 70"s it was common knowledge that disc brakes could not be used in the dirt, especially mud. I wonder what changed - was it just attitudes that changed or was there some major improvement that made the disc better suited to dirt riding conditions?
 

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I suspect it had to do with developing pads and self-cleaning rotors that would work in the dirt. Discs had been on street bikes since the late 60's, but through the 70s and early 80's they were the "dinner plate" discs, perfectly smooth. Sintered pads weren't really a thing yet, at least not on the consumer level, and the organic pads of the time would wear out extremely fast off road. Additionally the smooth rotors would tend to trap dirt in the pads, resulting in noise, dragging brakes, and the rapid pad wear.

The main development/revolution (although it seems totally common now) was deciding to drill the rotors, which helped dissipate heat better, and also self cleaned the pads every time you applied the brakes. The advent of sintered pads also gave disc brakes the durability needed to be a practical upgrade from drums.
 

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I race a 83 KX125 in vintage mx. In 83 discs on KXs didnt seem like such a big deal. When I try my buddys CRs and RMs with drum front brakes I cant see how they ride them so fast. I try not to ever let them inside of me entering corners because I think they are going to ram me because they cant slow down
 

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An old racer bud told me once that "Brakes are for pussies!"
Of course, he was a flat track racer...:eek:
 
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