Announcement

Collapse
No announcement yet.

220mm brake rotors

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    220mm brake rotors

    SRAM is offering 220mm brake rotors. I don't see anything about non standard thickness (which the biggest 223mm TRP rotors have). A 60IS bracket will mount them to the front of an IS system.
    They say they're intended for 4 piston calipers. But for my purposes that equlals Avid BB7 with metallic pads.
    200mm is working well for me on a 26" bike. But for a fast 29er, or fatbike I would probably get these.

    https://planetcyclery.com/specials/s...r-220mm-iso-6b

    #2
    Originally posted by Retrorockit View Post
    SRAM is offering 220mm brake rotors. I don't see anything about non standard thickness (which the biggest 223mm TRP rotors have). A 60IS bracket will mount them to the front of an IS system.
    They say they're intended for 4 piston calipers. But for my purposes that equlals Avid BB7 with metallic pads.
    200mm is working well for me on a 26" bike. But for a fast 29er, or fatbike I would probably get these.

    https://planetcyclery.com/specials/s...r-220mm-iso-6b
    I had BB7s on everything. They are great but fussy. Then on my last bike build I went with hydraulics and I will never go back. Set up is quick and then you are done. Set it and forget it.

    That rotor is interesting though.

    Comment


      #3
      So what does the larger rotor do to the stresses on the frame and hub? Why did bike discs start out at what 120 or was it 140? It was for downhill MTB wasn't it so it wasn't all about weight?


      What if we just made the rotors the same size of the rims? Hmmm.... something seems familiar about that idea.......

      Didn't one of the road groups have a hydraulic rim brake? I suppose the issue is getting a stiff enough caliper that doesn't weigh as much as the rest of the bike?

      Comment


      • Retrorockit
        Retrorockit
        Giga Member
        Retrorockit commented
        Editing a comment
        Rim brakes? Seriously dude. They wear out the wheels, don't work at the slightest sign of water, and if you prang a rim the bike won't move.
        If you put a BBSDH on a bike the forces are already there. The two options are to deal with them, or ignore them.
        The limiting factor on front brake torque is either the traction of the tire, or the torque to lift the rear wheel off the ground.The large rotor just allows the dissipation of more heat with less lever force required.The torque limit the bike can absorb remains the same.
        If you want to put skinny tire road bike brakes an an Ebike go ahead.
        Spend some of the money you saved on a GoPro so I can watch the crash and burn video.

      #4
      I already have the BB7s, with metal pads, and for street riding they're more than enough. Hydraulics always "feel" better. But if they're too small for the job they can boil the fluid and be a disaster. A set of proper DH rated Hydros is about $400. If that's in your budget it's the way to go.

      Comment


        #5
        What I am questioning is the forces on the hub and frame or fork. If those are not a factor or concern why did they start so small in the first place? Is just bolting 220's and hydros on something that came with 160's for sure a safe thing to do? I'm mostly thinking of the many cases here were people (including me) stated with a walmart quality bike. I know we have all gone well beyond the original intended design and use by bolting a motor on. I ain't saying right or wrong just asking if this is adding leverage and stresses in places that may not like it. Like you said for many of us and many conditions the tire to ground ends up being the limit but I'm thinking I would rather have brakes maybe slightly softer than have the caliper snap off my frame or fork and maybe take part of the frame with it.

        Comment


        • Retrorockit
          Retrorockit
          Giga Member
          Retrorockit commented
          Editing a comment
          I never would convert a Walmart bike.I only convert bikes with a fork that has some offroad capability to begin with. This is for street bikes, the same with wheels and brakes. Old 26" 3x8,or 3x9 speed MTBs are cheap, common and up to the task.Anything that came with BB7s will have a decent fork and wheel set included. 160mm brakes can lock up the 2" knobbies in the dirt that those bikes came with. 29ers and wider tires upped the braking requirements. Motors,DH racing, and sticky street e bike tires have raised the bar again.
          In fact I did a face plant in traffic once when I broke a crank on a Walmart bike. The chainring fell off the cranks. No motor involved. I won't even ride that shit.

        #6
        There is almost always a benefit of hydro brakes. High speed on pavement hills and big descents on MTB's really benefit from powerful hydro brakes. Even more heresy, there are notable advantages to hydros even on flat pavement. I mountain bike a lot in my home area, and while there is a good amount of technical terrain, there are not a whole lot of long extended descents like I encounter out west. The benefit?...powerful braking with an easy pull on the levers. Think of it as power brakes. I'll occasionally ride for 2-3 hours at a time, and the hands and fingers appreciate not having to increase grip force. It's a real thing.

        Then there's this. These bikes have motor assist. You can crank up some real speed on and off road. When the need to stop arrives, it's nice not to have to vise grip the levers. I recently went to 4-piston brakes for my Santa Cruz Nomad/BBSHD. The treatment of my fingers and hands have loved it. As long as the given brake set has modulation, you're not going to be locking up needlessly.

        This is one of the conundrums of these ebike sites. We're all over the board on the application of these brakes in this discussion, and it applies to discussions on many different components. Some here will be fine with any decent brake, rim or disc...some won't. Application is everything. I just know that more and more of the factory emtb's from Trek and Spec have 4-piston hydros for a reason. On my MTB/BBSHD I'd never go back to 2-piston hydros, much less mechanicals of any kind. But...application is everything and on this widely varying forum of all kinds of ebikes, there is no one-size-fits-all.

        But I still say that good hydro disc brakes are like power brakes and make life easy even if you're not a competitor on the Red Bull Rampage.

        Comment


          #7
          The 220mm rotors will improve hydro or mech brakes. Especially with larger diameter tires. I'm pretty sure they won't help with rim brakes. I guess that makes them useless!
          A high powered E bike can overload organic brake pads on small brakes. On small hydros adding metallic pads can boil the fluid and be UNSAFE. This is from the brake pad manufacturers.
          The only solution is to replace the whole system with a DH rated 4 piston setup. On good mechanicals like BB7 you can safely add big rotors, and metallic pads. This also help eliminate constant brake adjustment.

          Comment


          • Retrorockit
            Retrorockit
            Giga Member
            Retrorockit commented
            Editing a comment
            To get more power from hydro brakes you can add more Pistons.
            On mechanical braked bigger rotors will increase the leverage..
            2x more speed = 4x more heat.
            On mechanical brakes metallic pads are the solution.
            On Hydros due to different fluids, piston material,and pad designs you need a whole integrated system of the proper capacity.
            At TRP the DH racers adopted their E bike hydraulic brake setup.
            This is an example of a proper E bike hydraulic brake setup.
            https://trpcycling.com/product/g-spec-emtb/

          #8
          Retro, Tektro has been doing the 2.3mm rotor for awhile now to match the heavy duty 4-piston brakes. They also offer brake sensor wires to integrate into some of the ebike conversion motors on selected models. I did their HD750 4-piston set front and rear without brake sensor wires as I didn't need them. Here's an interesting thing about most of these Tektro's. I was comparing them at the shop to some of the 2 and 4 piston Shimano hydros. They appear almost identical to most of the Shimano sets. Mine look exactly like XT 4-piston units...even use the same pads. It looks like someone is copying each other. Tektro is a big Taiwan company. Just curious. A lot of folks get the idea that Tektro only makes low end brakes for entry level MTB's from Trek, Spec, etc. They're actually more like GM in that they make econo-cars and Cadillacs. I'm wondering if they make some of the Shimano product too. Most think Shimano makes all their own components. They contract out a bunch of it...to their spec, but contracted out nonetheless.

          TRP makes some good brakes. It's interesting how TRP, Shimano, and Tektro seem to share a lot of similarity in design and even down to appearance. TRP 4-piston also uses the same pads as Tektro and Shimano. On this "ebike specific" brake deal, honestly I think it's only down to the fact they're using 2.3mm rotors. These rotors are definitely a better match to the 4-piston caliper power in light of the much heavier weight of nearly every serious ebike...especially off road models. It's why I went 4-piston. In my case it was more for just that ease of lever pressure trying to haul this beast down instead of World Cup Downhill descents. My hand, finger, and wrist fatigue on a long ride has been greatly diminished.

          Comment


          • Retrorockit
            Retrorockit
            Giga Member
            Retrorockit commented
            Editing a comment
            Just because a brake pad fits doesn't mean you can use them. The metallic Avid BB7 pads that have been around forever also fit the Avid Juicy7. But they warn not to use them in those.Also the lightweight aluminum backed XC pads are not recommended.They both transfer more heat into the hydraulic fluid.
            The Shimano, Tektro, and TRP brakes may all use different fluids, and tolerate different amounts of heat.

          #9
          TRP stands for Tektro Racing Products. So the similarity there is no coincidence. TRP had to improve the fluid, and the plastic in the brake lines to get where they needed to be for offroad racing E bikes. This is a lot different than brakes for OEM 350W world market E bikes like Bosch, and Yamaha sell. In Shimano DH rated disc brakes I've seen Saint brakes with finned heatsinks sticking out of the brake pads to dissipate the heat before it reached the fluid. Probably to avoid having more than one fluid spec. There is no standard for bicycle brake fluid. they vary greatly.
          Since this is a DIY thread I like to post about upgrades for cable disc brakes to have safe, powerful, and dependable brakes for the kind of bikes we build. The TRP 223 rotors have been around but they are 2.3mm thick and will only work with the matching TRP calipers. The SRAM 220mm are the standard 1.8mm thick and more useful for DIY due to that.
          A lot of bikes come with Tektro and Shimano hydraulic disc brakes. Putting a BBSHD on a bike with entry level hydraulic brakes could be a dangerous mistake.
          From best to worst brakes I would say
          1-DH rated 4 piston Hydro. ( don' run metallic pads unless mfg. rated for them) No cheap way to do this.
          2-Upgraded cable disc brakes ( big rotors, metallic pads) BB7 preferred due to good modulation (for cable brakes). Moderate cost. DIY skills. Vintage DH setup.
          0- Brakes I would not use are- any small 160mm front rotors. (I run 180f/160r on pedal bikes for even brake feel).
          -1 Cable with organic pads, due to brake fade. These can be upgraded to #2 status.
          -2 Small OEM hydraulics not at all, due to total loss of brakes if the fluid boils, or the plastic lines melt. Metallic, or light weight XC racing pads can CAUSE this! They can't be fixed!

          I forgot about skinny tire rim brakes. I think you should too.
          Retrorockit
          Giga Member
          Last edited by Retrorockit; 08-16-2021, 09:00 AM.

          Comment


            #10
            TRP sells the big brakes in Europe for street licensed 50kph "Pedelecs". I the US these would be E Mopeds. 50kph speed limit= our 28mph limit. Many BBSHD conversions can easily exceed that.
            They upgraded their DH racing brakes for that market.
            Retrorockit
            Giga Member
            Last edited by Retrorockit; 08-16-2021, 09:53 AM.

            Comment


              #11
              Retro, the TRP, Tektro, and Shimano brakes are designed to run each others pads that are compatible. The aftermarket pads don't even distinguish between them other than pad material guidelines for riding applications. As to mineral brake fluid, I don't care what each manufacturer claims...they have to cover their butts logically from everything from warranty to liability...Shimano and Tektro mineral brake fluid will interchange with no issues. We've been doing it for years at the bike shop in who knows how many bikes. There are plenty of articles and industry speak on this issue that have been around for years verifying the compatibility. You'll never get Tektro or Shimano to admit to any of that. Lawyers and in-house marketers are cowering in the corner...LOL!

              Comment


              • Retrorockit
                Retrorockit
                Giga Member
                Retrorockit commented
                Editing a comment
                Mineral oil can be distilled to have different boiling points.They would still be chemically compatible.
                Their asses may be covered for the OEM bikes they sell. But is your ass covered when you add a BBSHD to that same bike? That's what this forum is mostly about.
                Actually Shimano and Tektro get sued as often as not for their front brakes being "too powerful" on consumer bikes, and ""causing" OTB injuries.
                This is not so much the case with MTB and racing products where the rider is expected to assume the known risks.
                On my list the best brakes are hydraulic discs. the worst brakes are also hydraulic discs. I've given the reasons for that opinion.
                Personally I'm not going to spend the money for high end Htdros, or the expensive bikes they come on. I also won't use the small hydors on any E bike conversion. From a DIY standpoint cable brakes with big rotors and metallic pads simply work.

              #12
              Interesting how Retro mentioned getting sued for having too good of brakes. I recently did a BBSHD on a friends Trek that had Tektro I think V brakes? The ones where there is a bent pipe that the cable slides in on one of the arms. When I first got the bike from him and did a quick evaluation ride around the block I think you could stop faster by dragging your feet. They were at least 5 years old, and poorly adjusted on untrue rims. I got new pads, cleaned, and trued up the wheels and that got them from worthless to terrible.

              For lack of any other ideas I ordered some new cables and went ahead with the conversion. When installing the new front cable and trying to pull tension (by hand, not with a tool) it seemed like the cable housing was moving in that pipe thing. I assumed I just didn't get the ferule end on correctly so pulled it back out and didn't see anything wrong so back it went and this time it seemed to adjust correctly. That was when I noticed the spring on the ground which had to have come out of that tube. I checked the rear and it didn't have one but the tube was shorter and you could see didn't have that extended area for that spring.

              That spring must be there to keep people from hitting the front brakes too hard and going over the bars. With a big person on the bike even before the conversion the result is if you pull the rear all the way to the bar you start slowing down. If you then pull the front to the bar you slow down a little more. Front by itself you could barely feel. Maybe a 100lb person could skid the rear tire tire this way? Not a 250. Without the spring in there I could fairly easily skid the back tire at least.

              Comment


                #13
                73Eldo you are correct in the function and reason for that spring in the "noodle" as its called. I don't know about all brands, but I didn't start seeing that during the assembly of new bikes until about 2010, maybe 2012...didn't write it in my diary that day...LOL! It's a stupid litigious issue more than a real feature. It's funny in that what is more dangerous?...being able to stop before an actual hazard or not being capable enough to modulate your brake lever pressure to cause your front wheel to skid out of control. I've always thought the over-the-bars scenarios are more unlikely because have you ever tried to do a nose wheelie on the level of bikes that have these spring-in-noodle ABS systems?...using ABS reference as strictly a joke. In the Trek lineup, it's interesting to note that the MTB's with V-brakes even down to the lowly 820 entry bike do not have the spring noodle. However, many/most hybrids and such do have them. There's probably some decent logic in that decision...size, width of tires, etc.
                TNC
                Giga Member
                Last edited by TNC; 08-17-2021, 07:47 AM.

                Comment


                  #14
                  Retro, we've been using Shimano mineral oil exclusively at the shop for Tektro and obviously Shimano hydros. It even goes into the Promax hydros. Magura is clearly the outlier. Their Royal Blood brakes use what appears to be a clearly different fluid. It has a crap low boiling point too. Overall I'm not a Magura hater, but they're way down on my list for best hydros. Here's one of the better articles about bicycle brake fluids and systems. It's a few years old but still quite applicable.

                  DOT Brake Fluid vs. Mineral Oil - and the Winner is.. | Epic Bleed Solutions

                  Comment


                    #15
                    Originally posted by TNC View Post
                    Retro, we've been using Shimano mineral oil exclusively at the shop for Tektro and obviously Shimano hydros. It even goes into the Promax hydros. Magura is clearly the outlier. Their Royal Blood brakes use what appears to be a clearly different fluid. It has a crap low boiling point too. Overall I'm not a Magura hater, but they're way down on my list for best hydros. Here's one of the better articles about bicycle brake fluids and systems. It's a few years old but still quite applicable.

                    DOT Brake Fluid vs. Mineral Oil - and the Winner is.. | Epic Bleed Solutions
                    SRAM's recommended fluid is DOT
                    ⚠ WARNING
                    Do not use mineral oil. Use only DOT 4 or DOT 5.1 fluids with SRAM® hydraulic brakes. Do not use any other fluid, it will damage the system and make the brakes unsafe to use, which could lead to serious injury and/or death.
                    I use 5.1

                    Comment

                    Working...
                    X