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Thread: Ask the experts

  1. #4351
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    Quote Originally Posted by dfinn View Post
    Will the saint/zee pads fit the new shimano 4 piston calipers? I've bot a bunch of of those pads but it doesn't look like they are going to work with these new brakes.
    The finned ones don't. The actual pad shape is the same though, so the non-finned versions are a go.

    TRP uses the same pad shape too, so those are another option.

  2. #4352
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    All this talk about Specialized sucking back in the day, and no mention of how mediocre VPP was? Every new and improved iteration of VPP was the same wonky curve that me and plenty of others didn't like. The latest iteration is pretty good and it's because they went straight progressive like everybody else.
    Remind me. We'll send him a red cap and a Speedo.

  3. #4353
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    Quote Originally Posted by HAB View Post
    A while back Shimano changed the ID of their hoses, and changed the barb material so there was a visual difference between the two. The stainless ones are the newer version.

    Which generation brake are we talking?
    They are the hot of the press, BR-M8120 4-piston version so the newest.

  4. #4354
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    Quote Originally Posted by HAB View Post
    Harvey Mudd College, since you asked.
    Your school is better than mine. I’ll just say that I graduated from one of the Canadian ones.

    I did win an award for vehicle dynamics simulation work when I was in college, and then had a brief career in motorsports after graduating, so that’s gotta count for something, right?

    The race team’s manager’s daughter actually graduated from Mudd, and that’s the first I’d head of it. She ended up working for Prodrive, but not on the WRC program, alas.

    I did get to work alongside the guy who was the former Prodrive crew chief for Colin McRae and Richard Burns when they were winning their Subaru WRC titles.

  5. #4355
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    Quote Originally Posted by HAB View Post
    The finned ones don't. The actual pad shape is the same though, so the non-finned versions are a go.

    TRP uses the same pad shape too, so those are another option.
    Awesome, thanks!

  6. #4356
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    Quote Originally Posted by bagtagley View Post
    All this talk about Specialized sucking back in the day, and no mention of how mediocre VPP was? Every new and improved iteration of VPP was the same wonky curve that me and plenty of others didn't like. The latest iteration is pretty good and it's because they went straight progressive like everybody else.
    Leverage ratio curve is kind of independent of the linkage design, so it’s a bit of a different topic than has been discussed.

    That said, the falling-then-rising rate curve seems like one of those things that seems to work better in theory than in practice. In theory, it should provide nice small bump compliance around the sag point, and then since it ramps up in both extension and compression you should get some additional resistance to both topping out and bottoming out.

  7. #4357
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    Quote Originally Posted by J. Barron DeJong View Post
    Leverage ratio curve is kind of independent of the linkage design, so it’s a bit of a different topic than has been discussed.
    Seems like that’s exactly the topic being discussed.
    Remind me. We'll send him a red cap and a Speedo.

  8. #4358
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    Quote Originally Posted by Fred Pabst View Post
    They are the hot of the press, BR-M8120 4-piston version so the newest.
    You want the stainless one then.

  9. #4359
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    Quote Originally Posted by bagtagley View Post
    Seems like that’s exactly the topic being discussed.
    Leverage ratio has come up, but the conversation started with a discussion of whether Horst Link is any good compared to newer linkage designs, and that’s really looking at how the wheel moves through it’s travel. Shock actuation is separate from that.

    You can design to get nearly identical leverage ratio curves regardless of whether you have a Horst Link, single pivot, VPP, etc. it’s quite independent of the linkage layout.

  10. #4360
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    Quote Originally Posted by J. Barron DeJong View Post
    That said, the falling-then-rising rate curve seems like one of those things that seems to work better in theory than in practice. In theory, it should provide nice small bump compliance around the sag point, and then since it ramps up in both extension and compression you should get some additional resistance to both topping out and bottoming out.
    I think in the early 00's, shocks and the valving within them were kind of terrible. So suspension designers tried to work around that by building seemingly desirable traits into the suspension design. It sort of worked, but not as well as everyone would have liked. Then shocks got a lot better, but those better shocks were held back by all of the goofy leverage curves since it's really hard to tune a shock properly when the leverage curve has a bunch of inflections. It took until ~2018 for the guys designing the frames and the guys designing the shocks to get on the same page and design frames and shocks that actually work well together.

  11. #4361
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    Quote Originally Posted by toast2266 View Post
    I think in the early 00's, shocks and the valving within them were kind of terrible. So suspension designers tried to work around that by building seemingly desirable traits into the suspension design. It sort of worked, but not as well as everyone would have liked. Then shocks got a lot better, but those better shocks were held back by all of the goofy leverage curves since it's really hard to tune a shock properly when the leverage curve has a bunch of inflections. It took until ~2018 for the guys designing the frames and the guys designing the shocks to get on the same page and design frames and shocks that actually work well together.
    Air shocks, specifically. There have been pretty good coils for a long time, and just to stick with the Santa Cruz example, the V10 has also had a reasonable leverage curve for a long time. All their pedally bikes just had goofy leverage curves, until they went to the lower link-driven shocks. What sucked was when companies made fucked up leverage curves to try to compensate for the fucked up spring curves of older air shocks, and the results were... still fucked up.

  12. #4362
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    Quote Originally Posted by toast2266 View Post
    I think in the early 00's, shocks and the valving within them were kind of terrible. So suspension designers tried to work around that by building seemingly desirable traits into the suspension design. It sort of worked, but not as well as everyone would have liked. Then shocks got a lot better, but those better shocks were held back by all of the goofy leverage curves since it's really hard to tune a shock properly when the leverage curve has a bunch of inflections. It took until ~2018 for the guys designing the frames and the guys designing the shocks to get on the same page and design frames and shocks that actually work well together.
    So you’re saying bring back regressive/progressive leverage ratios and combine them with a new generation of shocks with position sensitive damping?

  13. #4363
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    Quote Originally Posted by J. Barron DeJong View Post


    So you’re saying bring back regressive/progressive leverage ratios and combine them with a new generation of shocks with position sensitive damping?
    I think you're onto something there.

    Do you think we could work some piezoelectric dampers into the mix?

  14. #4364
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    Quote Originally Posted by J. Barron DeJong View Post

    You can design to get nearly identical leverage ratio curves regardless of whether you have a Horst Link, single pivot, VPP, etc. it’s quite independent of the linkage layout.
    Yeah, that’s what I was getting at. VPP was mentioned earlier as being earth shattering, but it was still mediocre because it was designed that way. There were plenty of questionable mini link bikes back then.
    Remind me. We'll send him a red cap and a Speedo.

  15. #4365
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    Quote Originally Posted by toast2266 View Post
    I think you're onto something there.

    Do you think we could work some piezoelectric dampers into the mix?
    I’m only working on it if it includes Graphene as well.

  16. #4366
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    Quote Originally Posted by jono View Post
    Lulz. My BSME comes from an ABET-accredited school. My senior project was a design of a suspension system. But not everyone who took ME took kinematics, it's typically a 400- or 500-level course. I once met a new BSME grad from Cal Poly Pomona who didn't know the term. So it's a bit of a specialization. But it's not rocket science, it's a well-understood field. I've lost track of how many bikes I've ridden in the last 10 years. I'll bet toast has, too.

    Specialized tried everything except what works: 100% anti-squat and pointing the chain at the wheel's instant center of zero velocity WRT the frame at the point of sag. Their bikes needed a certain look and they stuck with it for marketing. Because fuck those guys.

    This seems complex and it is if you're not using the tools often, but it's not black magic.

    Quote Originally Posted by J. Barron DeJong View Post
    Your school is better than mine. I’ll just say that I graduated from one of the Canadian ones.

    I did win an award for vehicle dynamics simulation work when I was in college, and then had a brief career in motorsports after graduating, so that’s gotta count for something, right?

    The race team’s manager’s daughter actually graduated from Mudd, and that’s the first I’d head of it. She ended up working for Prodrive, but not on the WRC program, alas.

    I did get to work alongside the guy who was the former Prodrive crew chief for Colin McRae and Richard Burns when they were winning their Subaru WRC titles.
    That's awesome, you did a senior project.
    That explains why you know waaay more than people with the same education (or better) who do this every day.
    If only the bicycle world knew about you. Hell today's bikes would be pedaling themselves.
    (BTW, mine was from Purdue. No, I don't think I know more than engineers who do this every day, regardless of where they went to school)

    It's a shame companies like Specialized employ only stupid people as engineers. If they had just asked you, they could have made this perfect HL and nothing new would have ever been needed.
    In fact, the whole industry could save tons of cash by firing all their engineers and just "Ask the Experts" here.
    The entire budget could be marketing and TGR.

    And yes, my knowledge on suspension design is seat-of-the-pants. But when the engineer tells you this works better. And your experience is that it does, in fact, seem to work better?
    Maybe he's not such an idiot after all.

    Quote Originally Posted by bagtagley View Post
    All this talk about Specialized sucking back in the day, and no mention of how mediocre VPP was? Every new and improved iteration of VPP was the same wonky curve that me and plenty of others didn't like.
    And yet it was miles better than anything else available at the time, even in it's infancy.
    VPP was the first design to show the promise of being active AND efficient.
    Based (again) on experience. I'd say it's lived up to that promise pretty well.
    Quote Originally Posted by Jer View Post
    After the first three seconds, Corbet's is really pretty average.
    Quote Originally Posted by Ian Malcolm View Post
    I mean, it's not your fault. They say talent skips a generation.
    But hey, I'm sure your kids will be sharp as tacks.

  17. #4367
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    Quote Originally Posted by bagtagley View Post
    Yeah, that’s what I was getting at. VPP was mentioned earlier as being earth shattering, but it was still mediocre because it was designed that way. There were plenty of questionable mini link bikes back then.
    Got it, misunderstood what you were getting at.

    It all comes back to the fact that they can all work pretty well if designed properly, and they can all work like shit if not.

  18. #4368
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    Quote Originally Posted by rideit View Post
    Do we all agree that the SuperD format was a bit silly?
    Super D was awesome
    Quote Originally Posted by Jer View Post
    After the first three seconds, Corbet's is really pretty average.
    Quote Originally Posted by Ian Malcolm View Post
    I mean, it's not your fault. They say talent skips a generation.
    But hey, I'm sure your kids will be sharp as tacks.

  19. #4369
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    Quote Originally Posted by toast2266 View Post
    What jono said. I think everyone pretty much agrees that the specialized bikes from 10 years ago were a mushy horrible mess. But none of that is inherent to the horst link design. It's just because specialized designed a bike with ~75% anti-squat, which unsurprisingly peddled terribly. A VPP or DW bike with 75% anti-squat would also pedal terribly.
    But isn't that the issue with HL?
    It's a tradeoff between active and efficient. By choosing the 75% anti-squat, they were choosing active. Bump that number up for pedaling efficiency and you lose active.
    That's why lockouts were always the only option to get both with HLs
    Quote Originally Posted by Jer View Post
    After the first three seconds, Corbet's is really pretty average.
    Quote Originally Posted by Ian Malcolm View Post
    I mean, it's not your fault. They say talent skips a generation.
    But hey, I'm sure your kids will be sharp as tacks.

  20. #4370
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    Things I have learned from this thread:
    I was wrong, bring back superD!
    Maybe the one race I did was kinda crappy.
    Forum Cross Pollinator, gratuitously strident

  21. #4371
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    Ask the experts

    Quote Originally Posted by Beaver View Post
    Well, I just flew at it and got it apart. The pressure stick is fuct. A new one costs 75% of the whole post so I think it's going in the trash.

    Any comment on Brand X from chain reaction?
    PM incoming

  22. #4372
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    Quote Originally Posted by Roxtar View Post
    But isn't that the issue with HL?
    It's a tradeoff between active and efficient. By choosing the 75% anti-squat, they were choosing active. Bump that number up for pedaling efficiency and you lose active.
    That's why lockouts were always the only option to get both with HLs
    It is a tradeoff, but it's also a tradeoff on DW link or whatever other design you care to mention. Pick any design you want, and you can choose how you want to balance that tradeoff. Formulating your whole opinion of horst link around how Specialized decided to strike that balance for a long time (which I agree, kinda sucked) is silly.

  23. #4373
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    Quote Originally Posted by HAB View Post
    It is a tradeoff, but it's also a tradeoff on DW link or whatever other design you care to mention. Pick any design you want, and you can choose how you want to balance that tradeoff. Formulating your whole opinion of horst link around how Specialized decided to strike that balance for a long time (which I agree, kinda sucked) is silly.
    But that's exactly what I'm talking about.
    From the bikes I've tested, ML bikes seem to do a whole lot better at giving you your cake and eating it. They go down as well as HLs but, in my experience, as a group, they really do pedal noticeably better. They don't give up anything when the trail gets flat.
    And I'm not talking about Specialized. My talking about current model Norcos, Transitions, and Konas.
    Regardless of what your suspension theories tell you, ML bikes really do seem to do a far better job with that compromise.

    You guys seem to be saying that, regardless of design, all suspension with the right curve and rate will act the same.
    Sorry, in my experience, that's just not the case.
    Quote Originally Posted by Jer View Post
    After the first three seconds, Corbet's is really pretty average.
    Quote Originally Posted by Ian Malcolm View Post
    I mean, it's not your fault. They say talent skips a generation.
    But hey, I'm sure your kids will be sharp as tacks.

  24. #4374
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    Quote Originally Posted by Roxtar View Post
    But isn't that the issue with HL?
    It's a tradeoff between active and efficient. By choosing the 75% anti-squat, they were choosing active. Bump that number up for pedaling efficiency and you lose active.
    That's why lockouts were always the only option to get both with HLs
    Like HAB said, it's just a tradeoff. That tradeoff is not design specific.

    The older Stumpy's had a ~75% anti-squat, which stayed super active over small bumps, but pedaled fairly terribly. The older Pivots (to name a DW example) had much higher anti-squat numbers but weren't nearly as active.

    Mostly, Specialized got ahead of themselves with trying to solve kinematic issues with shock valving. They thought they could get away with low anti-squat numbers if they valved their shocks for additional support. In theory that's not a bad idea. In practice, it didn't work very well. But none of that has anything to do with the HL layout. It just had to do with what the Specialized designers were trying to accomplish. Specialized has since abandoned that approach to suspension designs, much the same way Santa Cruz and Yeti abandoned their prior suspension designs (and by that I mean their kinematics are very different now, even though the basic layout of their linkage is similar).

    Edit to add: You specifically named Norco, Transition, and Kona. The Optic, Sentinel, and Process 134 / 153 all have lower anti-squat numbers than your Ripmo. So it's not surprising that they pedal a bit worse. The Ripmo has high-ish anti-squat numbers and (by modern standards) a leverage ratio that's closer to straight linear. That all makes for a bike that's pretty snappy on the pedals. But it's going to be a bit less naturally plush over small chatter, and it's going to rely pretty heavily on the progressiveness of the air can, the high speed valving, and the bottom out bumper to handle bigger hits compared to the Norco.

    But wrapping back around to what Cy said, you're conflating your personal preferences with the actual design of the bikes. Just because a given bike doesn't suit your preferences doesn't mean that particular pivot layout is incapable of suiting your preferences. It just means the design of that particular bike had different goals in mind.

  25. #4375
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    Quote Originally Posted by rideit View Post
    Things I have learned from this thread:
    I was wrong, bring back superD!
    Maybe the one race I did was kinda crappy.
    I think that, moreso than most other race formats, the course matters a lot for Super D. It's super fun on a great course, and super not fun on a bad course.

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