I expect your difference in experience has less to do with the caliper (BB7s vs Klampers are similar designs) and more to do with your dropouts or perhaps your skewers. The problem is caused by slight differences in how the wheel is seated before and after you remove the wheel. With rim brakes, those slight differences wouldn't matter so much, but with discs the tolerances are so low (that's the whole point after all) that even a slight change in alignment will require you to reseat the wheel and/or recenter the brake caliper. I use Pitluck locking skewers (city life) and I wonder if that explains part of my difficulty – QR's would probably be easier to create a consistent seating. And perhaps some dropouts are better than others for this (thru axel dropouts being an obvious example). Finally, it could depend on your brake levers and how much deadband you are trying to achieve in your adjustment. Backing the pads off a bit will allow more room for slight changes in alignment.
I've had hydraulic disc brakes on other bikes and they don't address the issue of pad *alignment*. Where they do help is in adjusting for pad *wear*. Newish hydraulic calipers with dual pistons have a seal around each piston that is intentionally designed to slip as the pads wear and travel distance increases. This has the effect of managing the deadband so that the pistons and lever always move the same amount before contacting the rotor. It also means that when you do change the pads you'll need to pry the pistons back to reset them to their fully out positions – otherwise rotor won't fit between the new pads. Without this feature (ie with all mechanical systems), you have to adjust the pads as they wear thin and effectively move further from the rotor. Not a big deal if it's just turning knobs, but it is a thing you have to do. It's worth noting that this isn't unique to disc brakes – you have to adjust rim brakes to compensate for pad wear too – but, less often. Again the system is made more sensitive to adjustments as a direct result of the low tolerances that are a feature of disc brakes. Best, William On Wednesday, December 27, 2017 at 1:31:19 PM UTC-8, Patrick Moore wrote: > > Eric: question about hydraulics versus cable. I've read in more than one > place opinions by experienced disc brake users that, when it comes to pad > rub and adjustment to avoid it, there is little difference between > hydraulic and at least the better cable systems (I include BB7s in this > last category). Has this been your experience? > > For my own purposes, the simplicity and trailside fixability of cable > systems is a very big plus -- tho' I realize that having to stop trailside > to fix a hydraulic system is a long-shot. I have also found that my 4 BB7 > -- perhaps 1 was BB5 -- setups worked well enough that I have no real > desire to improve them; the only time I tried a hydraulic system -- my nd > neighbor's new mtb -- I found that a wee tweak with 2 fingers almost sent > me over the bar. > > I will add that, with BB7s, the pads stay centered when you remove, and > when you replace, the wheel. I will add, also, that Jan's deprecation of > BB7s in the last BQ is entirely wrong -- IME, as above. > > So, the only reason for me, I stress "me", to swap would be pad adjustment > and avoiding rub. In your experience, do hydraulic systems have fewer rub > problems than cable systems? Your data point will be useful. > > Thanks. > > On Wed, Dec 27, 2017 at 1:51 PM, Eric Daume <eric...@gmail.com > <javascript:>> wrote: > >> I think hydraulic disc brakes would address most of your concerns: >> >> - the pads basically stay centered, so wheel removal is easy >> >> - once they're set up, maintenance basically involves changing the pads >> when needed (this takes about one minute). Yes, I guess you could bleed >> them every year, but so far I haven't seen the need. >> >> - strong, progressive, etc. >> >> I bought some TRP Spykes, hoping that with their dual pad actuation they >> would be as good as my mid level Shimano hydraulics. They're nice, but the >> hydraulics just feel so much better. Sometimes I find myself braking just >> to enjoy the feeling of braking, which is pretty silly. >> >> That being said, I really like V brakes as well, especially if I'm >> changing cockpit around quite a bit. >> >> Eric >> >> On Wed, Dec 27, 2017 at 1:41 PM, William! <william.c...@gmail.com >> <javascript:>> wrote: >> >>> Apologies for resurrecting such a stale thread with a giant post, please >>> feel free to ignore while I add yet another two cents to the discussion… >>> >>> The reason I've always been attracted to Rivendell bikes is their >>> resistance to the general trend of making bikes more complicated then they >>> need to be. So much of "progress" with bikes (and with stuff in general) is >>> about applying technology for technology's sake, making bikes complicated, >>> expensive and generally worse to ride in the name of performance or >>> "efficiency" or whatever. Before I discovered Rivendell, I mostly built and >>> rode old bikes for this reason. But of course, not *all* new technology >>> is bad. Sometimes new technologies come along and they really do make >>> riding better. My general rule of thumb is, it's better if it makes things >>> *simpler*. >>> >>> For me the perfect example is riding with dynamos wheels. They are >>> new-fangled, technically more complicated, more advanced. And you do deal >>> with some extra complexity during your wheel/bike build. But after that, >>> you never have to worry about your lights again. For folks that ride at >>> night, a bike with generator lights is far simpler. It feels freeing, it >>> feels like less to worry about, the way a bike is supposed to feel. I >>> sometimes wish dynamo hubs were easier to take apart and service, but in >>> practice they last plenty long and like most sealed hubs the bearings >>> rarely fail. >>> >>> So what about disc brakes? I've owned bikes with disc brakes before, but >>> they were always special purpose bikes like tandems or cargo bikes that >>> needed tons of stopping power. I was never happy with how fussy they >>> seemed, but I did like how well they worked in the rain. They seemed like >>> they primarily belonged on special purpose bikes, and I never considered >>> putting them on my daily driver. It seemed like disc brake technology, >>> driven by racers and extreme mountain bikers, were chasing things I didn't >>> care about: theoretical stopping power and "modulation", weight savings, >>> etc. Meanwhile, they were ignoring things I did care about by heedlessly >>> making bikes more complex: lines to bleed, new tools to own, and an insane >>> parade of new frame and hub "innovations" that promised obsolescence was >>> just around the corner. >>> >>> A few things convinced me to put disc brakes on my "normal" bike. One, I >>> was in a wreck where stopping distance was the primary factor in me walking >>> away OK. I knew that in the rain with cantilever brakes the result would >>> have been different (which isn't to say disc brakes alone would have saved >>> me). It rains all winter in Portland, and that experience had me spooked >>> enough that I started thinking seriously about disc brakes for my commute. >>> Two, the aforementioned wreck ruined the fork and buckled the down tube and >>> top tube on my Atlantis. When I decided to repair it, I had a once in a >>> lifetime (hopefully) opportunity to change the braking system at minimal >>> extra cost. Three, there finally seemed to be some decent, no-nonsense >>> brake calipers on the market. The Paul Klampers were particularly >>> appealing. They are made by a company that I trust to provide support and >>> replacement parts for the life of the bike. They prioritize simplicity in >>> their design. They are unabashedly mechanical. You can completely take >>> apart and re-assemble them with basic tools in a few minutes. And, in the >>> name of dependability, they are wonderfully overbuilt, just like my >>> Atlantis. It'd be a stretch to say the Klampers are designed for normal >>> people (as their price belies), but they are the closest thing I've seen so >>> far. So, with some reservations, I decided to go for it. But I wondered, >>> would it be an improvement on a bike I loved dearly that already braked >>> just fine? Would they make my bike simpler or more complex? >>> >>> The answer for me is a mixed bag. Good disc brakes do make bikes simpler >>> in meaningful ways. They are things technophile complexity-hawkers never >>> talk about. Your bike and especially your rims stay far cleaner with disc >>> brakes, so when you stop to change a flat you don't end up with filthy >>> hands. That's a big deal, especially if you ever ride for practical >>> transportation! Your rims don't wear our after a particularly hard wet >>> season. You don't have to worry about stones in your pads or riding when a >>> wheel is slightly out of true. You don't have to disengage the brakes or >>> deflate to remove a wheel with a plump tire. With the Klampers at least, >>> pad adjustment is easier than any brake system I have owned (which is >>> important because you'll probably adjust them more often than rim brakes). >>> Klampers have two big wheels you can turn with your fingers. It's more >>> intuitive than adjusting brake shoes and it doesn't take any tools. Last >>> but not least, disc brakes really do work better – not theoretically better >>> but honest real-world better – in the rain. All these advantages are ones >>> that make riding a bike nicer, simpler, more fun for just about anyone who >>> rides a bike. Not performance-oriented gear heads, but normal folks who >>> want to just ride. >>> >>> However, there are also a bunch of everyday problems with disc brakes. >>> Again, not stuff people usually talk about. Stuff that will be a nuisance >>> for most people and a total bummer for some. Number one, reinstalling the >>> wheel is harder. You have to align the disc into the very narrow gap >>> between the pads. I have a friend who got a new commuter bike with disc >>> brakes and the first time she got a flat she couldn't get the rear wheel >>> back on without taking it to a shop. She's no newbie, she's changed flats >>> before living in canti-world, but aligning the rotor into its tiny slot >>> while holding back the derailler cage and getting into the dropouts was >>> just too much. Her's were hydraulic disc brakes, and sometimes with those >>> you also have to wedge something in between the pads to push them to back >>> out far enough to fit the rotor. Could component makers make this easier? >>> Maybe add a quick release function so it's easier to get the rotor between >>> the pads? I'm not a component designer, but the point is I don't think the >>> industry is trying to do these things. The goal isn't simplicity, it's >>> lighter calipers or integration with the latest drivetrain fad or some >>> other such nonsense. >>> >>> Number two, when you reinstall the wheel you typically have to do some >>> fine tuning or the pads will rub slightly. Ideally anyone who rides a bike >>> should be able to fix a flat themselves, but now they have to learn extra >>> things and take an extra 5 minutes on each flat and boy is it a pain to get >>> the pads to stop rubbing when you don't have a stand or a friend to hold >>> the bike up while you spin the wheel and adjust the pads. There are some >>> little tricks you can use but none of them are intuitive and it's just that >>> much more to learn. Hydraulic disc brakes also claim to be adjustment-free >>> but in my experience that just means you can't adjust them and they rub all >>> the same. At least the Klampers make adjustments easy. Still, I can't help >>> but wonder if brake makers could make this more practical if they were >>> focused on the needs of normal riders. The industry probably thinks it has >>> already solved this with thru-axels but you can count me suspicious. A >>> brake system that demands a whole new frame and fork design (not to mention >>> rack placement), a new hub design, new skewers – that doesn't seem simpler. >>> What will happen when the industry moves on to some other standard? >>> >>> Number three, you can't keep an eye on pad wear - to check it you >>> generally have to remove the wheel. I don't see any reason why someone >>> couldn't design a caliper where you could easily inspect the pads, but no >>> one has. Perhaps because they are all busy chasing performance and the next >>> thing? With Klampers, you can just barely see the pads from one angle but >>> you'll probably have to get off the bike to see the front pads and you'll >>> have to flip the bike over to see the rear. Perhaps some folks are not >>> going to pay attention to pad wear no matter how obvious you make it, but >>> it seems to me that hiding them away makes the bike more complex and maybe >>> even more dangerous. If you can't see it, it's harder to check it, harder >>> to understand it, harder to explain it – it turns the whole brake caliper >>> into a mystery braking box instead of a simple machine. >>> >>> -- >>> >>> More than ever I feel that Rivendell is both right and wrong to resist >>> the disc brake trend. I believe disc brakes probably *could* make bikes >>> simpler and more joyful but for an industry that pursues all the wrong >>> things. And perhaps someday they will. More and more commuter bikes have >>> them, and perhaps we will see the emergence of a new component line that >>> priorities simplicity and maintainability over theoretical performance and >>> weight savings. Will they be able to do that without inventing yet another >>> frame standard? Will we ever see the emergence of a classic, timeless disc >>> brake design that will still be available and work just as well 30 years >>> down the line? One can only hope. >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "RBW Owners Bunch" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to rbw-owners-bun...@googlegroups.com <javascript:>. >>> To post to this group, send email to rbw-owne...@googlegroups.com >>> <javascript:>. >>> Visit this group at https://groups.google.com/group/rbw-owners-bunch. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "RBW Owners Bunch" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to rbw-owners-bun...@googlegroups.com <javascript:>. >> To post to this group, send email to rbw-owne...@googlegroups.com >> <javascript:>. >> Visit this group at https://groups.google.com/group/rbw-owners-bunch. >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > Resumes, LinkedIn profiles, bios, and letters that get interviews. > By-the-hour resume and LinkedIn coaching. > Other professional writing services. > http://www.resumespecialties.com/ > www.linkedin.com/in/patrickmooreresumespec/ > Patrick Moore > Alburquerque, New Mexico, Etats Unis d'Amerique > ************************************************************************** > ************** > *Auditis an me ludit amabilis insania?* > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. 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