The "New Standard"
August 17 — 2012
Revision 1.6 - The new "standard" when designing a bike frame.
Words by: Joe Graney, SCB Engineering
Each time we work on a bike design - and we're always working on new bikes- the engineering group and our product manager sit down to haggle about what the frame is going to be like, and what type of parts it will accept. This used to be a fairly simple process - it basically consisted of deciding 68 or 73 mm width on bottom bracket width. We try to make a lot of components interchangeable between our various models. If there's not a damn good reason to have different diameter seat-posts or front derailleur clamps, then those numbers remain the same. Recently, however, we've seen a proliferation of new "standards" representing conceptual minefields that must be crossed when designing a bike frame. An incomplete list would include (stick with me through the list, there's a point somewhere near the end):
Headsets: 1 1/8, 1.5, 1 1/8 to 1.5 tapered. And then you have integrated and semi-integrated options for each of those. Stems and forks are both subject to these dimensions, and each one can affect clearance between the fork crown to down-tube as well as influence bar height and frame geometry. To figure out what makes sense for what, we have to balance stiffness versus weight of the entire system, including the frame, headset, adaptors, stem AND fork. I've been told that the purpose of the tapered steerer "standard" (Sram and Fox have different taper lengths...) is to make it easier to find stems. WTF? So they're basically saying there is a new standard (1.5) that hasn't yet been adopted fully, so we're introducing another standard to address it, even though finding a headset or a fork will be more of a pain than finding a 1.5 stem ever was.
Bottom Brackets: 73mm BB shells are fairly standard now for 135mm rear axle spacing, but now we've also got 83mm BB shells, and 100! (my knees ache typing that), and Shimano's new press fit version that still gets you the same chain-line with no weight difference or discernable advantage, and now the "BB 30". Kill me please. In reality, there are only two chain-lines being widely used at the moment; 50mm and 57-ish mm (there's some squabble about a few mm around that one), so why does everyone want to change this? The BB is the part that frames are built around. It's "Manhattan real-estate" for a frame design.
Hubs and Spacing: 135mm QR rear, 135x12mm rear, 150x12mm rear, 100mm QR front, 110x20mm front, and now 100x15mm front. Let us not forget the special dropouts needed to accommodate the old Saint, or the current Maxle, on a frame. And of course there are Maverick's special hubs, and some other company w/ even bigger front axles.
Brakes: 120, 140, 160, 180 and 200mm rotors, you got your six-bolt and your center-lock action. Plus different adaptors for post mount, Boxxer mount, ISO mount, post mount for 200mm, not to mention the Dorado mount, Hayes 22, etc.... Now and again people who make brakes try to tell me that we should put post mount type attachments on our frames, cuz' everyone knows post mount is rad, right? So, uh, how do you face those tabs in a shop anyway? A die-cast fork leg is different than a welded swing-arm assembly. I've been told - multiple times, actually - that it's better for the bolts. Yeah, those M6 bolts used for an IS mount are just crying out, can you hear 'em? Can you?
Wheels: This is a subject that is not only related to axle diameter and spacing and rotor attachment, but also spokes and rims. These are fairly abused items on a bike, rims and wheels being the things that actually hit those rocks we ride over. There are very few "cool" wheels on the market today that can be repaired without a long wait, special tools and lots of patience. Oh, and they cost more. Cuz its freakin' bitchin' to have white spokes when I'm x-in' up, yo. I'd be remiss if I didn't mention the 29" and 650B wheel sizes. Yup. At least the hubs remain the same for those things, thanks to the freaks for leaving that much alone. [Late update: I just read about 135mm spacing front hubs for 29ers, what a relief!] I can see the message boards lighting up now, a boycott might start any minute now.
ISCG "standards" include about 13 different ways to configure three stupid holes around the bottom bracket. And even then half the chain-guides on the market don't fit right without spacers, and putting your cranks on, then taking them off, and on, and off to get it right. And then there's ISCG05, same 3 holes 'cept we moved 'em! These holes initially held a back-plate to orient rollers that weren't abused much, but now people are hanging "taco" style bash guards on there which puts a lot more force on that little frame tab. And how do you weld that tab on anyway? It's only in the way of the freaking DOWN-TUBE on a lot of bikes. Beauty standard you got there. Well thought out.
Seat-posts: I don't have to list every diameter post there is, but to add to that mess, road and XC bikes are now getting super neat by not saving weight and adding a new way to screw up your bike by integrating the seat-post into the frame. Anyone ever cut a steerer tube too short by accident? I wonder if anyone out there has had to buy a "tall" saddle to make up for a mistake... Wanna sell your bike ever? Here's a great way not to.
Saddle/Post: There are different rail diameters of course, along with the unfortunate execution of the I-beam concept. I predict this relatively constant area to blow up in the next few years. It's just too predictable and easy not to have new "standards". Roadies are already getting into one piece molded post/saddle combos.
Bars and Stems: Forget about the varying stem length and bar widths, that's something justifiable. But if, speaking as a bike company, you figure on two steerer diameters, 5 stem lengths, and two bar diameters (25.4 and 31.8), then we've got 20 different combos right there. No wonder you can't find the combination you want for a particular type of riding (from a product manager point of view) that doesn't suck or cost a ton. Nobody can commit to tool up that much crap.
Derailleur mounting and cable routing is another thing, but probably more arcane than is worth getting into - top and bottom pull, top and bottom mount, 31.8, 34.9, E type, etc. Shimano should be applauded for doing a great job in recent years of making their FDs work in multiple situations though with adaptors and clever design. Just wait though; new "standards" are coming your way.
I won't even get into shock mounting or annual height increases of fork top caps, as I think my point is made. There are lots of different "standards". Fans of evolutionary theory might argue that this sort of proliferation is good for mountain bikes, and I tend to agree with that sentiment - in theory. However, the concerns I have are when a trend conflicts with two core values I hold when designing a new bicycle: choice and long-term support. There's a crew of mountain bike freaks that work at Santa Cruz Bicycles engineering department. We're not old-school curmudgeons and don't sit around lamenting the day that clunkers weren't used anymore. We get paid to push the envelope and be creative and come up with new stuff. But evaluating "performance gains" versus our core values is something we take very seriously - we put a lot of time into figuring out if the new way will be better than the old way. And I mean things that are fairly basic, albeit time consuming, like calculating the system weight by switching a frame to integrated headset from a plain old boring press in style. Call us crazy, but that seems like something that should be considered in the decision making process. Turns out, it doesn't save more than a few grams, it decreases your choice in headsets, and it looks kinda dumb with some forks.
Choice, as we define our customizable mountain bike builds, depends on compatibility. Long term support, to a great degree, does as well. It's hard to be confident that the newest steerer tube diameter or BB attachment scheme is going to be supported for a long time by the company introducing it, and for that reason it's difficult for us to spec a frame with a new "standard", since we want our customers to use our bikes for a long time. And if only one or two companies adopt the new specifications, one's choices and chances for long-term support are even more restricted.
On the surface, this multiplication of options seems a boon for cyclists that appreciate performance gains. Look a little closer, however, and sometimes new options are introduced merely because the manufacture has nothing new to offer, so they create "buzz" by making something different even though it doesn't provide much in terms of increased performance. Companies introducing new standards have a vested interest in their success, and we should all be wary of accepting the marketing claims. The performance data (if there even is any) should be independently vetted. Often, it takes years of evolution with any new design to optimize it, since engineers are typically (and hopefully) initially conservative with the design to ensure rider safety.
Some critical questions that get in the way of the rad factor with any new product can go a long way in determining if that product has been well thought through. Beyond the system weight comparison mentioned previously, there are some even more basic ones: How do you get those bearings out? Does your local shop have a tool? How much does the tool cost and when will it ship? How exactly does pressing bearings in make a difference? Did you make up a problem to solve after you made this thing? What other problems does it create? Let's take this marketing BS down to brass tacks here, because I don't want to screw with my bike all the time. I want to ride it, put it away and go drink beer, okay? Tomorrow, I want to pick it up and do that again. Maybe some people have the time and patience to screw with their bikes all the time, but I bet many of these people (a) don't ride enough, or (b) don't have a life, or (c) consider working on their bike a hobby. (If you are (c), I have some stuff to sell you, gimme a ring.)
There's plenty of opportunity for improvement on bikes. Hey, it's what I do for a paycheck, so there better be. There's a flip side to the coin though. I have the first frame I ever designed (a fixed gear made in Waterloo) that I can't get the bottom bracket out of, because the new "standard" tool that the manufacturer dreamed up in 1996 is extinct, and it worked so poorly anyway that it destroyed the interface the last time I tried to remove it six years ago. I'm lucky that the spindle still turns, which is more than I can say for some of these brand new "oversized" bearings that don't last six months without seizing up (and those were created by the people that want us to change). Does anyone understand how much work that is? There's moving front derailleur mounting, pivot locations, tire clearance, down-tube welding, alignment, QC tooling, machining tooling, etc., etc... It better be for something, but the track record is not looking good.
Let's face it, we've all been burned before with glittering promises of radness, stiffness, and the newest bestest thing ever. But when you open the box, does it really deliver as advertised? When do we wake up and not believe the same old song and dance? Show me something that lasts ten years and I'll change to it tomorrow. Boring, huh? I just want my bike to work well and last a long time without spending more money on it.
Done well, product improvements can make our bikes lighter, stronger, faster and more fun to ride. Done poorly (no perceptible improvement but a 100% increase in incompatibility), they can disenfranchise riders who find themselves unable to get parts and have their vacations or after-work rides ruined by simple mechanical failures that can't be easily repaired, and create a whole scrap heap of prematurely obsolete bicycles that could otherwise have had longer functional life-spans. The "market" (that's you by the way) has the last word in this. If you can control your addiction to shiny new stuff for a few minutes, and ask the right critical questions when faced with "new standards", manufacturers and suppliers might think twice - or even once - about those questions before they dribble out their next batch.