It is a shame that the idea of finished build stack and reach has not become more widespread...with algorithms for determining this from frame stack and reach and knowledge of the cockpit components. Actually for complete bikes, the maker could easily provide the finished bike stack and reach once standard definitions of that were agreed to. Now that would really simplify bike buying.

yeah, but if you knew what you were getting ... you might get it elsewhere. How can you be convinced to buy according the the decal on the down tube if you actually know about the bike?

The bolded part is the premise by which we claim to operate. But clearly manufacturers' expect us, or at least those of us who are smaller than average, to not. Smaller riders are forced to adopt a position more forward than taller riders, or accept very short stems.

I guess the point of this thread (originally started over a year ago) was to question the whole 'stack & reach' concept because it seems clear to me that it either doesn't really matter given some popular frame geometries or matters much less than we all seem to think or smaller riders are out there suffering for no good reason, but since I can't change size I'll never know.

For now, I'll be happy knowing that the one very small female for whom I set up a road bike is on a bike with geometry that conforms to the norm for average cyclists, thanks to its use of ISO520 wheels. She may be riding wheelchair tires but at least they are good ones (Schwalbe Ones).

Terry used to, and may still. And 24" wheel road bikes are available, but marketed to kids and not small adults for whom I've found they work quite well. From my research, Japanese woman frequently ride 24" wheel bikes but it is virtually unheard of in the US.

What you suggest would be interesting but would require posting ranges for each as steerer tube height and stem orientation will affect each, and those are set by the bike shop not the manufacturer.

I am completely stumped as to why smaller road bikes dont use 650(b or c depending on need) more often. I just started a framebuilding class and one of the students is building a mixte for his shorter statured mom. It was really interesting to see on paper the difference 650b wheels make compared to 700c within the frame design.

Trek has a 650 Emonda, Fuji has an Ace 650, and Diamondback has a Podium 650. I know there are some others too, but they are far and few between. In an age of cycling where there is such a diversification and flood of different bike styles- 650c road bikes are almost totally ignored.

I fully intend on getting my oldest kid a 650 bike when she grows out of her current converted 26" bike.



How often have you seen/experienced/heard of a rider blowing 2 tubes AND a tire on a road ride? This is such a rare example that it seems there is no reason to mention as a fear/concern. If someone blows 2 tubes and destroys a tire in a ride- they need to just stop, call it a day, and try again later. I would think the odds of this all happening close to a shop that has a 700c tire would be slim, so whether a shop has a 650 tire or not is sorta moot. Odds are a rider would have to hitch a ride to a shop, so just get a ride home instead.

I am asking what chas58 does.

Or perhaps the issue is that taller riders are forced to adopt a position that is more upright than smaller riders.

I say this half joking and half serious. Joking in that its could just be all about perspective. Serious in that for example- Japanese road bikes in the 70s and part of the 80s which had large frames were often built with top tubes that were seriously short, relatively speaking.
Geometry at extreme ends of the spectrum is often head scratching, even with the knowledge of history and using today's tech.

This reminds me of Specialized making a huge deal when they first started optimizing tube diameters and carbon layup for different size frames, when a bunch of other manufacturer's had already been doing it for years or even decades. Good marketing that, pretend you are pushing the envelope when you are instead just catching up.

Maybe that falls under what I mentioned as standards. Perhaps 10 mm of spacers would be the standard. Then there are internet sites where the conversions for fewer and more spacers can be done like that one that is used to compare stem lengths.

True.

You'd also have to standardize which orientation the stem is installed. Aside from uncommon 0 degree stems it matters, too. Regardless, it would still likely be fine for manufacturers because by using 'standardized' measurements they could still conceal the fact that most frames of the same general size can be made to fit similarly regardless of the marketing label slapped on them.

So now we will have "Showroom weight" and also "Showroom cockpit set-ups"?

I'd suggest re-reading what they're saying. The "just" is an acknowledgement that everyone does this. And, actually this was taken from a CroMo frame page, so nothing about carbon layup.
"Rather than limiting frame size variations to just different length top, seat and head tubes lengths, we take an all-inclusive look at each frame’s total configuration. Every SSD frame will also feature size-specific BB drop, rear center, fork offset/trail and SST technology."

Here's a Spesh diverge Geo chart.. how many BB drop variations are there (Jamis has 5 different drops depending on frame size). Spesh also with only 2 different chainstay lengths, Jamis has 4. Also notice how the Diverge Trail just keeps dropping as you go up in frame size, vs making an attempt to keep the trail (bike handling/feel) in the same ballpark through the sizes.

You misquote me. I said "or ruin a tire." The interesting thing is that some bikes, notably tandems, have been set up to run either 650B or 700c, depending on the ride. Discs, of course. A 650B running the tires normally hyped for that wheel type is not that different in diameter from a 700c running the smaller tires normally associated with that wheel type. See: Wheel diameter with different tires ? Bike Tinker

Perhaps you meant 650A wheels, which are often used for smaller riders. However the same caveat applies for any non-standard wheel type, 26" and 700C being the standards on this continent. It depends on how much one rides and how far from home. I've ruined many a tire on crummy roads far from home. It's really easy to do. I always carry a spare, though I've lent it more times than used it. Many riders only carry one tube and a CO2 kit. I've lent those folks tubes, too. But I can only lend tubes and tires to those with the same wheel type. "call it a day" is not usually a fun option. Then there's the problem of trying to get home from a mountain road in the rain when you may not have seen a car in the last hour and there's no cell coverage. Even in less trying circumstances it's a serious PITA which could have been easily avoided. Non-standard wheels = carry spares. I ride with a guy who once had 8 flats on a single pass climb, all from different causes. He's always well prepared and finished the ride just fine.

BTW, when I flat I just throw on the new tire with a new tube. No need to look for the cause, much faster.

I certainly didnt mean to misquote you. I took 'ruin' to mean blowing the tire too. Basically, ruining a tire could be any number of things- one of which is blowing a hole in the casing which was my example.
Even if I was used your exact word, ruin, my point still stands- it is incredibly rare for someone to need to replace 2 tubes AND a tire on a ride. So rare that it isnt planned for by most and for good reason- it isnt needed for most all people during most all rides.

I would disagree that 'its really easy' to ruin a tire while riding paved roads(the forum we are in).

Also, riding with a spare tire is exceptionally rare. Excellent that you have needed it. The riding you describe- remote, rural without cell service, mountain climbs in the rain is not even attempted by probably 80% of road cyclists.

You seem to take your experiences, which are hardcore and probably awesome, and apply advice for that style riding to all riding by claiming 650 is a bad idea due to your sub-sub-section of road riding. Most people ride within 50mi of their house. Most people live in an area where cell signal exists at all times for calls, even when in the country away from city roads.
Most dont carry an entire extra tire because it isnt needed for the majority of road riding. Your riding is really cool sounding, but hardly common.

Someone who rides like you surely knows the grueling needs and requirements to be successful and can opt to rock a 700 wheel even in a 50mm frame. That doesnt mean 650 shouldnt be available for the super-majority of smaller riders who stick to riding closer to home and who dont have the tires that ruin really easily.

If someone is carrying their own spares, how does it matter in any way what tire size their bike requires? If someone is riding in remote-ish areas or in any situation where an expedient repair is required, they should be carrying their own spares. Tire size is irrelevant.

All methods are "relative to the BB". Stack and reach use the BB, a vertical line, a horizontal line and a 70-some degree line. The vertical and 73° are converging, so the resulting numbers are only useful relative to stack.

The ETT method is also relative to the BB, but instead of measuring with vertical lines, we measure height with a number that is parallel to the slope of the headtube. Before sloping frames, the "stack" in such a system would have been identical to the Center to Top measure of the seat tube, and "reach" was a constant distance between the parallel seat and head tubes.


A useful replacement for Stack and Reach would to have a "stack" that is measured at a universally useful seat tube angle (like 73°) to the horizontal line that goes to the top of the head tube, and then "reach" would be ETT length. Using a universal virtual seat tube angle would remove the caluculation of adding or subtracting 1cm of TT length for each degree of STA difference.



Tire size and wheel size are mainly relevant because we're mainly talking about racing bikes, and racing bikes are supposed to be more alike than different. Which allows them to receive neutral support wheels and that sort of thing. No one frets about tire size with MTBs or recumbents because there isn't that history and group rides don't happen the same way. There is no reason not to use 650c wheels if you want to, but it is understandable that people don't feel like they quite fit their conception of road bike. They also seem to work fine down to 5'2" if the bike is designed well.

Actually, this is the Road Cycling forum. For race specific equipment discussions, try the '33' which would be less generic.

Who's talking specifically about road racing bikes here? No one has previously mentioned 'neutral support' which is a laughable concept for most of us. I have never gone out on a bike ride with the idea that someone other than myself would be responsible for repairing my bike or making arrangements to get me back home. So far, so good (and I've never been stranded by a tube/tire failure).

I'm more likely to go on a group MTB ride than a group road ride FWIW, and based on what I see on Strava I'm not alone there.

All I see against smaller-than-700c wheels so far in this thread is tradition and a basic reluctance to accept that one size doesn't fit all.

The reason I commented is really that 650B was for a time much favored by randonneurs, who do very lonely rides on bad roads. The reason for the favoring in the first place was that they are pretty much interchangeable with 700C as long as frame clearances are large enough. I don't see them much anymore, perhaps for the reasons I gave. I believe there are other reasons for the 650B thing among randonneurs, probably something to do with trail or some such handling difference. Or maybe just that with 650B, the large tires favored by some will fit in many ordinary 700C frames, while such tires on 700C wheels would not.

In any case, there's no reason for a small person to favor them because they're about the same as as 700C. Whereas 650A is a completely different, much smaller size, with ordinary road tires available for it. To whom on occasion I have not been able to loan a tube, falling back on patching.

BTW it's really very easy to cut a sidewall, for instance coming around a sharpish bend at speed, holding your line, and having few sharp rocks very suddenly appear right on that line. Or finding oneself on a bit of gravel with similarly sharp rocks. Let's see - when else have I cut a sidewall - riding on an unswept shoulder with a scattering of 1" - 1.5" rocks and not being clever enough to avoid them all. Etc.

Yeah, yeah, "most people." They're all fine until they're not. There's a reason I carry the ten essentials on even the most mundane day hikes. Boy Scout motto, you know.

In any case, there's really no strong reason to carry a spare tire or even tubes. All you need is a patch kit, a boot kit, and a pump. The patch kit is only problematic in the rain, but then most people don't ride in the rain. Or if you're trying to stay with a group, but then most people don't ride with a group, etc. When I was a kid, that's what I did. Patch kit and pump. And 2 peanut butter sandwiches.

And there you go...

I'm sorry, I thought I was replying to the most relevant part of your post. But to address the rest of it:

Smaller bikes aren't "screwed" if they are designed with care. Shorter top tubes are possible with small frames without massive toe overlap by making the head tube stack, but then correcting for that slack by increasing fork rake to bring trail back to a useful range closer to neutral. With the same trail, bikes tend to steer fairly similarly despite differences in HTA.

STAs are also sometimes steeper on smaller bikes, but this is mainly done (it appears) to make ETT appear shorter. But some bike companies have resisted this. Cervelo uses 73° STAs on all frame sizes, for instance. And back in the '80s Cannondale was doing the same, as well has using well raked forks to neutralize fairly slack head tubes.


But some companies are lazy, use fixed rake forks across size ranges, cheat with steep STAs and have even raised BB heights to make it easier to assemble small lugged frames (Trek). But that's a shame-on-them rather than a built in problem of smaller geometry road bikes. At my last job we supplied a custom Seven to a woman who is 5'2" by using Seven's variably rake carbon fork and something like a 70° heat tube. It rode very nicely.

I didn't mean that we are all engaged in racing, I was talking about the origin of the 700c 'tradition", which road bikes are generally wrapped up in while other cycling types don't care much about wheel size. I was talking about the psychology of the pressure to use 700c, not about whether it is important to do so.


It seems "laughable" that you failed to read when I said: