I gave a response to a question recently about geometry that places too much weight on handlebars. The reason behind greater weight on handlebars is based on stack height, which is lowered by shortening head tubes. Here is the response I gave:

“Many bikes today are designed to give the experience you describe, by reducing stack height. Lower stack heights place a rider in a more “aggressive” downhill position with the handlebars being more weighted. The increased weight on the front plants the front tire for better turning.

With that said, I can’t stand low stack heights. A low stack, to me, is only optimal when aggressively riding downhill or climbing steeper grades. The design is not best for long, beater rides with a lot of rolling and/or rocky terrain. This is especially true on long rides when backpacks are generally heavier.

i opt for a bar height that’s even or slightly higher than my seat. For me, it’s more comfortable over the long haul (literally).”

 

You are not alone. This is exactly why I got a Hightower XXL. MASSIVE stack and HT length. The moment I got on it I knew I had spent too many years in a gawdaweful time trial position. I'm 6'5" and too damned old for that crap anymore. Thanks Santa Cruz!

 

Yes, XXL Santa Cruz is a God send. My Megatower has a 666mm stack. I run a 20mm rise bar with 25mm of spacers under the stem.

 

"Golly, nobody will buy our righteously stacked XXL bikes"....said no designer or sales executive at Santa Cruz.

 

Totally concur. My last dalliance with a short head tube was a Knolly Fugitive. Never again. Literally. Never again.

I am not a true Clyde (6’2, +2 ape), but I’ll generally take ALL the stack height and head tube I can get.

 

Steeper HTA would give higher stack height. Plus it'll put more weight on the front tire.

Pairing the steep HTA with a short offset fork would give similar steering stability to slacker HTA, and also rein back WB.

The angle at which bumps are absorbed is a bit different, but that's just a problem inherent to telescopic forks. Trade-off between vertical compliance and hang-up from plowing.

 

IDK, for me at 6'4" +220lbs (which is not really that big) the last thing I want is a steeper hta. Not a good combo with a much higher center of gravity than shorter riders. If anything, HTAs need to be slacker for bigger rider because of this. And wheel base is not an issue. I am 12" taller than someone who is 5'4" riding a small, yet my XXL is only 3" to maybe 4" longer. No issues manhandling the longer bike, because they are not really that much longer and because clydes have huge wingspans along with long legs which means not only a lot more leverage, but a much larger range of motion to shift a hell of a lot more weight around a bike that weighs about the same. For me, weighting the front tire has never been an issue because of this, but going over the bars because of a high center if gravity, low stack and steep sta has been.

I think around a 6" head tube for XL bikes seems to be a pretty good sweet spot. That with a 120mm fork gives about a 650 stack. Add an extra 10-20mm fork travel and now 660-670 stack for a longer wheel base to get the bike more proportional.

My XXL I have on order has a 650mm stack with a 120mm fork. I plan to up the travel to 140 so I can get the bikes little taller as well as more proportional for my size by adding an angle adjust headset to get a slacker and longer (1260-1270) wheelbase. I am guessing the bike will still be a little small, however.

 

Ahhh, the old first world problems. Tall handsome guys complaining about stuff, while us hobbits try to “get by”, and everything “average” has been SOLD OUT for a year. J/k, always good / fun topics from S’party.

 

Ahhh, the old first world problems. Tall handsome guys complaining about stuff, while us hobbits try to "get by", and everything "average" has been SOLD OUT for a year. J/k, always good / fun topics from S'party.

Pretty sure every XXL Santa Cruz frame is sold out too.

 

Same here, I am only 6’1” and used to buy large frames, but now most large only have a 100mm or 105mm head tube. Just bought a XL bike with 120mm head tube and have 50mm of spacers and a 25mm riser bar AND just ordered a fork with a 20mm A/C increase to get my bars slightly above the saddle to a proper position. Freaking ridiculous.

 

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Increasing stack by steepening HA with this angleset (in reverse) will come with the bonus of allowing your fork to clear your downtube on a Trek Rail. Not wise to rely on the knockblock.

^ busted knockblock chip

 

I'm not even tall (5'9") and I'm frustrated with 100mm headtubes and lack of stack height.
One of my riding buddies is like 6'3", on an XL Hightower, overforked to 170mm, with probably 40mm of spacers, a riser stem and 40mm riser bars. Poor dude has lost so much reach he's basically on a Large at this point.

I feel for you guys.

 

Steeper HA helps with that problem of losing reach too.

XC race side of things probably fueled this issue. Lots of problems fitting shorter riders on 29ers, esp on bikes with 60mm BB drop or more.

Steep STA exacerbates the seat to grip height difference too. Can make the bars feel higher with longer cranks, thinner pedals, and thinner sole shoes.

Size-specific HA would fix things. Slack HA for short riders, paired with long fork offsets to keep steering sharp. Combine with size-specific CS length.

 

After reading a couple post here about the amount of spacers some of you run, it brings me to mind that I read somewhere that fork Mfr's only recommend 35-40mm of spacers under the bar for safety/liability issues. Please correct me if I misunderstood something.

 

Zinn has an excellent response to this here:

Technical FAQ: Headset spacer stack height

Lennard Zinn has a lengthy answer for what is far from a simple question regarding stack height.

www.velonews.com

The caveat is that it's not just about the steerer's integrity. The upper headset bearing is a fulcrum to all that force, and it's entirely possible to overload and crack the head tube if the steerer is too long.

The solve for this is a high-rise bar. Deity has one at 80mm. They've been aesthetically acceptable for years (unlike the poor long-legged folks on road bikes with equally squat head tubes, forced to go max-Fred with a high-rise stem).

 

two reasons a frame manufacturer would elect to use a shorter head tube, which I am actually in favor of:

1) it keeps wheel base within reason and front center within reason. As you increase the HT length and try to keep the ETT target the same (which is still how frames are sized regardless of reach numbers), the bottom of the head tube is forced forward. to get a monster stack by increasing the HT length, the wheelbase gets unmanageably long quick, and you lose the ability to weight the front tire as much because that wheel base gain is in front of the bars.

2) it allows riders to size up or down based off of their body dimensions and preferences. it creates more fexibility in the lineup where a rider can add spacers and choose a 45mm rise bar if needed. you can always add to the stack height, but you cannot take away from it.

If you have a 125mm head tube and ad 100mm of spacers with a 20mm rise bar, you have 245mm effective stack height. if you have 170mm of stack height, you need 55mm of spacers to get the same effective stack height. Both of those are incredibly tall. How close to level is the relationship between your bars and your saddle?

 

Back in the day, like back in the 90s and early 2000s, they went overboard the other way, with crazy long headtubes for the larger sizes that resulted in crazy high TT, among other things.

I find that the lower HTs are great for aggressive riding, going uphill and downhill (with dropper posts). Still got to space them up a bit, but it's nice to have the option IMO.

What they absolutely suck for IME is long flat rides. It's hard to notice the above effect if all you do is tech stuff, getting up and down out of the saddle all the time, climbing and descending, but when you start mixing it up with touring and other flat extended stuff, holy crap that low front end can be pretty terrible.

 

Hey Sparty, I’m 6’ and the tiny headtubes and low stack height are not for me. My current bike has a 105mm head tube and low stack height. To get my bars almost level with my seat I need an inch of spaces and a 75mm rise bars. I’m amazed how many conversations the bars start on the trail. The conversations go one of 2 ways. 1. “You know only newbs or grouchy old guys on hybrid bikes run bars like that?” or 2. “I am so sick of these low stack heights how do you like those bars?”

 

If you were living 3.5 decades ago this is the bike you'd be riding. I'm guessing the thinking behind short top tubes is to maintain the same height as a 27.5" Or maybe they just think shorter head tubes dont look as dorky as this (Although this is a SWEET! vintage ride <not mine>
).

 

Yep, short HTs drive me crazy. It's made worse by all these trends: slacker HTA, wider bar, shorter stem, fewer riser stems for 31.8 stems and none for 35mm s tems, carbon steerer tubes, disappearing headset cups, shorter cranks, and few 180mm crank arm options. OK, I'm done.

 

Exacty. All that **** needs to be reigned in for real world riding, and I don't mean flow trails for the kids.

 

Might as well throw in the rider size-specific wheel size suggestions, and complaints about the inability to reuse currently owned forks with cut steerers...

It's like some exercise to balance out the geekiness of running lots of spacers, riser stem, riser bar, head tube length, and unfashionable head angle, seat angle, & crank length, etc.

 

What's "real world riding" ?

I rather suspect most folks are just over-biked.

 

Ahhh this is such a great discussion and I could rave on forever. At 6'5" I'm not particularly tall, but I rock a +4" ape index. I bought my Pole Taival because it was pretty much the biggest thing I could find at the time. Nice 675mm-ish stack with my 150mm fork, but my long legs get me at 895mm BB to saddle with 175mm cranks.

I've ridden road and track for about 13 years and MTB for maybe 6. I was bumbling along for a lot of years on bikes that were too small for me. I'd look at the "normal" people and how they would fit on their bikes and cry just a little inside. Almost all properly big road bikes came with short head tubes, compounded by the fact that most forks only came with 300mm steerer tubes. I saved for many years and made the leap to a Canyon 3XL and a custom track bike. I was fitted to both for a spirited position and it was a total revelation to feel like a rider should on a bike. After that I sought about ditching my MTB for something far closer to what I needed. Since getting the Taival, I've been able to properly assess it's shortcomings and I have a good direction for the next rig, although not the $$ as yet.

My reading between the lines on short head tubes. They're made for the smaller riders. I see lots of recommendations across the web for riders to ride bikes larger than normal, like 1-2 sizes up. This gets them down into the bike rather than on top of it. Great for descending, bike parks, etc. Crap for tall people that actually need a decent stack so that they ride in some sort of normal~ish position.

Talls also get a rough deal if they're looking for something XC related. I ride mostly XC because that's just the majority of trails where I live and there's very little on the market that would suit. Most proper big bikes come attached to long travel suspension and hefty weights. My Taival has about 675 stack before I crush the forks, but with my long legs, that's still low. I have 40mm of spacers to a 35° stem and a 50mm riser bar to put me in the region of 150mm~6" more stack just to get level with the saddle. Once I'm on the bike, I'm still down, but it's just so much better to ride and control. If I was off to a bike park or rode more downs I'd be happy lowering the front a bit, but for my XC duties it rides really well.

 

My reading between the lines on short head tubes. They're made for the smaller riders.

Perhaps you've come closest to doing what I asked in my original post. Which is to answer the question -- why? Of course I'd made my own speculation before asking the question and your answer pretty much confirms it. Make a bike that fits the widest range of rider heights so that it might appeal to the greatest number of riders and therefore sell better.

After all, as you pointed out, only 1% of the population is 6'4" or taller (according to this statistical website). "What if we could sell our size XL frames to, say, riders who're only 5'8", too?"

But this seems to be wrong thinking on behalf of bike frame designers. Sure, as a tall person I can run my 80-100mm stack of stem spacers (or a 35mm stack plus 60mm rise handlebar) but offering the tall rider this option sidesteps a fundamental question: What short rider is going to choose a size XL (or 2X, 3X, etc.) frame? Any rider short enough to want a 125mm head tube will be way too short for the reach of these otherwise gargantuan frames.

To me, putting a teeny tiny head tube on a size XL(+) frame is synonymous with putting 140mm cranks on such a frame. Sure, someone could do it, but doing so would simply be way out of step with every other dimensional decision appropriate for that size bike. So I'm still left wondering... why? Do the bike companies really think they'll sell more size XL frames? Or is it something else? Is it possible there's actually a good reason for it?

If so, I wish I could be certain what that reason is. Might make it easier for me to accept what I currently consider a design flaw of my new frame.
=sParty

 

895mm BB to saddle with 175mm cranks at 6' 5"? I'm at 710mm BB to saddle with 152mm cranks.

In another thread, a 6' 4" rider measured their hip to shoulder length at roughly 600mm, while I measure at 410mm.

Close to 200mm on both #s. I'm 5' 7" (170.5cm)

People already know frame sizing runs are **** for people who aren't of average proportions, but people choose from what's conveniently available. You guys who know better should consider doing BikeCAD to figure out what you want. Maybe have Marino Bikes in Peru make a proto.

 

People already know frame sizing runs are **** for people who aren't of average proportions,

It's not just frame sizing. Airlines are a particular hell, and as others have stated.. I'm not particularly tall. Just tall enough that finding pants is a pain, same with shirt sleeves etc. The world, in general, is just not meant for people in anything over about the 70th percentile (which is about 5'8"). We just cost too much to cater to such a small market place.

FWIW head tube length on my banshee is ~130mm an XL would have been about 140.. stacks in the ~670mm range. Since the head tube's obviously formed, having 1cm of difference is likely just a cut. Much more than that and they'd have to retool. So it's likely cost, like always.

 

I don’t begrudge bike companies for not catering to tall people. My height and higher is <1% of the population in even taller average height countries, let alone worldwide. Then I would throw it down that we’re an even smaller percentage of the cycling population. That’s not economically viable for most big companies. But it does leave a door open for some boutique manufacturers and it is a good time to be one with the internet making it possible to touch base with and purchase from all over the world.

However in my cycling journey I have found that there are companies that can make big bikes, and then there are those companies that know HOW to make big bikes. My Canyon road bike is a pure delight to ride. My Duratec track bike rides like it’s on rails on a velodrome. It’s the biggest non tandem frame they had made and it’s solid as all hell without being a tank.

I’m at the point where I’d probably move on from my Taival and get a more XC rig and a DS later on. Duratec has some nice geo on their site for big guys, but I’d like to do some customising. I have my eye on Nicolai for a DS and their Saturn in particular. They aren’t cheap but all reports say they build a great bike and for a bit extra they can work with you to change things up a bit from standard. I touched base with Dirty Sixer recently to check on future plans out of curiosity, but the one MTB model they have left is too small and no plans as yet to do another.

Of course there are straight out full custom makers out there there that can make almost anything you want like Marino mentioned above but not many want to head on that path

 

I think we’re at a point where it would make sense to have more things gain or lose size with rider height.
As you said, it’s „funny“ to see smaller guys upsize their bikes, which then leaves taller people without options even to get a „regular“ fit.
I’m not that tall at 6‘4“, but even for me it’s a hassle to find something that fits.



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Just a note that Banshee bikes fit taller folks. Not crazy tall as there are no XXL, but if you’re under about 6’4 or so, you should get a nice fit.

 

I'm not super tall, used to be 6'3" a few years back but age has shrunk me about a half inch or so, but I have no troubles finding a bike that's big enough. Or one that has a big enough head tube. Usually there are bigger sizes available than the one I ride, maybe I'm just oddly proportioned?

 

I thought 5' 8" was kind of on the short side, so I cherry-picked this graph to support that.

I find that size L bikes often are the best-tuned. When the Yeti demo truck rolls by, and I test the same model in S, M, and L, I often find one just feels more natural. It does a lot more work, requiring less effort from me, which allows me to focus much further up the trail and confidently feel free to pop off bumps playfully. SB150 was one of the rare exceptions, with size M feeling best-tuned instead of L.

I presume the reason for this is because they use world-class athletes for feedback, and tune things to help their factory athletes win events. Examples: Trek with Travis Brown, who seems taller and skinnier than average. Canyon with Fabien Barel (5' 11") who likes their bikes on the long side. They size their proto frame for their tester and extrapolate the other sizes from it.

Interesting to watch a video where Jack Moir (6' 4") is contemplating between size L and XL during the offseason, leaning on the more dialed handling and balance of the L (more weight on the front for cornering) over the XL's comfort.

I've been exploring this hip-to-shoulder measurement. This measures 410mm for me at 5' 7", while it measured 185mm longer for someone 6' 3". Jeff from Worldwide Cyclery is about the same size as me, and he's infamous for getting an XL SB45 for "reach".

I'm exploring with a shorter reach for my next bike. I'm on a large since I wanted better weight bias (60:40 rear:front weight distro because of longer front-center). The smaller sizes were too front-heavy for my liking. I would've been better off with an -2° Works Angleset on a smaller size (adds about 22mm to front-center, equiv to 1 size up). On an L I feel too stretched and the saddle gets in the way on a large when riding terrain that is this steep:

Pictured below is me on a size small, I think (maybe a med). Gives an idea of how a shorter torso, arm length, and leg length has less capacity to move fore-to-aft. I envy how tall guys can get pretty much over the rear axle.

Taller headtube would reduce the stretched position, to make these steeper sections feel less extreme.

Gotta get away from the idea that we need a certain reach, ETT, or stack to fit properly though... same goes with HA, SA, CS, and whatever. Gotta juggle it all, hence why I suggest people try out bikecad.

Doesn't help that XC racing has this trend going on (with everyone copying it 'cuz N1NO):

They're seemingly married to their steep HAs. The stem and stack would be lower if the HA were slacker. I seriously think size-specific HA (and fork offset to go with it) should be a thing.

When I see the media criticize bikes like the Commencal Meta AM 29 or Spec Status, saying that they're not the best for racing (in size L+), and are more for fun... that gets me excited, since it's so rare. When I see mega long CS, like on the Banshee Titan LT, I just see that as being something for the tall guys. Sad to see naive people of average proportion boldly proclaiming that you can't buy a bad bike these days. Also sad to see tall people trying to teach riding techniques to shorter riders, unable to see the difficulties they face. I assume tall riders have their own troubles adapting technique...