Anyone here knows or has the tools to measure the lower chain-stay length of a Bike Friday Tikit? I'm curious about its length for a belt-drive project.

Measuring is easy, it's just crank/bottom-bracket center to rear axle center, and directly between those points, not horizontal distance at ground, that's something else. Just a tape measure needed. I think you mean to ask, does anyone have a BF Tikit, and would they measure the chainstay length (and make sure you describe)? If all else fails, you could try calling or emailing Bike Friday at their mothership and they could probably look it up for you in a minute.

415mm, ℄ BB to ℄ vertical dropout.

Much appreciated!

A chain-stay of that length would be too long and make for a bike with "weird geometry"*, if go by Jipe's logic and statements here.


* It ain't.

With the small wheels on a Tikit, I would bet a bit more wheelbase is helpful in bringing it closer to typical handling.

john m flores has noted significant differences in handling between his (very similar appearing) Bike Fridays and his Zizzo Liberte(?), IIRC, positively toward the BF. I think this was due to both wheelbase, and probably other factors such as fork trail, but I can't recall.

I was not sophisticated enough upon my '89 Cannondale crit racer purchase to know differences in handling resulting from its geometry, I hadn't sampled other bikes, I just bought it because it looked really racy. Based on the riding I did (not criteriums), I would now have chosen a different bike.

Yeah, I've ridden small wheelers raging in wheelbase from 91cm to 105cm, and in 305, 406 and 451 wheel sizes. I've probably got the most experience across sizes, and their feel and handling on this whole channel.

There's also a lot of confirmation bias in these subjective assessments of handling. You as the engineer should be attuned to these biases and the various confounding factors that make human accounts unreliable.

Oh absolutely. It's really hard to do a double-blind test when riding a bike unless the bike is disguised by a third party, not the tester and not test personnel. It is really tricky with subtle differences.

That university study on bicycle dynamics that I've referenced in the past, I was so impressed with the computer model they created, that when input with values, provided graph outputs of stability curves. That was with a greatly simplified two wheel vehicle for test purposes alone, not resembling a typical bicycle. But I think by now they have gotten to the point of high-fidelity simulations, I think driven most by the motorcycle industry, but the same sim models should apply to bicycles, although bikes are so much lighter, they can have more subtle differences, so I don't know for sure, I'm not in the 2-wheel industry. The industry does dynamic simulation programs, then compares with actual tests, refines the sims, etc, and year by year, things get closer and closer. It's really amazing. But (for cars, at least) they still do a couple weeks of final ride and handling tuning with at least 3 different variables of each part (target, higher, lower) at the test track before final production sign-off. Sometimes that takes a couple months because it's in a nice warm and sunny location versus the winter in Detroit.

Your experience is only valid for your height of 170cm and weight of 71kg which is smaller and lower than the average European male cyclist height and weight: those small bikes with short wheelbase, short reach, short saddle to handlebar distance won't for for the average male European cyclist!

I don't know whether you've gotten the memo, but Europeans are a tiny minority on our planet, less than 10% of world population, and the continent ceased to be the center of the world several decades ago. Living in a self-important, anachronistic bubble, you still think in terms of Europe. As if that means anything to the bulk of humanity. Sorry, I am under no such mental strictures. I think globally. Europe, GMAFB. Get some perspective, will ya.

​​​​​​Now, what about the Tikit's chain-stays? Are they too long? I mean, a couple of months ago you sprung up the BS that 40cm long chain stays (on the FSIR Spin) were too long leading to "weird geometry". It's all recorded in the forum record. If true, the Tikit has even weirder geometry and your Birdy with even longer chain-stays is weirder still.

What were you thinking? Were you so desperate to land a feeble punch, if just once, that you resorted again (remember your Korean beaches BS?) to actually making up bogus claims? 🙄
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But Ron, Jipe's statement is still valid. And this is as far as I can tell a Western-centric forum. You, yourself seem to me western educated.

Its also valid for US male.

Look, everything works better when it fits right. We're fortunate to live in an age of frame sizes in what, 8 or 10 sizes in 2cm increments in road bikes (at least it used to be), and at least small/medium/large/extra-large on other large-wheel bikes. I'm fortunate, my folder fits me dandy. It's supposed to fit 4'8" to 6'3", but I know that is mostly the seatpost, handlebar height and particularly reach are a whole 'nuther issue. The diverging seatpost and handlepost helps, put both up (with an adjustable handlepost) and the reach is longer. Bike Friday tried to market to schools, a 20" non folder with a telescoping monobeam frame (concept later used on the Haul-A-Day cargo bike first gen). I saw on here months ago, a folder with a very short frame, and I derided the handlepost setup (which I regret) because I couldn't see the logic of it jutting way forward and then up, instead of directly up; Now I realize that is to allow knee clearance when standing on the pedals, while allowing a very compact frame length. But, weight distribution will not be ideal.

For every height, amazingly, there is a folder available that fits. Wheel diameter might need to be proportional, might not. Geometry might need to be fine-tuned at size extremes. Bike Friday laudibly will build frames for very short-statured, up to NBA-center-tall, a bit easier for them because every frame is made-to-order locally, one of their pluses.

I'm a sailing enthusiast. Never owned a large keelboat. But I've read a standing-height stack of books on the subject, some by famous designers, some by marine architects, and looked at the specs of hundreds of boats on sailboatdata.com, and have reached a point where friends in the market ask me about a particular model, and if the specs are published, I can look at the numbers and tell the person about this boat, in relation to others.

For bikes, if you know what you are looking for, and the bike geometry numbers are published (that's the hard part), you can get a clue from those. But it can be tough comparing bikes with different wheel sizes; Smaller wheels, you think less gyroscopic inertia, so you would think you want a bit more fork trail/caster to compensate. Except, that can make the steering heavy when loaded, and cause more wheel-flop.

Ref: Good reads:

https://en.m.wikipedia.org/wiki/Bicy...cycle_geometry
https://en.m.wikipedia.org/wiki/Bicycle_fork



That last part, less offset, so more trail: The smaller wheel radius means a vertically shorter triangle at the road, so inherently less trail with the same offset. So to get similar trail as larger wheels, less fork offset, a "straighter" (or less angled if straight blades) fork. Put taller section tires on the same fork and wheel? Vertically taller triangle at the road, trail increases (and vice-versa).



Correspondence from Bike Friday in response to my questions regarding differences All-Packa versus New World Tourist:

"I'm not biased! You're biased!"

Except that it isn't. There's nearly half a billion (480 million) adults in Europe no taller than 175cm in height, including 120 million males, who could potentially fit well on a 16" bi-fold. And it's even less valid for the United States because mean height is lower there. If you go by the data and actually think for yourself rather than following Jipe blindly, that is. But birds of the same feather...right?

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You wrote that you are 170cm tall, so your experience is only valid for 170cm male adult, not 175cm male adults.

No Ron, actually read his statement. He says "Your experience is only valid for your height of 170cm and weight of 71kg which is smaller and lower than the average European male cyclist height and weight: those small bikes with short wheelbase, short reach, short saddle to handlebar distance won't for the average male European cyclist!" This is a true statement, IMO.

5'-6" male is unusually short for an American of European descent.

Anyway, this is not about that, per se. This is about him saying something in response to one of your posts that you saw being negative to you. For this you lashed out at him like a rabid dog. You did this in another recent post as well. As is your wont, you came up a straw man. In this case the people of the planet, which is not in his post at all. It’s about you and your ever so fragile ego. Did he say anything about Asians? Was it something he said about the people of the planet? So, if we cannot attack the statement, we can also try to associate it to that time he said the beaches in Korea are crowded.

You are so transparent that it is embarrassing. Most on the channel on a regular basis, see this. They don’t say it to you because they do not want you lashing out at them. In the past, I have supported you both for the issue of free speech and because you do contribute. But you also hurt the channel, too. You have caused many to leave the channel.

5'-6" is the average height of U.S. americans including women (not sure why you exclude them) and across ethnic descents, Ron is taller at 1,70m. I prefer bs to be called out - before you claim the opposite on my behalf. No need to mention how my 16" folders fit for me, 1.82m

We are all here from our shared love of bicycling.

We all have opinions. Some correct, some incorrect, but much is subjective so that may not be proven. Usually, probably a mixture.

But each person is worthy of respect. Disrespect comes to those not respecting others in tone, separate from merits of arguments. It is possible to disagree while still being respectful. It happens all the time in reasoned discussions, and the better conducted parliaments in the world. Often those intending to be polite will precede their statements with, "I could be wrong, but..." In reasoned debate, regardless of the particular merits of the argument, these are people I respect, rather than those who always assert they are correct, always, 100% of the time. Let us not give known public examples of such, lest this wander into P&R, and anger the mods, and they execute furious vengeance upon them to punish them for what they have done. (Jules, Pulp Fict... er... Ezekiel 25:17... DOH! No mention of R! Dangit!) Let's... just not go there. Trust me. Where was I? Oh yeah, polite discussion. No insults. That's the Tikit! (Jon Lovitz as Tommy Flanagan, SNL)

I don't like your many personal attacks. And I will feel free to say it. As for 16 inch bikes I would try one of I had the chance. I am quite sure I would not fit, since I barely fit on the Zizzo..

Knock yourself out. You gotta contribute at least something to the channel, right? 😂 We all know that the reason that you won't report the alleged personal attacks is because you don't have a leg to stand on for they are no such thing.

Speaking of personal attacks -- since you brought it up, thank you -- I didn't particularly like your unproven allegation, your bogus BS that I had been banned and censured in the past, or your explicit attribution to me of another member's BS in late 2024. I considered those two separate episodes as a personal attacks. Teapot calling the kettle black. Let he who is free of sin cast the first stone. Plank in your eye. You get the point. You do get the point, right? Right?

BTW, though a smaller 16" bi-fold may not fit you, it could fit about 44% and 94% of U.S. males and females, respectively. According to the public data rather than to personal made-up BS, that is.

I see FnHon frames available on AliExpress, though it kept kicking me off the site because I am not registered with them and not going to sign in with another site name and password. So 16" frames can be had, and not a bad deal if you buy components there too at low cost, as building up a bike with USA retail component costs gets expensive. But no one wants to order a frameset with no returns, if they don't know if it will fit them, and wouldn't until fully built-up. Chicken-or-egg. If not dealers, FnHon needs to have "agents", users of the product, in major cities, able to give test rides, in exchange for a small commission on each sale. I guess that would be too complicated for the low retail price.

But what FnHon could do, is show diagrams of a given frame and handlepost, showing persons of various sizes superimposed on a finished bike (or persons that size actually on the bike), indicating height and inseam, arm length, etc. That may not be definitive, but it would be something, for people who could tell what their riding position should be and know their body measurements.

Bike Friday is the opposite; You tell them detailed body dimensions, riding style, etc, and their programs spit out an optimum frame size and handlepost height. FnHon could have the same on their website, and then superimpose that optimum frame over their standard frame, and a customer could see that the frame is perhaps 50mm too short reach for a standard canted handlepost, but might work with that topped with a 50mm horizontal stem on a cylinder-topped post, or with 50mm double-clamps, provided that is within limits of good handling parameters.

If FnHons are selling fine, they're not going to do the above. If they want more sales, they or other framebuilders will go the extra mile.

All sensible recommendations. Bike geometry diagrams/tables should be made available. But...but...but if, for example, Pinigis refuses to release such a diagram/chart for the Origami Lotus -- this is not a "personal attack", but rather a simple statement of fact verifiable in the forum record -- despite requests, leaving the potential buyer in the dark and at the mercy of his assertions that cannot be independently verified while his captives support and applaud him, what can we really expect of FnHon? 😉

I wish I was programming-smart enough (and didn't have personal issues taking my time), as that would be a dandy project and to post online, all it would need would be folding bike makers to send their frame geometries, and bike-positioned percentile human models. This would be so much easier with modern parametrically-driven CAD models, you make a model based on linked parameters, and then changing any parameter automatically adjusts the whole model. This was introduced about mid-1990s and is now standard.

Lacking that, a website for bikes like sailboatdata.com, listing fundamental dimensions, would be great. Some of the numbers on that site I can interpret directly, from reading about yacht design, but some interpretations are based solely on comparison to other boats, so having quite a lot of published boats on there, is a huge help. It would be the same for bikes. Sailboat makers don't hold back data, because the very first article about the new boat in Sailing or Cruising World, etc, will publish those numbers, it's expected. Designs that are long out of production, usually an owner or one-design association or sanctioning body for racing a particular model, will contribute specs and a line drawing.

Because women body sizing is different than men body sizing with for the same height longer legs and shorter torso: for this reason, the experience of a man of a given height on a bike is different from the experience of a woman of the same height on the same bike.