prathmann

One thing that helps the BF PR is that a certain amount of customization is available with the tubing lengths and stem to match the size of the rider while most folding bikes are 'one size fits all'. Fine if that size really does fit you well but sometimes it doesn't. The Altena and some of the other bikes mentioned look like they'd be good competitive road bikes provided they are a good fit to the particular rider.

invisiblehand

If a Bike Friday is "faster", bike fit would be the big component. I suppose something like tire width could be important too under the -- reasonable, IMO -- assumption that a high quality supple wide tire will be faster. So if the bikes you shared can only fit say 28 mm wide tires but you can fit a 40+ mm wide tire on a Pocket Crusoe built as a fast road bike, the reduced rolling resistance will make a difference.

Abu Mahendra

No, I do not. For the reason mentioned before. 700c/622 wheels feel, handle, react differently to 406ers. The diamond frame geometry in big wheel bikes also plays a part. This is one reason I've got a 622er in the works. I am a big fan of 406/451ers, but no 'it feels like a big wheel bike' Kool-Aid for me, thanks.


622 rim vs. 406 wheel

The Altena is just an example. Everything that I've said before applies to the likes of the Tyrells, PCs, etc. That is, none of them will truly feel like a roadbike, but all, apples and apples, can go as fast as the others. Any claim that one is faster than the other would have to account for the range of cognitive biases.

Abu Mahendra

The Altena, for example (again, this likely applies to others. I speak of the Altena as an examole because I have experience building one), comes with a common 31.6 seatpost size. You can get a setback post in that size, if needed. It comes with a standard 1 1/8 threadless fork, so the range of headsets, and stems will work. Regular, standard BB shell. The frame comes in two sizes. Mine is an L with a 55.5cm top tube. When it comes to parts, there is nothing funky, arcane or proprietary so customization is perhaps even easier and wider ranging than a PR.

prathmann

That sounds better than most folders, many of which make it harder with proprietary parts, but still not as straightforward as with the customized Bike Friday models. AIRC, you send them a set of key measurements from your favorite road bike once you have your fit dialed in and they then make the Pocket Rocket to match so you have the same setback, reach, bar height, etc.

Abu Mahendra

Sure. For me, since I am not predominantly tall or short, neither lanky nor husky, seatpost length and insertion, stem length and angle alone get me to where I need to be: BB-to-seatpost rail distance: 62mm; Seatpost head to stem-clamp distance: 65-63cm. My Dash has a stem that telescopes up and down, and tilts over a range of 90 degrees, but I never move it. Micro-fitting is a solution to a problem that the mean of the population does not have. I don't need bespoke fitting. As I once said to another channel member here who brings up the micro-fitting possible with a BF time after time, I have dabbled in bespoke suiting, and the fit and look can be great, but one can also dress well and comfortably with an off-the-rack item.

Abu Mahendra

A Pacific Cycles Reach has disk brakes so it can take any tire available in 451 size. It also has short-displacement passive suspension, similar to a Moulton. So, if suspension, as you suggest plays a role in speed, one can expect a Reach to be faster.

I am running a 42mm tire on my Dahon Dash now, and it has a traditional diamond-shape geometry, no proprietary anything, and I can probably go up to a 55cm tire. Again, you folks need to get out of your BF tunnel vision. What's with the sect-, cult-mentality?

jur

There you go again... Bike feel... sigh. Very subjective, for a start. Secondly, one roadie does NOT feel like another roadie; wheel weight, fork geometry and a host of more subtle issues make a radical difference to "feel". If all roadies felt the same, there would be no point in having more than 1 manufacturer, would there?

The argument about say the PR or the Swift "feels" indistinguishable from a roadie doesn't imply it feels identical, but rather, it has that typical roadie feel of stiffness, responsiveness and lightness that characterise roadies in general. My Swift definitely feels like a roadie, but it feels radically different from a typical MTB or say a Brompton, the latter which does not feel anything like a MTB or a roadie.

The key word is LIKE. Keep your pixie dust and koolaid ridicule to yourself professor. You may have very nice looking bikes but a very poor social skills. Go home a do some rework there.

edelay

I've been seeing a lot of information lately that wider tires (all things even) have less rolling resistant that narrow tires.

https://www.schwalbetires.com/tech_i...ing_resistance

pinholecam

"Rides like a road bike", I think is often a mis-interpreted/misused term.
For me at the least, it just describes how the bike handles and feels, esp when pedalling with force and out of saddle.
Diamond geometry mini velos/foldables do have more of this "road bike feel" (no surprise here) as opposed to middle section fold bikes like Dahon/Tern ones, from my own experience.
"Rides like a road bike" certainly does not mean "Performs like a Road bike" to me. (and I do have both)

Any good bike (stiff, decent parts, reasonable geometry) will be in that league of small bikes considered fast.

A BF PR, with its minimalist frame is certainly a good base to start make the bike lighter (by implication little bit faster than the stock)
So too a Tyrell FX, Dahon Dash, etc.

invisiblehand

Hmmmm? Surely you must know by now, that there are other factors that determine whether a tire will fit the frame.

What makes you think a diamond frame is faster?

ThorUSA

a super light roadbike will be faster, no doubt.
As long as the geometry and the fit for the rider is ok a folder will be only slightly slower. In other words if you sit on a folder the same as on a roadbike it will be only marginally slower ( due to weight )
Most restrictive is any position which is aerodynamically not optimized. I do sell a lot of extralong seatposts and shorter stems for just that reason.

But in general its a personal thing.

Jur what pixi dust you are talking about ? From Abu or BF fan ? That would be anybody who really likes his personal bike, right ? And there is nothing wrong with that.
I don't dislike anybodies opinion with a Downtube or Oregami or Brommy, nothing wrong for anybody to voice theirs.

thor

invisiblehand

The biggest change in "feel" is for a decent bike is going to be switching from the popular high-trail bikes of today to a low-trail folding bike created by the small wheel. My experience is that the 406 wheel roadie folding bike rides a lot like a classic low trail road bike.

If you've never ridden such a bike, I can see how one get's a little confused on the "feel" ... whatever that means precisely. But if you put a bit of the load on the front wheel, it's a fine riding machine in my experience.

Abu Mahendra

Yes, pal, that's right, it is all subjective. My claim that my bike feels like so and so, and your claim that your bike feels like so and so are on equal subjective ground. One is not more credible or objectibly true than the other. I suggested that is the case a couple of posts before your own post.

You have led yourself to believe that you know me, therefore to pass judgement on my social skills. Does that belief empower you? You actually believe this to be true?

Abu Mahendra

Yes, rim width, fork clearance, brake clearance, rub against downtube, etc. And? You still think the Robinson Crusoe is unique?

I never asserted a diamond geometry is, in and by itself faster, but it can allow for a stronger, lighter frame.

Abu Mahendra

The pixie dust refers to the subjective perception, the mantra, the received wisdom, the untested assumption paraded as established fact or a foregone conclusion that a BF PR is somehow faster than other bikes, and basing it on hearsay, personal anecdote, brand recognition, place and method of manufacture, rather than on objective, verifiable indicators. Pixie dust. I get it. It is more difficult to dislodge a belief than to arrive at that belief. A range of factors push us toward belief, and to remain entrenched in that belief. I mean, just survey the reaction when I dare question the assumption, and try to deconstruct it. Scary.

invisiblehand

You're the one that mentioned disc brakes only when fitting tires. Anyway, you're just trolling now.

ThorUSA

What I am saying is ....
Its ok if you like your bike best.
Its ok to point out the benefits, if they are personal taste or raw data.
Its even ok if you have a negative opinion about a bike, as long as its not slander, or just because you don't sell them, or its a competitor.


Its not ok to not accept anybody's opinion and call it pixie dust or troll ....
That's my opinion anyhow


now lets go back to the fastest folding bike, instead of personal attacks


Thor

Rick Imby

The problem is you cannot have all things even with wider tires... Wider tires are heavier and unable to hold the same air pressure. As you go even wider the rims get heavier too. Historically 20mm and 140psi was thought to be the sweet spot for 700c tires. That has changed.
It is the sweet spot we are all looking for and it is different for different users and different equipment.

20mm is narrow and 28mm is normally considered a wide tire in 700c road bikes.

With 406 tire sizes 40mm is about as narrow as you can normally find and considered very narrow for 406. Too narrow for some 406 rims.

Rim width along with the matching tire width effect rolling resistance too.

Tire pressure has a lot to do with rolling resistance. Wider tires have less rolling resistance at "the same tire pressure" Narrower tires can usually be run at higher pressure. Again the sweet spot tire pressure may be different for different width tires.

Generally speaking most 451 rims have been designed for narrower higher pressure tires and narrower tires are more common with this size.

Generally speaking the bikes with 451 rims are more "Speed focused" bikes.

Higher pressure is faster--depending on tire design and just up to a point
Narrower is faster---depending on tire design and only up to a point.

I believe the sweet spot in 700c tires is going to end up close to 30mm rear and 25mm front but time will tell. Rider weight will be a factor also.

I think in 406 wheels the sweet spot will be around the same but we will not get the tire manufacturers to cater to our size wheels because of limited sales. Schwalbe is one of the few companies with multiple sizes and models of 406 tires.

Rick Imby

I just bought a 2017 Haro Subvert HT7 with 27.5+ x 3.0 tires on it. If wider is faster then this baby should fly. But is is quite slow.... compared to my Swift with 1.5 tires.

jur

I agree Thor, and it was Abu who called it pixie dust and koolaid, I just said he must keep that to himself.

invisiblehand

Greater tire pressures do reduce the contact patch size and rolling resistance sans suspension losses. With suspension losses from riding on imperfect roads, rolling resistance will increase with greater tire pressures. My understanding is that rolling resistance is U-shaped as a function of pressure where the bottom of the U is relatively flat such that as long as you still avoid pinch flats and tire squire, you can typically keep lowering your tire pressure with little change in rolling resistance. Naturally this depends on total weight and road quality. So there is no global answer: instead there are guidelines for experimentation.

There are some high quality supple tires in ERTO 406. Today, I'd point most folks to a Greenspeed Scorcher that's 40 mm wide. I've had them for a while as a road tire and pleased with their overall performance. But there are definitely high quality tires that are both narrower and wider.

invisiblehand

It's a ceteris parabis statement. So other things such as suppleness and tread (knobbies) matter too. When you're comparing two different bikes, presumably things like fit and aerodynamics matter too.

The person who did a bunch of research on the topic, Jan Heine, suggests that "wider is faster" is only true up to a point. From what I recall, it was based on experimentation rather than a theoretical reason. I don't recall a satisfying explanation from him. I remember wider is faster being true to something like 30-35 mm. But it's a fuzzy memory.

pinholecam

I can see where Abu Mahendra is coming from.
(Being in SEA and not in the US)
There are loads of folding/mini velo bike options here in SEA (often at good prices).
Someone based here gets to try/see lots of the bikes mentioned.

I too seem to see that there is a view here that the BF (and often Brompton) being the only best options. (implying most other stuff being 'cheap copies', inferior workmanship, etc)
Is it really true or is it because of the realities of availability, price (imported vs local), perception of quality, vocal user base?
Even the general size/weight/height of the user base play a part in this perception.


Take a Tyrell FX for instance.
Its a really nice bike, speedy, configurable, etc.
Sadly, most of the available English info on them are limited to distributor and 'self love' selfies type material.
Other info being in Chinese (from HK, Taiwan, China), and Japanese (where the bike originates).

The BF on the other hand, being more readily available in the US (which folks tend to be more vocal and willing to create good content), will turn out lots of good info/material on real world usage upon a google search.

Rick Imby

Yes ---I was attempting to say the same thing. Finding the sweet spot for tire/ rim weight and rolling resistance.

Many of our Physic's theories we have in our head are wrong.

The U of rolling resistance going back up as pressure in a tire gets higher until it was clearly shown is one of those facts many would have argued against.