davidhunternyc

I have a small apartment and can only get one. Which one would you recommend; The X11 or the Helix? Is the Helix as "fast and comfortable" over long distances as the X11? Based upon what I've seen, the fold on the Tern is clumsy and awful. Does the Helix fold better? Thank you for your thoughts!

Duragrouch

I also don't favor IGH. But on 349 wheels, you need an IGH to get an overdrive for a tall enough top gear, unless perhaps you use a rear hub with 9 tooth high, special. This was the driver for me doing 20"/406 wheel for my occasional-folder, 50-11 gets me 85 gear inches which is adequate for pedaling down a gentle grade or with the wind at my back, I don't need higher. But it's bulky folded, so if I go credit card touring in Asia, I'll probably fly over there, buy a Brompnot copy at 1/3 the price and no $300 shipping cost, ride it around in cities, bring it back home. But for my daily townie, it's 20" and all derailleurs.

Duragrouch

Helix looks definitely a better fold than any bifold (frame lateral hinge) like the X11, Dahon Mariner and Speed, et al. Helix appears to be designed to be as compact around the wheels as a Brompton, but with helix, both wheels overlap the frame on each side, plus the fork folds, so it looks really small for 24" wheels. I don't know how it compares in bulk to Brompton, but should be better than X11, only because with all bifolds, there's a lot of frame sticking out beyond the wheels. For that reason, for travel with my Dahon Speed bifold, I think I would need to pull off the wheels and place beside the frame on each side, that would eliminate the frame sticking out, but I still might need to put in two parcels to meet 62" max checked-bag girth. But that's not for daily folding. I'm just saying to point out why bifolds like the X11 are inherently more bulky when folded, versus bikes with a swinging rear triangle, such as Brompton, Helix, Bike Friday, etc. There's a new rear-swinger that was in another thread, the front downtube is split into two tubes with the rear tire swung fitting between the two tubes, slick, though for compact fold you need to pull off the front wheel and the axle QR clips to a bracket on the right chainstay.

EDIT: Search and ye shall receive, Brompton vs Helix folded (note, the beam rack on the Helix is not standard, and they have the seat up when it can go down):



Brompton vs bifold (Dahon single speed, no derailleur):

tds101 

I knew you'd eventually find the size comparison pics... Did you see the Dahon Curl pics also, just to see the differences? The Curl is supposedly a solid, small folder choice, if size folded is a major consideration.

Hrodwolf

Since I own both, I will try to answer to the best of my ability
Folding
The X11 folds faster because there's only one hinge. The Helix takes more time if you don't stop at step one (swingarm folded with the rear wheel brought forward). You have to rotate two knobs (fork lock and steerer), which takes several seconds. Honestly, it's not a bother because it's quick. I only fold the Helix when I need to. Usually, I can leave it unfolded on the train (in a space reserved for bikes if available or with me seated, using the space available). I can quickly fold it before boarding or in the crowded vestibule if the train is about to leave. The X11 takes up more space.
When I used to take the X11 on the train, I used a strap to keep the wheels in place. Otherwise the vibrations of the train were stronger than the magnetic force.
If you need to take the bike in "tight" spaces, or if you need to roll it folded, go with the Helix. The folding is better.
Performance
The drivetrain and thin tires of the X11 s make for an amazing ride. I'm sure someone more knowledgeable than me can explain why (10-42T for the X11 vs. 9-34T for the Helix). The X11 makes it easier to climb hills.
A YT reviewer called it a performance bike and I agree, the sensations are there.
The X11 offers better performance.
Support
I emailed Helix for help before I touched the bike when I was unsure and got clear and detailed answers quickly.
They also sent me a bumper (to protect the frame when folded) that I lost. Easy to find in North America, less so in Europe.
So I can say I'm more than happy with the Helix company.
I take the Ultralight to my local bike shop for service.
Servicing and repairability
They're the same except for the tires. Some brands have stopped making 24" tires compatible with the Helix. I see Donelly mentioned on their site for example. You have no problem finding tubes, but for the tires, you have to buy the ones made by Helix or some unbranded ones on Amazon or elsewhere. The Helix ones are fine.
The Helix disc brakes squeak in the rain and the bike shop adjusted them, but not as well as I'd like.
I had two punctures with the Helix in 7 months and the first one happened on the first day. I feared the worst because I saw some bad reviews for Tubolitos later (punctures on the first day, etc.). I rode on all kinds of roads (good, cobblestone, gravel,...).
Last year, when the weather was good, I went one step further and rode the X11 on forest trails, some with lots of roots. It is not designed for this, but the bike is strong. Sand patches stop it of course.
Rain
I never use the X11 in the rain because the tires are very thin. I'm more confident with the Helix and have ridden it in light and heavy rain.
Aesthetics
I was not a fan of the X11's satin black, blue and magenta colors at first, but I grew to like them. The silver was no longer available when I bought it after the Covid lockdowns (few bikes were available, only the expensive ones).
I prefer the Helix much more. I must say that I have neglected the X11 though it is great to ride on country roads.
Accessories
There are a lot of accessories for the X11, almost none for the Helix. That's the main problem. Mudguards and rear racks are on the horizon though.
Final Verdict
The X11 is much cheaper (although the price has gone up since I bought it). It's a wonderful bike.
I bought the Helix because I was going to change workplace with a 25 minute ride (+ train). I wanted a more compact folding bike (train often packed), lighter than the X11 (for my back pain). The Helix was a better offer than the Tern BYB (its folding seems awkward).
You can't go wrong with the X11. Some say it's overkill (I'm afraid it is) and the P10 is good enough.
I bought the Helix because it offered some of the things I was looking for: compactness, rolling when folded, light.
For me, the ideal would be a cross between the X11 and the Helix. A 20" Helix with more tire options and Klickfix compatibility.

davidhunternyc

Wow, @Hrdowolf, you have no idea how grateful I am for you insights. Amazing! There's so much to pour over and think about. Just off the top of my head, there are two comments that jumped out at me.

One regarding Performance. You say that the X11 offers better performance. It's my own uneducated guess that's because the Helix only has a 34T chainring up front. The larger 42T chainring on the X11 will propel you faster with less effort and less cadence. Could the performance of the Helix be improved by replacing the chainring (let's go extreme) with a 58T chainring? Would that help? Also, would a larger chainring interfere with folding?

The second comment is something that I've read before. You're not the only person bringing up this idea. That is, under your Final Verdict, you said, "the ideal would be a cross between the X11 and the Helix. A 20" Helix with more tire options." Some people have said that the 24" inch wheel on the Helix is too large for a folding bike. Not sure if I understand why. The larger the wheel the more like a full -sized bike the Helix is. As far as folding is concerned, yes, 20" wheels would be more compact but would the ride quality of the Helix be compromised? Also, could you replace the 24" wheels with 20" wheels if you wanted or is this not possible?

I'm hoping, tomorrow, to take an X11 out for a test ride. So excited. What should I notice about the bike, both positives and negatives? It's a used bike. What should I ask the owner about the X11? Hopefully too, I will get a chance to test ride a Helix. There may be someone willing to show me their bike. I will definitely report back. I'm still not counting out getting a Brompton T-Line. I test rode that bike already. It's light, for sure, but was slow when facing a headwind and the jarring, bumpy ride was kind of painful. It's the perfect folder though.

Stay awesome! Any other thoughts are always welcome.

silverx

50t chainring with 10-30t cassette
maybe can use 58t chainring but need change cassette with 28t or smaller also maybe need remove easy wheel also

Duragrouch

I have not seen side-by-side size comparison of Curl vs Brompton, but they should be darned close, and I'm very excited about the Curl D9, the i4 did nothing for me. The D9 promises all derailleur gearing and sufficient range, though I might need to fit a 9-36 cassette and freehub to get the high range I want. Plus disc brakes, and the brilliant mounting of the front caliper on the front of the right (mono) fork blade, eliminating the problem of QR pullout of the dropouts, without thru-axles; So simple, why didn't someone think of that before? I ashamed that I didn't think of it. But the questions on the D9 are price, and availability.

Duragrouch

With disc brakes, a possibility as same position of calipers and discs with respect to wheel center. But, two problems: a) The bottom bracket center was designed for a certain height; Lowering it 2" in radius may cause pedal strike with the slightest bike lean, although if they designed the frame for the longest crank arms, and you use a lot shorter, this might be mitigated. b) The fork geometry is designed around 24" to have a certain trail (caster, for centering), and going to 20" on the same fork may shrink or eliminate that, perhaps even going negative with the tire contact center forward of the steering axis, unstable. If you know the head tube angle, fork offset, and tire loaded radius, you can calculate trail. If trail on the 24" is known, all you need is the head tube angle and loaded radius of 20" tires to trig out the new trail value.

davidhunternyc

^^^ Duragrouch This is why I leave analysis up to the experts like you. Umm... what I gather is, "No, just leave the Helix as is."

Duragrouch

Yes, unfortunately. I also perused the Sheldon Brown tire size chart, to see if there was any size offering a wider selection of widths, that would be closer to 24"/507, not real close, but standard mountain bike 26"/559 is only 26mm larger rim bead radius, and if space for that and the increased tire size (the whole point of going away from 24"/507), that might be viable. I think that rise in bottom bracket height would be OK, and the slight increase in fork trail would only add stability, and I think would not be enough to cause "wheel flop". Both of the above are better a little larger than a little smaller. But again, this could be calculated before doing anything. 26" wheels are common, but to try out on the helix, assuming frame and fork clearance, they also need to be thru axle rear, and front needs to be thru axle compatible with that single sided fork. Lastly, the larger tires may be a factor in folding; I'm gonna go look at the past pics I posted. Probably if you asked Helix if 26" wheels were possible, they probably know and would tell you. EDIT: Clearance between tires and crank arms folded looks close, I don't think 26"/559 with larger section tires would clear. I think slightly bigger 24"/507 would, so hopefully Helix can persuade good tire makers to produce them.

I hadn't known this much about bike geometry until I got my 20" wheel folder, and wanted more stable steering, so did a deep dive into the subject.

davidhunternyc

I think, though, people were talking about going to a smaller 20" wheel size, not a larger 26" inch wheel size. Several people would like a Helix with 20" wheels like the Tern.

Duragrouch

Definitely possible with redesign, but on the current frame, just dropping in 20" wheels, I very much doubt due to significant (50mm) lowering of bottom bracket, and reduced fork trail. On the other hand, however, if 20" and really BIG section tires to eat up most of that, should work. But that's a big jump, I can't see 90mm (almost 4") section height tires on 20"/406.

I think Helix went 24"/507 as a distinguishing feature, "better than 20", but yes, it makes more sense to do 26"/559, or 20"/406, but the latter may have frame sticking out beyond the tires, folded, and the former may not fit checked baggage limit of 62" girth.

Jipe

The choice of ETRTO507 was indeed a marketing choice with the simplistic argument bigger is closer to full size wheels and as such better (they even claimed that its safer).

There is little clearance above the wheels, even very little to put mudguards, so ETRTO559 would not fit without a huge redesign.

And going to ETRTO406 will put the bottom bracket much lower unless wide tires would fit, maybe 65x406 or 62x406 would fit? It should be checked if the sidewall of the tires do not touch the fork or rear triangle side?

Another option would be to use ETRTO451 but there are few tires and no wide tires in this wheel size, so the bottom bracket will also be lower.

To change the wheel size, there is another problem: the front hub is proprietary and not easy to find as spare part.

splithub

Also to mention the OS20 standard - 451 size with wide tires, the range of available rims and tires is even smaller than for stock helix, and the frame and folding will probably not clear the width.
Schwalbe never fulfill their claimed specs - always heavier and smaller, which leads to a 47-507 Marathon and Road Cruiser that are in fact only 40 and 41mm wide, on a rim with 21mm inner width. A 50mm Big Apple is also just 43mm wide. So on the skinnier Helix rim, they might come out narrower. My experience with Kenda, Conti, Maxxis however - they are 40mm if 40 is specced.

Jipe

My experience with Schwalbe tires in ETRTO406 (Marathon, Big Apple, Big Apple Plus, Big Ben Plus, MotoX, Pick-up, Marathon Racer folding, Durano, Durano Plus, Ultremo, Pro-One) is that they all were always a little wider than their nominal width.

Marathon, Marathon Plus 35x349 for Brompton exact width.

Only the Big Apple 50x355 for the Birdy is slightly narrower than 50mm.

splithub

https://www.reifenbreiten-datenbank.d...e-Big%20Apple-
20x2.00.html
Reifenbreiten-Datenbank

..this page has thousands of entries from people who measured their tire width, with rim width and pressure. It's german, but tire model names and parameters are universal. The database has a clear tendency on Schwalbe tires.
Around ten years ago it boiled up here in germany why Schwalbe tires are always narrower than specced. Schwalbe stated that they give the width that they measure in the lab on a "reference" rim, that equals 2/3 of the specced tire width, for example 40mm inner width for a 60mm tire. And they measure with max. pressure. Will look for the article and link. Most other manufacturers give more realistic digits. The web is full of that topic, always about the same manufacturer.

tcs

You'll note this Brompton doesn't have fenders/mudguards or a rack, and a rather flat aftermarket saddle:



Here's the Dahon Curl and a BikeFriday tikit:



The Brompton with a 1980s Dahon Classic. (Sheldon Brown said the Classic folded smaller. I seldom disagree with THE MAN, but I'm not sure about that.)



The Brompton and a Dahon EEZZ (ISO305 wheels)



The Brompton and a Dahon K3 (14" ISO254 wheels)



Dahon K3+ (ISO305 wheels) v Dahon Mini 349 (ISO349 wheels)




Iruka v Brompton v Ori. The Iruka is relatively wide, however.



20" Caracle v Brompton. This Caracle's owner has fitted an aftermarket spring-thingy between the seatpost and saddle.



You want Santa Claus to bring you a folding bike? (This is a prior version of the CarryMe - the handlebar fold has been improved.) The CarryMe (8", ISO137?) is the only one he's getting down the chimney:

Hrodwolf

Check it like any other used bike. Pay special attention to the hinge and check that it folds well, with no damage or cracks on that part. If you have the slightest doubt, don't buy it. Of course, check that the original parts have not been replaced and work well. You should immediately see that it's a fast bike.
This reminds me that a few (many?) years ago there was a Tern scandal about faulty hinges and many people vowed never to buy a Tern again. I have never had a problem with the X11.

A Helix was customized for Hong Kong and its hills and I noted these parts: cassette E-Thirteen XCX Plus 11s Sram XD 9-42 with a rear derailleur Shimano SLX M7000 11V.

davidhunternyc

^^^ I can not count the ways you've all been helpful to me. This is a trepidatious decision since I don't know anything about bikes. So now I have 2 out of the 3 shortlisted bikes tested. I rode the Brompton T-Line and today I rode the Tern Verge X11. I'm waiting to be contacted by a guy that owns a Helix who might let me test ride his bike too. The advantage is that he's a bicycle mechanic. He can educate me further on these three bicycles... but let's get the suspense out of the way! Let's talk about the Tern Verge X11. In a word, "Wow!"

As I said, I checked out a used Tern Verge X11. Honestly, I don't care that it's used. I think Terns are kind of ugly anyway. They are engineering machines to do one thing... go fast! The one I rode today blew my mind. It seemed twice as fast as the Brompton T-Line but here's why. It's fully customized. You guys know this stuff. I don't but the parts on this bike are expensive. It has 12 speeds and uses an electronic shifter too which blew my mind. Here's the rundown on this bike:

We put the bike on a scale and it weighs 21 pounds.

Tern Verge X11 - Upgraded Carbon Wheels with Dt180 Hubs that fit a 12 Speed SRAM Casette $1000 Sram Force Axs Groupset 12 Speed $1100 SRAM Red Crankset With Ceramic Speed Bottom Bracket $950 SRAM Xtr brakes $550 Carbon Bar And Seatpost $300 S-Works Saddle Carbon $325.

Most of this stuff is a foreign language to me. Does all of it make this bike better than a stock Tern Verge X11? For instance I asked what the "red" things were near the crank, like the BSA Shimano Red Coated "something," retailing for $480. Of all the upgrades, can you all break it down and tell me what's good or not?

The bike was a little beaten up, as can be expected with a used folding bike. I would give the condition a 7 out of 10, but what do I know. I checked the hinge and it folded and unfolded well. Because the forks were upgraded there isn't a magnet on the fork to connect to the magnet on the rear triangle. The rear magnet is there but it's useless. I wonder if it can be removed. It does fold, of course, but it doesn't stay folded without a strap. It swings open and there's no way to wheel it around.

As I've said, it's ugly. I don't like the looks at all but it's a speed demon. The fold is awful. Because it's used, is there something that's broken or likely to break soon? I don't know. With 2 out of 3 bikes tested, I'm really excited to try out the Helix. I'm thinking that the Helix might be a great middle ground between the T-Line and this custom X11 in terms of speed and foldability. The parts on the Helix can be upgraded too but that's another story.

Duragrouch

tcs #2918 above: Wow that's all really informative pics, thanks. The Curl is cheating a bit in having the seatpost off versus the Brompton, but still impressive size, however having the seatpost off means it is not used to lock the fold in place like on a Brompton (a brilliant design feature), instead probably relying on magnets.

The Caracle looks impressive on 20" wheels and is new to me, I will look that up.

Duragrouch

The red things near the bottom bracket are "external" BB bearings, used with hollow-spindle cranks of all types these days. The price being quoted is ridiculously overpriced, IMO, fully functional and good quality ones can be had for less than $50 these days. That one has ceramic (coated?) bearing balls, may increase part life, but my cheap external BB is wearing great after two years and a lot of miles, it came with my crank for all of $65, and new BB parts about same quality would be about $30. Now, all the other parts are darned expensive, maybe not worth their full price, but pricey high-performance stuff, and carbon fiber stuff is pricey, so are Dt (Swiss) hubs I think. That accounts for a lot of the light weight of the bike even with that many speeds, that's near 700c (non-carbon) race bike weight. Having said that, a local respected bike shop recommends against carbon *anything* unless you are a competitive racer, they have a whole online page about it, let me know if you want to see; Basically, fragile, easy to damage even just from improper installation, usually not repairable (a handful of respected places will repair a carbon frame, if the damage is not too bad), and bad failure mode (fracture with sharp shards). It may be good to know the selling price of that X11 bike, versus a new X11 with warranty and zero miles, as those drivetrain parts, while high quality, don't last forever. I've never recommended a pre-purchase inspection on a bike, but if you are not knowledgeable, for something that pricey, ask about the price of that at a good bike shop; They'll check chain stretch and cog and chainring condition, bearings, inspect the carbon, etc, to make sure you don't need anything replaced immediately.

davidhunternyc

Great advice as usual. This bike is being sold at a respectable bike shop. The shop owner swears that it is a sound, solid bike but, then again, he's the one selling it. He's asking $3K for it. Deal or no deal? I can't tell. I do like the lightweight wheels, 54T single chainring, and electronic shifter. I'm on the fence. How can I say, "yes" if I haven't ridden the Helix yet?

Duragrouch

I agree, get a ride on a Helix. Looking online, I don't see any used for sale, that may say something. Lots of X11s and Bromptons for sale (many of the latter at list price like when they were hard to get, but not any more), but that may mean nothing as there were tons of both produced.

All other factors being equal, my current preference in frame material is:
1) titanium
2) high-end steel, like 4130 chrome-moly or better
3) aluminum
4) carbon fiber

And in my situation where durability is of paramount importance (what's my name?), I would not buy 3 or 4.

Jipe

There was a huge evolution in steel alloy while nothing happenec for titanium, the alloy used for bike frame is the same as 20 years ago.

Titanium is a great material but welding is a major issue: is there is oxygen contamination during the welding, then sooner or later, the frame will break and its impossible to detect this problem when buying a titanium frame.

For me currently, the best material to build bike frame is stainless steel like Reynolds 953 and Columbus XCr that allow to build frames almost as lightweight as titanium but with a better efficiency and no risk of contaminated welding..