TomRider

I own a Tern Link P9 since 2013 and I use it to commute and ride in the city every day, often taking it on a tram or a bus for part of the way. Till now it has been great, but it starts to fall apart... the next service is going to cost a lot and besides, now that my commutes are longer - about 5 to 15 km each direction - I feel that it's time to upgrade.

I've searched in second-hand websites and saw ads for three bikes in my area. I wanted to ask for your opinions and recommendations about which one would be best - maybe one of them is obviously better than the others? I ride only on roads and paved bike trails, and because of the longer riding distance and some hills on the way, I want to have a bike that's fast and feels like a solid road bike (which the Link P9 is far from).

Riese & Müller Birdy Touring
Dahon MU P24
Tern Eclipse P18

All three are old models, but seem to be in great condition, as they have been used very little. Their prices are similar.

Thank you!

Jipe

These 3 bikes are very different!

First the Dahon MU P24 is very similar to your Tern Link P9, its heavier, the 3 speed rear hub is heavy and has a lower efficiency than a derailleur only transmission, it won't ride better than your Link P9. It also folds similarly with a similar folded size.

The Tern Eclipse P18 has bigger 24" wheels with all the problems of finding efficient tires in that size (same problem as Helix) for this reason, Tern moved to 26" wheels on the current Eclipse. It folds similarly but bigger than your current Link.

The Birdy Touring is a totally different type of bike with a full suspension and a different, smaller fold. There were several versions of the Riese & Müller Birdy Touring, Birdy 2 and Birdy 3 with different transmission including one with a SRAM Dual Drive 3 speed hub discontinuated by SRAM. The Birdy rides great on all type of roads and trails.

Duragrouch

Jipe knows a ton about the Birdy. I don't, but from what I've read, the front and rear suspension will either be loved for its more supple ride than others, or unloved because of the bobbing of the bike in a less than road-racer fashion. I think this is something you just need to test ride yourself. Second, the tire size is a bit non-standard, not 20"/406, and I can't recall if 20"/451 or a different size, but you need to make certain that the type of tires you want for your style of riding, are available easily and at moderate price.

More questions and I think Jipe is the one to answer them.

Jipe

Due to its specific geometry, the front suspension of the Birdy doesn't dive when braking or bob when pedaling.

The rear suspension is classic but with a pivot well positioned, much better than on the Brompton.

Bobbing when pedaling depend a lot of the pedaling abilities of the cyclist, bobbing occur mainly when pedaling at low cadence with a high torque off the saddle, much less when pedaling at high cadence with a lower torque on the saddle.

The wheel size of most Birdy is ETRTO355/18" and accepts tires up to about 55x355 but the disc Birdy accept ETRTO406/20" wheels up to about 35x406. With rim brakes (its V-brake on the Birdy without disc brakes), the problem for ETRTO406 wheels is to move the brake shoes higher, there is enough space for 35x406 wheels too.

Schwinnsta

I have gone back and forth with Jipe on the subject of suspension. As I understand it, the Birdy dives or bobs less in the front because it is converting the up and down motion of the front wheel into a horizontal back and forth motion. I have never ridden a Birdy, but I have owned Bromptons and Moultons for years at a time.

My experience with Moulton led me to believe that, at best, suspension is double-edged. You can ride in synch with it sometimes, but not all the time. By making good choices on the frame and tires, you can eliminate the need for suspension. In the end, suspension is heavy and complicated. If there were Birdy dealers, I would give them a test drive, but I don't know of any say within a hundred miles of here.

Given the separation of Jipe and my views on Moulton we just agree to disagree.

Jipe

The front suspension of the Birdy works better than the front Leading Link of several Moulton (I never tried the front suspension of the New Series which by the way has several variant).

As said, if you ride off saddle pedaling at low cadence with a high torque and pulling on the handlebar for instance when climbing, there will be a rear bob, its the motion of the weight of the cyclist that creates this bob but this is an obsolete way of pedaling, the current trend is to climb on the saddle pedaling at (very) high cadence.

TomRider

Thank you very much for the replies. I see that the suspension is not a simple story, and because I ride 99% of the time on paved roads, it's an easy decision not to buy the Birdy.

I also learn that there wouldn't be a huge difference in riding the Dahon MU P24 compared to the Link P9 that I own for more than 10 years now.. that's good news! I may not even need to let go the old Link after all.

If I do, the Tern Eclipse P18 looks like the best choice of the three. But I wasn't aware of the 24" wheels on that specific model. So after searching a bit more about it, it looks like a Dahon Dash/Altena/GB-1, which I can't find for sale anywhere, or a new(er) Eclipse with 26" would all be ideal. On the other hand, the old Eclipse P18 is available near me for 500$ and the P20 is sold 2nd hand for over 2k. Not sure it's worth it..

Schwinnsta

Even pedaling at a high cadence, you still find yourself getting out of synch with the suspension as it bobs to the metric of the road conditions.

Ron Damon

Really? It's obsolete? It's possibly to be avoided, but certainly not "obsolete". If you climb or tour with a load on long, tall climbs, you'll know that you'll have to switch between in- and out-of-the saddle. Bobbing or not bobbing is not a "trend'. It's mechanics. Nice try.
​​​​

Duragrouch

I've not totally grokked the Birdy front suspension geometry, but I think it may incorporate some anti-dive under front braking. Under other conditions, with no torque acting in front, the suspension will move as do all suspensions, that's the intent. With a relatively short wheelbase, it's gonna bob a bit if the suspension is sprung soft, but that's a big qualifier and can make a huge difference. Certainly a bike with front and rear suspension would be better on rough surfaces unless you have huge cushy tires.

Sounds like the OP is reevaluating their current bike and perhaps a refresh of it.

Ron Damon

You best pedal sitting on the saddle for pedalling off the saddle is obsolete. Did you not get the memo? 😂😂😂

Duragrouch

I was doing a lot of both today. First warm day of the season, slowed me down, and I'm way out of shape.

I did notice on my climbs, a slight lateral rock in the steering. Stopped, checked out, not fore/aft under braking, just lateral, no cracks, and I can feel movement between the top and bottom stem base hinge, and the latch is plenty tight. I'll do a deeper dive tomorrow, I don't think the hinge pin is replaceable, i'll probably end up putting some soda can shim in between the two parts to snug things up. This is the early Dahon Speed non-telescoping steel stem, which I like for its durability and stiffness. But I think my increased climbing while standing has taken a toll on it. Might also need to tighten frame hinge, my improvised Deltech has reduced the bending moment on the hinge, but does nothing for torsional loading of it under climbing.

Saw a really nice sorta celeste green velo-orange mini-velo, very nicely equipped with discs and very fat tires. Stopped to fix a flat. Discs, but otherwise very classic 2X gearing, fenders, upright swept-back handlebars and cork grips, Ideal or Brooks saddle, etc.

EDIT: Long handlepost hinge a bit loose, no way to replace pin, I don't even see pin from outside, might just be part of steel forging, so I added "soda can shim" between parts to tighten up. Cut rough rectangle to fit, installed and closed hinge, trimmed outside with sharp knife to flush. Worked. Also tightened up frame hinge, and again, I've added locknut on that to stay put. Wobble gone. My increased climbing while standing this past year puts more load on both. Glad I could fix this, I don't think forged and welded steel handleposts are available any more.

Hey Ron, how about that? Are good steel posts still available? Forged aluminum posts are now pretty much standard so I expect they hold up (except for the rare past Dahon recall). How do your hinged posts hold up? Or do you trade them out often enough that it's not an issue? My old steel one depends on tightness of the pin or a shim, with an over-center clamp pulling the two hinge halves together; The newer aluminum posts seem to use a radial "wedge" at the bottom for locking, but I don't know if there is a wedge on the opposite side as well, or still depend on the hinge pin for tightness.

Jipe

The Birdy is not a MTB nor a gravel bike.

Its suspension is designed to be used on paved roads and it rides fast and comfortably on bad paved roads including cobbles on which small wheels bike with narrower tires (like the Brompton, the Dahon Curl...) are very uncomfortable.

Unlike most folding bikes (Dahon, Tern Fnhon, Zizzo...) its frame is one piece, without hinge. It folds using the pivot of its rear and front suspension with a small fold, smaller than bikes with a center hinge.

Its wheelbase isn't short, its about 103cm like the wheelbase of an average road bike. Unlike several designed in Asia folding bikes designed for riders up to about 170cm, its designed to accept average and tall EU-US riders.

For the Tern Eclipse now with ETRTO559/26" wheels, its pretty big folded, you should check if such a folded size fits your needs.

Ron Damon

Oh, come on, man. Have you forgotten about the Or!gami L0tus which fits folks up to 190cm (6'3") in height? 😉

Jipe

Your favorite Fnhon Gust has a very short wheelbase of only 900mm! Much shorter than a road bike, much shorter than the Brompton and Birdy who have almost the same wheelbase.

Its chainstay length of about 350mm is also very short.

Its a small bike designed for small people which is not a problem, this bike is designed for its main market. Same apply to many bikes designed mainly for the Japanese market like most Tyrell.

Ron Damon

Actually, you are wrong again. The wheelbase is a whopping 91cm. I don't see it as a problem as it makes the bike extremely maneuverable, agile and nimble. It's an absolute pleasure and hoot to ride. In fact, I have it out on a cross country tour of South Korea at the moment. You know, the place that you pontificated had ugly, crowded beaches.


FnHon Gust 16" on tour

To be clear, I do not recommend the Gust or its myriad imitators if you are taller than 175cm.

Jipe

Its 910mm, I rounded it down a little and the chainstay is 347mm, I rounded it up a little, source: https://handsonbike.blogspot.com/202...-geometry.html for the size of the cyclist, it depend of the gender and individual body dimensions (typically, for the same height women have longer legs and a shorter torso than men resulting in a sorter frame for women).

Duragrouch

I should rephrase; I didn't mean a Birdy wheelbase is short by bike standards, I should have clarified; It, and all bicycles except perhaps a long wheelbase recumbent, have a short wheelbase with respect to the center of gravity height (with rider), compared to a passenger car, especially one with an especially long wheelbase to CG, like a Citroen DS or an NSU Ro80, both of which had the engines forward of the front axle, but short engines. The Audi 5000, due to the driveline configuration, the long inline-5 engine was suspended entirely forward of the front axle, and that forward inertia gave good body motions for ride, "slow and floaty" like a luxury car, but harder to control for handling, as the front springs and dampers had less mechanical advantage on that mass for the same spring and damping rates.

My point being, high CG to wheelbase, always presents issues with suspensions, especially if drive torque is not smooth, which is an issue on all bicycles. Even with no suspension (except tires), high CG to wheelbase presents issues with weight transfer under braking and drive thrust. I rode a long wheelbase recumbent for years, and between the wheelbase and much lower rider CG, the dynamics of that were fantastic under braking or acceleration. But its huge size, severe difficulty up or down stairs, and inability to stand on the pedals when climbing steep hills, pushed me back to conventional bikes.

pinholecam

I'd go for the Tern Eclipse 26", based on my experiences with Moulton TSR (suspension ), Tyrell IVE (18"), various bi-fold 20".
That said, you do sacrifice fold size and there is no running away from the physics of a larger wheel (and that does not fold).

With the larger wheel size, you get better roll over and rotational losses if you want to ride fast.
You also get the option for better compliance with wide tires and a suspension stem and seatpost (needs modification) takes care of road traction in most cases as well as comfort (if you want to go this route)


There are no bad bikes, just what you like and feel that if fits your needs better.

TomRider

Yes, the Tern Eclipse 26" looks like the best choice so far. I'm still thinking about the Dahon Mu SL which is 9kg and must be great to own for long commutes, and is sold 500 less..