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Tech Factors for Smoother Rides on Small Wheel Bikes

Slowburner

Cruising
Sep 27, 2019
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I'd like to ask the forum some questions about my test ride experiences of the Tern Verge D9 and Verge P10 bikes I'm considering buying. Specifically, the P10 feels a lot smoother and more responsive than the D9, but I can't quite see why that should be so. The bikes have quite different technical specifications, and correspondingly large price jumps, and I'm curious about the technical reasons for why these components should provide such a different experience.

Naturally, I embarked on an intensive schedule of watching and reading widely about the relevant bike components, as I'm sure every red-blooded cyclist properly should :) but failed to draw any obvious conclusions about which of the components are affecting the experience, or why. So I started thinking that this might be misleading because people generally discuss road bike components in the context of road racing, which is very different to urban riding in so many ways.

Would forum members care to comment on the technical aspects of these bikes' components, and why they might be more or less significant for the urban riding experience?

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Official links: Verge D9, Verge P10, Verge X11
 

Half-Fast Mike

Lanterne Rouge-et-vert
May 22, 2007
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Main difference I see from the photos is the wheels. Why are are better wheels better? Any number of reasons. Lighter; good hub bearings; lower inertia; gets you to cruising speed faster. For the jump from rim brakes to disk brakes, the rim profile is completely different; less material is needed at the rim.
 

kiwisimon

Maximum Pace
Dec 14, 2006
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Firstly the P10 is lighter so for the same effort you will get more acceleration than the D9. The places you contact the bike, seat tube and handle bars have lighter and I'd speculate more flexible tubing and as Mike says the tires and wheels are better especially the tires. The cables and components are all higher spec so clearances are closer with less flex which should show in smoother shifting and more responsive controllable braking. Tern have the Bickerton DNA but style wise they are leaving the parent company well behind. This podcast from a few years ago introduces Tern and before that has an interesting Euro perspective of Tokyo 19:15. Tern is at the 29 minute mark.
 
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Slowburner

Cruising
Sep 27, 2019
42
21
Main difference I see from the photos is the wheels. Why are are better wheels better? Any number of reasons. Lighter; good hub bearings; lower inertia; gets you to cruising speed faster. For the jump from rim brakes to disk brakes, the rim profile is completely different; less material is needed at the rim.
Thanks, Mike. Can I assume that less material at the outer edge of a better wheel means again, less intertia, which we might think could be quite easily felt in the stop-go urban riding experience?
 

Slowburner

Cruising
Sep 27, 2019
42
21
Firstly the P10 is lighter so for the same effort you will get more acceleration than the D9. The places you contact the bike, seat tube and handle bars have lighter and I'd speculate more flexible tubing and as Mike says the tires and wheels are better especially the tires. The cables and components are all higher spec so clearances are closer with less flex which should show in smoother shifting and more responsive controllable braking. Tern have the Dahon DNA but style wise they are leaving the parent company behind.
Thanks, Kiwisimon. On this theme of everything being that much tighter, I wonder if the disk brakes are also significant in different ways than they might be on road race bikes. Urban riding is characterised by short distances with big cadence changes - from one junction to the next, and with more heavily loaded frames. So the fact that disk brakes allow you to carry more speed for slightly longer and slightly reduce your braking distance matters matters differently to you in town than if you’re riding in a group at high speeds out on the open road. Does this sound reasonable?
 

kiwisimon

Maximum Pace
Dec 14, 2006
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I think in any situation, the later you can brake the faster you will be.
Road racing I'd argue that braking is usually more predictable, so less panic stops, perhaps that is also a factor in a commuter bike favoring discs?
Town use in daily weather conditions I'd prefer discs just for improved wet weather performance.
 

Slowburner

Cruising
Sep 27, 2019
42
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I think in any situation, the later you can brake the faster you will be.
Road racing I'd argue that braking is usually more predictable, so less panic stops, perhaps that is also a factor in a commuter bike favoring discs?
Town use in daily weather conditions I'd prefer discs just for improved wet weather performance.
Watching and reading about disk brakes I’ve learned that for road racing in a peloton or training in your chain gang, the braking is more predictable and that it’s important to be braking at the same speed as your group. I think this tends to skew the road racing-based reviews to conclude that the choice is personal, when in fact the choice might be quite significant for urban riders.

The Kashiwa test route includes the pedestrian railway bridge over Kashiwa station and back, which has a spiral and a steep slope, so up the spiral then down the steep slope, and a hard 180° to go up the steep slope and down the spiral. That’s quite a common demand of urban riding and the P10 feels more secure, which I think equates to more confidence and more fun.

Again, my point is that whilst I wouldn’t think components would very matter much because buying a folding bike means accepting so many compromises, and we don't pretend think we're going up Alpe d’Huez or down Whistler’s A-Line, but in fact, it seems to matter a lot.

Can anyone recommend other folding bikes around that price point that I might want to be looking at because of the different components?
 
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Cactaur

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Feb 3, 2014
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P10 gets nicer tyres, Schwalbe Durano 28c vs cheapy Chengshin 37c. Geometry looks similar but 10mm shorter reach in the P10 could contribute to your comfort. And as noted its 500g lighter so that could contribute to a more zippy feel.
 

microcord

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Aug 28, 2012
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Ah yes, weight saving. Dave Moulton writes:

Consider this scenario. A standard size water bottle filled with water weighs a pound and a half. If you are riding with a friend and you hand him your water bottle, you have instantly lost 1 ½ lbs. and he has gained the same amount.

If weight were such a large factor, you would expect that you would suddenly shoot forward and your friend would drop back. The fact is neither of you feel the slightest difference, even if you are climbing a hill.

Reduced weight does however mean reduced unpleasantness when carrying the damn bike. (As I'm reminded every time I carry my own, "no weight spared" bike through a station.)

As long as you're not doing much braking while going downhill during rain or after heavy rain, rim brakes should be OK. (It may be easier to check the state of their pads, too.) Cheap tyres can be nasty, but you wait till they're worn (or, if you're impatient, you don't), and then you replace them with good tyres.

Can I assume that less material at the outer edge of a better wheel means again, less intertia

-- yes --

which we might think could be quite easily felt in the stop-go urban riding experience?

I for one am unable to think this. Unless, that is, you are tremendously muscular, the "go" parts of your stop-go urban riding experience are those of a competitive sprinter, and the "stop" parts have to rescue you from 40+ km/h. But if yes, this is you, then perhaps a bike with larger wheels is advisable.
 

kiwisimon

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Dec 14, 2006
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Ah yes, weight saving. Dave Moulton writes:
I will say this, if I am riding up hill on my 20 plus pound steel road bike with another rider of equal fitness level on a 14 lb. carbon fiber bike. I claim we would both arrive at the top at the same time.
I'd claim the heavier bike and rider have required more energy to get up the hill. They also expend more energy from a stop to get up to the same speed of the lighter combination. Weight is not the only determining factor but on a bike the lighter the wheels the faster a rider can get up to speed with less effort than heavier wheels.
 

microcord

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Aug 28, 2012
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The calculations on this page suggest that the savings will be trivial. Unfortunately its "Appendix A" has disappeared (and I can't find it via the Wayback Machine), but presumably the calculations were made for full-sized wheels. If the wheels are smaller, then the moment of inertia will be less, and reducing it by a given percentage will have less benefit.

There'll be more stopping and starting per kilometre in city riding than in any of the writer's three kinds of riding, so the effect will be somewhat increased; but anyone that keen to be fastest in the city would I think choose a different genre of bike.
 

Slowburner

Cruising
Sep 27, 2019
42
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The calculations on this page suggest that the savings will be trivial. Unfortunately its "Appendix A" has disappeared (and I can't find it via the Wayback Machine), but presumably the calculations were made for full-sized wheels. If the wheels are smaller, then the moment of inertia will be less, and reducing it by a given percentage will have less benefit.

There'll be more stopping and starting per kilometre in city riding than in any of the writer's three kinds of riding, so the effect will be somewhat increased; but anyone that keen to be fastest in the city would I think choose a different genre of bike.
Thanks for this link, @microcord; here’s a relevant excerpt from the article:
In summary, wheels account for almost 10% of the total power required to race your bike and the dominant factor in wheel performance is aerodynamics. Wheel mass is a second order effect (nearly 10 times less significant) and wheel inertia is a third order effect (nearly 100 times less significant).
I agree that the styles he was testing are unlike the demands of urban riding - being all road racing situations, as I’ve previously found. It’s also my inclination to agree that although there really isnt any stop-go riding being presented in the figures, it’s hard to see how much difference that could make.

All of which brings me back to the OP, that whilst there’s a tangible difference between the D9 and P10, and ¥50,000 of different components between them, but it’s really not clear to me as a less knowledgeable cyclist which components are making that difference. Which components would forum members pick to upgrade the ride in which order?
 
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Half-Fast Mike

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May 22, 2007
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which of the components they’d change out in what order to improve the performance
All other things being equal, better wheels are generally the most bang-for-your-buck upgrade from an entry-level bike. However, if you get the D9 frame there's no sensible way to convert it to disk brakes, so that option doesn't work.

What's your motivation for getting a lil' wheel folding bike, rather than a standard? Are you likely to need to take it on crowded trains, or discretely into your place of work...?
 

Slowburner

Cruising
Sep 27, 2019
42
21
What's your motivation for getting a lil' wheel folding bike, rather than a standard? Are you likely to need to take it on crowded trains, or discretely into your place of work...?
:) Well, as indicated...
I embarked on an intensive schedule of watching and reading widely about the relevant bike components, as I'm sure every red-blooded cyclist properly should
hence I found this forum, and thus obtained the consensus of the community that if someone thinks they want a small-wheeled folding bike, what they really want is a full-size bike with quick releases on every suitable point, and a good rinko bag, right? :)

I’m sure I wouldn’t want to argue with you guys (unless we all had a pale ale in hand, obviously ;)). I just think I may not be a cyclist wanting to use the trains so much as someone who‘d like to cycle a bit more, and take the trains a bit less.

I travel in to Tokyo a couple of times a week (outside of rush hours) which entails riding to the station, taking the train to Tokyo, then taking various other trains across the city and walking. I’d like to get to the city and ride the rest of the way

I do have full-size bikes when I’m visiting friends and family abroad, but I ride a small-wheel small-frame shopper a few kms to work every day, and feel I’d rather upgrade that than buy a full size bike.

I can see that a 3/4 sized bike would fit the bill once riding, but if I’m taking it on the train, almost anything beyond simply sticking it on my shoulder is too much work, so the fold needs to be pretty good, and I don’t think quick releases are going to do it for me.

The Dahon Lockjaw bikes have caught my eye, but in practice the fold wasn’t nearly as convenient as the video would have you believe (Dash P8 Lockjaw video ) Any thoughts on finding a slightly larger bike that could work for the situations I describe?
 
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Half-Fast Mike

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May 22, 2007
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I just think I may not be a cyclist wanting to use the trains so much as someone who‘d like to cycle a bit more, and take the trains a bit less
That makes a lot of sense.

My main take-aways from casual reading about the respective dis/advantages over the years are that mini-bikes can offer a small but significant aero advantage, although this rarely matters to the riders who choose them, and that smaller wheels are more vulnerable to (poor) road conditions. On the latter point, Tokyo streets are the smoothest and best-maintained I've ever known, apart from possibly Singapore, so it's not really an issue.

Every rider has their own unique combination of motivations for cycling, whether utilitarian, recreational, competitive, health & fitness, or whatever combination. Some have no choice, while others have so many choices it's a problem! At the moment I have a 45-min commute, which I do by bicycle and motorbike about 50/50, and regularly spend 6 - 8 hours a day in the saddle for fun. I've done some riding (and lots of maintenance ) on Bromptons, but wouldn't personally want to own one myself, but I recognise that that could easily change if my travel needs were different.
 
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GrantT

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Oct 2, 2012
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All of which brings me back to the OP, that whilst there’s a tangible difference between the D9 and P10, and ¥50,000 of different components between them, but it’s really not clear to me as a less knowledgeable cyclist which components are making that difference. Which components would forum members pick to upgrade the ride in which order?

Tires first. Replacing thick, stiff, heavy, dead tires with softer, livelier, quicker rolling rubber should make a big difference for a small amount of money. If the inner tubes are similarly pedestrian, changing those will help too.
 

Slowburner

Cruising
Sep 27, 2019
42
21
All other things being equal, better wheels are generally the most bang-for-your-buck upgrade from an entry-level bike. However, if you get the D9 frame there's no sensible way to convert it to disk brakes, so that option doesn't work.

Tires first. Replacing thick, stiff, heavy, dead tires with softer, livelier, quicker rolling rubber should make a big difference for a small amount of money. If the inner tubes are similarly pedestrian, changing those will help too.

Is it practical to swap out bearings in wheels and cranks too, or is that sort of thing not possible until you get into higher cost bikes; is it a feature of higher cost bikes that they support interchangeable components where cheaper ones do not?
 
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Slowburner

Cruising
Sep 27, 2019
42
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I’m also interested in the effect of the paired spoke wheels on the higher cost P10. The sum of the knowledge gleaned from my research into this technology is that if you hold a suitable patent on paired spoke designs, or are a rider sponsored by such a patent holder then paired spokes are the very best wheels you can buy. But if you DON’T hold such a patent, or AREN’T sponsored by such a patent holder, then the design just doesn’t make any difference at all. Ho, hum.

From my perspective, I wonder if maybe paired-spoke wheels will flex a tiny bit more in the spaces between the spokes, and therefore be a little more resilient, which might little difference to larger wheels on race bikes, but might translate to something you can actually feel on small wheels, where the ride will tend to be harsher. Any thoughts on this (frankly wild, and unfounded) speculation ?
 
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Half-Fast Mike

Lanterne Rouge-et-vert
May 22, 2007
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As a general rule, and with respect to these folding bikes too, can you usually upgrade things like wheel hub bearings, cranks and pedals, or do these require big upgrades and different designs, like completely different bottom bracket designs, and suchlike?
In general, yes. For folding bikes, I'm gonna say 'maybe, but it probably won't make much difference'. The wheel bearings are a tiny part of the whole system. Unless there's actually something wrong with them, the friction difference (and ultimately its effect on the watts-per-kilogram equation for rider and machine) between a standard bearing and a high-end one is only significant if you are chasing 1st vs 2nd place in a race. For small-wheel bikes, the wheel bearings do more work, inasmuch as they need to rotate more times for the same distance, but they'll be selected with that in mind from the start. Pedals are generally interchangeable, but I know that Bromptons have special pedals (one side folds up against the crank, to allow the origami magic to take place). Crankset swap is possibly possible, but for the Verge P10 at least the specs say 'built for Tern' so there might be some idiosyncratic geometry going on there.

D9 -> P10 - as well as the better wheels, you're getting a big upgrade on components (9 speed to 10 speed, so more gear choices and a bigger range, with 40T at the low end for easier hills). That drivetrain cost difference alone is about 20,000 - 25,000 yen with Shimano groupsets. Considering the disk brakes, you couldn't make all those changes afterward if you wanted to. And even if you could (1) it would be more expensive than the difference in retail price, and (2) you'd end up with all sorts of unused parts sitting around like @bloaker.
 

Slowburner

Cruising
Sep 27, 2019
42
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In general, yes. For folding bikes, I'm gonna say 'maybe, but it probably won't make much difference'. The wheel bearings are a tiny part of the whole system. Unless there's actually something wrong with them, the friction difference (and ultimately its effect on the watts-per-kilogram equation for rider and machine) between a standard bearing and a high-end one is only significant if you are chasing 1st vs 2nd place in a race. For small-wheel bikes, the wheel bearings do more work, inasmuch as they need to rotate more times for the same distance, but they'll be selected with that in mind from the start. Pedals are generally interchangeable, but I know that Bromptons have special pedals (one side folds up against the crank, to allow the origami magic to take place). Crankset swap is possibly possible, but for the Verge P10 at least the specs say 'built for Tern' so there might be some idiosyncratic geometry going on there.

D9 -> P10 - as well as the better wheels, you're getting a big upgrade on components (9 speed to 10 speed, so more gear choices and a bigger range, with 40T at the low end for easier hills). That drivetrain cost difference alone is about 20,000 - 25,000 yen with Shimano groupsets. Considering the disk brakes, you couldn't make all those changes afterward if you wanted to. And even if you could (1) it would be more expensive than the difference in retail price, and (2) you'd end up with all sorts of unused parts sitting around like @bloaker.
I can believe the drive train bits are a lot more expensive, because quite apart from the nutty gear range on the P10, the shifting was way smoother than on the D9. I remarked on this to Ken-san at Hasiwa cycles, and - apparently appalled that the D9 might not be perfectly set up, dropped a rather disreputable-looking rollie in the gutter, and immediately set to fettling the bike until satisfied.

Only then was I allowed to test ride the D9 again, and from which ride I instantly concluded that the bits on the P10 were way better. But again, and with reference to the OP, I’m clueless about why that should be. Derailleur tech is at least 100 years old; shouldn’t we be able to pick up cheap group-sets at Daiso by now?
 
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