mlau

Xootr swift.
Moulton
Bike Friday pocket rocket
Airnamal chameleon
dahon smoothhound

Dahon and tern second tier in speed due to frame design

Brompton third tier. Great fold, just better for pootling about.

Citizen and others later

Sentinel1

Tern 2nd tier. The X18/X20 and especially the X30/X11 will smoke any wannabee for acceleration and speed. I've hit 30.1mph on my X11. And im 60 years old and weight 92kg.

Fentuz

on flat??? How did you record that?

In theory, a tern x11 with 52T chainring and 10T cog on 28-451 tyres is geared at 30mph @97rpm and that is without taking into account wind resistance and rolling resistance.

I had a bit of a play today during the training session, my smooth hound (7.5kg) with 69T chainring and 11T cog on 35-406 tyres is geared for 30mph@85rpm or 34mph@97rpm.
Yet, on a TT segment today, with this ratio between 450 and 500 W and 85rpm, I recorded 24.6mph because of wind and rolling resistances so ~85% of isolated theory.
I did again on a later between 88 and 90 rpm and I go 29mph so 92%.
So if we consider 10% loss due to various resistance looses, your isolated speed would have to be 33.3mph which 107/108 rpm on 52/10 ratio. That is required serious fitness, similar to CRIT racers...

Barchettaman

100% the fastest bike I own round town: the Swytch electric front wheel conversion pulls to 20 mph / 32kph and it’s utterly hilarious to ride, if slightly terrifying.

splithub

Battery is taken off? Where it's located when in place?

Barchettaman

oops sorry. It’s handlebar mounted.

splithub

Thanks! For a moment i thought it's one of those builds where the battery is spread all over the bike where is space for those 18650 cells.

Sentinel1

I agree 100% as I said I am 60 and weigh nearly 200lbs. A super fit pro cyclist would easily hit 35mph. Especially on the X30 and X18 with are closer to road bike gear inches. I broke 30mph in favourable conditions. Back wind and very even hard pack road. I was 56 at the time. Best I can do now is about 27mph. That's still pretty good for my age and the limitations of a folding bike. The X30 can live with a road bike alot better. With its lightning acceleration and 121 inch top end gearing. But you have to assume the roadie hunched over posture. My friend who owns one weighs 167lbs. And has hit 34mph on the X30H.

Fentuz

i know people who race in crit and are super fit and capable to produce ftps over 350w and yet, on Swork or pinarello race bike and yet, on flat in summer without wind, they do 32 to 36mph. Again this is on race specific bike and you think this in achievable on a 20” folding bike with a up right position…

since last week, i keep reading the apologia of the tern verg x18/x20/x11 etc. but a lot of it is not accurate and not substantiated. Just a vast amount of poppy cock.

if you did 30mph on flat on a verge and still do 27mph, then you should be an elite rider…

Sentinel1

Not at all. That was peak time. An elite cyclist would be able to hold those speeds for a while. I simply peaked at those numbers for a few seconds.

Fentuz

Your Honor, I rest my case…

tcs

Wow, this post is a real 'blast from the past'. I hope those contributors who no longer post here are doing well.

john m flores 

Thought that I'd add to this recently resurrected thread...

I've noticed a significant difference in speed (and the perception of speed/feel of the bike) between ETRTO 406 and ETRTO 451. On two nearly identical bikes, a Bike Friday Pocket Rocket with narrow and high pressure ETRTO 451 wheels and tires, and a Bike Friday Pocket Crusoe with narrow and high pressure ETRTO 406 wheels and tires, the 451-shod bike felt appreciably faster and able to maintain speed. I am faster and feel faster on the Pocket Rocket. As I've mentioned elsewhere, the 451-shod Pocket Rocket feels like a nice, steel, 700c roadbike, while the 406-shod Pocket Crusoe falls just short of that feeling. It looks to have a slightly longer wheelbase, so that may be a contributing factor, but I suspect that the biggest difference is the 451 vs 406.

Also note, that I also have ETRTO 406 folders with large volume tires (2.15" and larger) that seem to match the circumference of the ETRTO 451 on the Pocket Rocket, yet those bikes do not match the speed or feel of the Pocket Rocket. The weight of the wheels + large volume tires likely have an effect on performance and perceived performance.

Based on my experience, there's something about ETRTO451. Not only does Bike Friday spec them, but the Tern Verge, the 40th Anniversary Dahon, and other performance-oriented folders are fitted with them.

Has anyone else ridden ETRTO 406 and 451 and have thoughts? I'm curious.


Pocket Rocket with ETRTO451 wheels/tires

Pocket Crusoe with ETRTO406 wheels/tires

Ron Damon

I've ridden 451 quite a bit in the past on the several minivelos that I've owned. Depends on the surface. Sure on smooth tarmac 451 will feel and likely be faster. I've thought of building a 451 tourer for places like Korea and Japan that have nearly immaculate surfaces, but it's not worth the effort in the end.


My old 451 Dahon Dash Altena minivelo

Where I live, surfaces are a lot more varied and even pavement suffers from significant irregularities. The flip side of that coin is comfort. However faster 451 is, it's also a more jarring, less smooth ride for to the narrower, shorter profile, higher pressure tire. There is no avoiding this. Ten out of ten days I'll take the greater tire availability, comfort and ability to ride roughshod over stuff of 406. Ten out of ten days I'll take this, 58-406, over 451. Sure, it's not as fast. So what? My point is this: the real world, the more interesting world, offers a range of surfaces, for most of which high-pressure, narrow 451 is ill-equipped, bone-rattling umcomfortable, sub-optimal.


Nothing like this for the wide range of surfaces of the real world and not worrying about wheel damage.


Even 47-406 at 25/35psi will more comfy, cushy, compliant. And likely faster over rough terrain.

I don't know that 451 will be faster on a surface like this. In fact, it's likely slower and sketchier to ride.



451, been there, done that. And like 2x, never again!

pinholecam

I have the same experiences.
In fact, I had the same bike in 406, then converted it to 451, so the speed difference is there.
I attribute it to better rollover and rotational losses as the wheels get bigger.

I have all my folding bikes in 451 now because of this.

Ron Damon

Isn't your ChangeBike 589?

Jipe

I guess you mean ETRTO584/27.5"/650B ?

Ron Damon

Yes.

Jipe

Its an old rim size (therefore the old definition 650B), resurrected for MTB, then used for gravel bike to allow (very) wide tires without a too big overall diameter which is a problem for small size frames.

There are few high performances, low rolling resistance road tires in this size and the rolling resistance of gravel tires is usually quite high.

Ron Damon

The question was whether that's the wheel size on Pinholecam's ChangeBike folder.

pinholecam

I was referring to a Raleigh MV8 (probably some no name China mini velo frame they sell here under the Raleigh name, but nice frame nonetheless)
It was stock 406 and then I converted it to 451 after a few years riding it.

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