Sturmey 8 speed is 1:1 in first gear .. Alfine 8 speed is 1:1 in 5th gear .. Alfine 11 has no 1:1 direct drive ratio..

R'off is 1:1 in the 11th of 14.

It and the New S-A 4 speed use a 13t smallest cog, the S-A 8 speed uses its own specific cog , minimum 20t.




...

My original statement was backwards, but the conclusion that the SA is better for big gears on small wheels is accurate.

Thanks
Yan

You've got that backwards Yan.
Sturmey-Archer | X-RF8
Shimano Nexus and Alfine Eight Speed Internal-Gear Hubs

I find that odd.

Odd as in you don't believe it , or odd as a design?

I hear this everywhere but don't understand it. Sure Bromptons are great shopping carts and great box shaped wall hole fillers, but great bikes? Why? How do they ride better than other folding bikes?

Odd in design.

I didn't say they ride better than other folding bikes, I said they're great bikes. The OP is focused on 16” wheel bikes, so that's what we're talking about. I have two, a Brompton and a Dahon Curve, and they both ride about the same to me. The Brompton folds smaller and has more character, so I like it better. I don't consider either one to be especially fast, but I don't ride for speed.

I don't think anyone will argue they ride better, but I would argue they ride as well - same thing can be said between a folder and a traditional bike. Course the big advantage the folder has over a traditional bike is what you can do, and where you can go, when you are not riding - same thing can be said between a Brompton and other folders. My '91 Dahon was my first big bicycle revelation... my '16 Brompton was the second.

but its true , one gear is almost , but not quite 1:1.. look it Up. (If it actually matters)

I think that gi/rpm combo equates to more like 32mph.

Easily the most relevant question. I've heard so many people say they like going 'fast' when that's as meaningless as saying they want the 'best'.

brompton 6-sp and the +12% 54t option was mentioned early on. you then get a top gear close to 110 with low friction. just one planetary gear to crank, and a 13 cog in the rear that is big enough not to cause noticeable drag or wear. good enough, and considerably better than draggy multigear hubs.

what to tweak then? well the rather high top gear is not backed up by gear ratios nearby. the jump between the highest gears is big, the top gear tends to live on its own.

you get a tighter setup if you instead buy a 3-sp brompton and make a 6-sp conversion; then the difference between gears is roughly 17 instead of 24 percent. to reach 100+ gearing you then also need a bigger chainring, preferably over 60t. up to 63t is possible without modification, if you wish to go further than that, the catch on the left side of the front wheel needs to be replaced by the s1e model, sits further up on the left fork. then the limit is around 72t.

or you can buy a 3sp kit for the brompton derailer. the ones on the market tend to favor range over thightness, i would go for a 13-15-17.

there are other ways, but these mentioned here are readily available, and easy to mount for a general public. i have myself a 2x5 13/14 cog sturmey-archer brommie from the 90s and a 2x10 dura-ace/schlumpf, both take technical skill and effort to materialize.

what you in my opinion should avoid are for one multigear hubs of models where planetary gears are stacked. some hubs like the sa5 use alternating planetary gears, that works better, only one is used at a time. in a hub gear, parts therein have to rotate really fast with a small wheel, and their already with big wheels troublesome friction gets augmented.

and also try to stay away from solutions with small cogs. already 11 is of little practical use, gives a noticeable drag and wears itself and the chain out in short time.

been there, done that.

Had a 16" folder with ISO349 tyres. Used a modified Capreo cassette (11-19) on it and had a 53T/39T q-ring on it. It had 33-105.78 gear inches that allowed me to reach 43kmh at around 100-110 rpm (I think). I used it to draft roadies. Maybe you might find this gearing useful.

Adding a Schlumpf High speed drive geared crank multiplies the chain ring size by 250% (ie 34 ; 85 or say 42; 105..teeth)

TiCrazy, welcome to the forum, i am almost new myself

in case you didnt have planetary gear somewhere in your driveline 53/11x16.5 gives 79.5 gear inches. enough to draft only very slow roadies..

only reason i know to buy capreo would be to able to mount 9t cog; however according to my personal experience already 11 is suboptimal because of wear and drag.

Actually I've gone 1 full cycle. SRAM dual drive with normal 53/39 and 11-23 - hate the heaviest gear on the dual drive as there's so much resistance. Also tried a 56/39 q-ring (which is actually 59/42 at the peak) with a 11-27 - hate the slow pick up. Feels really heavy from a stationary position. I find the modified Capreo 9-19 with the 53/39 q-ring best for my riding style. Every gear jump is about 2kmh which is ideal for spinning. I'm not a masher. Also realised over time that I cycle in the range of 25-45kmh most of the time. So I don't need anything more than 108 gear inches. Just sharing my experience after more than 10 years of riding different types of foldies from 16" wheels to 24" wheels.

Riding too fast is unsafe IMO, esp. in traffic and downhill. You could rollover, or get under a truck, etc.

Do you wear a helmet, adequate lighting and reflective material? Do you give your bike a safety checkup every 200 miles? Do you have good knowledge of traffic rules and bicycle checkups?

George3, you are of course right that speed may be dangerous. but for a bike in traffic, so is going too slow. you get passed by cars or other vehicles from behind all the time, have to keep yourself to the side, being passed by sometimes small margins.

in many back streets, if you are able to get up to the speed of the cars, 20-25 mph, you can go with them in the middle if the lane, minimizing passing and encounters. not to speak about suddenly opened car doors.

TiCrazy, so you had dual drive, with its planetary gear? i really agree that gearing past 108 is of limited use. especially an unsupported one, with no close ratio gears nearby.

but if you have a situation with friction in your gear train, that limit can be considerably less. and as i have flagged for, 11t cogs and smaller create drag to an extent where i find them not useful.

in my experience, the friction or drag from the schlumph gear itself is within limits. however, that is not the case with the sped up chain passing the jockey wheels of a derailer. when i had a 57t chainwheel on a speed drive the was clearly over the limit. i now have 53t which works ok. 50t was even better in this respect, but the difference between 53 and 50 is much smaller.

so accordingly, as you pass about 90 as an effective tooth count on a chain wheel using normal cadencies, chain speed picks up so much it can become a problem in itself. there seems to be a threshold effect.

this efffect may also present itself in peleton racing, where they with 53t chainwheels and extreme 100+ cadencies push the same limit. according to the often cited hpv society report from 2000 already a cadency of 70 presents a measurable extra drag. lately larger jockey wheels have been presented, they should help to lessen this problem.

Have not tried a 50/34 and 12/27 on the Sram Dual Drive kais01. Could be workable and might be a good solution. The other thing with SRAM DD was the weight. Compared to Capreo which was much lighter and the cassettes isn't really that expensive, I chose Capreo. Weight weenism won over. I also took the bike on overseas holidays and did not want to wrestle with the unfamiliar task of removing the rear wheel in the event of a puncture. Am more familiar with a normal derailleur system. The issues with friction and high cadence on the 9T, I don't really find an issue. Truthfully, I seldom use the 9T for extended periods or even the 10T. Fast cruising speed around 35/36kmh probably uses the 11 or 12 tooth only. Which is why I also concluded that it is not necessary to go above 108 gear inches. I won't be able to sustain above 43-45kmh for more than 3-5km drafting a group

Since OP is new to the activity, I don't think he needs that high a gear unless his base fitness is already there from some other activity (eg. running; etc)

So, if 16" is what its going to be, then anything with a 53T or 55T chainring and a 11-xxT cassette will do.

Going up one wheel size (ie. 18" ) makes it easier to get more GI.

Or a Bike Friday Pocket Rocket ( 451 wheel ), they will build it up with Di2 electronic shifting if you wish.

Excellent suggestion pinholecam. Considered upsizing my wheels to ISO 355 18" initially but there was not enough clearance on my 16" foldie frame. So I'm now on a 20" 406 with Capreo and 46/39 q-rings. So I've upped my top end from 106 gear inches to 108 now.