Folding Bikes - Trek Lime 3 speed hub on a folder

I test rode a Trek Lime autoshifting 3 speed hub last Saturday and I was impressed with the hub. It shifted well going up gear even under load! Unfortunately, going to first gear under load was a no no and you need to slow down when going uphill to allow the hub to shift down.

Here's why I think this hub has promise and should appear on folders for 2 reasons.

1. It has 3 usable gears ---- The new Nexus Auto 3 speed impressed me because I was actually using ALL three speeds in a five minute ride! This is not the case with a Sturmey Archer AW-3 where you hardly ever use 3rd gear because it's too high. The Nexus hub must be a close ratio drive because when the bike shifted to third gear, the pedals did NOT become hard at all! The transition was so fluid, the bike made me want to go faster. The trick was making 3rd gear only 4 or 6 inches greater than 2nd gear.

If the Trek Lime were using an AW-3, below would be the numbers.
Chain ring ---- 33T
Cog ---------20t

1st gear --------31.9 inches
2nd gear --------42.5
3rd gear --------56.6

As you can see, third gear is close to 57 inches which is way too high (practically useless) and will rarely be used during a commute. This is the error of the wide gear hub.

2. Electronics don't effect speed

I didn't notice the front hub scrubbing away speed. In fact, I lifted the bike and spun the front wheel and it moved quite freely. I estimate, my speed in 3rd gear was about 12 or 14 mph. It's unfortunate, this Nexus Auto 3 is placed on beach cruisers because it's clearly ment for folding bikes. I would love to see Dahon or Strida build a folder using this hub.

The only thing I want from this hub is a slightly lower 1st gear and a (one more gear) higher 4th gear.

That would be perfect!

http://www.trekbikes.com/lime/

57 gear-inches too high for commuting? YMMV. I use almost double that on a daily basis on the downhills. But that is beside the point I suppose.

I like this bike for its clean looks. No cables or brakes in sight. For that, the low GI is probably suitable - you don't want to go very fast with only a coast brake.

I agree with Jur (although I'd have no use myself for a gear of 114 inches). 57 inches is a gear I'm happy to start in and ride up hills. My SRF3 (AW clone) as supplied with a 14/52 cog and ring setuo by Merc has gears of 45, 60, 79. I have fitted a lower set of ratios by virtue of a front mech and 39 tooth ring. This gives me something like 39, 54, 73 give or take an inch or so.

I'm an old git of 56 years and find that suitable for anything I'd meet on a ten mile commute. I live in a city with hills and strong headwinds too.

I agree with Jur and EvilV. 57 inches is a very useful gear, and if I had a good downhill, I'd want something higher.

Well, it could be nice, but....

1) Is it really that hard to manually shift?
2) How much harder will it be to repair the automatic shifting mechanism?

I can see how you like the gearing ratio better, and it's a cute bike. But I think automatic shifting on a bike is overkill and the possible maintenance issues could be a real drag.

57 gear-inches too high for commuting? YMMV. I use almost double that on a daily basis on the downhills. But that is beside the point I suppose.

I like this bike for its clean looks. No cables or brakes in sight. For that, the low GI is probably suitable - you don't want to go very fast with only a coast brake.

You missed my point.

I don't believe the Trek Lime shifted to 57 inches at all in 3rd gear. I can't find the specs of the hub but I suspect it's lower (maybe around 52 or 54 inches) and it just works in getting you up to speed. As I said before, direct drive was very low, in fact too low for my taste. I believe the designers did not intend for you to ride in 2nd gear at all but wanted you to ride in 3rd gear 95% of the time! Direct drive is just a startup gear. I was riding the bike in 3rd gear over 80% of my short journey so my overall straight line speed was faster or just as fast as riding an AW-3. Within about 25 feet from a dead stop, the bike shifted to 3rd gear to give you more speed. I just like this idea.

It's true that I lost downhill speed but then again, it's fine for utility bikes like the Strida, Curve or Brompton.

I think the concept should be carried over to the Nexus 8 speed.

Well, it could be nice, but....

1) Is it really that hard to manually shift?
2) How much harder will it be to repair the automatic shifting mechanism?

I can see how you like the gearing ratio better, and it's a cute bike. But I think automatic shifting on a bike is overkill and the possible maintenance issues could be a real drag.


It's not hard to shift but I like the concept of autoshifting after trying it out. I never like third gear on the AW-3 and felt the wide gear concept made that hub basically a 2 speed. I would love to see Shimano come out with a close ratio 4 speed hub that doesn't auto-shift.

I don't know how hard it's going to be to repair the shifting mechanism. I don't know if anyone knows?

You missed my point.

I don't believe the Trek Lime shifted to 57 inches at all in 3rd gear. I can't find the specs of the hub but I suspect it's lower (maybe around 52 or 54 inches) and it just works in getting you up to speed. As I said before, direct drive was very low, in fact too low for my taste. I believe the designers did not intend for you to ride in 2nd gear at all but wanted you to ride in 3rd gear 95% of the time! Direct drive is just a startup gear. I was riding the bike in 3rd gear over 80% of my short journey so my overall straight line speed was faster or just as fast as riding an AW-3. Within about 25 feet from a dead stop, the bike shifted to 3rd gear to give you more speed. I just like this idea.

It's true that I lost downhill speed but then again, it's fine for utility bikes like the Strida, Curve or Brompton.

I think the concept should be carried over to the Nexus 8 speed.Ahh, I get it. It is basically a lowish speed bike, and the gears take care of of pulling away from a stop or for some uphill, without you having to think about it. And the closer ratio means 1st and 2nd gears are just part of the getting up to speed, then it's over to 3rd and basically it stays there until you slow down again. If 3rd gear was too high it would often be too high and you would tend to struggle a bit to use it, but now all 3 gears are used instead of 1 & 2 and occasionally 3.

Good for cruisers. For my long distance commute it would be too slow, but for others it would probably be fine.

Try running a AW-3 hub with a 58t ring and a 16t rear cog in a 406 rim...3rd is good for fast downhills and 50+kmh on the flat, 1st gear will climb most hills as well, 2nd is good for general riding...........Now, where did I put that 14t cog?, when I had that on, I could only just spin it out on the steeper hills :eek:

.... I would love to see Shimano come out with a close ratio 4 speed hub that doesn't auto-shift....

Ever tried a Nexus Inter-4? The overall range is just a little wider than the AW, so maybe the ratios aren't close enough for you.