I'm such a Newb! What's an Alfine Hub?

[MacB]

SA 3 speed would be 33% and 25% down from the direct drive which is the middle gear. There are other variations but that would be the classic AW or the modern equivalent SRF3. A lot of people run this with a 2:1 ration chainwheel to rear cog so you get a low of 40 inches, middle 54 and top 72. The 72 is good for general riding and the 54 for heavy traffic and stop start stuff. The 40 is a bail out for a steep hill, heavily laden, or if you're just knackered. On mine I've only used the 54 and 72 in earnest so far. The ride style is different as in you tend to modulate via pedalling tempo rather than lots of gear changes.

Alfine will give more weight at the rear but overall weight of bike should be comparable to a reasonable groupset derailler setup. Rohloff is heavier, I-9 heavier again. The 3 speeds will give you something that's a bit lighter overall. None of these will be as light as a fixed/single speed and the weight is always going to be more rearward.

A 3 speed is simple, it has one planetary gear the others are all more complex, ie more to go wrong. SA 3 speeds are self maintainable or you can choose from many bike shops that can sort them, spares are easily available and cheap. Shimano are the next best for maintenance options available. SRAM and Rohloff are generally a return to Germany option for maintenance. However their track records, especially the Rohloff, are superior from a reliability perspective.

A negative on 3 speeds are the axle lengths available as many won't fit a modern frame of 130 or 135mm dropouts. I had to order my SRF3 from the US as I wanted the 175mm axle and they don't import that to Europe.

If you search on my posts/threads you'll find a lot of info on hub gears. Rogerxilla on YACF and CTC is pretty good and Graham on CTC is excellent for SA info, how to strip, maintain etc. Shimano are also bringing out an Alfine 11 speed which could be a serious bit of competition for Rohloff.

 

[TheDoctor]

Which hubs have you tried? I'm guessing this isn't a problem for the Rohloff (well, it shouldn't be given you'd have spent £1000 on the damn thing!) and it *certaintly isn't a problem on my Alfine* wich shifts better than my brand new 105 on my road bike. I'm guessing it's also not a problem on the SRAM i-motion either (but I'm happy to be corrected).

Shimano Nexus 4, 7 and 8 speed.
Sturmey 3 speed
SRAM 3 and BWR (that's a Brommie-specific wide range 3 speed) These two had the added complication of a two-speed dérailleur too.

It wasn't that I stopped pedalling, just a momentary (like small fraction of a second) easing of the pressure.

I've not tried an Alfine, except on Bottlemashers 'bent and I was far too scared to try changing gear! It was all I could do not to soil my Lycra...

 

[gouldina]

I can't believe you missed the opportunity to name this thread "What's it all about, Alfine?".

 

[NigC]

I can't believe you missed the opportunity to name this thread "What's it all about, Alfine?".

Sorry - I'll try harder next time

 

[Jezston]

SA 3 speed would be 33% and 25% down from the direct drive which is the middle gear. There are other variations but that would be the classic AW or the modern equivalent SRF3. A lot of people run this with a 2:1 ration chainwheel to rear cog so you get a low of 40 inches, middle 54 and top 72. The 72 is good for general riding and the 54 for heavy traffic and stop start stuff. The 40 is a bail out for a steep hill, heavily laden, or if you're just knackered. On mine I've only used the 54 and 72 in earnest so far. The ride style is different as in you tend to modulate via pedalling tempo rather than lots of gear changes.

Thanks for the very detailed reply there but err afraid to admit I didn't really understand it!

 

[MacB]

Thanks for the very detailed reply there but err afraid to admit I didn't really understand it!

Gears inches are just a way of giving a value to a given chainring and cog combination, like having gears 1 to 5 in a car. If you looked at a 27 speed bike, you have 3 rings at the front and 9 cogs at the back. The range covered by these 27 gears can be expressed in inches, ie bottom/easiest at 30 inches and top/hardest at 120 inches. Yet you don't actually have 27 gear steps between the 30 and the 120. There are 4-6 combinations where it's best not to ride, these are the ones that would place the chain at the biggest diagonal lines.

I had a look into this stuff when I got my 27 speed bike as I, foolishly as it turned out, thought that I had 27 seperate and progressive gears. Once I'd removed the poor chainline ones and the duplicates(for duplicate purposes I count anything with about 4 gear inches of another gear) I was only left with 14 gears.

A lot of road bikes won't have a gear lower than 40 inches, hence why I consider the 40 inch low of the SA 3 speed plenty. For people riding single speed or fixed bikes a gear choice in the range 64 to 74 inches seems popular. Another way to look at it is via speeds for given rpm's:-

40 gear inches - gives about 5mph at 40 rpm rising to 14.6mph at 120 rpm, add 0.6mph for every 5rpm increase

54 gear inches - gives 6.5 mph at 40 rpm rising to 19.4 mph at 120 rpm, increases are 0.8mph per 5 rpm

72 gear inches - gives 8.6 mph at 40 rpm rising to 25.8 mph at 120 rpm. increases are at 1.1 mph per 5 rpm.

If you want to cycle with as little variation in rpm, ie how fast your legs turn, as possible then you need more gears. These allow you to keep the same cadence as the elevation changes. If you're happy to vary your cadence, and often speed, more widely then less gears work well.

There are many good/fit riders on this forum but two of the best would be Mikee and Will1985, that I know personally(though any of the young ones could apply for the latter, ILB, Radius etc). Mikee rides everywhere fixed on a 72ish inch gear, this has included severe hills that have seen the rest of us grovelling up in our lowest gears. Will would be more likely to flick up and down the gears concentrating on his cadence, though never needing the low gears the likes of me do. Either of these riders could set a pace, over a long ride, that I couldn't come close to living with, but in very different styles.

Ok, that was a really long way of saying, read up on Sheldon Brown about gears then experiment to find what works for you