Which rear hub?
- Thread starter twister
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Freewheel if you're going to "get on it"; 3speed if you wanna take it easy and have the luxury of some variable gearing. FWIW, i'm pretty close to building up a NuVinci bike for riding trails, singletrack, etc.... but they're kinda pricey and really heavy...
Which hub are you looking at? Best prices i find on NuVinci N360 hubs is $250... http://www.ebay.com/itm/NuVinci-N36...-Disc-Brake-/301677895060?hash=item463d675d94
Keep in mind that the Sturmey 8speed has the direct ratio as first, with all others being overdrive--up to 325%. In short, it's geared very, very high.
Gear Ratio
• Overall Range - 325%
• Gear 1 - 100% (Direct Drive)
• Gear 2 - 130% (Gear 1 + 30%)
• Gear 3 - 148% (Gear 2 + 14%)
• Gear 4 - 169% (Gear 3 + 14%)
• Gear 5 - 192% (Gear 4 + 14%)
• Gear 6 - 220% (Gear 5 + 14%)
• Gear 7 - 250% (Gear 6 + 14%)
• Gear 8 - 325% (Gear 7 + 30%)
Ealy versions of this hub were prone to premature failure, but it seems like they've gotten it right and hubs these past 5 years have been reliable. But, with a direct plus 7 over situation, i wouldn't put this on anything with wheels bigger than 20"...
Gear Ratio
• Overall Range - 325%
• Gear 1 - 100% (Direct Drive)
• Gear 2 - 130% (Gear 1 + 30%)
• Gear 3 - 148% (Gear 2 + 14%)
• Gear 4 - 169% (Gear 3 + 14%)
• Gear 5 - 192% (Gear 4 + 14%)
• Gear 6 - 220% (Gear 5 + 14%)
• Gear 7 - 250% (Gear 6 + 14%)
• Gear 8 - 325% (Gear 7 + 30%)
Ealy versions of this hub were prone to premature failure, but it seems like they've gotten it right and hubs these past 5 years have been reliable. But, with a direct plus 7 over situation, i wouldn't put this on anything with wheels bigger than 20"...
If you're gonna ride any singletrack, there's always singlespeed hubs, which are the most reliable/robust. Obviously, the gear range is as limited as can be. Both the NuVinci and the wildy expensive Rohloff are unique in that their manufacturers recommend their hubs as being suitable for offroad use. Every other IGH manufacturer discourages use of their hubs offroad, as the high-torque gearing requirements and riding conditions tend to destroy the planetary systems. That being said, many folks have had very good results with Shimano Alfine 8speed hubs, even using ratios lower than the 2:1 that Shimano specifies as the minimum. That may be the hub for you; it's got a 307% range, with the direct drive occurring a little higher than midway thru the gears, in fifth.
By comparison, the Rohloff has a 526% range, with the direct occurring in 11th gear out of 14). The NuVici n360 goes 360%, and while it is a CVT without stepped gears, the direct drive occurs close to the middle of the range. The unique thing about the Sturmey-Archer's 8speed is that all the planetary gears are overdrive, without any steps down from direct. This is a departure from other Sturmey multispeed hubs, in that the 3 speed has the direct in 2nd, and the 5 speed has the direct in 3rd. Their 3speed fixed hub has direct in top gear (3rd), with 1st and 2nd being underdrives....
I guess the only hub i've left out of this discussion is the SRAM g8 and i think SRAM still makes a 3speed with a disc mount. Truth is, I don't have much experience with these hubs, and it seems to me that these hubs have been losing fans steadily since SRAM bought Sachs out in the 90s. Oh, and yeah, they make a disc version of the Nexus 3 and the Sturmey 3 (hard to find these days), and those would both be excellent options for casual rides on streets and paths, but I suspect you'll kill'm quick if you ride hard with them offroad.
By comparison, the Rohloff has a 526% range, with the direct occurring in 11th gear out of 14). The NuVici n360 goes 360%, and while it is a CVT without stepped gears, the direct drive occurs close to the middle of the range. The unique thing about the Sturmey-Archer's 8speed is that all the planetary gears are overdrive, without any steps down from direct. This is a departure from other Sturmey multispeed hubs, in that the 3 speed has the direct in 2nd, and the 5 speed has the direct in 3rd. Their 3speed fixed hub has direct in top gear (3rd), with 1st and 2nd being underdrives....
I guess the only hub i've left out of this discussion is the SRAM g8 and i think SRAM still makes a 3speed with a disc mount. Truth is, I don't have much experience with these hubs, and it seems to me that these hubs have been losing fans steadily since SRAM bought Sachs out in the 90s. Oh, and yeah, they make a disc version of the Nexus 3 and the Sturmey 3 (hard to find these days), and those would both be excellent options for casual rides on streets and paths, but I suspect you'll kill'm quick if you ride hard with them offroad.
The regular 135mm-spaced SA disc 3 speeds are getting scarce, but they'll probably make another run of'm. That'd be a great cruising option, for sure. I like building "Coaster Mullet" bikes, with a c/b rear and a disc front....
For casual trail riding, I would go with the SRAM 2 speed Automatix hub, just a low gear and normal gear. Auto shift at about 10 mph. It has a freewheel and coaster brake version. It's still under 70 bucks on amazon.
Yeah, the thing with 2speeds is, you can get the SA or the SRAM with a disc brake, although i've never seen the Automatix with the disc mount offered for sale. Just pictures. Here's an auction from the Limey eBay: http://www.ebay.co.uk/itm/Sram-2-Sp...tomatix-black-incl-Mounting-set-/331486043736
In the interest of fairness, here's the Sturmey 2speed kicker with disc mount:
Yeah, Sheldon Brown had suggested buying 2 of any SRAM IGH you ever buy--- one to lace into the wheel, and the other for parts, b/c parts support is non-existent for them. The other issue, of course, is that the internet anecdote mill seems to suggest that they blow up quickly and easily, especially if ran off-road. And, let's face it: that plasticky "click-box" is a dog, too. The Automatix 2speed is, by all accounts, a bombproof hub and i will be building a wheel around one soon. It's a shame, though, b/c the SRAM g8 and g9 hubs looked promising. But, most users reported early failure, and SRAM has already taken it off their US site....
In the interest of fairness, here's the Sturmey 2speed kicker with disc mount:
Yeah, Sheldon Brown had suggested buying 2 of any SRAM IGH you ever buy--- one to lace into the wheel, and the other for parts, b/c parts support is non-existent for them. The other issue, of course, is that the internet anecdote mill seems to suggest that they blow up quickly and easily, especially if ran off-road. And, let's face it: that plasticky "click-box" is a dog, too. The Automatix 2speed is, by all accounts, a bombproof hub and i will be building a wheel around one soon. It's a shame, though, b/c the SRAM g8 and g9 hubs looked promising. But, most users reported early failure, and SRAM has already taken it off their US site....
I haven't found a Automatix with disc yet, just coaster and freewheel. The kickback 2 speed SA is a good choice too, especially with disc brake.
Tempted by that Sturmey two-spd. with disc mount. I am thinking now(scary) about running one of those on a prewar steel frame with reverse dropouts. This would require custom-welded caliper mounts and a small chain tensioner setup....maybe even with a skip-tooth drivetrain for a super Ratty setup!
