Geared Coaster Breaks

Anyone have experience with one of these?  When I consider the cost vs breaks/pads/front and rear derailleurs/cassette in the back/all those cables and housings this thing doesn't seem so bad especially when considering all the maintenance saved.  My reservations are: do I get a gearing that still lets me speed on the LFT? Is the breaking smooth or is it a slam break that will bald my tires? If I need it can I slam the breaks? It's flat here in Chicago so it's not as if I need the 21 gears I have now.

I commute to work every day, bike pretty much everywhere to the point that a pair of sneakers will last me years. Anyone have one of these and how does it work for you here in Chicago? I am just mesmerized by the idea of having 1/2 of the maintenance time I spend going away and my ride getting incredibly simple. Thanks.

Shimano Nexus Inter-8 Coaster Brake Hub

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Permalink Reply by Far'arned Retrogrumpalunkus #63 on January 9, 2014 at 12:04pm

Gearing is a complicated issue that goes beyond simple counting of teeth.

I can't even come close to giving out a number until I know the size of the wheels and even the size of your cranks. After that it still is a matter of personal preference, bike type, and your own physical condition & experience.

The place to start is to educate yourself on gearing.  The best place to start is to plug in the values of the bikes you already have (and like the gearing on) to see what ranges you like/prefer.  Then you can take a hypothetical bike you want to build/re-gear to match these ranges.  Sheldon brown has a decent basic gear calculator with a lot of good internal hubs built into it which you just need to select under the "internal hub" row.  Then plug in the rest of your stats and then play with different chainwheels/cogs until you get what you like.

http://sheldonbrown.com/gears/index.html

I also like this gear calculator because it shows a better visual representation of my gearing.

http://www.gear-calculator.com

For example, my personal road bike has a pretty wide gear range with a 3 x 8 derailleur geartrain, a range which a simple 3-speed hub, or even an 8-speed IGH won't be able to replicate:

http://goo.gl/VnStx

My personal City bike using a Sturmey AW 3-speed hub:

http://www.gear-calculator.com/#KB=48&RZ=22&GR=SAAW&TF=...

This works well for me, but might not for you.

You'll have to make those decisions yourself.

Permalink Reply by Haddon on January 9, 2014 at 3:21pm

OMG - how about you just sell me your bike?

James BlackHeron said:

Gearing is a complicated issue that goes beyond simple counting of teeth.

I can't even come close to giving out a number until I know the size of the wheels and even the size of your cranks. After that it still is a matter of personal preference, bike type, and your own physical condition & experience.

The place to start is to educate yourself on gearing.  The best place to start is to plug in the values of the bikes you already have (and like the gearing on) to see what ranges you like/prefer.  Then you can take a hypothetical bike you want to build/re-gear to match these ranges.  Sheldon brown has a decent basic gear calculator with a lot of good internal hubs built into it which you just need to select under the "internal hub" row.  Then plug in the rest of your stats and then play with different chainwheels/cogs until you get what you like.

http://sheldonbrown.com/gears/index.html

I also like this gear calculator because it shows a better visual representation of my gearing.

http://www.gear-calculator.com

For example, my personal road bike has a pretty wide gear range with a 3 x 8 derailleur geartrain, a range which a simple 3-speed hub, or even an 8-speed IGH won't be able to replicate:

http://goo.gl/VnStx

My personal City bike using a Sturmey AW 3-speed hub:

http://www.gear-calculator.com/#KB=48&RZ=22&GR=SAAW&TF=...

This works well for me, but might not for you.

You'll have to make those decisions yourself.

Permalink Reply by Tony Adams on January 10, 2014 at 8:08am

I had Blue City build me a wheel with the SRAM 2-speed automatic during their free wheel building special last month. The bike it is going onto is out of commission temporarily, but I will report back here after I've actually ridden on it. 

I had a new SA 3 speed hub catastrophically fail on me after like a year or so of use. It locked up solid nearly throwing me off the bike. On a very busy street. In an intersection. YMMV of course.

James BlackHeron said:

Shimano and SRAM also have 3-speed coaster brake hubs as well. 

Another option is the SRAM 2-speed Automatic coaster-brake hub which is like the old Sachs Torpedo vintage hub that is so highly prized and difficult to source these days.   The advantage of this hub is that you can dispense with the twistgrip shifter and all the associated cabling needed to shift.  This automatic hub doesn't even need to be "kicked-back" like the Bendix hub we were talking about above but automagically shifts up at a certain speed and then back down when the bike slows.  It's seamless shifting although you are sort of stuck with the speed it shifts at as that is dependent on wheel rotation RPM, and that depends on the wheel size for what ground speed it shifts at.  This point will be different for a 20" 26" or 700c wheel (or any other different wheel diameter.)  In the old days the Sachs Torpedo came in two different flavors -one for a 20" wheel and one for a 26-27".  There was a way to tweak the weights inside but it was finicky.  I suppose this hub might be adjusted the same way by a skilled mechanic who knows IGH hubs inside and out.  I haven't run into this hub yet in my shop so I can't say any more about its durability or even ultimately its adjustability.  But it's a hub, not a rocket engine.  How hard can it be to tweak it a little?  It's just a matter of finding a real bike mech and not a typical LBS wrench monkey who is afraid of IGH's. 

Permalink Reply by Mike Bullis 5.5-6.5 miles on January 11, 2014 at 11:45am

I have two of the Power Brake hubs, one fixed and one unmolested. That proprietary cog is the weak point of the design but I have a few. Also sucks that 18 and 19t were the only sizes available.

James BlackHeron said:

That's a sweet hub.  Had one on a bike once and really liked it.  As bullet proof as the hub it is has one weekness -the cog itself.  Keep an eye on the chain stretch.  If you let it get bad and wear out that rear cog you will be bumming.  The whole cog is integral to the proprietary driver assembly and they are getting really hard to find these days. You can't just find any old cog to replace it.  You need the Bendix version and if I remember right there are two different styles too. The yellow band and the blue band ones are not interchangeable if my memory serves me. NOS replacements go for $45+ on ebay if you can find the right one at all. 


Mike Bullis 5.5-6.5 miles said:

.

As far as the coaster brake goes, keep the hub adjusted and lubed properly and it will last quite awhile. My 1952 Bendix PowerBrake two speed keeps on chugging along.

Permalink Reply by Allen Wrench on January 12, 2014 at 1:31am

I have a couple bikes with the nexus 8 sp hub that are by and large no problem, but all have roller brakes. This is my usual around town setup. Smooth even reliable braking but you can lock the wheel if you try hard even with the "power modulator". The roller brake is a separate assembly and can be swapped out, and some work better than others. The newer ones (higher numbers is better) are pretty foolproof and all of them work as well in the wet and cold. Considering what is noted above about coaster brakes I'd consider the rollers more strongly. Disc (Alfine) is another option for this hub but that gets you back to maintaining it. Use a regular brake on the front wheel.

The hub itself has slightly different jumps between gears, some wider than others, but you don't really notice it in real life. If you set 6th speed to be your usual cruising one you have plenty of space above and below especially in flat Chicago. It shifts very smoothly and reliably and it's hard to wreck. Each shift does something and there are no cross gears so it's simpler and more satisfying than a multi chainring derailer setup in city traffic. The different versions, red line Nexus and Alfine and so on, are not very different in terms of how they ride but there may be slightly better reliability with the expensive ones - I don't remember now but I think they have an extra set of planetary gears or something. They claim to have less internal friction but doubt you'll notice it. Maybe someone else here can fill in the details. I don't think the fancy one is worth the extra money. Sheldon Brown has info on the hubs and the brakes.

In 6 years of using several of these hubs I've only trashed one (very early production model), still not sure how, and the internals could be replaced without rebuilding the wheel. They have another small disadvantage if you want to swap a tire or fix a flat off the bike, which is that they are complicated to remove (reaction arm, shift cable, chain guard). 

Find a bike on the street with the hub you like and count the gear teeth on its chainring and cog to use as a starting point.

Not a bad hub at all for Chicago and general use. Like an automatic after a stick shift. 

Other nice options include the 7 speed Nexus, which has more even shifts, and the SRAMs though I think they shift less smoothly in my limited experience. 

Good luck.

Permalink Reply by Tony Adams on January 12, 2014 at 5:17pm

Took the SRAM 2 speed Automatix out for a shakedown ride tonight. It is great! Comes with a 19t cog - which seems perfect for me with a big chainring. I was assuming that I'd have to tweak the chainring and/or the cog, but perhaps not. 

The coaster brake works great - much more crisp than the Archer Sturmey 3 speed.

I should note that Blue City's free labor wheel build special has been extended. You buy the parts for the build from the shop and they'll build your wheel for free.

Tony Adams 7 mi said:

I had Blue City build me a wheel with the SRAM 2-speed automatic during their free wheel building special last month. The bike it is going onto is out of commission temporarily, but I will report back here after I've actually ridden on it. 

I had a new SA 3 speed hub catastrophically fail on me after like a year or so of use. It locked up solid nearly throwing me off the bike. On a very busy street. In an intersection. YMMV of course.

James BlackHeron said:

Shimano and SRAM also have 3-speed coaster brake hubs as well. 

Another option is the SRAM 2-speed Automatic coaster-brake hub which is like the old Sachs Torpedo vintage hub that is so highly prized and difficult to source these days.   The advantage of this hub is that you can dispense with the twistgrip shifter and all the associated cabling needed to shift.  This automatic hub doesn't even need to be "kicked-back" like the Bendix hub we were talking about above but automagically shifts up at a certain speed and then back down when the bike slows.  It's seamless shifting although you are sort of stuck with the speed it shifts at as that is dependent on wheel rotation RPM, and that depends on the wheel size for what ground speed it shifts at.  This point will be different for a 20" 26" or 700c wheel (or any other different wheel diameter.)  In the old days the Sachs Torpedo came in two different flavors -one for a 20" wheel and one for a 26-27".  There was a way to tweak the weights inside but it was finicky.  I suppose this hub might be adjusted the same way by a skilled mechanic who knows IGH hubs inside and out.  I haven't run into this hub yet in my shop so I can't say any more about its durability or even ultimately its adjustability.  But it's a hub, not a rocket engine.  How hard can it be to tweak it a little?  It's just a matter of finding a real bike mech and not a typical LBS wrench monkey who is afraid of IGH's. 

Permalink Reply by Homebuilt on January 15, 2014 at 5:51pm

I have the SRAM i9 with disk brakes, so I can't answer your questions on brakes (I like the disk, BTW). The range is just fine. Look up a good gear calculator and put in your current and the hub you're thinking of. Then you can look at front/rear gear combos.

I probably need to gear mine down as I never hit 9 and fully loaded up a hill (think trailer with 100 lbs) I wish I had lower than 1.

Permalink Reply by Tony Adams on January 16, 2014 at 3:55am

Are you thinking a smaller chainring? or a bigger cog? I plan to experiment with lowering my range a bit also. The SRAM 2 Speed Automatic stock cog does not look like I can remove it with any of the tools we have in the shop. I'm thinking of trying a smaller chainring. 

Homebuilt said:

I have the SRAM i9 with disk brakes, so I can't answer your questions on brakes (I like the disk, BTW). The range is just fine. Look up a good gear calculator and put in your current and the hub you're thinking of. Then you can look at front/rear gear combos.

I probably need to gear mine down as I never hit 9 and fully loaded up a hill (think trailer with 100 lbs) I wish I had lower than 1.

Permalink Reply by Homebuilt on January 16, 2014 at 4:55pm

There are two cogs that are available for the i9, then you have to work with the chain ring. I don't know about other hubs.

Tony Adams 7 mi said:

Are you thinking a smaller chainring? or a bigger cog? I plan to experiment with lowering my range a bit also. The SRAM 2 Speed Automatic stock cog does not look like I can remove it with any of the tools we have in the shop. I'm thinking of trying a smaller chainring. 

Homebuilt said:

I have the SRAM i9 with disk brakes, so I can't answer your questions on brakes (I like the disk, BTW). The range is just fine. Look up a good gear calculator and put in your current and the hub you're thinking of. Then you can look at front/rear gear combos.

I probably need to gear mine down as I never hit 9 and fully loaded up a hill (think trailer with 100 lbs) I wish I had lower than 1.

Permalink Reply by Haddon on January 18, 2014 at 6:16pm

Follow up question (if anyone sees this) WILL THIS WORK? Which do I go with??

Measured my back spacing (MTN bike).  The outside distance is 150mm and the inside distance is 135mm

The SA3 has these spacings listed, I think I have to go with the 175mm but I'm unsure.

Specs for 175mm Axle

• Hub Shell Material - 6061 Aluminum
• Axle Diameter - 13/32” Slotted
• Axle Length - 175mm
• Over Locknut Dimension - 116mm
• Right Axle Protrusion Length - 30mm
• Left Axle Protrusion Length - 29mm
• Spoke Holes - 36
• Pitch Circle Diameter - 67mm
• Center to Flange Right - 26.3mm
• Center to Flange Left - 30.3mm
• Flange Width - 53mm
• Spoke Compatibility - 13g or 14g
• Sprocket Teeth - 13T through 22T
• Chain Line: 1/8” Flat 45.6mm
• Chain Line: 1/8” Dished 44mm, 47.4mm
• Chain Line: 3/32” Flat 45.2mm, 46mm
• Chain Line: 3/32” Dished 43.5mm, 47.5mm
• Indicator Chain - HSA420 Mark 5

• Weight - 1300g

Specs for 163mm Axle

• Hub Shell Material - 6061 Aluminum
• Axle Diameter - 13/32” Slotted
• Axle Length - 163mm
• Over Locknut Dimension - 116mm
• Right Axle Protrusion Length - 26mm
• Left Axle Protrusion Length - 21mm
• Spoke Holes - 36
• Pitch Circle Diameter - 67mm
• Center to Flange Right - 26.3mm
• Center to Flange Left - 30.3mm
• Flange Width - 53mm
• Spoke Compatibility - 13g or 14g
• Sprocket Teeth - 13T through 22T
• Chain Line: 1/8” Flat 43.9mm
• Chain Line: 1/8” Dished 42.3mm, 45.7mm
• Chain Line: 3/32” Flat 16T - 43.5mm, 44.3mm
• Chain Line: 3/32” Dished 41.8mm45.8mm
• Indicator Chain - HSA316 Mark 4

• Weight - 1290g

Gear Ratio

• Overall Range - 177%
• Gear 1 - 75% (-)25%
• Gear 2 - 100% Direct Drive (Gear 1 + 33%)
• Gear 3 - 133% (+)33.3% (Gear 2 + 33%)
ADDITIONAL INFORMATION

Permalink Reply by Mike Bullis 5.5-6.5 miles on January 19, 2014 at 1:02pm

Axle length isn't as important as OLD or Over Locknut Dimension. What that means is that you'd need to space out the OLD on this hub from 116mm to a minimum of 130mm. Then decide on the axle length. With the chubby dropouts in your pic, the 175mm would be the choice. That gives you about a half inch on each side to play with, but don't forget the anti-rotation washers. If you place those on the inside of the dropout, you may be able to drop the OLD to 120-125mm.

Then there is the problem of mounting the reaction arm of a hub designed for narrow rear spacing to a wide spaced frame.

Followed by the issue with vertical dropouts. That's a whole 'nother can of worms. Best bet there is a chain tensioner. You can try to shoot for the 'magic ratio', though, more trouble than it's worth. There is also a 'ghost ring'.

These are all issues that can be overcome, but you need to decide if it's worth the effort.

Permalink Reply by Haddon on January 19, 2014 at 3:03pm

Is it do-able in the 'give-someone-smarter-than-me-a-hundred-bucks-doable?'

I fantasize about reducing the upkeep and maintenance on my bike to a minimum (ok I'm not going fixie -there are limits).  I just want to get my ride down to it's simplest and least complicated.  Perhaps not by me but can a set up like this be done?

H

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