Shimano Nexus Alfine 8 speed How it works

I found this boring and very difficult to follow

That is an epic voice. You should get stacks of voice over work.

Thanks for the explanation of how it works. It is still complicated but I don't know if there is a simpler way to explain

James Speak ..down to you talk..

3:1 difference between low and high ratios but only 8 ratios total, which means they are spread out widely, which is undesirable to many people, including me. Imagine on a piano for example, spanning 3 octaves using only 8 notes (7 intervals). Instead of being only about 5.9% apart, each ratio is about 17% apart from the neighboring ratio(s). That is like a double shift to me (skipping a ratio in between). I need close ratios, as sometimes I feel I need something between 18 tooth rear and the next ratio which is either 20 or 16 tooth rear. This leads me to my conceptual design. Have all 21 tooth ranges in the rear (from 10 tooth to 30 tooth inclusive), but since that will be so wide, have the front sprocket/chainring move laterally to keep the chain properly aligned. That way you have 3:1 difference between highest and lowest ratios, but have 19 more close ratios in between. That is my ideal design and I am waiting to see if someone makes it in my lifetime. If 21 cogs turns out to be too wide, then just reduce it to whatever can be made to work, such as 15, but then make the difference between high and low ratio only about 2.5:1, to keep the intermediate ratios close, or maybe let the user select their own set of ratios, following the manufacturers compatibility rules for them.

Very good video explanation of the Nexus gear system. I have the Nexus 8 speed 2013 or 2014 model on my commuter bike. I have been having issues with the 5th gear slipping. When I shift from 4 to 5th gear or from 6th back to 5th gear the 5 th gear will slip randomly re- engage the slip again. It doesn’t matter is I back Pedal and then pedal forward again it will randomly slip in the 5th gear only. After watching your video the issue is that transition to the ring gear. Is there a suggestion you could make with how I can adjust the gear system to stop that problem. Thank you for you help, David.

I like the way you pronounce Alfine, I would love to hear you say “I’m fine” 😎

Is that actually how "alfine" is pronounced? I never knew. Always thought it was AL-FINE.

I'll be watching this several times!!!

Damn, I'm feeling pretty stupid now!!!!

Looking for one those for a FAT BIKE in a 💯 mm. Rim 29er× 4.8 =5" is out there ' one of those.

I'm finding it literally impossible to buy one without the coaster brake! And with a wheel! I thought in capitalism you could get anything? Guess not!

These seem like a great option until you try to buy one and realize you literally can’t.

Good for car automatic power train in future

Hi Dan. Excellent detailed video!

How Shimano 8 speed hub can lose all the gears? (Alfine8 SG-S501)
Do you (or anyone) has an idea what may have happened when with a loud bang hub lost all the gears and rewarded me with scrunching freewheeling pedals on every gear and a walk back home. Took the planetary assembly off the axle and didn’t found nothing wrong with the thing. And by looking it neither found a way how it even may lose the connection from the sprocket to hub in the first place. Then carefully looking the detailed explanation here neither found a way that could happen. At the end, just washed &oiled it and put it back together and everything works fine now. Has ran it with ATF oil for some 10 years now since it was new. Commuter bike driven broadly some 20 000km. When that happened, it was frosty -14C out and the bike hasn’t been wet previously just simply to frost up on me..

Your voice sounds like Carl Sagan's :)

if the hub shell was held stationary such as in gt's gearbox concept bike or allen millyards downhill bike, how is drive transmitted out of the unit?

Pls where I can get ?? Reply

I found one for $69.

Thanks for the video, youre a great teacher!

thank you for this video. i have been looking for an explanation to this mechanism for some time now.

i would like to know if these hubs will handle the torque of a 1000 watt electric motor

Output not Ootpoot.

dreaming that kind of internal gear hub.. thats awesome

Excellent! And you sound like a Canadian version of my high school mechanics teacher 😀

Excellent! I didn't follow every detail - will watch again at least one more time to get a little deeper - however I have a basic understanding now thanks to this video. I have never run across any other explanation like this and I truly very much appreciate it!

I put over 10,000 miles on my former belt-drive Nexus-3 bike, and I recently upgraded to a new belt-drive bike with an Alfine-8 - approaching 1000 miles on the new bike now.

I had not understood the two-range, four-ratios per range architecture before I watched your video. Your explanation makes it clear why 5th gear should be the most efficient (least drag), as this is a direct drive with no planetary sets in the power path. I think I can feel this when I ride. After this, it would make sense that 1st, 6th, 7th, and 8th are the next most efficient, having only one planetary set engaged, either just the low-range reduction set (1st gear), or just one of the three overdrive ratios (6th, 7th, and 8th gears). Finally, 2nd, 3rd, and 4th involve two planetary sets in series, the low-range reduction set and one of the overdrive ratio sets, and so would seem to be the least efficient. I believe I can feel this while riding. One thing which I think is very noticeable while riding is the increased efficiency (reduction in drag) in changing from 4th gear to 5th.

Thanks to your video I now understand that there are never more than two planetary sets engaged in series in any gear setting.

Approaching 1000 miles, I like the Alfine-8 a lot. My new bike has 700c wheels and came set up with a 50 tooth "chain ring" and a 22 tooth rear cog. With 170 mm cranks I like how this choice of "chain drive ratio" balances the extent of the low and high gears. For sure, 1st gear could be lower - I can't take on just any hill, but the ones I normally encounter are manageable. I do like where 8th is at and feel like it's a pretty good balance on my commuter bike.

When riding, the gap between 5th and 6th is the one I sometimes wish were a little closer. It's not uncommon for me to run into a riding situation where 5th gear feels like I'm spinning out but I can't make the force needed to hold 6th gear. I end up having to drop back to 5th and slow down to keep a comfortable cadence.

Now that I understand how the three overdrive ratios are all based on separate sun gears, I'm not sure why the design couldn't be made with more uniform gear step sizes. However, I suppose it's also possible the the 5th to 6th gear span is driven by the necessary commonality with the 1st to 2nd gear span, where a closer ratio would not be as desirable compared to the design as is.

One request would be to provide the gear ratios as exact integer ratios (gear tooth counts) vs. the provided decimal approximations. I suspect studying the integer ratios may provide insight making it clear where the difficulty is in realizing a design with a more uniform set of gear steps. If you have these integer ratios in the form of the actual gear tooth counts, and could provide them here in the comments, that would be awesome and much appreciated.

My first bike had a Sturmey-Archer 3-speed. I loved that bike and missed it when I "upgraded" to a Schwinn 10-speed. Now decades later I'm back to riding bikes and back to internal gear hubs. They are so cool. One thing I notice while riding is that I'm shifting gears very often while riding because shifts are so easy allowing a nearly continually optimized cadence vs. pedal force. I don't know if modern derailleurs are this quick and effortless to shift, but if not I'd miss the super easy gear shifts if I went to a derailleur bike.

Thanks again so much for the excellent, informative, and highly useful presentation!
Joe

Thank you very much for that detail explanation.

Is it normal for the hub to produce a ticking sound when coasting on gears 5-8?

Hi Dan, I was going to give my nexus 8 R36 an oil bath and re grease. What NLGI level do you recommend for the white lithium grease? I don't want to spend $20 on Shimano's grease. I was looking at a NLGI 2 at my local auto parts store. Thanks

Thanks again. I'm not going to admit to the number of times I have watched this video but it has done the trick. I understand how my Shimano gears work. Through watching your videos I have a good understanding of my 3 and 5 speed SA hubs and now my Shimano hub. Great video.

I'm building a custom e-bike and this will definitely be apart of it!

Got an issue with Gears 1-4 on a Nexus 8... trying to figure out the issue... think it's the clutch according to some forum helpers...

I have a question comparing this hub to the the classic Sturmey Archer 3-speed AW hub. The AW has just one planetary gearset (and no stepped planet gears), and power flows in opposite directions to achieve different ratios, namely 3:4 or 4:3. In comparison, on the Alfine 8, does power flow in just one direction? Looking at your video, it seems that's the case. This would seem to be an important distinction in the design of these 2 hubs. Thank you for producing the best videos on how bicycle planetary hub gears work. You have a deep understanding.

Yes a brilliant set up, almost like a automatic gear box linked to a Bosch performance line motor . 😊

if you use a derailleur or a chain tensioner you can still remove the back wheel to change the tire without having to break the chain every time.

perfect explanation

how does an 8 speed neus handle hills?

Wow!

So which internal hub would you recommend for the average city rider doing mainly flatish bumpy roads short distances & a few low inclined hills

That sounds great -- until the cheap grease Shimano uses dries out, by design, then you have to buy another one -- no one will fix it.

What a tediously boring video

Thanks for the video. Very illuminating. If the internals are not engaging, what do you recommend to get it working again? Thanks!

its already a year but ididnt have it

Fascinating, are real marvel of mechanical engineering. Well explained too.

Walter Cronkite is back!

Exelente shimano kardan spezialized...

Hello @dan burkhart, i have a nexus 8 and i feel like a friction noise on speed 1 to 4 and as soon as i go to speed 5 its completely silent
Do you know what i could do? Open and grease? Thank you in advance

Ahh, that's so clever, for Stage 2, power is transmitted through the Carrier (all 3 bussed together) and the Sun is free-wheeling. The Sun is braked when the pawl selects it, and so transmitting power through to the Ring.

I should stop procrastinating