Shimano Nexus for commuting

tez001
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Shimano Nexus for commuting

Postby tez001 » Fri Mar 11, 2016 12:33 pm

I've seen a second hand hybrid with the Nexus 8 speed setup.

I'm thinking of purchasing this to use in the wet weather. How are the hub brakes on these in the wet weather?

Also is the Nexus a fairly straightforward and easy to maintain system?

Thanks

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MattyK
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Re: Shimano Nexus for commuting

Postby MattyK » Fri Mar 11, 2016 12:45 pm

There is only one adjustment, cable tension. The rest is pretty much maintenance-free, though you do occasionally have to retension the chain.

They have some shifting idiosyncrasies, but not hard to deal with.

I have a rim brake version so I can't comment on the hub brakes.

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find_bruce
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Re: Shimano Nexus for commuting

Postby find_bruce » Fri Mar 11, 2016 1:35 pm

I have an alfine 8 which is the same hub but a different shell for disc brakes, after about 3 years of commuting my hub developed an internal bearing issue which requires a "deep service" at a cost that exceeds buying a new hub.

Lots of users, like mattyk, get lots of largely maintenance free riding. The lucky few, like me, end up with more maintenance than on a conventional system. I also noticed that the shop I bought my bike from no longer sells alfine equipped bikes

axeman74
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Re: Shimano Nexus for commuting

Postby axeman74 » Sun Mar 13, 2016 12:05 pm

The problem with Nexus/Alfine IGH's is that they are very poorly sealed from the factory. So when water enters the hub from wet whether riding (which it will), it corrodes the internals of the hub. There is a bunch of planetary gears, shift plates, pawls, hair springs, bearings etc with very close tolerances, and a nice layer of corrosion is enough to ensure that these will not operate correctly.

This is the reason you need to crack open the hub on a regular basis and relube (Shimano has its own "special" oil that costs a measly $120 per bottle!), at least once per year or preferably every 6mths if you riding in the rain frequently. This isn't exactly "low maintenance", but its what you need to do if you want the hubs to last.

I have fully rebuilt these hubs, including the very complicated and intricate shift assembly which Shimano say's should never be touched. You kind of need the skills of a vintage clock repairer to repair the shift assembly as it has lots of pawls, shift plates, springs etc that need to be reassembled a certain way. This is the reason Shimano won't let their service agents mess with these hubs, nor do they sell any spare parts for them aside from a complete "cartridge assembly" - if your hub fails, you buy a new one.

The Shimano 11spd is heaps better in the sealing department, and a Rohloff is better again, but then you are paying for the privelidge.

So, returning to the original question, they are ok in the rain if you are prepared to do the maintenance, but perceived low maintenance is the reason people buy them in the first place, so they really don't make a lot of sense. Not to mention that they are heavier and you will go slower than on an equivelant derailleur equipped bike.

Axeman74

Edit- after this rant, I reread the original question and noticed it was referring to Hub brakes in the wet. Sorry! Hub brakes are fine for gentle inner city type riding, but any more than that and they overheat and you will be very disappointed. Discs would be my choice for any IGH bike.

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MattyK
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Re: Shimano Nexus for commuting

Postby MattyK » Sun Mar 13, 2016 12:58 pm

Your service experiences differ from mine. Daily commuter in all weather, I tore it down once out of curiosity but it was perfect inside.

eeksll
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Re: Shimano Nexus for commuting

Postby eeksll » Sun Mar 13, 2016 4:25 pm

axeman74 wrote:Edit- after this rant, I reread the original question and noticed it was referring to Hub brakes in the wet. Sorry! Hub brakes are fine for gentle inner city type riding, but any more than that and they overheat and you will be very disappointed. Discs would be my choice for any IGH bike.


op also asked if they where easy to maintain .... so still on topic :)

very unhappy to hear the above. I really disliked the huge gear range (huge steps anyway) but i think I could get over that. But the rest does not sound good, I have also read they slip under power (whatever that means) and tensioning isn't maintenance free either but thought that might be more of a frame issue.

A bit bummed, I was pretty keen on the belt drive.

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trailgumby
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Re: Shimano Nexus for commuting

Postby trailgumby » Sun Mar 13, 2016 6:55 pm

Not such a fan of belt drive. It might have been the awesome amounts of power I was putting out (in my dreams) but they were prone to slipping if you didn't stay on top of the tensioning.

This was on a single-speed 29er on rocky trails. Might be less of an issue on roads, with gears.

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Re: Shimano Nexus for commuting

Postby axeman74 » Sun Mar 13, 2016 7:34 pm

trailgumby wrote:Not such a fan of belt drive. It might have been the awesome amounts of power I was putting out (in my dreams) but they were prone to slipping if you didn't stay on top of the tensioning.

This was on a single-speed 29er on rocky trails. Might be less of an issue on roads, with gears.


Add to this that Shimano 8spd IGH and belt drive are not a good combination anyway. The belt needs to be tensioned quite tight to avoid slipping, which then puts the hub under all manner of stress that it wasn't designed for. I have seen a bent axle on belt drive IGH bikes rendering gear shifting very difficult and have heard stories from bike mechanics of the same. Nice idea that wasn't given enough thought in this case.

Axeman74

eeksll
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Re: Shimano Nexus for commuting

Postby eeksll » Sun Mar 13, 2016 11:22 pm

axeman74 wrote:
trailgumby wrote:Not such a fan of belt drive. It might have been the awesome amounts of power I was putting out (in my dreams) but they were prone to slipping if you didn't stay on top of the tensioning.

This was on a single-speed 29er on rocky trails. Might be less of an issue on roads, with gears.


Add to this that Shimano 8spd IGH and belt drive are not a good combination anyway. The belt needs to be tensioned quite tight to avoid slipping, which then puts the hub under all manner of stress that it wasn't designed for. I have seen a bent axle on belt drive IGH bikes rendering gear shifting very difficult and have heard stories from bike mechanics of the same. Nice idea that wasn't given enough thought in this case.

Axeman74


atleast I haven't spent the money. The chain is really the main part of the maintenance of a derailleur system so not sure I would bother without the belt.

dinga78
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Re: Shimano Nexus for commuting

Postby dinga78 » Mon Mar 21, 2016 2:44 pm

i have 10000km commuting on an alfine 11 and carbon belt with nothing but praise. if the bike was 3-4kg lighter it would be the perfect commuter

ianganderton
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Re: Shimano Nexus for commuting

Postby ianganderton » Mon Mar 21, 2016 3:56 pm

I have a chain driven alfine 8 on my 2012 focus urban planet I brought 2nd hand. The gearing has been spot on for Sydney city riding

It doesn't feel as positive, direct or strong as my cassette geared bikes but I haven't had it slip. I would like to get it serviced though. Apparently it's pretty simple, it's just a case of removing the outer casing and dipping it in the right oil. Many bike shops don't have the right tooling though.

I've read up a lot about the belt drives. Key advantages are no oil and silent running. Chains are more efficient though. Belts do need setting up/tensioning just right
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mikedufty
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Re: Shimano Nexus for commuting

Postby mikedufty » Mon Mar 21, 2016 4:10 pm

My feeling is it depends how hard you want to pedal. I've got the alfine 8 and have had issues with both the gear slipping and the belt slipping. Internals of the hub look nicely greased so I don't think it is a sealing issue. It was really only ever a problem when pushing 100% to take off fast or get up a steep hill. Since adding an electric front hub I think I only ever bother with about 95% and haven't had any slipping issues. The extra 200w also makes the steps between gears no problem.
The belt still squeaks a little when pedalling hard, which is probably the biggest reason I wouldn't get a belt again. Not that bad a noise but negates a major attraction of the belt which was to get rid of annoying little chain noises.

I have managed 13,000km maintenance free if you don't count belt tensioning or pulling the hub apart to see what might be causing the slipping/skipping.

axeman74
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Re: Shimano Nexus for commuting

Postby axeman74 » Mon Mar 21, 2016 4:16 pm

dinga78 wrote:i have 10000km commuting on an alfine 11 and carbon belt with nothing but praise. if the bike was 3-4kg lighter it would be the perfect commuter


Alfine 11 is a completely different hub to a Nexus/Alfine 8, and was probably designed with belt drive in mind (stronger axle, better tolerances etc.), not to mention being a better hub overall. Can't compare Alfine 11 with 8, the 8 is far older, far less refined and more agricultural than the 11, not to mention substantially less expensive.

Axeman74

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Re: Shimano Nexus for commuting

Postby axeman74 » Mon Mar 21, 2016 4:30 pm

ianganderton wrote:I have a chain driven alfine 8 on my 2012 focus urban planet I brought 2nd hand. The gearing has been spot on for Sydney city riding

It doesn't feel as positive, direct or strong as my cassette geared bikes but I haven't had it slip. I would like to get it serviced though. Apparently it's pretty simple, it's just a case of removing the outer casing and dipping it in the right oil. Many bike shops don't have the right tooling though.

I've read up a lot about the belt drives. Key advantages are no oil and silent running. Chains are more efficient though. Belts do need setting up/tensioning just right


Just FYI, no special tools are required to do "dip" service on a Nexus/Alfine hub, just a standard set of cone spanners, the special Shimano oil and some knowledge and understanding of how the hub works. If you want to break into the hub internals further, than you need some special tools (although I have rebuilt hubs without them). Many shops use this excuse because they think IGH are some sort of complex mystical device that only Phd graduates in engineering can understand, so don't want to invest any time into understanding the servicing of these hubs. Shop's that specialise in commuting/touring bikes generally have a much better understanding of these hubs than your regular bike shop.

Axeman74

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