Sunday, May 5, 2019

Greasing a Nexus

Niholas usually have hub gears, and these days those are usually Shimano Nexus 8 after the unfortunate demise of SRAM's P5 and S7 on the market.  These need grease once in a while.  For me, that means whenever they have a hard time holding one or more gears, or otherwise seem too crappy.  (Fun thought on crappiness: at least in hilly Oslo conditions, switching between Nexus 7 & 8 and SRAM S7 is a process of relief from the irritations of whatever hub you were riding, followed by growing irritation at the issues of the one you are now riding.)

So for a while after moving to Oslo I took my hubs down to Copenhagen for greasing, which came to an abrupt end after one visit to a well-established chain-store shop in Birkerød (north of Copenhagen).  I brought them two wheels without the bikes, one a Nexus 8 and the other a Nexus 7, and got back to two nicely cleaned hubs a couple days later.  All was well until I arrived home in Oslo and put the Nexus 7 to use as winter began.  Soon it was leaking, and smelled fruity.  Actually the smell was exactly like a "Muc Off" chain lubricant which has the distinction of not only smelling fruity, but being somewhat pink in color, achieving who knows what.  (The leakage wasn't pink of course, it was filthy, but I am really suspicious about the origin of the lubricant they used at the shop.)  So it leaked and stank, and eventually seemed rougher, and if I recall correctly was not as secure about holding a gear.  To cut the story short, the Nexus 8 had the same issue.

Screw the so-called professionals, it was time to fix this myself (the internet explains how).  I don't intend to write a hugely detailed rundown of how to take apart a hub, but basically you take the hub apart on the drive side until the sprocket is removed, then flip it over and use two thin wrenches (cone wrenches) to remove two nuts from the axle, then lift off the non-drive-side end of things and drop out the internals via the drive side.  I like to put the axle nut on the non-drive side to make it nicer to hold, and I made a handy hub-holder by drilling a hole in a board.  High tech stuff here.

tools of a nonprofessional hub greaser
10 year old Nexus 7 (SG-7C18)
after a dip
Nexus 8 (SG-8C31) dripping out
some pink stink after two
dip & grease rounds
I clean the hub shell out thoroughly via baby wipe and toilet paper, and also remove some grease-mess from the surface hub internals, but not so much.  I have not thus far attempted any disassembly of the hub internals, although I think the Nexus 8 might benefit from getting grease into gears that are not otherwise exposed (thats on the to-do list).  Hubs with coaster ("foot") brakes (as mine have) can have the brake pads jump off and they need to be set back correctly.  The brake pads on Nexus 7 have a spring which pulls them a little closed, so they need to be pried open a bit to sit on the hub.  You'll figure it out.  Kind of like Legos, with grease.

Shimano recommends a dipping kit, so I found one online, plus their official hub grease.  I dip the hub for "a while" and then remove it so it can drip for "a bit" before I put grease all over interesting places.  One thing I wondered in the years before I attempted this was how to grease the coaster brake components.  My answer: a whole ton of grease, just go nuts at that end of the hub.  Often I have extra grease pressing itself out the non-drive-side the first ride, but I don't much care.  Dry brake pads are lame, and there are hills here in Oslo.  I have read that some people may want different grease for the braking surfaces, so far I have not been sufficiently professional (or wise) to do anything like that.

So I have now done this procedure on a Nexus 3 & 8, plus at least three Nexus 7's, and of these hubs I've opened several more than once.  (Score keeping: I have 5 Nexus 7 hubs, also a rare Nexus 5 SG-5R30.)  But about opening some more than once.  You see, there is a drawback to doing this yourself.  Shimano likes cup & cone bearings, and those need to be tightened correctly, or else.

Nexus 7 (SG-7C30) with sad bearings
Nexus 8 (SG-8C31) with sad bearings
Now, I have read a bit about how to tighten cup & cone bearings and honestly what I read was not super helpful in this context, which is a gear hub with a coaster brake and bolt axles.  My current procedure is to get the wheel set in the frame, pull it back so the chain is sufficiently tight, and then tighten down the drive-side bolt in a serious way.  The frame should either be upside-down or hanging on something; the rear wheel needs to spin freely.  Then I loosely attach the brake arm and non-drive-side axle bolt, but do not tighten it so much that any pressure is applied to the nuts that adjust the bearings.  Then I turn the first (the larger) of the two tightening (cone adjustment) nuts until the wheel shows signs of increasing resistance when spun.  At some point I decide that it seems tight enough, then I tighten the second (smaller) nut good and tight (while holding the larger in place) and properly tighten the axle nut.  Now the wheel is probably tighter than it was before the axle nut was tightened.  If its too tight, rewind a bit, loosen things, tighten things again.  Spin the wheel a lot and go by feel.  If it spins really easily, thats probably bad.  Next time I go by a Danish bike shop, I should remember to spin some back wheels and get a feel for factory-fresh resistance.

My first bearing tightening issue was a bearing retainer failure (non-drive side) during or shortly after a big downhill on a hot-for-Oslo June afternoon, apparently braking was the final stress that tipped things over.  Once I reached the flat at the bottom of the hill, it was a fairly short distance before the wheel started crunching.  The bearings had lasted about 6 weeks after I had greased the hub.  I was surprised by this, because it wasn't the first Nexus 7 that I had greased up (the first one was the hub contaminated in Denmark).  I greased the first hub on the 1st of Feb 2018, and has done fine since.  I concluded that the cone adjustment nuts had probably loosened on this 2nd Nexus 7.  I grabbed the bearings and retainer from a different wheel, put things together again, and its been fine since.

I also greased the Nexus 8 that was Muc Off'ed in Denmark.  I was very pleased how the wheel spun so easily and had no observable looseness (as in, I observed no play).  Seemed good.  I guess I rode a couple hundred km's before I decided to do an uphill stretch standing on the pedals in 5th (direct drive).  As before, the bearing retainer (also non-drive side) broke into bits and this time the wheel was partly jammed, couldn't even roll the bike all the way home.  With this failure, it seemed clear the cone adjustment nuts where not loosened, apparently they were just not set tight enough.  So I fixed that also by replacing the bearings and retainer, but it wasn't so long ago that I can say how it will last.  (Side note: the bearings and retainer for Nexus 7 and 8 are interchangeable, at least for the hubs I have, and spares are possible to order.)  This second failure was the point that I adopted the procedure outlined a couple paragraphs above.

Anyway moving on to farther in the past, in 2017 we had bought a gear-hub bike for our son down in Denmark and almost immediately it went out into the forest and got a bit wet.  Apparently more wet than we realized.  We left it in Denmark until the next summer, and when we returned I noticed some roughness while spinning the rear wheel.  Upon returning to Oslo with the bike, I took the hub apart and was met by rust, as shown.

rust in the drive side bearings
of a Nexus 7 (SG-C3000-7C)

rust on the guts
rust in the shell
In light of the amount of time that bikes with these gear hubs are ridden or parked in the rain, I'm pretty amazed that this hub had sufficient water ingress to rust.  We did get it discounted from a bike shop, maybe it had more of a history than we realized, or perhaps these hubs are particularly vulnerable to water found in forest settings.  Or perhaps my son submerged it.  Anyway it works pretty fine except when coasting, then it rumbles.

A bit of a shame that the newest Nexus 7 in the fleet was damaged so soon after purchase, but I'll see about getting some years out of it anyway.  As much as I love to hate these things, they last forever.

Monday, April 22, 2019

Trends and perceptions

At work, two colleagues have in the past few years been shopping for cargo bikes/trikes and ended up with two-wheelers despite having me gently feed them testimony of life with a trike.  (The front brakes do make a Nihola a difficult sell in Oslo, so maybe that was blunting my otherwise smooth sales pitch.)  I don't think these two colleagues have made poor choices in the end, and I've never even riden a cargo bike, so who am I to judge?  People just love two-wheelers.  Related observation: trikes that tilt are trending (see Butchers & Bicycles MK1, Babboe Carve, Sblocs).  Generalized: it seems to me that the greatest challenge to trikes is the way people view them, which is apparently slow.  Maybe slow and boring, who knows.

Does a tilting trike actually address a real issue, or just a trike-newbie's perception of a real issue?  (The classic box trikes where the whole box rotates do have an issue.  Perhaps this is the root of the problem.)  I don't doubt that an empty tilting trike can corner faster than an empty Nihola, but who is qualified to say if that additional potential for speed makes any sense?  We are talking about a heavy machine either way, a machine designed primarily to carry your own kids.  My recollection of driving the Nihola with kids on board is that I could already drive dangerously fast (with a downhill slope to assist) and that I could hold the magic 25km/hr perfectly safely on flat ground.  It corners pretty well, and gets better with more load in front.

In case someone wandering the internet searching for opinions on this matter should find their way here, I want to state clearly that I think tilting trikes represent pointless complexity and have significant drawbacks, when compared to a one-piece design such as Nihola.  (Yes I know, these words will vanish into the vast vortex of the internet, where they shall be entirely irrelevant in the face of social trends.)  I must say I have never ridden a tilting trike.  I have heard from my colleague doing his shopping that the tilting hardware can make you suffer in difficult situations, and I certainly believe that.  I specifically like the feature of the Nihola that it is one piece and no nonsense, its good for climbing curbs, parking crooked on the roadside, starting again, climbing steep hills, and generally doing whatever is asked without a fuss.  I note the high load floors of the tilters, and I look at the additional moving parts, to me this all screams of a solution that is worse than the problem it was intended to address.

Now, I'm not just someone wedded to one particular manufacturer of trikes.  (Though my particular brand of choice does stand out.)  I saw this the other day in Oslo, looks like a fat-tire, no-tilt, disc brake, proper-steering trike.  Seems to be made in Asia, and sold as CargoKid in Denmark.  Comes only with electric assist, and I wonder if those tires can possibly be sufficiently durable.  Quite interesting, I would give it considerable thought if I was in the market.

its a CargoKid product, not a Nihola
I've been spending some time today catching up on the state of things, and I got reading in depth about the Swedish maker Livelo, which was openly inspired by Nihola.  I like a lot of their choices, although I would hesitate to choose a bike/trike that is too optimized for child transport, it should also work after the kids grow up, after all.  I could make a similar complaint about the CargoKid trike above.  My trikes have certainly gotten some paint damage from transporting awkward items such as wood and other bikes, don't imagine that would go well on fabric.
a picture grabbed from the Livelo page

Saturday, March 30, 2019

A small dog

Life goes on, kids get big and heavy, also strong enough to turn their own pedals.  I'm going to have to admit that in the hilly edges of Oslo, a person might think twice about rolling out the 32+ kilo trike when a bike at half the kilos will do the job.  I can haul a good deal of food on two wheels.

But we have a dog now, at 6kg and "small" he fits really nice in a Nihola box, and surprise surprise its not a bad way to take the dog out past boring car-filled places to somewhere he can stretch his legs.  Quite relaxing on a trike really, easy to start and stop.  I can just go slowly along and he runs around sniffing, then back up on board when we come to somewhere overrun with cars.  I would say the speed of a Nihola is well suited to giving a dog of this size a nice gentle run.  Our particular dog seems well aware that getting squashed would be bad, and he likes to run in the proximity of the rear wheel, but at a safe distance.

We have a foam mattress section in the bottom of the box, wrapped in a towel.  We take a roll-up leash and lock at at a length so that it hangs from his neck when he stands up, to remind him where he is supposed to be.  He's not totally wild about bumpy roads or sudden changes in direction, but also we haven't done this too many times yet.

quite a big fancy truck for Norway, which does not impress the small dog

Saturday, August 13, 2016

Nihola updates

Change comes slowly in the Nihola world, and the mother company often says nothing about the changes it does make, so its my solemn duty to comment on it when I happen to notice from my remote perch.  When I spotted an unusual example while on a Nihola-spotting vacation on Ærø, I ran right over to take a picture.

So, this is by the look of things a pretty newly manufactured specimen and has some features I've never seen before:
  • Mechanism to prevent axle movement, which is often a problem in my experience
  • Huge massive roller brake, apparently from the factory but I can't really know that, possibly the optimal choice for rear brake in relatively flat areas
  • A different version of Nexus 8 (SG-C6000-8R), which might be a simple re-skin of the existing SG-8R31 but anyway is a hub I haven't seen standing around before
A few more things of note:
  • The new crank-mounted electric motor
  • The very-low stepthrough frame (difficult to see above)
  • Apparent contact between the shift cable and the chain... appears that they used 7L-7R gray-black anti-rotation washers while I used 5L-5R brown-yellow on mine, which I actually got from the Nihola store in Copenhagen... also looks they switched left for right in order to make it sort of work
They used a regular brake lever for the roller brake, which is a bit of a missed opportunity I think, because a roller brake should have the right cable pull for the locking brake lever.

Also I think that its not too much to ask that the versions of Nexus 8 that come with superior bearings be used, for example the SG-C6010-8R.  Its a lot of hardware being pushed around by a pretty modest hub as sold.