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View Full Version : Fixing a flat on a rear wheel with 8-speed internal hub.


Cruizer
08-17-2008, 07:16 AM
I'm intrigued by the advantages of an internal 8-speed rear hub, especially in Portland's rainy winters, but what stops me is that I've heard it's really awkward to fix a flat on them. That is a sticking point for me, as I would not want to lose the independence of being able to replace a tube or patch a flat on the road.

I would appreciate hearing about people's experiences with this. Thanks :)

Camel
08-17-2008, 10:15 AM
I'd figure it would be as difficult as repairing a flat on a fixed gear. NOt too difficult, a bit more time. Just allways carry propper tools. Most fixed gear riders run narrow tires, at least I did back east.

-For an internal hubbed "city bike", I would run more puncture resistant tires anyways (like Schwalbe or Specialized). Thereby greatly reducing the chances of flats.

Also-you can repair a tube without removing the wheel (on any bike), IF you know where the puncture is.

donnambr
08-17-2008, 10:16 AM
I'm not going to lie - the rear on a Nexus 8 is a PITA. There are ways you can make it easier, though. Putting a Schwalbe Marathon Plus tire with a thorn-resistant tube on the rear greatly reduces the possibility of flats. There is one book (http://www.amazon.com/Complete-Do-Yourself-Bike-Book/dp/1600940242/ref=sr_1_11?ie=UTF8&s=books&qid=1218992996&sr=1-11) that I know of with step-by-step instructions for removing a wheel on a Nexus 8. I'm glad I own it. The photos are excellent, as is the narrative.

You could also set up an appointment at a shop like Clever Cycles where they work on Nexus 8's all the time and learn how to take it apart and put it back together yourself. Then you'll have confidence when the inevitable flat happens.

In the 2 and a half years I have owned my bike, I have had 3 rear flats. Not too bad.

tfahrner
08-17-2008, 10:51 AM
I'm intrigued by the advantages of an internal 8-speed rear hub, especially in Portland's rainy winters, but what stops me is that I've heard it's really awkward to fix a flat on them. That is a sticking point for me, as I would not want to lose the independence of being able to replace a tube or patch a flat on the road.

It is slow to replace a tube or tire, yes. It is not hard at all to patch a flat without removing the wheel from the bike. In fact it can be faster than removing the wheel if your tire beads are tight, and certainly cheaper. Just fish the tube all the way out (unless you know exactly where the puncture is), pump up to find the leak, patch. While waiting for the vulcanizing fluid to cure, find and fix what caused the flat in the tire casing. Of course you can't always patch -- say you have a blowout or the valve fails. But I bet the occasional grief of having to replace the tube is more than offset by the reduced drivetrain maintenance time you'll accrue over the years.

Chain of Fool
08-18-2008, 06:20 PM
The Shimano hub has a "cassette joint" to receive the business end of the shift cable. Put the controller in lowest gear. Give the cable some slack by holding the spring tension with a 2mm allen wrench, or a piece of spoke or, ...a nail poked into the little hole. Wiggle the lump on the end of the cable out of its hole. Pull the cable tube out of its holder. Similar concept on the other side if you're lucky enough to have the roller brake too.
Summary: keep a piece of spoke in your tire kit. Say goodbye to derailler adjusting and chain maintenance. Marvel at the absurdity of the derailler system with all of the mechanism exposed to road grit and weather. Imagine God designing an animal with it's reproductive parts hung outside in the breeze subject to harm.

tfahrner
08-18-2008, 11:53 PM
Marvel at the absurdity of the derailler system with all of the mechanism exposed to road grit and weather. Imagine God designing an animal with it's reproductive parts hung outside in the breeze subject to harm.
i admire your sense of humor. now, i'm told that the male gonads sleep on the porch because it's too hot for the sperm inside. i think this answers the old chicken-and-egg question: sperm came first and guys' bodies adapted to serve the needs of sperm. having witnessed childbirth, i have trouble with the idea that a benevolent god who worked out the nifty marsupial system of micro-babies slipping out of the uterus early and clambering into a nice floppy wide-mouth pouch to get big -- that this god went on to set up humans to push out 10lb babies, frequently killing the mother without medical intervention.

ira37
08-26-2008, 09:48 AM
I'm intrigued by the advantages of an internal 8-speed rear hub, especially in Portland's rainy winters, but what stops me is that I've heard it's really awkward to fix a flat on them. That is a sticking point for me, as I would not want to lose the independence of being able to replace a tube or patch a flat on the road.

I would appreciate hearing about people's experiences with this. Thanks :)

And it can be tricky on any Shimano Internal.

SRAM makes a 9 speed that is supposed to be a bit easier.

What I will say is I love my Alfine for the commute.

I had thought the same thing, Disk Brakes Internal hub for rain riding and little maint.

So far so good

bonny790
08-26-2008, 12:17 PM
I have no experience with geared hubs, can someone state briefly the difficulty of removal? I wouldn't of thought there would be anything to it, but like I said, I know nothing about them.

Thanks

Ante
08-26-2008, 03:44 PM
If you have a Shimano Nexus hub like I do, Sheldon Brown has a bunch of technical information and even the service manual for the Nexus 8 available on his site.

http://www.sheldonbrown.com/nexus-mech.html
http://www.sheldonbrown.com/nexus8/

Page 10 seems to show the spoke or allen wrench trick to removing the shifter cable that an earlier poster mentioned.

http://www.sheldonbrown.com/nexus8/pages/10.htm

I also came across a mention of a YouTube video of someone performing this process with the three-speed hub, and it may be this one:

http://www.youtube.com/watch?v=yHpoVZbNU7k

(but I can't check it at work to make sure)

Fortunately, I haven't had to try any of this yet, so I don't know how complicated it really is in practice. But it doesn't seem like rocket science, really.

Jeff Wills
09-11-2008, 09:26 PM
I have no experience with geared hubs, can someone state briefly the difficulty of removal? I wouldn't of thought there would be anything to it, but like I said, I know nothing about them.

Thanks

The shift cable is connected to the hub in some fashion. (Different hub, different fashion.) When you remove the wheel, the cable has to come off, too, and then reconnected so that the gears function when everything is put together again.

FWIW: my experience with Sturmey-Archer 3-speeds is now over 30 years old. I never had a problem changing a tire back then.

Jeff

keithwwalker
09-15-2008, 01:11 PM
As mentioned by others, download the manual from Sheldon's site.

Briefly, unbolt the roller brake bracket and disconnect brake cable, and then with your bike upside down (in first gear), put the allen bolt/spoke into the hole by the terminus of the shifter cable, and rotate counterclockwise.

This relieves the tension on the cable and you can then remove it from the shifter mechanism. (this is the key to an easy change)

From there, you take off the nuts holding the axle on, and then push forward the wheel to remove the chain. The wheel then comes off.

Installation is reverse, with the exception that you calibrate the cable alignment with the shifter in 4th gear. Make fine adjustments to make sure that the yellow lines align, and you are done!