Sunday, March 30, 2014

Rear Fender

This is the Axiom Rainrunner MTB Reflex 26" which I bought from Amazon.  Having a fender serves two purposes.  First, and foremost, it keeps water from accumulating in the rear battery bay.  Without it, the water from the back wheel drips down from the bulkhead into the battery bay.
Secondly, it keeps mud splatter from covering the back windshield.  Since I ride on the dirt/gravel trail, this is actually pretty important too.

As you can see from the picture, I drilled a hole in the frame to mount the fender.  The hardware that came with the fender works for this installation and the only modification was to bend the tie bars near the mounting bracket.  This isn't a perfect installation since there isn't much clearance above the back wheel and the bottom of the storage tray.  I also tried to use the bracket provided with the fender by drilling a hole in the ELF just below the OT logo.  You can see the screw there that would hold that bracket.  Unfortunately, the clearance above the wheel wasn't high enough, so the bracket rubbed on the wheel.  Without the bracket, the fender occasionally rubs on the wheel and needs to be re-centered by hand.   But it's not been much of a problem and I've been removing the fender (only 2 screws) when the forecast is clear. 

The front of the fender is just sitting on top of the parking brake.  This keeps it from rubbing on the front of the wheel.  I've thought about using a twist tie to hold it in place but so far it hasn't been necessary since it seems to be staying and it's easier to remove the fender without it. 

Although the hardware that comes with the fender work pretty well, I recommend replacing the screws and nuts with ones that fit the installation better.  

Snowed In

Good thing I got that cover.  This picture was actually taken in February but I was too depressed by all the snow to post it :P  Can you tell which is the ELF and which is the Leaf?

Saturday, September 21, 2013

Gear changer repair

The gear changer suddenly started sticking and I wasn't able to change the gear ratio on the Nuvici hub. This is somewhat ironic given my recent post about how cool the Nuvinci hub is with its continuously variable transmission. 

Anyway, the problem was that I couldn't twist the handle. Luckily Organic Transit included the users manual for the Nuvinci Hub which has a good description and pictures showing how to replace the gear cable. 

The first challenge was finding a replacement cable since the ELF has a very long cable. My local bike shop said its called a tandem shift cable but didn't have one in stock so I ordered one from Amazon.   

The next challenge was figuring out how to install it. There are actually two shift cables on the Nuvinci Hub and you have to thread the cable through a hole in the handle and wind it around a guide ridge and pull it all the way through until the grommet is seated in the housing.  I added some oil to the cable housing before threading the cable through to the end of the housing. There is a special clip that needs to be attached to the end of the cable which clips into the hub. The trick is to wait before trimming the cable until after all adjustments have been made. 

It actually took me two tries and a second replacement cable to get it right. The first one ended up getting frayed inside the handle just like the original cable. It appears that if the cables are too loose, they come off the runners inside the handle, and get caught up in the handle mechanism. So the key is to keep both cables relatively tight. The manual says to check the cable tension by pulling on the cable housing near the handle to see how much leeway there is. Then adjust the thumb screws on the handle to keep the cable snug.  I'll be sure to do that often now to avoid more broken shift cables. 

Here's the pagoda I pass on my ride home. It's near the old naval hospital in Silver Spring. 

Saturday, September 7, 2013

Fixing a front wheel spoke

One of the spokes on the front wheel broke inside the nipple so I had to remove the wheel in order to replace it.  It was a really easy operation only requiring removal of 3 hex bolts, one on the wheel and 2 on the brake. The disk brake caliper needs to be removed so that the wheel can be removed from the hub.  Here are some pictures of the front hub and brake caliper assembly after they've been removed. 

I ended up taking off both wheels so that I could have the bike shop check the tension on the rest of the spokes since they were making a creaking sound whenever I turned the wheel sharply.  I also let them replace the spoke which required the brake disk to be removed due to the location of the broken spoke on that side of the wheel.  The bike shop said that the wheel is built with an unusually large amount of dishing to one side and was curious to find out the recommended tension for the inside vs outside spokes.  I'll update this post once I get those numbers from Organic Transit.

After the repair was complete it took a while to get the brakes adjusted just right.  I found that the disk wasn't exactly in the same position on the wheel so I had to do some fiddling with the brake adjustments to minimize rubbing and squeaking.  Now they're working great and the spokes aren't creaking any more either.

Check out the nuvincii hub video

Ever wonder how the NuVinci Hub works?  I didn't think too much about it until my wife asked recently and I had to admit that I really had no idea.  So, I looked it up on the interweb and sure enough it's really cool.  Of course, I'd expect nothing less from Organic Transit!  Check out this demonstration which does a pretty good job of explaining the magic:

And here's a link to the full site:  Fallbrook Technology NuVinci 360

Saturday, August 3, 2013

So this plant heard that it's called Organic Transit and decided to climb right in.  I don't know where they want me to take them.  Maybe they just like the color.

I've been changing my commute in subtle but significant ways over the last few weeks.  One change I've made is to use the power as a true power assist.  Rather than running the motor intermittently to get up to speed and then trying to keep it there by peddling, I've taken to running the motor slowly while peddling at full strength.  This has allowed me to get a bit more exercise while not getting so tired that I need to take a break.  The end effect is that I can sustain my pedaling more like when riding a traditional bike and still get over the hills. 

The weather has been really dry and sunny for the past month so I've been able to go all solar for the recharge at work.  I ride about 10 miles to work and park in the sun for about 9 hours before riding home.  I also usually take the ELF out for a quick ride at lunch but usually only run the motor for a few minutes.    So far I haven't run out of battery power during my ride home but I have noticed quite a variation in the time it takes to recharge the battery after I plug it in at night.  Sometimes it only takes about 2 hours and other times it takes up to 4 hours. 

Last weekend I had to remove the rear wheel for the first time to replace a couple of broken spokes.  I'm not sure how they got broken but it might have been caused by the time I accidentally left the cable lock on the back wheel and tried to drive away :/  Needless to say it didn't get very far but there wasn't any apparent damage at the time.

Anyway, since the spokes had broken off inside the nipples, I had to remove the rear wheel and tire to replace the spokes.  This required loosening 3 bolts on each of the two brackets that secure the rear wheel to the frame so that the chain can be lifted off the wheel cogs.  Then I loosened the axle bolts as on a standard bike and removed the wheel. 

I forgot to mention that I had previously lifted the back of the ELF and placed a stack of bricks under the frame to hold it up off the ground.  Also, before loosening the bolts, I marked the spot on the frame where the brackets are located so that I could replace the brackets in the same location (or at least the same distance from the original markings on both sides of the frame).  I also had to remove one of the rear brake pads to get the tire past them even after releasing the quick-release on the brake.

Once I had the wheel off I didn't have too much trouble removing the tire from the rim and pulling the rim tape back to expose the spoke nipples.  I used a screwdriver to tighten the spoke nipples and replaced the tape.  Next I used the tire irons to help replace the tire on the rim.  Unfortunately I punctured the tube while prying the tire back onto the rim :(  So, I took the wheel over to the local City Bikes so they could replace the tube for me.  I've since patched the tube so now I at least have a spare tube.

Replacing the back wheel works best by reversing the steps outlined above.  First, replace the chains and tighten the axle bolts.  Then you can pull the wheel back while pushing your feet on the end of the frame to get the right amount of chain tension and align the brackets to the marks you made to indicate where they were originally located.   You might need a friend to tighten the 6 bracket bolts while you pull on the wheel.

As you can tell, this is not anywhere near a "quick release" rear wheel.  The good news is that I don't have to worry as much about someone stealing the rear wheel.  It takes a while and you have to have the right tools.