Tuesday, October 26, 2010

Fork Mod and New Wheels

I now have 700 miles on the recumbent. I've entered the modification phase where I'm fixing all those little things that I ignored when the bike was new. I've modified the handle bars and I'm quite happy with the result. Now it's time to address the wheels and tires.

I have had no less than 7 broken spokes on the 16" front wheel. I finally concluded that the reason is......(no-brainer here).....this wheel is a KIDS BIKE WHEEL! Not meant to carry my significance over bumpy road surfaces at 30+ mph. I hate to admit this, but I've also felt a little discomfort with this fact when I've looked down at the speedo going down a big hill and saw 40mph+. Bearing condition, rubber speed, wheel design and age, temperature and my insurance coverage have flashed through my mind on several occasions.

So, to make things short here, I ordered an real front wheel (Avenir 16X1.5) from Niagara Cycles. It took a week to leave their facility (10 days total to get to me), and when it arrived, it was loose in the manufacturers cardboard box. Inside the box, also loose, were the spoke wrench and patch kit I ordered. They had been poked in through the hand hole cut in the side of the box. I'm lucky they didn't fall out of the box during shipping - "Come on, people, at least put tape over the hole."

I ordered a Kenda Kwest 100 psi tire from Bike Tires Direct. This would be a good place to mention that I loved dealing with Bike Tires Direct. What a nice experience - they have given me hope for the future of customer service in America. No more Walmart tires for me, Bub, I have a new dig.

Now, my front fork wasn't wide enough for the 'real' hub on the new wheel, and the stoutness of it prevented me from just bending it out even a little. My solution was to cut the legs off of an old fork (the one I cut the top off of to make my under seat steering pivot), and insert them into the arch of my fork. I built a wood jig block to fit the old fork to retain my steering geometry, cut some spacer blocks to add the required width, then made a few judicious cuts with the chop saw. After fitting the legs into the arch, I added a couple of slits up the sides to allow for added weld strength, then drilled a hole in the back of each joint to allow an extra spot weld for good luck. I welded, polished and painted, then installed the finished product. I'm impressed with how good it turned out.




And since I was looking at tires and wheels, I decided to find a narrower solution for the rear of my bike. The slick balloon tire I had rolls well at full pressure, but if it's a only few pounds low, it feels like I'm dragging a sand bag due to the soft rubber. It's also not terribly aerodynamic (26x1.90"). I had an older 10 speed front rim (it had a 26X1_3/8 tire on it) from a garage sale bike. It's a nice sturdy rim, but I needed to swap in a rear hub and freewheel. I dug through my parts box and pulled out a nice hub, but ordered a new freewheel from JensonUSA when I couldn't get the old one apart to clean/lube it. It has 34 teeth in low gear (6 more than my previous, worn out freehub), which will be nice for hill climbing. I used Sheldon Brown's spoke calculator then picked up spokes at River City Bikes (why can I never leave there without buying extra stuff?), and the build was pretty uneventful. I dressed it out with a Schwalbe Marathon 85 psi tire, also from Bike Tires Direct (turns out it's a 650b rim, not a 26x1_3/8 as the previous owner thought).

With the new wheels installed, there were a few issues to contend with. The fenders needed some creative adjustment, as the rear wheel is slightly larger than the design diameter I used to build the bike. The larger gear on the freewheel presented some new challenges, though. In the largest/largest gear combination, the chain wasn't long enough. The upper idler wheel conflicted with the large cog. With the front switched to the smallest chain ring, the derailleur ran up onto the large cog in the rear.

After pondering the options and looking at a bazillion pictures of other recumbents on the internet, I decided that the easiest solution was to increase the reach of my derailleur. By chopping the hanger and inserting a one inch piece, I gained the needed clearance under the large cog. Inserting 2.25" pieces into the lower arm of the derailleur gave it the extra capacity to take up the chain links I would need to insert to allow operation on the largest chain ring. I added 5 links to my chain, and viole! The whole things works quite well. Now for some weather suitable for a test ride....Jack

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