With Kessa learning to ride I wanted to rebuild the railing I once had in the driveway for Sydney. That one rotted and is long gone. I decided to use my skinny as the base, some old trampoline poles for supports, and some spare railing mounts that were once sent to me in error. The railing is number two of two that was once in the basement stairway. I might cut down the poles at some point.
One of the unicycles Kyle has been riding on occasion is the Barracuda I bought on craigslist over 3 years ago. Unfortunately one of the cranks was loose tonight. I went to tighten it and found the bolt spun. The threads on the spindle were stripped. I think I recall tightening this bolt years ago and feeling it start to give just at the end. So now with no way to tighten the crank and with it being a cheap uni, I decided to fix it by welding the crank to the spindle. I did both while I was at it. With no training, I've "successfully" welded about 4 or 5 items at this point using an arc welder. My welds are embarrassing, but I expect that will hold for driveway riding. If not, I'll hit then with the welder again.
For weeks Dustin's KH 26 unicycle has been making a clicking noise. It seemed to be getting worse over time. It's rather annoying and we've both been concerned something was going break or get ruined.
One time before riding, I had tried tightening his crank bolts to the right torque. That didn't help. Neither did tightening his bearing holding to spec. Yesterday Dustin stopped by in the evening and we tried some more ideas. Before getting too technical, we swapped seats and posts, and then pedals but none of those helped. It wasn't the typical pinging noise I've heard from spokes, but still I tightened all the spokes 1/8 of a turn. No help. That was all we had time for.
Later I read a lot of messages on the unicycle forums regarding what sounded like the same problem. There were many suggestions. This evening Dustin stopped by again and we worked on it some more and pretty much did everything that was suggested.
First I wanted to further eliminate the possibilities of spokes rubbing. Sometimes spokes make noise when they flex and rub against each other. So we worked thin plastic spacers between every point where two spokes crossed each other. The clicking remained.
Then we removed the wheel and took everything off the hub spindle: cranks, outer spacers, bearings, and inner spacers. On the way home from work I had stopped at AutoZone and borrowed a bearing/gear puller. It was the first time I'd used a bearing puller. I'm not 100% sure it was the right model for this application, but it did work fine. On one side of the hub the inner spacer was very tight and had to be carefully pried off. The other inner spacer came off with no tools. I assume this was just because of manufacturing tolerances, though I did file some very tiny spurs on the stubborn spacer. It still didn't go back on easy, so I doubt that did anything.
With the inner spacers off we noticed some tiny metal filings at the connection between the spindle and hub body. It looked more like something left over from manufacturing than something generated from friction. After cleaning everything up we reversed the process. One forum suggestion was to lube the spindle before putting the spacers and bearings on. We did this. We also swapped parts from one side to the other. Why not. To seat the sticky inner spacer and the bearings I used a deep socket of the right size and hammered. I'm not sure if a press is normally used, but this technique worked fine.
After putting the wheel back on the frame and tightening the bearing holders to spec, it was time to put the cranks back on. First I cleaned the crank holes with a toothbrush. Then I greased the spindle splines. I have never done this before because grease seems like a bad idea for parts held together mostly by friction, but apparently it's a not uncommon. I tightened the crank bolts, put the pedals on, and it was time for a test ride.
Guess what. The clicking is gone! So, what was the fix? It's hard to tell what specifically did it, but for now Dustin and I are glad that annoying click is gone and hopefully gone for good.
Days ago I got my new Spirit cranks to replace my broken Moments but just got around to installing them. The quality of Kris Holm parts is first class. These cranks feel like they're from the future.
I also bought a new seat post. The one I've been using has extra hardware on it to make the saddle adjustable. The one I got is fixed, though the slotted holes still provide enough adjustment. I figured it would be lighter but I couldn't find any numbers online so I just bought it. Sure enough it is about 100 grams (0.22 lbs) lighter.
Back in the spring I mentioned I was trying to make my muni lighter, but I never got around to posting the details, until now.
Weight matters because it affects acceleration, deceleration, hopping, and the response of the uni. The most critical location to remove weight is on the wheel. This rotational weight is the biggest contributor to the factors I mentioned.
So back in March I took my my unicycle apart, down to the nuts and bolts, and weighed everything on an electronic scale. I didn't want to make any assumptions about where I could remove weight. (Google spreadsheet of part weights)
I researched and purchased lighter weight parts. Here's what I replaced and the weights:
Old Part
Weight
New Part
Weight
Savings
Odyssey Trail Mix pedals
566 g / 1.25 lbs
Wellgo MG-1 Ti pedals
300 g/ 0.66 lbs
266 g / 0.59 lbs
KH Moment cranks - 125mm/150mm
585 g / 1.29 lbs
same, but aggressively milled
444g / 0.98 lbs
141 g/ 0.31 lbs
Duro Razor 24x3.0 tire
1421 g / 3.13 lbs
Panaracer Fire FR 24x2.4
850 g / 1.87 lbs
571 g / 1.26 lbs
24x3.0 DH stock tube
425 g / 0.94 lbs
Schwalbe A 10 24x1.5/2.5
165 g / 0.36 lbs
260 g / 0.57 lbs
KH two bolt seat clamp
67 g / 0.15 lbs
Woodman Deathgrip SL Ti
11 g / 0.02 lbs
56 g / 0.12 lbs
1294 g / 2.85 lbs
That brought my muni weight down from 17.91 lbs to 15.06 lbs... almost 3 lbs! And all but 0.12 lbs of that was rotational!
The tire and tube change removed 1.83 lbs of weight at the outside wheel, where weight is the worst. That's huge. But the tire is less wide, has weaker sidewalls, and the tube is thinner and more prone to flats (I got one in June).
The pedals and crank changes removed 0.9 lbs of weight. I love my magnesium pedals with titanium spindles. When I held one in my hand it the lightness was incomprehensible.
When it came to the cranks, I had seen a few examples online of people drilling and milling material away to make them lighter. I remembered a friend of mine had a milling machine in his garage and he was willing to do some work for me. Thanks again Mike!!
Here's the before and after:
We went extreme. It should be clear to anyone that removing so much material would significantly weaken these cranks. But I'm lighter than the average rider and I don't do big drops, so I figured they had a good chance of working for me. And they did... for about 5 months.
This morning I went back to Whiting to power up some more hills. On the White trail I was on attempt four of a hard climb when PING! I stepped off as if I was stopped by a root and found my pedal was on the ground.
When I first rode these cranks I feared if they broke I might get cut in the leg by the resulting sharp spikes. My Achilles tendon was going to get severed. Thankfully that didn't happen. I'm also thankful I wasn't in a race or out of town. In fact, I was at the trails closest to home. Though, I was about as far away from the parking lot as possible. I jogged back to at least get some exercise out of the trip.
On a positive note, I got home and ordered some new cranks. This year Kris Holm replaced the Moment cranks with Spirits. They're made of 7050 aluminum instead off 6000 series aluminum, making them lighter. In fact they're 424 g / 0.93 lbs per pair, which are actually a bit lighter than my crazy milled Moments! I got a few other goodies too.
Tomorrow is the start of the Park Ave Weeknight Series races and I plan to attend and ride muni.
So this evening I decided to tighten my cranks and make sure my uni is good to go. As soon as I took it off the hook in the garage, I noticed the tire was flat. Crap. I figured it was a pin-hole leak caused by some thorn or nail I must have run over.
I took my wheel off and removed my tire. I still haven't gotten around to posting about the weight saving changes I made to my uni over the winter, but here's a sneak preview. I'm using a lightweight tube made by Schwalbe. It's lightweight because it's thinner, and maybe a less durable rubber. When I removed the leaking tube from my tire I found it looking all worn.
Worn Tube
I inflated it outside the tire a bit but didn't see, hear, or feel any obvious leak. I'm assuming there are some tiny holes within the worn areas, but for now it's not important to me.
I had a second Schwalbe tube so I installed that. It was kind of a pain because I screwed up a bit. I put the wheel on backwards first. Duh, right? Somehow it can be tricky when the uni is upside down. Once I switched it to be correct, I noticed an obvious foolproof way to get it right every time. My cycle computer sensor and magnet are only on one side.
One other problem I had has been haunting me for a while. For some reason the wheel sits in the frame a bit cockeyed. It's slight, but it can be seen when looking at the distance between each brake pad and the rim wall. There's no adjustment for the rim position in the frame. The hub bearings just sit in bearing holders that get tightened down. It could be caused from minor manufacturing variations in the frame, bearing holders, bearings, the wheel build, or an accumulation from all of these. I did notice that with the wheel in backward, it centered itself very well, but I can't ride my geared hub that way.
In the past I've just tried to put pressure on the rim while I tightened it it an attempt to take advantage of any play available. It helped a touch. But this time a cut a super thin piece of flat rubber to shim one bearing holder, so the bearing in the side sat the tiniest but higher. This worked well.
I rode my reassembled uni once around the block. It seems to be running fine. I'll check my tire tomorrow morning and hopefully it will be holding air.
I'm a little nervous heading into a race tomorrow with these changes, but it will likely be fine.
I wanted to try a lighter weight tube in my KH24. The whole unicycle is heavy, especially with the Schlumpf hub, but there isn't a lot of room for weight loss. One thing I have heard of is "rotational weight". It's something about how it takes more energy to move a pound of the rotating wheel and a pound of the rest of the uni. Weight on the outside of the wheel has a greater effect than on the inside.
The tube I've been riding with is the stock one, so I assume it is a heavy duty Duro brand tube that normally comes with it. By "heavy duty" I mean it is made of thicker rubber to help it endure the stressed of the most extreme muni riding. While riding a unicycle off-road may be considered extreme by itself, there are plenty of riders out there doing way more extreme riding than me. So I'm hoping a lighter tube will survive just fine and give me a lighter wheel.
I've read about some riders do this have having no problems, while others get flats soon after. So I'm still a bit concerned.
I had to call 5 bike shops before finding a 24x3 tube. Giant brand. I had heard Specialized brand tubes were good, but none of the Specialized dealers in town stocked a 24x3 tube. It's kind of odd. I found it at Towner's. I weighed both the new and old tube using a cheap postal scale. I don't now how accurate it is but here's what I got:
Duro: just over 15 oz. (425g) Giant: 10 oz (284g)
I gave my new one a test spin around the neighborhood. I want to say I felt a difference, but it could easily be psychological.
But then again, my wheel's circumference is about 77", so that's about 4114 rotations in a 5 mile muni ride, which means I'm moving over 20,500 extra ounces around... that's 1285 pounds! Sounds good to me... whether it's logically sound or not!
With Kessa learning to ride I wanted to rebuild the railing I once had in the driveway for Sydney. That one rotted and is long gone. I decided to use my skinny as the base, some old trampoline poles for supports, and some spare railing mounts that were once sent to me in error. The railing is number two of two that was once in the basement stairway. I might cut down the poles at some point.
