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A big day with a big unicycle
The weather today was beautiful so with the lawn freshly mowed and the family out doing their various things I set out to take a ride on the prototype Harper Hub unicycle. To refresh your memory - This unicycle is almost identical to Harper's Blue Shift except the hub and frame were built over seas. I have assembled it with an Alex Adventurer 700c rim, 28 x 2.35 Schwalbe Big Apple tire, 170mm cranks, magnesium Wellgo pedals, bike seat post with rail adapter and carbon fiber based air saddle. It's a very nice ride! With Ken Fuchs' recent thread about his hour time trial, I decided that's what I should try too. I drove to a paved bike/walking path that's a big figure 8 with straight sections of paved path leading in and out. It has some sharp turns and one short but steep spot - also people on the path - so it wasn't ideal for trying to set a speed record, but good enough for today. I unloaded the uni, suited up and set off! about 1/2 mile into the ride I realized that I left my water bottle in the truck. Oh well ... I'll just tough it out rather than go back. Last weekend I played lumber jack using a chain saw to cut up a large tree for firewood. I strained my back wrestling logs around. About 15 minutes into the ride my back started hurting. I concentrated on *trying* to keep my back muscles relaxed and just spin the pedals smoothly but this unicycle is not easy to ride and I find it hard to really relax so I just did the best I could and pressed on. The pavement was rough in several places and as I tired, I went slower over these spots. In fact the bumps caused more than one UPD. The short but steep part caused a few UPD's as well. With my back killing me and very thirsty (remember - no water?) I managed to ride 1:02 and a distance of 9.6 miles or and average of 9.3 miles per hour. With that done I went to my shop to tinker around a bit - mostly clean up a project I was working on yesterday. I drank a bunch of water and my back started feeling pretty good so I was off again - this time in 29" mode for some MUni. The trail I set out for is known as the "Prison Loop" because it runs next to the Idaho State Women's Prison. It's a very popular trail with the mountain bikers because it's handy - it literally starts in town about 1/4 mile from my shop. The published information for the Prison Loop is 5.4 miles and 860 feet of elevation gain. For the time trial I had the Big Apple inflated to 52 psi. I was great on the pavement but I figured I'd better let some air out for off road so I set the pressure to 38 psi. I've ridden this trail many times on both the 24 x 3.0 Gaz and 29" MUni's but the ride that the Big Apple gave was super plush! I rolled over rocks with ease that are a challenge on my 29'er with WTB Motoraptor. I was amazed at how smooth and easy that thing rolled! Then about 1/2 mile into the ride I realized I left my Camelback in the truck! What and idiot! I decided to press on anyway rather than go back. The geared hub uni felt great off road - just like my regular 29'er only better because of the Big Apple. The extra 5 pounds of hub wasn't anything I noticed. I rode smoothly through rocks and was able to lower my cadence and ride farther between rest stops because the Big Apple just seemed to roll through the "dead spots" in my pedal stroke. As I climbed up the trail I started getting thirsty. The single track is a steady climb but a mile or so up the trail there's a gully with some down hill then a sharp climb out that I've not been able to ride. This little bit of down hill into the gully was the first indication that something wasn't right. I rode to the bottom and as far up the other side as I could, then walked up the steep part until the trail flattened out a bit. From there the single track comes to a nicely graded dirt road that is a steady climb for about 3/4 mile. Besides being *very* thirsty by now, the climb up the road was the best I've done yet because of the smooth rolling Big Apple. At 2.25 miles the climbing is done and it's back to single track - mostly all down hill. This is the payback for the "death march" to this point. I started down the smooth dirt trail that's about 14" wide and worn 6" - 8" deep in the center but something was very wrong: I couldn't seem to ride straight down the trail! I was twisting my upper body and flailing my arms in all kinds of directions just to stay on the trail. The Big Apple wanted to climb up the sloped sides of the trail in the worst way! What is usually a great downhill ride soon became agony! My back was hurting again because of all the wierd contortions I was putting is through just trying to keep going straight - and was *really* thirsty by now. What could I do but just press on? It was a very tough ride down and back to my truck. Some of it I just couldn't do because my back was hurting so bad and it was almost impossible to keep the uni on the trail. Within 1/2 mile of my truck the trail flattens out and I was able to ride that ok. I was like a horse heading to the barn at this point. The first thing I did when I got to my truck was pick up the Camelback (sitting right there on the front seat) and take a nice long drink of delicious warm Camelback water! This time I rode 5.33 miles in 1:05 for an average speed of 4.8 miles per hour. The bottom line is that the Harper geared hub uni is great both on and off road. I would like to have brakes on it and switch it to 43.5" mode for the off road down hill sections. That could be interesting. The Big Apple turned out to be a serious bummer off road. I don't know if it's because of the very round profile or the lack of tread or both but even as nice as it rides over rocks and bumps I won't be riding it off road again! Steve Howard -- showard - ------ ------------------------------------------------------------------------ showard's Profile: http://www.unicyclist.com/profile/452 View this thread: http://www.unicyclist.com/thread/27613 |
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#2
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A big day with a big unicycle
I enjoyed your post Steve. Now go drink some more water. --chirokid-- -- chirokid "Unicycling can make you proud then humble in very quick succession." Mikefule ------------------------------------------------------------------------ chirokid's Profile: http://www.unicyclist.com/profile/4140 View this thread: http://www.unicyclist.com/thread/27613 |
#3
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A big day with a big unicycle
i think that low psi combined with a narrow rim for the ride down may want to ride in unwanted directions. i havent gone below 50psi on my MotoRapter yet,it soaks up more bumps while lower but as my speed increases it gets wishy washy so i keep it higher to prevent fold over. its definatly an eye ball rattling ride at 65psi,but the boat goes where i point it. -- jagur - Random Unicyclist --------------------------------------------------- -searching for the real one wheel deal,the one that wont but will... all i ask is one rotation,on this vision of singular creation...-[image: http://newserver.unicyclist.com/gall...x_flipped.gif] ------------------------------------------------------------------------ jagur's Profile: http://www.unicyclist.com/profile/502 View this thread: http://www.unicyclist.com/thread/27613 |
#4
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A big day with a big unicycle
It sounds like the hub is holding up pretty good. I'd like to see you try it on a few small drops (like maybe a foot) in both modes to see how well it survives, to simulate more intense off-roading. But I only want to hear about it if you bring water next time. You made -me- thirsty! -- paco - Proud owner of 2 opposable thumbs Sometimes crap works fine. ------------------------------------------------------------------------ paco's Profile: http://www.unicyclist.com/profile/3715 View this thread: http://www.unicyclist.com/thread/27613 |
#5
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A big day with a big unicycle
On Sun, 7 Sep 2003 23:14:57 -0500, showard
wrote: I've ridden this trail many times on both the 24 x 3.0 Gaz and 29" MUni's but the ride that the Big Apple gave was super plush! I rolled over rocks with ease that are a challenge on my 29'er with WTB Motoraptor. I was amazed at how smooth and easy that thing rolled! The geared hub uni felt great off road - just like my regular 29'er only better because of the Big Apple. The extra 5 pounds of hub wasn't anything I noticed. I rode smoothly through rocks and was able to lower my cadence and ride farther between rest stops because the Big Apple just seemed to roll through the "dead spots" in my pedal stroke. This little bit of down hill into the gully was the first indication that something wasn't right. the climb up the road was the best I've done yet because of the smooth rolling Big Apple. I started down the smooth dirt trail that's about 14" wide and worn 6" - 8" deep in the center but something was very wrong: I couldn't seem to ride straight down the trail! Within 1/2 mile of my truck the trail flattens out and I was able to ride that ok. I've extracted your references to the Big Apple and the trail characteristics. Clearly the tyre does a great job uphill, an OK job on the flat and it is terrible on the downhills. What would cause that? Is jagur on the right track with his rim width remark? But then why would that affect the downhills more? Klaas Bil - Newsgroup Addict -- If the crank is moving then it really sounds as if it's loose. - onewheeldave trying to pinpoint the cause of a clicking crank |
#6
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A big day with a big unicycle
Klaas Bil wrote: * I've extracted your references to the Big Apple and the trail characteristics. Clearly the tyre does a great job uphill, an OK job on the flat and it is terrible on the downhills. What would cause that? Is jagur on the right track with his rim width remark? But then why would that affect the downhills more? * The downhill part of the trail had the additional challenge of a rut running all the way down the trail. There are many mountain bike tires that have the same nasty characteristic of wanting to climb the walls of a rut when you're trying to ride in the center of the rut. It's not a problem unique to the Big Apple. Some tire designs like to try to climb the sides of a rut and other tire designs are less inclined to do that. The Gazz is happy to stay at the bottom of a rut, which is one characteristic that makes the Gazz a well behaved tire for muni. -- john_childs - Guinness Mojo john_childs (at) hotmail (dot) com ------------------------------------------------------------------------ john_childs's Profile: http://www.unicyclist.com/profile/449 View this thread: http://www.unicyclist.com/thread/27613 |
#7
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A big day with a big unicycle
Nice description, Steve! My preliminary results with the Kenda Klaw (front) on a 29er with Rhino Lite rim give the same problems -- a real difficulty riding it under seemingly benign conditions. As time goes on I'll be able to be more detailed. Yesterday bopping around Manhattan on my freestyle with a ~70psi The Wall tire I lost it a couple of times by getting into a sidewalk rut. That tire is a real bear on sideslopes as well, I find. I bet it has a similar profile to the Big Apple. -- U-Turn - Mounting a Revolution Weep in the dojo... laugh in the battlefield. 'Strongest Coker Wheel in the World' (http://www.unicyclist.com/gallery/albup39) -- Dave Stockton ------------------------------------------------------------------------ U-Turn's Profile: http://www.unicyclist.com/profile/691 View this thread: http://www.unicyclist.com/thread/27613 |
#8
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A big day with a big unicycle
Klaas Bil wrote: Is jagur on the right track with his rim width remark? But then why would that affect the downhills more? [/b] I reckon its more likely to be to do with tyre pressure. I once had a terrible ride on an Arrow 24x2.75 tyre where I couldn't stop the uni from climbing up the slight camber of a gravel road. I tried several different tyre pressures but to no avail. More recently I've put the Arrow on a German Pichlerrad unicycle and it rides OK - I guess I happened to pump it up to the 'ideal' tyre pressure. Tony -- TonyMelton - NZUNi The first NZUNi Weekend - October 25-27, Wellington. More info at 'www.unicycle.co.nz' (http://www.unicycle.co.nz) 'My Photo Gallery' (http://gallery.unicyclist.com/albur10) has new photos and has been generally re-arranged and spruced up. 9/9/03 ------------------------------------------------------------------------ TonyMelton's Profile: http://www.unicyclist.com/profile/2118 View this thread: http://www.unicyclist.com/thread/27613 |
#9
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A big day with a big unicycle
On Mon, 8 Sep 2003 21:13:22 -0500, john_childs
wrote: The downhill part of the trail had the additional challenge of a rut running all the way down the trail. I saw the rut (gully) only being mentioned once while the correlation with downhill seemed to be stronger, through several downhill and uphill (and even flat) datapoints. However, I think jagur and Tony are right. It might have to do with tyre pressure, combined with a narrow rim, more than tyre tread per se. And it's worse for downhill. I'm not sure I can adequately explain the effect in just words but I'll give it a try. Suppose you ride at a place where there is some sideways slope. This could be road camber, or a downhill or uphill trail where you drift out of the centre of a rut. The tyre, as usual, begins contacting the ground at the front of the contact patch and that particular bit of tyre doesn't slip. But once that bit of tyre is in the middle of the contact patch, the soft tyre and narrow rim allow the wheel to sink down locally with respect to the tyre. This gives a steering momentum that on an uphill tends to steer the uni to the steepest gradient, while on a downhill it tends to steer the uni away from the steepest gradient. Hence on an uphill the effect stabilises the uni in a straight line, while on a downhill any deviation from the straight line (which might be e.g. in the centre line of the gully) is intensified. Klaas Bil - Newsgroup Addict -- If the crank is moving then it really sounds as if it's loose. - onewheeldave trying to pinpoint the cause of a clicking crank |
#10
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A big day with a big unicycle
Klaas - I think you are onto something there. Another thing to consider: When riding uphill the center of gravity is in front of the axle but riding downhill puts the center of gravity behind the axle. For what ever reason, the lack of control is more pronounced on the downhill for sure. I set out tonight to re-ride the trail with 60psi in the Big Apple. That much pressure in the tire is not good on a rocky trail. Unfortunately, one of the pedals came loose before I got very far so the ride came to an abrupt end and I walked back. I'll try again another day. Steve Howard -- showard - ------ ------------------------------------------------------------------------ showard's Profile: http://www.unicyclist.com/profile/452 View this thread: http://www.unicyclist.com/thread/27613 |
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