Oct 19, 2005

     I wanted to lower the top tube, chop the seat post shorter, and lower & shorten the seat stays.  So, for phase 1, I welded in a piece of .064" x 1" box tube.  I used box tube because it is also going to serve as the seat rail, plus I hate working with round tubing :)  I could have been keen and made the down tube and new top tube parallel, but I didn't want to get too fancy with the first one.

     I welded in the new top tube, but won't be cutting anything until I get the stays modified.  I want the frame as rigid as possible when I cut the top tube and seat post so that twisting is minimized.  I was very careful and kept the heat low while welding near the head tube so as to not weaken the brazed joint.  It didn't even burn the paint off.

     1 hour into it so far.

Oct 20, 2005

     Phase 2 was to cut the seat stays free up near the seat tube, and use the MAP gas torch to heat the bottom of the seat stays so they could be gently bent forward and down to be re-welded to the new, cut-down, seat tube.  I used a big piece of bike frame as the bending jig.  I welded two 1/8" x 1" tabs to the big tubing and bolted the tabs to the rear drop outs.  It worked very nicely for my first effort.

     After the stays were bent down slightly lower than my new square top tube, I used the torch again to heat them, one at a time, just above the rear brake boss.  I squeezed one stay inward until it touched the seat tube, and tack welded it in place.  Then I heated and bent the other stay to the same position and tacked it too.  I cut the excess off the ends of the stays, heated them cherry red with the torch, and hammered a chamfered end on them.

     Here is a quick mock-up with a seat borrowed off one of my trikes.  Just trying to get an idea of what it will look like, but to be honest, it didn't really show me much :)  I have a general idea of the seat height now, but I want to keep the BB as low and as close as I can, but I'll make sure that the BB is high enough so there is no wheel - crank interference.

     I should be able to keep the power side of the chain pretty straight, but may need to route the return side a little lower initially at the back, to get past the right side chain stay.  I made a double pulley out of high density plastic with 3/8" sealed bearings, so I'll use it to route both sides of the chain.  "Real" high racers are designed specifically to allow as straight and simple chain routing as possible for max efficiency.

     Tomorrow I make the boom and mount the BB with my 48/38/28 rings on 152mm cranks.  I'll adjust the seta fore/aft later once the boom is in place.  Pretty happy with the progress at 3½ hours spent so far.

Oct 21, 2005

     I put the boom on it tonight using pretty much the same method that I do on the trikes and using 1" x .064" box tube. It produces a pretty rigid setup with no bounce, no twisting and only about a 1/2" of yaw.  The boom appears to be nice and straight but I'll have to come up with a way to tell for sure - shouldn't be too hard to check it and then bend the frame slightly to align it if it's out.

     The 152mm chainring is on it and I have lots of clearance with the front wheel - maybe too much.  I'll see if I could have made the boom lower and shorter, but I also wanted to try to get my feet up near the height of my body so my body follows the dirty air from my spinning feet.  The weight, without the seat, is 19 pounds, and the steel chainring is about 3lbs of that :)

     I have 3 new lengths of Z-51 chain and I think the chainline will be nice and straight with ample room to clear the seat.  Tomorrow, time permitting, I'll make the seat, and then hook up the rear seat supports.  Then, run the chain and position the pulleys.  See what kind of handle bar I'll need, and then it's test ride time.  5 hours building time to date.

Apr 9, 2006

     Finally got back at the high racer after a lot of distractions.  Started with adding the seat rails, then mounting the bottom seat tabs.  I picked a rough seat angle of around 35 degrees.  Very comfortable to lay/sit on and should be really nice for aerodynamics, but we'll see what disadvantages there are on steep hill climbs.  The rear seat supports are 5/8" aluminum tubes.

     Next was running the chainline.  The power side of the chain runs under a Delrin pulley with ¼" sealed precion bearings and I tried to keep the chain as straight as possible while still missing the seat stays that I moved.  The return side of the chain was a little more problematic.  Starting at the front, I ran the non-power chain between the power side and the frame.  The two chains are close, but I use a chain tube to keep dirt off my leg so the plastic tube will also act as a separator as it runs over a grooved rollerblade wheel and down towards the bottom bracket.  The second roller blade is mounted on the lower front of the BB shell so the chain can run under the right hand chain stay to the rear derailleur.  Whiule I envisioned I might have to be a little creative with chain management due to using a diamond frame, it worked out quite nicely in the end.  There is no discernable drag on the chain due to the routing.

     Next up was the handlebars and steering.  I roughly used Mark Stonich's guidelines for the layout but I was limited somewhat by original bike's geometry.  I made the stem so it will pivot forward, and is adjustable for handle bar height, the same as many recumbent two wheelers use.  I have an old MTB handlebar on it but plan to make a U-shaped bar out of EMT, but it gives me something to test drive in the mean time.  The U-bracket at the base is a 1¼" x .125" box tube with one side cut off.  The riser is a piece of 1" x .049 SS tube.  If the riser tube is too thin and bends, I'm already mentally prepared to replace it with something more bullet-proof.  I drilled a ¼" hole through the top and bottom of the riser, welded a ¼" but to the bottom, and a ¼" bolt with a jam nut is used to set and hold the bar height.

     I have a rear brake and the rear derailleur mounted, but not hooked up yet.  My concern was to make sure the pedals cleared the front wheel, but they could have been brought down and to the rear about 4 inches.  I'll know better on the next one :)

     I took it for it's first test ride and I'm very happy with it.  It rolls very easily and wasn't difficult to control even with the reclined seat position.  No wobbles or drag on the chain line and the seat feels very comfortable.  The only problem is that with a style of seat that I build, it isn't really applicable to this style of bent because a narrow seat with your legs on the outside makes it easier to get your feet on the ground.  It's pretty high, but anyone 5'8" or taller should have no problem with it.  For the next bike I adapt to a high racer, I'll change the seat base-to-seat back angle to 45 degrees instead of 60, and that should make the seat base a little more comfortable than what this one is.  I plan to put a lot of miles on it and eventually experiment with some fairings.  That's getting ahead of myself though.  First, I want to finish it up, and then see how fast I can get it going because there's races coming up :)  19 hours worth of work so far on it.

11 Apr 2006

     Last night, after about half an hour, I made a handle bar that I liked out of EMT.  After I got it fitted, I realized that the OD was too big for any of the controls to fit on it. :(  Smooth move . . .  So, I made ANOTHER set of handle bars that I was even MORE happy with (mainly because this time I checked the pipe diameter FIRST) and got it mounted, and that was pretty much all I got done in an hour.

     Tonight, I fitted the shifters, grips and brake levers, ran the cabling and hooked up the brakes.  So now, when I do test drives, I can actually stop without wearing my shoes down to my socks.  A good thing.  Anyway, I ran the front derailleur cable down to the boom, but stopped there as I don't have the post or derailleur mounted yet - tomorrow hopefully.  As for the rear derailleur, even with the longest cable I have, it still wouldn't reach.  Looks like I need a tandem derailleur cable, and I'm zero for two in checking the local bike shops for one.  I have 3 more bike shops I can try before I start weeping bitterly.

     Due to the boom and chain locations, the assortment of brakes I have collected are just about useless in stock configuration.  The front brake was a custom job that I built out of modified parts from some U-brakes, center pulls and side pulls.  It works fine, but the cable sticks out too far for my liking and my calf hits it while pedalling.  Not that big of a deal, because it doesn't cause any handling problems, snags or inadvertent braking, but it bugs me.  I have a V-brake noodle I'll try on it and if that doesn't work, I have a mod for a side pull brake that I have.

     For the next high racer conversion, I will definitely keep in mind the derailleur cable length issue as well as the front brake design concerns.  I could easily go to disc on the front, but not sure if the fork legs would take it or not.  I'll pose the question in the frame builders list and see what the experts think.  21½ hours so far.

16 Apr 2006

     So, over the last couple days I ran the cabling, welded on some cable stops and guides, and put on some 130mm cranks I'd shortened.  After hooking up the front derailleur, I did some drastic cable housing shortening as the twist shifters seemed to do little more than compress the housing instead of actually shifting.  I left a small section of housing at the top of the handlebars, and a short section at the base of the stem to accommodate turning and folding the steering stem.  Even still, it's still not a set-up I'm happy with.  For the rear derailleur, I got a few tandem shifter cables and got the 6 speed cluster hooked up.  The rear shifter works pretty well, but maybe there's a little too sharp an angle up by the shifter grip because it's a little sluggish when shifting to the highest gear sometimes.  I took the twist shifters apart and greased everything up in them and that seems to have helped a little.  It works well enough for now but I can forsee going to bar cons like I used on my last trike.

     5 of us went on a 15km ride to test a couple re-assembled bikes so we took the high racer too.  First, the cranks seemed way too short to effectively get power to the road and they were quite difficult to accelerate with, and spin up hills.  I think the cranks might be a little too short and that combined with the reclined 35 degree seat made them pretty miserable to use.  Additionally, the handlebars started twisting in the handle bar stem, so that made it a bit of a pain to control and I didn't think to bring a couple wrenches with me either.  Viewed from the rear, I also realized the frame is a little twisted as the wheels don't follow in exactly the same track.  I'm not sure if the original bike was like this (as I never rode or checked it for that), or if it is a result of my frame mods to the seat stays.  I think it is likely the latter.

     After the ride, I switched the 130mm cranks out to 152mm ones and the bike responds much better.  You don't feel "jammed" when pedalling it, and you can get good power and good acceleration on it.  I adjusted the rear wheel slightly in the dropouts and took care of most of the alignment issues, but the bike didn't seem to handle badly before the adjustment, and nothing seems to have changed after the adjustment, so perhaps it was mainly cosmetic.  Lastly, I readjusted the stem tightening collar, re-tightened it, and I think it's got that fixed as well.  I took a couple km road test and everything seems good to go.  I'll use it to commute for a couple days next week and if all seems well, I'll send it in for powder coating.  Tomorrow, I plan to add a few tabs for fairing mounting and clean up a couple welds.  28 hours to date.

28 May 2006

     The high racer was powder coated Mercury Blue and ready and assembled for the first race of the season at Windel.  I only had about 50km on it by the time I took it to the velodrome so I wasn't as confident on it yet as I could have been, or needed to be.  In the top picture, I had the 48/38/28 chainrings with 152mm cranks on it because I felt the 42/34/24 chainrings wouldn't provide a high enough top speed to challenge the track record.  I also cut the handle bars back a bit because I found I preferred a higher hand position for the grips and actually spent most of the riding time with my hands up top, near the stem, in the "praying hamster" position if I didn't actually need to shift or brake.  The front of my shoulders got a little sore due likely to the fact that while holding my arms up I wasn't completely relaxed yet, but it eventually went away.  Lastly, I extended a 1" piece to the front of the seat tubes and curved them downward slightly.  This made the seat much nicer to sit in while both stopped and pedalling.

     The high racer handled well enough at the track but I wasn't quite used to hard cornering on the banked track at over 40kph, but I got more relaxed as the day progressed, unfortunately I started to get tired too.  The one problem that came to light was the lack of suspension.  It feels fine riding on roads, but on the track, when it was a little rough and going fast through the banked corners, a couple times, I was almost bounced out of the seat.  While I improved my PB, I think I need suspension if I'm going to challenge the record.  I'll keep riding hard, commuting and getting more used to the bent, and next time I go to Windel, I'll see if my time has improved.  The only thing that sort of sucks is the fact that it has an old 6 speed cluster on it.  I miss the tight gear ratios of some of the newer cassettes, but that just means I need to hone my riding style more, and to be more flexible in both my power production and cadence to maximize the performance with older gearing.  It's certainly not enough of a problem to consider replacing the rear or both wheels.  The rear triangle feels a little more "flexy" but I anticipated that when I decided to modify the seat stays.  It just means I pay more attention to developing a smooth pedalling technique, and the frame differences are minimized or eliminated.

     In the bottom picture, I installed some plastic fenders and an old bike rack I had so I can use the bent to commute back and forth to work.  I also switched out the original 48/38/28 152mm cranks for the modified 130mm 48/38/28 set that I originally tried, but didn't like.  After about 150km with the short cranks now, I'm slowly getting used to them.  They are definitely a little more work on hills than the 152's were, but using the 38 tooth chain ring and the 28 tooth rear cog is all you need for anything but the steepest of hills, and on anything else, they're fine.  I normally spin about 90 to 100 rpm, but with the 130mm cranks I am usually in the 120 rpm range.  I think the legs need to be a little stronger than with the longer cranks because you can definitely feel that your spinning produces the power, not pushing hard with your legs with lower RPMs.  I think they'll be fine with a little more time on them.  The other thing I like on the high racer is my average cruising speed, which is faster and more relaxed than what I could do with my Python.  On flat or slight up-hills, 30kph is just spinning the pedals - just making your legs go 'round.  At 35kph on the same roads, you are just starting to push the pedals but not enough effort to prevent you from comfortably talking to another rider.  At around 40kph, you're exerting some effort, but it's still something that can be maintained for extended periods.  If you really want to push, you're well up into the 40s and maybe low 50s.  With any kind of a tail wind, you can add almost 5kph.  Even with a stiff head wind, you can still be well into the 30s.

     I'm very happy with it for a first attempt and will definitely convert more DF frames into the high/med/low racer style.  It's fast, much easier because the complete frame already exists, and it's much cheaper than manufacturing a completely new frame.

8 Oct 2006

     After about 1600 km on the bent, with about 20 broken spokes in the rear wheel, I decided to try something a little different than the stock 27" AL wheels.  I tried tightening the spokes, loosening the spokes, switching to heavier gauge - all no change.  I think the fundamental problem is the weight distribution. Too much weight on the rear wheel and when I have my backpack on the rack too, that's another 20 to 30 pounds on the rear wheel, and apparently that and my 210 lbs is too much.  So, I have/had a bunch of 26" wheels hanging in the garage and decided to use them instead because they're theoretically stronger (for MTB use) and the rear wheel I picked takes an 8 speed cassette vs the old 6 speed freewheel AND it also has a 32 tooth for hills and an 11 tooth for . . . well . . . hills.  Anyway, a 32 - 11 is far better for my riding style than a 28 - 14 and already I've had it over 75 kph (and wasn't even spun out) while I had to spin like a demon to even hit 70 kph before.

     So some of the mods were to pull all the guide pulleys and pulley guards off, drill some holes in the guards for cosmetic/lightening, and then paint everything flat black.  I also added a strip of inner tube to the power side pulley to make the chain run quitely and it seems to be working fine until the rubber wears out, if it ever does.  I used a short piece of ½" square tobing to make another centre mount for the front and rear brake calipers and then temporarily painted the forks and chainstays flat black too.  After the Windel races on 15 Oct, I just might strip the frame and have it powder coated again.

     So far, the seat definitely feels lower (probably feels lower than it actually is) but its definitely easier to get on and off of.  I have some high pressure IRC Smoothies on it and the bike rolls very nicely and I have no fear of popping spokes anymore.  I also like the improved gear selection and faster top speed.  I'll take new measurements to compare to the old configuration.

1 Aug 2007

     After over 8800km on the highracer, I finally had my first breakage. With the changes I did to the bike frame and the resulting strength loss and weight distribution, I actually thought I would have had more problems than this. What happened is the seat broke at the bottom, right where it clamps to the seat rails on the top tube. I think I actually cracked it prior to this, back on the Spin the Lakes century ride at the end of May. I hit a bump rather hard at speed, and the bike didn't quite feel like normal any more, but I checked it over as thoroughly as possible and couldn't find anything askew. I thought I might have just bent the seat side tubes a little bit and left it at that. But, 2500km later, after climbing a hill, on a fairly unremarkable stretch of road, it finally popped. The seat back was on a weird angle and I initially thought I'd lost a bolt, or bent/cracked a seat stay or seat support. On closer inspection though, and with some seat wiggling, I spied the cracked tube. I did a little flexing and testing, and thankfully I was only about 5km from home, so I managed to ride it by perching mostly on the left side of the seat and casually spinning in easy gears. A little powder coat removal and a good healthy repair bead, and the seat was good to go again with a spray bomb touch-up in about 15 minutes. The seat feels much better too now, almost as good as before the Spin the Lakes Tour. Unfortunately, I don't know how much I'll be riding Ol' Blue anymore because once I get the tailbox made for the Raptor 74, that'll be my main ride from now on. As fast and smooth as Xine is, the Raptor is faster and smoother.