Carbent Raven ride report

We finally (!) had a nice day today (Saturday, June 5, 2010); it was beautiful. It's been mostly rainy most of the time for what seems like a long time now. I hadn't made up my mind what bike to ride today after lifting weights (my strength training routine is lackluster and unenthusiastic, but I try to get after it twice a week, in the interests of maintaining as much lean mass as possible as I wobble towards decreptitude), but I went downstairs to the bike room and found myself switching out the handlebars to the Carbent, which meant (I guess) that I was going to ride the thing :).

The Bacchetta bars that came on it were just on the edge of being too short. They were (just barely) fine on flats and downhills, but on climbs, for some reason, when I pushed back in the seat, they seemed to want to recede from my grasp. I'm having a hard time believing I'm capable of flexing the Carbent seat or frame such that the handlebar distance actually changes, but...whatever, that's what I was experiencing. I knew Dana, as a matter of course, swaps these handlebars out for ones that fit (I'm sure Bacchetta makes them in at least 3 sizes), but....who wants to wait for that, right? I happened to have a pair of these fine RANS HR 3-way hiracer handlebars (http://www.shoprans.com/proddetail.asp?prod=BPHB0079), so I went through all the necessary steps to install them. It was a bit of a pain, but in probably 45 minutes, I had handlebars that I could actually reach. They're actually a bit wider than I need, and the grips point down in a way that, while probably providing a more biomechanically neutral hand position, also tend to get in the way of my thighs a bit more on turns than straight bars (which I prefer). But bars that I'm not comfortably reaching are kind of a non-starter. In the process of swapping the bars, I had to snip off all the very nice neat ziptie cable fastenings that Saul (mechanic at SpeedyReedy, the LBS that did the final few steps of the build upon receiving the bike from Bent Up Cycles almost completely built) had very meticulously put on there. Saul likes this bike better than my other bikes :). It's more like an upright bike, more like the high-end roadbikes and TT bikes they sell at SpeedyReedy. He told me in test-riding it after assembly, that he found it more comfortable, and he thought it was the fastest of all my bikes. I think he's a little biased, but there's no doubt it's a fast bike; very comparable to my TiCa's. I won't know for sure until I repeat the hiracer/lowracer tests (like I did with the TiCa and Duncan Watson's Corsa) with as much rigor as possible, but my totally unreliable and subjective sense of it is that it's a tad faster than the TiCa with the ti mono disc fork (which gives up a little speed to be more practical) and is very close to the speed of my faster TiCa (the first one, which still has the M5 fork and light 18 spoke front wheel and so forth). Like I say, I won't know which one is faster without testing, and it wouldn't surprise me at all if they turn out to be so close that I can't reliably distinguish them (given all the variables and uncertainties that remain in my testing protocol; I've done my best, but....there ya go). My viewpoint is, if they're so close I can't tell the difference without refining my protocol, then for all intents and purposes, they're the same, as far as I care.

However, one thing is for sure, the Carbent feels slower than my lowracers. This is to be expected; being closer to the ground causes a subjective sense of greater speed that is a bit of an illusion. It's a bit hard to pull back on the Carbent, because I think I'm subjectively pushing to try to make it feel as fast as I'm used to, and it just doesn't ever get there. But when I look at the Garmin 705, it's a bit of a shock to see how fast I'm actually going. So....like I said, it's a fast bike.

When I took off on it this morning, I found it almost feeling like it was flexing back and forth with my pedaling. As I thought on it, I realized this was totally an illusion. The CB is a shorter wheelbase than the TiCa's, and there's very much a sense of the rear wheel being tucked underneath me, which I'm not sure I care for so much (compared with the M5's). The steering is really pretty quick, maybe even a little quicker than I prefer, although it is unquestionably stable and well-mannered. Disclaimer: I find the Lightning P-38 to be a bit quicker than I prefer, as a reference point, and in fact, most roadbikes are too quick for me. My old Colnago C40s (which I utterly adored) had a relatively slack 71.7 degree head angle, yet a normal 43mm rake fork, combined with a 130mm stem. This resulted in a bike with a lot of trail, for a roadbike, and a bit of wheel flop in front. I loved it; it was a very stable platform, and when I had a custom Calfee S&S coupler'ed Tetra Pro travel bike built, I had it spec'ed to the exact same geometry. Anyway, my point in all this is that I probably prefer a bit slower, more stable steering geometry than some folks do; what some folks call 'sporty', I'd probably call 'nervous'. However, the truth is, I get used to whatever the personality of any given bike is after awhile (as long as it's not pathological, and the Carbent's handling is most decidedly not that). Every time I've ridden the Carbent so far, by the time I've done ten miles or so, I'm utterly used to its steering manners, and I'm fine with it. As I say, it's a quality bike.

It's also a very stiff bike. This is both good and sometimes, something a little south of good. The 700c wheels definitely help out with smoothing out rougher road. There's a certain level of washboard-like quality in the road that it seems to tolerate quite well. I never ride on chipseal, in fact, I 'm a little fuzzy as to what chipseal actually is (given that nearly all my riding is in-city), but I have the sense that (for folks who do a lot of riding on county roads or whatever that employ this construction method) you get a bunch of closely spaced tiny little imperfections that result in higher rolling resistance and roadbuzz. I'm guessing the Raven's dual 700c wheels and carbon construction probably shrug this kind of thing off well. What it has a little more trouble with, are bigger imperfections, the kinds of road blemishes that are almost a pothole, but not quite (or are honest-to-goodness potholes). I'm finding myself needing to avoid things (in order to avoid feeling like I'm unnecessarily beating the bike up) that the TiCa's (with their rear wheel cantilevered out on flexy carbon stays much further rearward of the seat than the Carbent) would roll right over without much complaint. Actually, to be fair, the faster TiCa (with the skinny little M5 carbon fork and 18 spoke front wheel) kind of falls in the middle between the TiCa with the custom ti disc monofork and the Carbent. Right now I have a 28 spoke HED Jet aero wheel on the front of the TiCa with the custom monofork, and when I ride with a non-aero wheel, it's a 36 spoke Sun ICI-1 rim. Both front wheels are very strong, and the ti monofork, even thought it seems much stiffer than the M5 carbon fork, seems to just track straight and true without drama and, while I try to avoid road imperfections as much as possible, it just seems like (mostly) a non-event when I hit something unavoidable, and the compliant nature of the way the rear wheel is mounted means it can take some pretty big hits without a whimper. I find this less true on the TiCa with the M5 fork; I have managed to break spokes on both M5 wheels a couple of times, despite making every effort to steer around problems. The Carbent seems a little worse in this regard; I'm not worried about my 28 spoke Zipp 404 Clydesdale clinchers (well....I want to avoid denting the braking surface, but I'm not too worried about that), but....I just hate for the bike to take a beating. On the other hand, the fact is, this is the roll-wrapped, very stiff tube on this bike, and the thing is probably quite capable of taking these impacts; it just registers them to the ride more than the TiCa does. It's perfectly comfortable, but it certainly incents me to try to stay out of trouble even more.

However, the bike is less happy with the tree roots that the Burke-Gilman trail on the Seattle side seems to be rife with these days. I wasn't sure when I set out how far I was going to ride today; I usually just do a 20 mile loop on weekend days (my riding mileage is pretty light these days), but for some reason, on impulse I decided to loop Lake Washington (about 50 miles, maybe a little less). The bike certainly is fast enough and climbs well enough that 50 miles just isn't a big deal. (Site note: I'm sort of toying with the idea of doing the Flying Wheels summer century next weekend, just for grins; I haven't trained for it at all, but....50 miles was not a big deal today, I'm pretty sure I could have gone 75 as long as I stopped from time to time to eat. Flying Wheels is very hilly, but there's nothing saying I have to push very hard. I'm quite sure I could fit in with a group of riders who are going slowly enough that I wouldn't have to push very hard; as long as I stay a little bit sub-threshold, I think it'd be no problem). The loop around Lake Washington, taken counter-clockwise, means that for the last 15 or so miles I'm on the Burke-Gilman trail.

Man, the Carbent really doesn't like those tree roots! It really bounces around alarmingly on them. I guess I don't like them much either, they're not much fun on any of my bikes. I don't really like riding the BG trail much, but it just seems like over the years these tree roots have grown and grown (they probably have). The TiCa's handle them better, though, because the frame is so longitudinally compliant, I think. It's really astonishing to me how well the TiCa's (both of them) climb and sprint, given how flexy they are. They seem to be flexy when you need them to be, and stiff when you need them to be; I don't really get it. Part of it (I think) is the way the seat interface is really quite rigid, but the main frame tube and rear stays are free to flex as necessary to track the road properly. This is not what the Carbent is about at all. It is just plain stiff; like a high-end carbon roadbike. Of course, on a roadbike, you unweight the frame more, because your arms and legs are used as suspension. This isn't so possible on an extremely reclined, high BB recumbent, so...it's a tradeoff you have to accept. None of this is a criticism of the Carbent, you just have to accept the bike's personality. The Fujin SLII, which is a marvellous bike, is none too happy about that section of trail, either. I've actually had the chain de-idler (if that's a proper verb), i.e., come out of the chainkeeper and get jammed into the midship chain management hardware, in response to the extreme stuff on the trail, taken at speed. It's just a fact of life; that portion of the trail can be taken at a greater speed without incident on either the TiCa's or the EasyRacer's TiRush (which is a flexy titanium LWB, and is almost like having suspension) than on the Carbent or the Challenge Fujin. I think the main lesson here is to just stay off the trail as much as possible, and when I absolutely have to do it (like I want to loop the lake), just take it easy. There's lots of good reasons to just go slow through this stretch; save the bike, save me, avoid endangering people, etc. I normally try to take it easy here anyway, but....the syndrome I alluded to earlier (the way the Carbent feels slower than it really is) tends to get me pushing harder than I should.

Another issue that made itself very apparent today was the challenge of managing a highly reclined highracer at stops and starts. The Raven is as low a seat height as a dual 700c stick bike can possibly be. The seat is bonded right on top of the main tube; you just can't get it any lower than it is. And it really is low enough for me. When I'm leaned back into the seat, I can reach the ground on one side with a bit of tippy-toe going on. Obviously, this is to some degree self-inflicted; if I'd ordered the bike at 25 degrees, it would be less of an issue, and if I'd chosen the dual 650c SeaDragon as opposed to the 700c Raven, it would be utterly a non-issue. I actually sat on a guy's SeaDragon down at the Leschi Starbucks one day a few months ago; I could sit utterly flat-footed on it. But I wanted dual 700c wheels, for lots of good reasons, and I wanted the bike to be as reclined as possible, because I wanted it to be competitive, speed-wise, with my TiCa's (or better yet, be faster :)). My old 700/20 Carbent's, which were set to a 30 degree seat angle (because I hadn't worked out my neckrest issues in those days) were just slow enough that I didn't really like riding them, compared to the Velokraft VK2 I had in those days, or the faired-and-socked Calfee Stiletto. The 30 degree Carbent climbed very well, but it just didn't pay back when trying to lay the smack down on the flats.

This bike (the Raven) gives back what I put into it, in spades. A little wattage into the pedals, and it just hurtles down the road at breakneck speed quite satisfyingly (well, it's satisfying when I look at the cyclometer, anyway....it doesn't necessarily subjectively feel all that fast, but it really is). As I said, if it's any slower than my fastest TiCa, it ain't by much (and it well may be faster; more testing is called for).

So, I'm content with taking the bike on its own terms. I'm just in that phase where I'm figuring out what those terms actually are. The drama on big bumps is no surprise, the 700/20 guys were the same. It's my sense that the Raven actually tolerates more of this kind of stuff, up to a point, but at the point it doesn't, well....it's pretty clear when I messed up and needed to have avoided something. One consequence of being as reclined as it is (combined with my less than stellar eyesight) is that I'm having a bit of trouble seeing road decay. I've heard it said that you see the road better on a hiracer than on a lowracer. Boy, for me this statement is about as far from the truth as possible. There is absolutely no question that I'm better able to tell what's going on with the TiCa's, especially the one with the M5 fork, which has a lower BB than the one with the ti monofork. The TiRush is in some ways worse about this; I don't see the road close up to front wheel at all (due to the fairing and sock), but....it's a heckuva lot better equipped to take this kind of thing, given the lightly loaded front wheel, and the LWB flexiness.

Anyway, as I say, this is not a flaw of the Raven; it's just what the bike requires of the rider. I'm learning its ways. The issue of seat height is actually the biggest issue I'm having. During the 50 mile loop this morning, there were many, many points where I was stopped at stoplights, in traffic, crunched forward with my torso skyward so my right foot could hit the ground better; I'd watch until the other direction's light went yellow, then lean back into the seat and hold my position on my tippy-toe, then push off when it went green. I'm still trying to get the hang of getting clipped into that right pedal quickly; it's a lot easier on the TiRush, where my right foot is flat on the ground at stops, and of course on the lowracers I never clip out (one handed trackstand).

I'm also having a harder time with situational awareness on the bike, compared to the TiCa's or the TiRush; I have a hard time seeing behind me at 150 degrees when I'm stopped, because of the contortions I'm going through to reach the ground; when I'm in the lowracer trackstand position, I am free to twist around in all directions and see what's happening. I totally don't get how people think they see things better on a hiracer in traffic; nothing could be further from the case for me. And of course, the EasyRacer's bike is unmatched in this regard; I personally think there is no better design for urban riding.

I'm also finding myself not giving hand gestures and directions a much as normal, because I'm a little uncomfortable with the quick steering and being up that high. I actually had a guy on his roadbike crash into me on the trail from behind, because I stopped at a cross street for a car. We both ended up sprawled in the road, and he said, "don't you know they have a yield sign there?". Oops. But.....I dunno if I would have barreled through, even if I'd realized the motorist had a yield sign; that was exactly what happened in my big bike vs. car in April 2000 - the motorist waited until I was totally committed, then ran the yield sign. I think the real problem here was that I failed to give the hand-pointing-down signal that indicates folks in the rear need to slow down, because I'm still a little uncomfortable taking one hand off the Raven's handlebars. It's not like I don't signal, but....I probably don't do it as much. This will undoubtedly get better as I get more acclimated.

(N.B. I'm pretty convinced the bike suffered no damage here; the handlebars were a bit askew; I straightened them right up. The handlebars and my body took the brunt; I'm pretty sure the main tube and seatstays were untouched by the bike and ground. But of course, now I need to leave the bike with my LBS for a complete inspection, bummer. As I said, I'm pretty certain it's fine, but better safe than sorry.)

I am convinced that most of this is just unfamiliarity with the hiracer. It's just part of its nature. I know that a lot of people might say that the bike is not intended for city riding, it's for the open roads; of course....that means I shouldn't be riding it at all. But lots of folks seem to think the lowracer is unsafe in city riding, also....and I just totally disagree. I know Dana commutes on his Raven to work in Van Nuys basically daily, and he has no longer legs than I (I'm not sure whether Dana's bike is 23 or 25 degrees, but....there's really very little difference). Just as I got comfortable with the challenges of commuting on the lowracer, I'm convinced I'll get comfortable with the stop/start business on the Raven. I'm just not there yet.

It's true that I instantly connected with the TiCa, in a way I haven't yet with the Raven, but...it's also true that I had already gone through the whole experience of getting to a point with the Velokraft VK-2 where I was really comfortable. It sure wasn't that way in the beginning. Heck, I actually bought the VK-2 three times from Dana. I would buy it and try it, and sell it, convinced I couldn't get comfortable on it. It wasn't until the 2nd or 3rd bike that, at some point, the gestalt happened, and suddenly I was one with the bike. Even then, it took a lot of riding in city traffic until I finally figured out how to set it up such that I was always seen by the motorists, and such that I really understood, at a really cellular level, how to manage the bike instinctively in traffic. I have a whole host of 'lowracer-in-traffic' coping mechanisms now that are just totally automatic, and I don't have to think about them; I just do them. I most definitely haven't gotten there with the 22 degree hiracer.

Still, if do Flying Wheels next Saturday, maybe I'll do it on the Raven. It certainly would require as little effort to do it as any bike I have (and less than most), and it might make a dent in the required riding I need to do to get my hiracer skills up to snuff. On a century like this, of course, no one will be stopping at stoplights at all, for the most part. Despite my best efforts, and despite the fact that I normally never blow through stoplights, I won't have much choice in a group ride like this; when you're surrounded by bikes, the important thing is to conform as much possible so as not to take anybody down. In any case, while I'm personally more comfortable riding at close quarters with roadbikes on the Stiletto or TiRush, hiracers are renowned for being suitable for this kind of thing, and I have a bit of an itch to see how well this could turn out. We'll see; I may be too slammed with work to be doing this kind of thing.

How do you measure seat angle?

So this is kinda supplemental to the April 19th (http://bentdreams.blogspot.com/2010/04/given-same-seat-angle-hiracers-are-just.html) entry.

I recently received my CarBent HPV Raven dual 700c hiracer from BentUp Cycles. Beautiful bike, of course, very well executed. But I was surprised to find that, using the same method of measuring seat angle as I did in the earlier article, that it measures about 19 degrees (!). My bike is supposed to be approximately 23 degrees seat angle. So, I called Dana (owner of BentUp Cycles and CarBent HPV), and chatted about it.

It turns out Dana measures seat angle by putting a straightedge on the bottom of the seat, and measuring that angle, in order to factor out the ambiguity caused by the lumbar curve present in most of these 'potato-chip' style seats. I did the same on my CarBent, and indeed, it comes out at 22 degrees on my little iPhone app. I need to get a straightedge of my own to measure the TiCa, but the bottom line is that, using my somewhat less precise method on both the CarBent and the TiCa in question yields a 23 degree seat angle for the TiCa, and an 18-19 degree angle for the CarBent.

The TiCa in question came with a medium M5 seat. This is really a little small for me (I have a long torso), so I had replaced it (or rather, my LBS replaced it) with a large Velokraft seat I had lying about. The thing is, the original M5 seat has a V-shaped cutout at the front of the seat to accomodate the TiCa's main tube, and this allow the seat to be positioned further forward (where M5 intends it to be); when the Velokraft seat was installed, it got forced back a bit. It's not really a problem, I just shorten the boom, and all is well. But it has the effect of lessening the seat angle to 23 degrees, as measured on my iPhone. I speculate that using Dana's method, if it can be done accurately on the TiCa (I need to get a straightedge and see what if there is nothing obstructing measurement underneath the bike), we'd probably get 26 degrees, I reckon.

When using my method, it's really less sloppy than it sounds like. You get about a 2-3 degree variation when you push the iPhone to one extreme of the lumbar curve to the other. Putting the iPhone kinda in the middle and eyeballing it so there's the same amount of 'gap' (which is quite tiny) on one side or the other results in a number that's exactly between the two extremes. so....good enough for me. Or at least, it's my opinion that this is as close as is meaningful to measure, given that the seat shapes themselves differ somewhat, i.e. we're kind of down to the 'noise' level of measurement, I think.

I was kind of excited to pit the CarBent and TiCa against each other. However, it looks like the only way to get them to be more-or-less the same seat angle is to pop the M5 seat back on my TiCa. This I have done, and it now measures 18-19 degrees (using my iPhone top-of-seat method), just like the CarBent.

When we get a dry day, and I'm not too shot otherwise, I'll repeat the same tests, but with CarBent and TiCa. I expect to get somewhat faster speeds than the earlier test, given the lower seat angles, but we shall see. I'll do a general ride report on the CarBent Raven in another post (it's a super nice bike, of course).

Oh....Robert Chung (from BROL) has given me access to a build of his Golden Eagle software for measuring drag - a protocol using this potentially is (hopefully) more precise and (certainly) a lot less physical effort to implement than my method. However, since I seem to be struggling with the software a bit, and just for consistency with the earlier test, I'll probably duplicate my earlier protocol once more. At least that's my current plan. Hopefully, at some point, I'll get it together with the Golden Eagle software, and render these 225W runs unnecessary.

I will note that, among the many uncertainties my test was rife with, there was the issue of using a different PowerTap/rear wheel on each bike. We assume they read the same, but....it'd be nice to be able to remove that assumption. For that matter, it would'be been nice to have exactly the same seat on both bikes, measuring at exactly the same angle via whatever method is used. Unfortunately, I seem to be able to get closer to the same seat angle (between CarBent and TiCa) using the M5 seat on the TiCa, so....this is probably the closest I can get to minimizing this variable. I plan to explore getting my LBS to cut a notch in the Velokraft seat; if that works, perhaps I can revisit this. In any case, I'll have the benefit of being able to use exactly the same rear wheel and PowerTap on each bike, which would be nice.

When I did the Corsa vs. TiCa tests, perceived effort on the Corsa was greater for managing 225W. Possible explanations:

• It's all in my head.
• I'm more used to the TiCa, and more easily able to generate power.
• The EuroMesh seat/frame interface is not as stiff, and it takes more effort to get the same wattage delivered to the rear wheel.
• The 2 PowerTaps vary a little bit.
• Something else I've failed to conceive of.

In any case, using the same wheel on both bikes will eliminate one small uncertainty.

Oh, and lastly....there was at least one person on BROL asking about tire pressures. All tires in the previous test, front and rear, were pumped to exactly 120 psi. The Zipp clinchers spec a max of 125 psi, and the Stelvio on the front of the TiCa is a max 120 psi spec. I'm not sure if 120 psi on the 23 psi 650c front tire of the Corsa is "equal" to the 120 psi of the Stelvio 28/451 front tire on the TiCa, but....that's the assumption I was operating under, for good or ill.