andychrist

Greetings SpeedRacers.

I am currently building up a LWB and am trying to choose the best crankset. The frame is based on Easy Racers' Tour Easy, it is called a Mach 2 and I had it built for me by this guy who recycles vintage rides. I have available both a traditional, square tapered, 48-36-26T Sugino and 44-32-22T Shimano LX that uses the external Hollowtech II system. They are both quite spiffy looking and I am torn between the two.

Now there are some killer hills up here where I will be riding this puppy. So far, my vintage Fuji touring/commuter with the same crank rings as the Sugino gets me by pretty well save but on one super tough grade, a road that goes up to Olana (the local attraction). With just a small load in my trailer, this ascent has left me totally winded, it really takes all my might to make it to the summit. So the 22T granny gear on the Shimano kinda cries out to me.

While the controversy about how well/poorly bents climb has been addressed ad nauseam here and elsewhere, I am still curious about how they compare with road bikes in certain circumstances.

For instance, when I am on my road bike, going up a steep hill where the gradient varies, I find it impossible to stand and mash, both because I can't shift gears as needed, and because it's just too exhausting. So I sit and spin.

On a bent, I would imagine that one would still have an advantage while turning over the lowest gears, compared to doing the same while in a seated position on a roadster. In which case, I might be able to get away with the same gearing on the Mach as on my commutouring bike. Then I'd still have the 48T ring for a little bit more speed on the downhills (there are no flats here.)

The other thing I wonder about, is whether one can pull on the handles of a Tour Easy-like bent for extra oomph, like on some of the RANS bikes. Or is the steering too twitchy or the general design just not conducive to that kind of maneuver?

Thanks for any insight you could provide me, fellow riders!

iconoclast

I faced the same decisions about crankset selection for my EZ Sport.
I live in a hilly section of Oregon and I'm always going up hill or down hill.
What I did was determine the slowest speed I could peddle going uphill and the fastest speed I really needed going down hill.
For me it turned out to be 4 mph and 30 mph.
Then I used one of those online gear inch mph calculators to create tables for different gear ratios.
I even plotted out the results using Excel spreadsheet graphs.
I decided to go with a 44-32-22 crankset and a 11-34 cassette.
And it has worked out very well for me.
Most of the time I use the 32 chain ring with a full 11-34 cassette range.
And the 22 chain ring works great on steep hills.

LWB_guy

I also live in a hilly region. I'd go with the smaller chainrings, assuming they will fit your chain as well as the Sugino will. However, I should mention I am not familiar with the external Hollowtech II system.

Since you're building an LWB, I should mention that I built one in 2008 with a 26" rear wheel and a 24" front wheel. I walked it up the steepest hills. In the spring of 2009, I replaced the 24" front wheel with a 20" front wheel. Now I ride up the same steep hills I was walking up last year. However, while ascending the steepest parts, I still zig-zag back and forth to compensate for my not having a very low granny gear.

iconoclast,
would you please point me to one of those
"online gear inch mph calculators" ?
Are they designed for flat ground only, or do they take uphill/downhill/flat into consideration?

andychrist

Thanks guys. Yeah, I figured I go with the lower geared, Shimano system to start. Was afraid that 22T Granny might be overkill, but guess not now. At least the Hollowtech system is easy enough to remove should I ever HTFU. Would be more of a PITA to install and remove a traditional bottom bracket for the Sugino.

The Mach 2 I am building will have a 20" (406mm) wheel front, a 700c rear. But I don't understand how the front wheel size affects climbing. Does it have to do with the bike's angle to the ground, or the rider's position?

Also, can you pull on the handlebars on your bents to use your upper body a bit and increase power to your legs, or would that be a useless task?

iconoclast

I found that when I switched from 20" to 24" front wheel that it was easier to pedal up steep hills on my EZ Sport.
For me, with the 24" wheel, there is less twitchiness and more stability.
I guess it may depend on which bicycle you have and it's original geometry.
Obviously, LWB_guy has experienced the opposite result.

For LWB_guy
If you google gear inch calculator you will get lots of them.
The one I liked to use was at jbarrm.com
That's because it has an MPH page option.

andychrist

I see. So it's just a matter of how the bike handles, rather than mere efficiency.

Fortunately, the Mach 2 I am building was designed to work well with a 20" front wheel. Anyway it better had, because it won't fit any other size!

Will have to experiment with the handlebars to see how ergonomic I can get everything.

Giro

Also check that the rear derailleur can accommodate the difference in teeth (22 chain rings or 26 with the 22 tooth granny plus 23 if using an 11-34 cassette = 45 or 49 with the granny). If this is too much for the derailleur, you could decide to not use the extreme cross-chain combinations (or get a longer arm derailleur).

However, one nice thing about recumbents, particularly long wheel base recumbents, is they allow a large amount of cross-chain due to the long length of chain minimizing the angular differences at the chainring and cassette.

Edit: For example, the SRAM X.9 rear derailleur has a capacity of 37 teeth for the medium cage length and 45 for the long cage.

andychrist

Well the total tooth difference is the same for both crank sets, it is 22T, I have already purchased a front derailleur capable of handling that. The Megarange cassette has a difference of 23 so the total in either case would be 45 and yes, my SRAM 7 rear derailleur is rated 45T.

Anyway I never intentionally cross chain, it would kinda defeat the purpose of having a wide gear setup. But yeah, the long chain line of a LWB does even things out. Only trouble is the idler on the Mach 2, it doesn't float, so I am considering the purchase of an idler kit from TerraCycle. Problem is that the complete kits seem to be designed for mounting on factory installed tabs or braze-ons, will have to jerry-rig something using their clamp-ons and assorted parts.

JanMM

Better to have gearing too low than not low enough.

madhouse

+1

I went with an 11-26. I have a 20" rear wheel so I use a 54-42-32 up front. I used the full range of gears on the Tour De Kota last week. I didn't need the extreme on either end, but used them just to see. On the lightly rolling terrain I usually ride in I stay in the middle chain ring.

Last night I spec'd out a 44-32-22 11-26 with a 700c wheel... It should be perfect for my riding.

BlazingPedals

A 22/32 combination will get you an 18" gear. The big question is, what cadence will you be turning on a big grade, and how low a speed will you be able to maintain without falling over? At 60 rpm, an 18" gear will be traveling 3.2 mph. Personally, when I had a 17" low gear the only time I used it, I flipped the bike over backwards. That, at least, would be harder to do on a LWB. But a 21 inch low gear (26/32) might be a struggle on a 15+% grade, especially with a trailer. Making the granny ring smaller necessarily limits the size of your big ring, but this may not matter to you at all. Your call.

PaPa

Gardner Martin chose the 700c/20" combination for the Tour Easy, for valid reasons:

1. The larger 700c rear wheel permits easy gear inch selection by using off-the-shelf, readily available road bike parts.

2. Using a smaller front wheel provides four key elements;

a.) It positions the laden bike's center of mass further forward - (to better optimize weight distribution).
b.) It places the rider's shoulders closer to the steering axis. (to help minimize excessive 'tiller').
c.) The smaller front wheel reduces the rotating mass about the steering axis.
d.) The smaller front wheel also reduces the overall bike length.

Three of the design criteria listed above, vastly improves low speed balancing and maneuvering, without seriously compromising the bike's high speed attributes - This isn't blind speculation, it is fact.

tshelver

Not sure one of your questions answered, but IMHO I would not count on being able to exert any pulling force on the bars when climbing. My EZ Sport (similar configuratio) bars flex noticeably with even mild force.

andychrist

Thanks for all the thoughtful replies.

Well, after much back and forth I finally obtained a set of EZ-1 handlebars and corresponding stem from Easy Racers and just got the bike somewhat ready to ride. This is what I have learned thus far, in my first twenty miles or so:

The 44-32-22T crankset seems like way overkill. Haven't tried out the longest, steepest of hills yet but on my lowest gear combo the steering gets real twitchy, I am spinning out of control. And having sacrificed the largest, 48T ring of the Sugino, I can't reach the high speeds on the down hills that the aerodynamics of the bent would otherwise afford me. Fortunately the Hollowtech crankset is a breeze to install/remove, so if I can't eventually get accustomed to the current setup, I can swap it out with a 48-36-26T. Also perhaps I can pull the handlebars a bit farther back, which might reduce the twitch a tad. Of course this will also increase the tiller-- not a biggie, because of the steep rake on the head tube-- but it will also lower the grips, and there is not a heck of a lot of clearance between them and my knees as it is on tight turns.

The EZ-1 bars feel pretty strong and rigid, I can actually pull on them for some extra oomph, which actually allows me to climb in higher gear than on my uprights. (Though I haven't tried it out with a trailer or even rear rack and baskets yet; an additional 70 lb. load might take some of the spring out of my step, so to speak.) Surprisingly, the next day I did not experience any of the back soreness that had accompanied my ride on a Bike-E.

But while the mesh seat on the Mach 2 is comfortable, the ride is kinda harsh. Guess having such a high proportion of my weight over the rear wheel transfers shocks more directly to the seat than the long frame would seem to suggest. Shooting down gravel makes my field of vision shake so violently that I fear getting a detached retina. So I gotta figure out some way to soften it up, either with some kind of cushioning somewhere or maybe just by learning better how to adjust my posture.

Also the chain tends to fly off the return idler, which causes it to jam unexpectedly. TerraCycle say they should be able to come up with an idler with their SS chain keeper, much to my relief.

AFN

The Smokester

I have a hi racer which is a completely different style recumbent, BUT, my seat is over the rear wheel also. It is screwed to a plate with rubber washers between the seat and plate. The seat is a "Bacchetta Euromesh" (here https://www.bacchettashop.com/sess/ut...%3D281005%3D29) and is comprised of mesh stretched tightly across a frame with about 2" of foam on top. This serves to dampen road shock considerably.

Maybe you could adapt or copy something like it.

andychrist

Good idea Smokester. I was trying to figure out how to add springs, but maybe rubber washers would do the trick. Right now the seat is connected by plates that are secured with hose clamps; I tried wrapping the contiguous tubes with strips cut from old tires but that didn't seem to help. Guess the clamps hold the plates too tightly. But if I drill through the upper plate and the seat frame, then I can just bolt them together, with rubber washers or o-rings in between. A little foam on the seat might not hurt either. Thanks!

LWB_guy

It just dawned on me that the Hudson valley must be the location of the Hudson River, the estuary responsible for the oldest settlement in North America. I have never been there, except for a brief visit to Manhattan, in December 2003. I understand the Hudson river was cut away more by a glacier of the last ice age, giving New York City some of North America's deepest harbors. Did your tour include The Narrows?

andychrist

Thanks for your interest, LWB_guy. Well the Narrows is way down in NYC, while my flickr stream is of the Mid Hudson Valley. I live in Manhattan, but have a crappy little campground in Columbia County, about 120 miles North of here. Incidentally, I once did cross the Narrows by bicycle, taking the Verizano Bridge near the end of a Midnight Bike Ride. It was so foggy that morning we couldn't see anything from the bridge-- of course it cleared up the moment we reached the other side. D'oh!

Guess I should start another stream with pics from down here.

I'm on my way!

purplepeople

If the derailleurs could handle the range, I would have gone with 52/38/22. Spinning wildly in a low gear does not mean anything. Shift up. The whole point of low gear is to have it when needed. Downhill is where ADC's bike will really shine and that's why you'd want the 52... anything else will spin out.

For example, I've got a 20" FWD low racer and it's a got a 52/42 on it. The big ring is way too low and needs at least a 72-tooth.

:)ensen.

andychrist

Yeah purplepeople, it's pretty obvious to me now that I'll need a larger ring up front if I want to take full advantage of the Mach 2. But I can't find any rear derailleur that could handle such a wide differential, considering that my rear cluster is an 11-34. And as I mentioned earlier, I haven't yet attempted the steepest ascent yet, nor have I loaded on my trailer, so I still don't know whether I really need the lowest gear combo. Because the rear cluster is a seven-speed MegaRange, there is a pretty wide jump between the two lowest gears, which has thrown me a few times. Have a similar cluster on my oldest bike, but that has a 48-36-26T crankset so down shifting to the lowest gear combo does not have such a dramatic effect. Once I get the new idler with chain keeper, I'll be able to get some more practice with my shifting.

andychrist

Update:

Well it seems the EZ-1 handlebars and Kalloy adjustable stem are just a wee bit short for the Mach 2. In order to overcome the twitchiness of climbing in the lowest gear I had to pull the handlebars back a tad. This lowered the grips, so that my knees can hit my thumbs when turning if I am not careful.



But my shifting is getting better now that I have switched from Sun Race thumbies to SRAM twists. Practicing a bit riding on back roads that I don't normally go on, but still have not had the chance to climb up to Olana. Hope I can before the end of the season, the leaves are already falling.

purplepeople

You should see if ADC can replace the idler with a second derailleur cage or some other kind of tensioner. Together with the rear derailleur, that might give enough chain to go from 22x34 to 52x11.

:)ensen.

andychrist

The good people at TerraCycle said they could devise an idler for me, once I supplied them with the tube diameter. But with the terrain where I'll be riding this thing, I really don't need such a large front chainring after all. The Mach 2 coasts so fast down hill that there is no need for me to peddle (I am not racing this thing.) And on the flats-- Well, there are no flats. That said, if I can find a front derailleur capable of handling a 30T spread, I might be in the market for a new HollowTech crankset. Because I am just that crazy.