Wednesday, February 28, 2007

Looks like a keeper.

Their words:

Folding Bikes | Places To Ride | Reviews | Sitemap

Cycling news & info with a special focus on notable bike tours, bike trails, bikeways, lanes and bicycle routes as well as innovative bicycling products like space saving & easy to transport folding bikes.

What do I think? I don't do polls, and I think this one will be a whole lot more useful

Bicycle Meditations

Most of it is harmless nonsense but some good stuff too.

I frequently say, riding a bicycle is for mental conditioning, the physical is just another benefit that comes along in the package of robust living.


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What one 110mm BCD installation looks like

I recently junked out a MTB with a Shimano Exage triple crankset (110 BCD) with a 74mm - 5 bolt circle granny. The middle and large chainrings were total junk so I pitched them--actually I turned them it wall decorations, the land fills are no place for art.

The 26 tooth granny was in good shape, it is a bit smaller than I would prefer, none-the-less it is an easy ride and provides a basis for comparison. Hard pedaling is not a something to be forced put up with when checking out a bicycle for comfort and actual use.

I took this pic to show what it looks like with the chain on the chainring aligned with the DT SA8 hub. It is mounted in the inside position for chainline allignment. The 110mm BCD bolt pattern holes can be seen behind the granny(middle & large chainrings removed, i.e. "art"). If you buy new you can keep the larger chainrings or trade them. [click the pic for greater detail]

When I get around to it, I will probably replace the 26 tooth with a 32 but right now I am going for a MTB snow ride. The DT will be waiting to accompany me when I travel off to parts unknown.

(Speed)* is Not the Answer
Ride a Bicycle

* War, Oil, well you fill in the blank

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Saturday, February 24, 2007


Downtube Folder/Cruz Bike Conversions

I see the buzz on DT Cruzbike conversions is showing up on the

Cruz Riders International Yahoo Group

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Friday, February 23, 2007


Another fun thing to do with a Downtube

From SesameCrunch

"Downtube folding bike with Cruzbike recumbent conversion. Add Rhode Gear child seat and Dad and Son have lots of fun!(nice pic)"

submitted by ballsofstone

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Downtube in a suitcase

When you travel respect the locals, we believe in

International Fair Trade in Tourism

and we encourage other to learn about it and do the same. pic to see full size detail!

I acquired an American Trunk&case 28"(x20x14)Upright that has some reinforced sides at a department luggage sale (<90USD). It is comparable to the 29" Samsonite hardside roller for space but it has 20" roller wheel spacing so that it dosn't fall over all the time, plus it has some exterior pockets and 1200 denier poly exterior w/ some padding so that it looks like a regular piece of luggage (could be used that way by anyone who would actually need that kind of space if not taking their folder along), but people can still see you're cheap.

A bit of disassembly is required but the Dowtube VIIIH w/ SA8 fits right in. The preliminary step-by-step and a couple pics are all I have at the moment. Please try this at home. After a couple of practice runs it can be done in less than 15 minutes with a minimum of tools

Putting the Downtube VIIIH SA8 in a suitcase (20x28x12):

1. release brakes so wheels can be removed
2. loosen bar ends enough so they rotate
3. loosen the front reflector
4. remove the pedals
5. remove the rear rack (be smart - replace screws with allen heads)
6. remove the kick stand (throw it away when your partner isn' looking)
7. remove the seat post (did I have to include this?)
8. fold the stem down and give the SA cable some slack by pushing back through stays (disassembly not required)
9. remove front wheel-remove the quick release
10. loosen rear wheel
11. take chain off sprockets
12. remove rear wheel and fold under frame,
13. release hinge, remove hinge bolt (simple to do)
14. fold front frame assembly back under the back half
(front fork should nest in rear triangle- the left side thru the seat and chain stays)
15. remove handle bars and loosen stem angle screw
16. fit the pieces in the suitcase (don’t forget the pieces you removed as shown in the pic)
17. note: the rack has to nest with the back wheel- crank position as shown
18. have a beer--it works.

Stay tuned for greater details, an guide to put inside the suitcase, maybe even a vid with audio.

Here is a link to some guidelines for checked baggage (this is a fluid deal so caveat-emptor. Check with the carrier and get a written statement just in case.

Basically this is it:

Checked Luggage
Most Airlines will accept a total of two pieces of checked luggage, subject to the same maximum weight limitation as stated for domestic travel, which is 50 pounds per piece and not more than 62 linear inches per piece.

Carry-On Luggage
Most Airlines will accept one carry-on item, with a maximum outside linear dimension of 45 inches. This piece must be of a size and shape to fit under the seat in front of the passenger, or in an enclosed overhead compartment. In addition to the one piece of carry-on luggage, customers may also carry a briefcase or a laptop computer or a purse. Luggage not meeting these specifications must be transported as checked baggage.

from WrencherWOACock

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Monday, February 19, 2007


BikeCentennial 76 -aka. Adventure Cycling

Visit their site - Great Maps - Great People

It is probably high time I added this organization to my links

yeah, I did it, all 4500miles. Now I am a life member.

Riding across the US on America's Bicentennial - what a life changing experience.

Someday there might even be pics.

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Thursday, February 15, 2007


Amazing Bike Tricks

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Monday, February 12, 2007


Just for the fun of it


Ray's MTB Indoor Park - click here and watch the video or better yet

I don't know if this is for people who ride folders, travel folk, or what, but it looks like great fun and what a passionate dream scape.

Friday, February 09, 2007


Online Street Theatre ... sort of

In the days of the online poll, the Daily News, the South Park, and gray hair, everyone is looking for an answer . . . the Feb 8 Rant was:

1. an electric koolaid acid test,

2. an allegory of a climate change discussion,

3. about psychology not physics,

4. found in the Uncyclopedia under WOAC,

5. some of the above, most of the above, parts of the below.

Click and listen to the music.

Thursday, February 08, 2007


Measuring a chainring for size

Click on picture to show full size.

Even abad pic tells a story, >75 but well short of 80mm. That is a baad snapshot

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RANT: When an ounce is not an ounce

I have been reading bike forums again. I know. I know. but the misunderstanding about reducing weight on a bicycle is astounding. Folks are weighing every part, as if speed was all that mattered.

It is rotating mass and frontal area that limits speed. Reducing either or both will increase speed if nothing else changes. In all cases.

Rotating mass (pounds if you don't remember mass from high school physics) is much more important than just pounds hanging on the frame. Otherwise small people would go faster and the rest of us would finally see that big is only worthwhile in stoopid sports like basketball, football, ad nauseam.
While that is true it is beside the point.

Without getting into the detail the reason is that rotating mass must be multiplied by the radius (half the diameter of a circle) around the center of the rotating mass. Consider the radius as a weighting factor (pun intended) that just plain old mass, like the fat on your ass, does not have, fortunately.

Simply put, if you want to go faster (believe me there will be another rant on this later), reduce the weight on the wheels, crank, and shoes. Oh for slim and svelte calves and dainty feet. Maybe you ought to try an aerodynamic profile first, but that addresses the frontal area. Most people don't know that racers don't use skinny tire just because of reduced rolling resistance (a minor issue) it is the frontal area and the rotating mass they are after.

If speed matters, look at the rotating parts. I see all kinds of blather about how small wheels are faster. Sure they are. They have a lower moment of momentum, i.e. the mass times the radius (mr). Which is larger 500gm X 20 or 400 X 26. You do the math and the result demonstrates the obvious. Just do a bit of looking and see how much a 400 gram tire costs these days.

In closing, if you want to reduce weight--forget the titanium seat post and go on a diet instead. Remember an ounce is not always equal to an ounce.

by WrencherWOAC

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Wednesday, February 07, 2007


VIIIH Chainrings: Turning the outside in

After giving a bit of theory in post 960, I will give you some actual applications. When I got the new VIII H SA8 out of the box, I noticed the bottom bracket was so tight it would hardly turn. I pulled off the cranks to adjust that and while I had them off I figured I might as well experiment a bit.

I dug around in my junk parts cache and found an old Shamano STX triple crankset from a mid 90s Kona MTB. The STX is kind of an odd ball deal that has the middle chainring and the granny gear attached to the small 5 bolt circle. [Most triples have the middle and big chainring on the larger bolt circle and the granny on a smaller bolt circle.] Since I was just chasing gear and chainline combos, I just turned the granny (24) and the middle (32) around and put it on (the granny is just a weird looking washer in this configuration. (I guess I could cover the teeth with reflective tape :-)

Next I shortened the chain and used a connector link (good hint, pine cone) to put it back together. It is sweet, but let’s just say you aren’t going to see this in LBS. I am not so sure I want to go with it either, but it promises to give the gear heads whiplash and it does ride like a dream. No, this is not trick photography.

It gives me, and you, an idea of the kind possibilities there are when you are looking for used parts. I would still recommend going with the 110 (preferred) or 130 BCD with the 74 (see post 960) granny for chainline position, gear tooth flexibility and wider availability, but who knows what you might have to do in a pinch?

The Sheldon Brown "Touring Triple Crank" section lists two Sugino Cranksets for less than a $100 twhich I'm guess would be about for the DownTube VIII. It also provides a benchmark when shopping for used parts.

I also disassembled the stock crank/chainwheel and in can be seen in the picture below.

Click on the pic to see full size.

According to Sheldon Brown, it is possible to get a 130 BCD 5 bolt 38 tooth chainring ($20)that would get closer to a reasonable gear but merely replacing the chainring would not solve the chainline issue,o'wtf,how about washers and longer bolts ???.

Like I said before, "Change the cranks. You will be glad you did." And don't forget the new sealed bottom bracket!

by WrencherWOAC

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Tuesday, February 06, 2007


Investigation of Downtube VIIIH -----------------------------SA8 Gearing

I purchased a DownTube VIII H with the 8 speed SA hub and front suspension. I have seen some discussion on the bike forums (DownTube) about the high gearing on the bicycles equipped with the SA8 hub. The SA8 is direct drive (1:1) in the lowest gear (1) all the rest, i.e. 2-8 are overdrive. The stock crankset has a 48 tooth chainring (lower quality 130mm BCD removable) so the gearing is way to high for all but the most aggressive hammer heads–who typically don’t ride folders.

The Sheldon Brown Internal Gear Calculator ( makes it a snap to compute the ratios. For illustration I use 20 inch nominal wheel size, gear units of inches, and the stock 23 rear tooth size. I used 30, 36, 48 for the chainring sizes.for insructive purposes.

This computes some numbers that are basically meaningless to most people. The good thing about the inch gear unit is that it makes comparison between bicycles of different wheel size. In other words, a 60 inch gear will require the same pedaling effort regardless of the wheel size of the bicycle. When you go to the LBS (local bike store) for a "test ride" to get the feel of what a 60inch gear is like, tell them you want to ride a bike with a 60 inch gear.

I find that an even more useful number is to divide the inch gear by 5 to get the speed in miles per hour (mph) for a normal rider (about 68rpm) ok, ok if you spin at a bit over 80rpm like you should, divide by 4. Mph is a much more common number for the American cyclist. If you are metric and think in kph like most of the world divide by 3 and 2.5 (gotcha).

Okay to put it to the test hit the compute button and

gear 30x23 36x23 48x23

8 79.6 95.5 127.3
7 62.1 74.5 99.3
6 54.8 65.7 87.7
5 48.5 58.2 77.6
4 42.8 51.3 68.5
3 37.8 45.4 60.5
2 33.4 40.1 53.4
1 26.1 31.3 41.7

This table was taken from the SB calculator. Thankx.

Well average rider, you do the math, how often do you ride 127/5 = 25 mph, hoe about 80/5=16 mph with a wind aided spinning 80/4 = 20 mph. Now how about climbing the local nut buster hill at 41.7/5 = 8 mph (for about 2 min or 1/4 mile for your average rider), now 26/5 = 5.2 is about all you can do on a steep hill. Put 25 pounds of baggage on that trip to your favorite hideaway and you will probably still have to walk the steep ones with the 30 or 36, but it will be a bunch better and a whole lot less often than with that 48.

You really have to look at the middle range gears 4 or 5 to investigate your average riding speed–most people can ride 12-13 mph in calm or low wind conditions without looking like they just came out of gym after trying to impress the coach on how tough they are (you know what I mean). That would be gear 3 with 48 tooth chainring ( stock) and gear 5 with the 36 tooth chainring. If you only ride downhill or with the wind stay with the stock, otherwise, change the crankset.

I see “pine cone” (p37- nice job) changed to a 39/53x tooth and that’s probably okay (a bit high in my opinion), but he didn’t say anything about chainline.

I have found that the SA sprocket requires the front chainring to be very close to the bottom bracket to get a straight chainline that looks and performs like it should, i.e. chainring and rear sprocket are in the same plane and the chain runs straight reduce friction and wear.

The LBS will know what I’m talking about and your will find it in the discussions on the Sheldon Brown single speed sections. Although the SA hub provides 8 “speeds” its chain configuration is like a one speed so the chain should be straight. It is not straight with the stock 48 tooth crankset ??? btw, the Sheldon Brown site is superb.

How do you get what you want and need?

Tell your LBS you need a standard road triple with 110mm or 130mm BCD and a granny BCD of 74mm. This is very common and believe me there lots of them around, new and used. The best part is you don't need the middle and large chainrings which are usually the ones that are worn out.

While you are at it tell them to replace the bottom bracket with a sealed unit (the best $40 you will ever spend).

The 74 mm granny bolt circle is the key. Its interior position provides the correct chainline and chainrings are available in any size from 24 to 36 tooth, check the 74mm BCD page from Harris ( to see what I mean.

Hey you will be glad you did if you really plan on riding this honey of a folding bike. Make the changes, get what you want and enjoy the ride. After the gears get a quality seat and start getting the pleasure you deserve. Look you will have a custom for $5-600 which is almost too good to be true.

Change the cranks. You will be glad you did.

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