Tuesday, December 20, 2005
There are several AWD bike design out there. Some use a scary combinaison of chains. Others use cables to propel the front wheel. I never saw a AWD bike design a clean a those from Christini bikes. The idea is tho use a shaft to transfert power to the front wheel. The shaft runs in the frame and the fork, with a clutch located in the headset. What is quite amazing is that this design allow the use of modern suspension design and parts, like you would find on any high-end bikes. This bike use proprietary hubs, headset and a custom-made White Bros. fork. It should be really tough, since a motorcycle version is made! The complete setup add 2.3 lbs and an XT/XTR full suspension bike is about 3700 USD. Not bad, when you see this marvel of engineering and machining. Idea: use the shaft drive to make a completly enclosed sealed maintenance-free drivetrain for real mountain bike use. Pictures: manufacturer website: http://www.christini.com/
Sunday, December 18, 2005
These days, there is a lot of hype toward single-speed bikes. They are just about everyware. It is a kind of conter-culture against the complexity of todays mountain bikes. I think that they are a good thing since you spend less time maintaining and more time riding. BUT, I'm I interested in purchasing a bike with such a limited usage? What if a want gears in about 5 years? The solution can be purchasing a normal frame and adding a chain tension adjuster. But this is a looser solution. What if a could change the drop-outs the suit my attitude toward gears? The Dean's drop-outs address this problem. They are fully interchangeable. And not to expensive at 50$ per set. Not so bad, since they are titanium. Another benefit is that they can be completly changed in the case of a crash, for the price it would have costed for a simple poorly shifting replacable derailleur hanger. If I would have to money to buy a Dean, sure that I would pay a premium for these drop-outs. And on all my bike. Why not converting a road racer to a track bike for the end of the season. Or having a single-speed at spring when it is so muddy that gears don't change anyway. That is very great design.
Saturday, December 17, 2005
The idea here is to have a perfect pedalling motion by storing energy in the most powerful part of the cycle to release it in the so-called dead spot. This is done by two steel coil springs. This may work, but it is sure that it is a more complicated and heavy unit. The price for these Austria made crank is not provided by the manufacturer.
Why are we obliged to shift with both hands? Having two derailleurs to choose from makes us doing chain-crosses and no-so efficient shifts. Why are drivetrains marketed with 27 gears when there is just about 14 usable ones? Synchro-shift was made to address this problems. You keep your regular derailleurs, both the shifter takes care of which gear selection is optimal. It has barrels that accuate both derailleurs as you turn the grip. No more big-big, small-small combinaison. The shifter shift the front and rear derailleurs in tandem to have a real ''sequential'' shifter. The chain can be shortened. This is good, BUT: if the rear D is reliable under tension, but the front isn't. In sketchy situations, I will avid to shift up-front because I'm not sure of the result. You can't choose that with the syncro-shift. Shifting up-front is a good thing if you what a big change, like just before a big climb preceded by a downhill. Altrough Syncro-shift have a racing team and an titanium racing unit, I rather keep these shifters for commuting or idealy for my girlfriend. She's the perfect consummer for synchro-shift: someone who don't know how to shift. Great design, but with limitations.
Thursday, December 15, 2005
Think about a moving bicycle part that you almost never hear about. Not the crankset, it is just two pieces of metal. What impress me is the durability of sealed bottom brackets. They cost about 30$ for up to 5 years. There are 100% maintenance free and they are one of the most solicited part one a bicycle. Quite amazing. When the were loose bearing with cones, they were crappy unit. After they went to a cartridge form, they are one of the most durable part on a bike. How are they that good? Maybe because they are not sexy, so they don't have to be to light or underbuilt. Don't know. What I'm sure of is that every component should be as well designed.
Monday, December 12, 2005
Components makers have started a good move these days. They are moving from the racing type a parts to a more board type a riding type. Shimano Hone group is a good exemple. It is made to be very tough, but not to heavy like it Saint counterpart. A group for everybody. It should displace LX, which could be marketed now as a group for racers on the budget. I'm glad to see that manufacurer make such a move. They have solved one of the greatest problem of mountain biking: solidity. But I urge them to look at another big issue: contamination. It is quite amazing to see that a bike a almost always covered by dust and mud and that most of its parts are not sealed. The whole drivetrain is completly exposed, which cause awesome wear and a lot of maintenance. My ratio is 4 h biking: 1h washing and fixing. This could be solved by good engineering. One exemple is Jagwire Raincoat. It seals the housing for about 10$ per bike and now cables and housing can last more than a season, which a a big leap forward. Why not sealing derailleur pivot and cage? Protecting the chain? It is possible.
It is quite incredible to see how many rear suspension design are there. It is even more surprising to see that telescopic forks are on about every bikes. Surprising too that so few design competes with it. It still amazes me to see that frame manufacturer competes heavily on rear suspension design and that they left the front end market to fork makers. The telescopic design as so many flaws. Brake dive, pogo-action, sloppy bushings (especialy on Manitou and Fox). Prone to desintegration (Rock Shox). There is the Cannondale Lefty, but it is about it. There were a few linkage forks (AMP, Girvin) but they are now out of the market. Both were prone to sloppy bearings and an heavy maintenance routine. The post is about the USE anti-dive fork. This design is said to resist brake-dive, which is a very annoying problem with telescopics. The pivot is located so the brake torque extend the suspension instead of compressing it, leaving more travel to absorb bumps. The design is quite impressive, with a massive linkage and a Lefty-like monoleg. The wheel is held by a special hub and axel combinaison. The price also is impressive: 1400$, which is about 200$ more than a top-of-the line Fox. The fork is air and coil sprung and air damped. I wish it had a platform damper and maybe a lock-out, but these things are maybe less needed than a on conventional style fork. It is great to see that people are still thinking out of the box about suspension forks. Some reviewers said that it rides like a 4 inches fork, since more travel if left after braking. Why not paying 200$ more if you were ready to buy a 500$ premium on a hyper-efficient frame?
manufacturer web-site: www.use1.com/
See http://www.justridingalong.com/biking/review_sub.php for a review.
Sunday, December 11, 2005
I'm not the only one interested by bicycle design. Check out http://bicycledesign.blogspot.com/
I always wanted to build a bike. Since my uncle is a composite engineer, we had the project to build a bike out off a pressure-treated cedar-carbone laminate. Then I went to college, so the project was postponed. This guy succeed in building a very clean looking bamboo bike. Composite are just a mix of two materials. Bamboo is not an exception since it is a mix of two natural structure that are the arteries and the veins of the tree: the xyleme and the phloeme (not sure it is written this way in English). Bamboo are around since the beginning of the 20th century, when they were lighter and stronger then their steel conterparts. Since this bamboo bike is around 4 pounds, I'm pretty sure that this number can be lowered by some optimisation and sanding. Anyway, the strengh of this design is its beautifulness, not the mention the shock-damping proprieties of the bamboo!
Picture from: http://www.bmeres.com/bambooframe.htm
This blog is all about design, right? So, why posting about a taiwanese bike? Because I'm currently in France for studying, so I would sale my soul for a performance bike that I could have brought from Canada and then travelled with. So come the Dahon Allegro. It's a full size road bike the folds in an airline friendly case. The idea is to avoid the pay for either the airlines fees and 500 $ plane-tough plastic box. The Allegro strenght is how clean is it's breakaway design. Just two special lugs, just 98 extra grams. It may sounds scary that the downtube is held to the rest of the frame by just a small collar, but it was designed by Tom Ritchey, so it inspires confidence. Ritchey's component have always been strong, functionnal and lightweight, without being overly complicated. So the Allegro should be. The frame is made from WCS steel tubing. Altough heavier than aluminium this frame is probably below the 3.5 pounds mark, the entire bike weighting just 18.3 lbs. The Allegro have an Ultegra 10 speeds drivetrain and ultra light American Classic wheels for just 2000 USD. So you have a fine steel bike for the less than you would have paid for a similary equiped bike. Pictures: dahon web site.