Bike porn

all these bikes with baskets, mudguards, fat wheels, massive clearences and moustache bars are really growing on me... this needs to stop now.

look at the adjustable crank length. 3Never seen that, what a bloody good idea.

New to cycling, are you? Stronglight and Look have both made adjustable length cranks in recent years, both using indexing inserts to give fixed intervals of 2.5 or 5mm. If you want continuous adjustability, Murray Tour de Force or Ruegamer Vf carbon cranks might be for you. Numerous patents have been granted almost since the origin of pedal-and-crank propulsion for variable length designs, which were particularly handy with the Ordinary (Highwheel, penny-farthing) since crank length was not just a matter of fashion but a determining factor in whether or not your pants yabbies™ rubbed on the tyre.

you sarcastic twat bag ! thanks though, but really, i have never seen it before.
Definitely a good idea.
I was just looking into it the other day, the actual proper length of crank according to your inseam length, and going by the 21.5% (i think off the top of my head) mine should be 19cm. exactly 2.5cm longer than i have now!
But anything that size is custom and £200 + which makes me sad.

mine should be 19cm.

What about pedal strike? they would be ridiculous...

What about pedal strike? they would be ridiculous...

yea that is the problem. But going by the equations that's roughly what it should be.
It's only an option if you custom your frame and specify a BB height to accommodate the length.
Mostly impractical for standard OTP frames.

but with a higher bottom bracket the bike becomes less stable...

I never heard of reccomended crank lengths before, do you mind me asking the benefit of following the equation/of a longer crank?

but with a higher bottom bracket the bike becomes less stable...

I never heard of reccomended crank lengths before, do you mind me asking the benefit of following the equation/of a longer crank?

better power transfer.

here is one link.
http://www.myra-simon.com/bike/cranks.html

there is another link i cannot find. It was all about bike dimensions and everything holistically if your a tall rider. It was bloody brilliant. I will find it

[URL="http://velonews.competitor.com/2010/06/technical-faq/technical-faq-with-lennard-zinn-why-tall-bikes-often-handle-poorly_121162"][/URL]edit-

here it is. Pure gold. Lennard Zinn is a ledge, just because he goes to great lengths to explain everything so eloquently.

http://velonews.competitor.com/2010/06/technical-faq/technical-faq-with-lennard-zinn-why-tall-bikes-often-handle-poorly_121162

cheers will have a read of this ^

look at those handlebars....

better power transfer.

Oh rly? It's a fine theory, but actual rigorous biomechanical testing has consistently shown that power output and metabolic efficiency are pretty much independent of crank length, with only riders of very small stature troubled by range-of-movement issues with cranks in the normal 170±5mm range. Archimedes knew 2200 years ago that a longer lever would allow him to exert more force at the working end, but since he would also have to move the handle of his lever faster, the only way to get more power out would be to put more power in. Sheldon "Gain Ratio" Brown set it out in tabular form a decade ago - if you keep foot speed and pedal force constant, longer cranks just mean lower cadence.

It's true that Leonard Zinn goes into eloquent detail about how people absolutely must have crank lengths outside the range covered by mainstream manufacturers, but has it occurred to you that his zeal may be in some manner influenced by the fact that he sells custom-length cranks? With the 125mm to 180mm range covered by mass market product, it is no surprise that it's a long-levers crank who goes out of his way to draw attention to his theories. Mike Burrows, who is at least Zinn's equal in the bike guru stakes, has no commercial axe to grind and would suggest that most people should be on shorter cranks than their current fitment.

Exactly, and Burrows did some tests to see how the shorter crank lengths worked in reality and they had some advantages due to lower leg movement, although higher RPM. The only issue he had was that they require a settling in period for the rider to get used to them so fine if you only use one bike, but not good if you use multiple bikes with a large variety of crank lengths on them.
Another area that can be put down to people thinking something is right (around 175mm) as that's what most bikes have!

I think everyone with an interest in bikes should read Burrows Bicycle Design book. It only briefly touches on many areas but it challenges assumptions and makes you think about all aspects of bikes rather than take everything as read.

http://velospace.org/node/16341

One of these doesn't belong.

What kind of motorcycle do you want around town?

Light weight and wide bars for manoeuvrability
Upright riding position for good vision and to keep the weight off your wrists as slow speeds.
About 40hp from a simple single cylinder motor, for lower weight and better fuel consumption than a multi-cylinder motor.
Only needs about 2 gallon tank, keeps weight and width down while providing all-day range for urban use.
Plenty of grip and good brakes from true road bike equipment, but with enough suspension travel to soak up our unmaintained roads.
Motocross plastic is crash proof, stops a trivial fender bender from turning into an insurance claim.

If you were designing the perfect city motorcycle, you might not end up with one of the current production super motos, but you might be quite close.

In fact, as bikesnobnyc keeps pointing out, for similar reasons we don't need no stinking Dutch bikes when a rigid MTB with Schwalbe SuperMoto Big Apple tyres will do the job better for half the price.

There was me thinking the Honda Cub was the perfect adaption for the city. Tried watching Super Moto once, it was like watching bike Polo. Awkward?

That's one sillly argument indeed, both MTBs and track bikes aren't ideal for riding around the city. However, an MTB is at least comfy whereas a track bike is just clumsy.
Track bike is just a road bike without gears and possibly with or without a bike, its fine for the street.

Get off your high horse autti cause if MTBs are the next big thing you'd be on the bandwagon in no time.
Bandwagon? I ride a single speed because its low maintenance to get to and from work/uni and rarely has a mechanical.
I've been mtb'ing well before i had a road or track bike, i just got this frame:

There was me thinking the Honda Cub was the perfect adaption for the city. Tried watching Super Moto once, it was like watching bike Polo. Awkward?

A C50 is a bicycle for people who don't fancy pedalling. An excellent device, but I'd feel better on a soft S-M like an XR250-Motard. SuperMoto racing is, as you correctly deduce, as mad as a box of frogs.

I think everyone with an interest in bikes should read Burrows Bicycle Design book.

I've got that and I fully agree.
Great how he deals with people who think that they know everything about bikes and can feen the smallest difference, e.g. in trail, stem length, number of spokes, etc...
Someone who is interested can have it for a while or I can scan a chapter.

quick release seatpost clamp (very stupid!)

please elaborate...?

please elaborate...?

Yes Ed, please elaborate. I would expect you to commend the public spiritedness of the owner in saving saddle-stealing scum the trouble of getting out their Allen keys.

Track bike is just a road bike without gears and possibly with or without a bike, its fine for the street.

Nope that's where you're wrong. A bit like saying that a cross country mtb bike is just a downhill bike without the suspension.

The angles are different - designed for a different type of riding

The angles are different - designed for a different type of riding

Yes, there's a world of difference, as you can see from the head tube and seat tube angles of the Look 585 (road) and 464 (track) respectively. 0°30' maximum variation between them, and we've only just been discussing how Mike Burrows shoots down in flames anybody who thinks they can feel such small differences.

There has been a divergence between road and track in the last 20 years, but not in geometry as much as build, with track frames staying heavy and getting stiffer and road frames keeping the old stiffness and getting lighter. In the olden days, the 531C tube set was the same between road and track, except for the fork blades. If anything, geometry has converged in the same period, with the old super steep 75° track frames disappearing, so that pretty much everything outside of extreme sizes now lies between 73° and 74° for both disciplines.

2 Attachments

Oh rly? It's a fine theory, but actual rigorous biomechanical testing has consistently shown that power output and metabolic efficiency are pretty much independent of crank length, with only riders of very small stature troubled by range-of-movement issues with cranks in the normal 170±5mm range. Archimedes knew 2200 years ago that a longer lever would allow him to exert more force at the working end, but since he would also have to move the handle of his lever faster, the only way to get more power out would be to put more power in. Sheldon "Gain Ratio" Brown set it out in tabular form a decade ago - if you keep foot speed and pedal force constant, longer cranks just mean lower cadence.

It's true that Leonard Zinn goes into eloquent detail about how people absolutely must have crank lengths outside the range covered by mainstream manufacturers, but has it occurred to you that his zeal may be in some manner influenced by the fact that he sells custom-length cranks? With the 125mm to 180mm range covered by mass market product, it is no surprise that it's a long-levers crank who goes out of his way to draw attention to his theories. Mike Burrows, who is at least Zinn's equal in the bike guru stakes, has no commercial axe to grind and would suggest that most people should be on shorter cranks than their current fitment.

I thought about what you said as i was reading the article by Zinn. Mike Burrows was also in mind about his tests about shorter cranks and that shorter is generally better.

In the context of a good bike fitting, not having much too much weight over the rear wheel as a result of longer cranks makes sense, especially on steep inclines, as Zinn said. For taller riders long cranks do make sense from that point, in terms of setting the rider in a better position on the bike to be able to deliver the power better.

In the sense of actual measured power it's probably not better, but when you consider the bike as system that has to fit you well so you can deliver the power, it is better. At least that's how i make sense of it.

Dear bike industry.

The most common (and often the shortest crank length availible), 170mm. Was arrived at for being ideal for the average european male. Which makes it too long for most of the worlds male population. This is a bit poo.

Yours,

short and seriously unamused cyclist

Sorted :)
....and they dont even look crap :S

Yes Ed, please elaborate. I would expect you to commend the public spiritedness of the owner in saving saddle-stealing scum the trouble of getting out their Allen keys.

Wouldn't the notion that the old lugged clamp aren't exactly design for removing the seatpost periodically?

Having been in Holland, Belgium, France and Italy over the last month, countries were bike use as a daily mode of transport is more of a norm, the one thing that really struck me is how the majority of us in the UK use completely inappropriate machinery for commuting around town.

You see thousands of people on old dutch/town hybrid style bikes with internal gears, none in Lycra, dressed up like a TDF or Downhill wannabe, cruising around on their way to work or the shops. Yet here we seem to be suckers for buying over specced machinery to do a mundane task.

The irony that struck me was that the machines they are using are exactly the type that the now defunct British Cycle Industry used to specialise in making.

I think it must be something in the British psyche, as whatever mode of transport we use, we always go for something totally useless for teh task at hand, the amount of people you see around London on superbikes when a highly manouverable125 scooter will shit on them for getting from a-b in London, and the same with cars in town.