The guy who used to own the Strawbury Duck at Entwistle sunk a load of cash into the production of a plastic handle which attached to the bottom of the seat tube to make it easier for the bike to be carried over gates / fences. 
Bike Forum
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Useless cr@p bike part inovations!
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Posted 2 years ago #
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I had a flexstem for ages, plus several layers of drop bar tape on Brahma bars. Was ok for something like SDW, when you're just riding along and it is difficult to get your weight completely off the bars. As soon as you start riding on your feet and not your hands (downhill) it gets a bit pointless.
What is currently considered cool and will be laughed at five/ten years hence? Remote control droppy seatpost? Remote fork lockout? Super-slack head angles? Six inch travel for normal bike? Or will they all still be with us?
Posted 2 years ago # -
those cranks work, science says so:
fibonacci seems to work for nature and that's been working on it a lot longer than we have
Approximate and true golden spirals. The green spiral is made from quarter-circles tangent to the interior of each square, while the red spiral is a Golden Spiral, a special type of logarithmic spiral. Overlapping portions appear yellow. The length of the side of a larger square to the next smaller square is in the golden ratio.
Posted 2 years ago # -
MRMW - for a luddite like me, can you please explain (in the manner one would to a 5 year old) how a force from top dead centre through the BB axle centre can give rise to a resultant rotational force with funky cranks?
Posted 2 years ago # -
i want a 36er, they are indeed "hawt"
Posted 2 years ago # -
i have absolutely no idea. but there's a formula for you:
Posted 2 years ago # -
science says so
What utter mumbo-jumbo
Until the Vatican approve them I don't see how "science" knows better, do you?!
Posted 2 years ago # -
i suspect although it's difficult to tell from the pics that the rings are not centred on the axis of the axle.
Posted 2 years ago # -
The cranks on handles to wind-up wells are shaped like that - I guess they lose less to bending.
Posted 2 years ago # -
actually forget that, it clearly is centred
Posted 2 years ago # -
As far as I can tell, what those test results are showing you is that the crank flexes. Because of the shape of the curve, it will turn the chainrings slightly due to flex when pushed straight down.
Strange how the graph only shows results for 0 to 60 degrees. I wonder what happens around the rest of the rotation - for instance at 180 degrees?
Posted 2 years ago # -
at 180 degrees theres no force is there?
Posted 2 years ago # -
i guess that depends very much on how smooth a pedaller you are. there will be a point where there is no force but it is only momentary. at this point the other crank will be (hopefully) applying more force due to the flex characteristics.
i might order some now
Posted 2 years ago # -
at 180 degrees theres no force is there?
There is if there's a force at zero degrees
Posted 2 years ago # -
29ers......singlespeeds we don't live in the dark ages.....flatties great is you want to fall over in the mud,lose 50% effiecientcy,and look like a american skater boy....coil shocks.heavy and crap...tubes....why not tubeless?....baggies...just plain silly.
rant over calm........
Posted 2 years ago # -
flatties great is you want to fall over in the mud,lose 50% effiecientcy
good rant
Posted 2 years ago # -
Posted 2 years ago # -
Why would flatties make you fall over in the mud?
Posted 2 years ago # -
bikerbruce reads MBR...
Posted 2 years ago # -
flat pedals lose about 15%-20% efficiency depending on the rider/shoe/pedal combination.
Given that the average ride isn't done at 100%, the disparity between fittesdt and least fit on a ride is probably massively more, tire choice probably makes a bigger difference, and im not racing its hardly a big deal?
And anyone who thinks they pedal perfect circles is sadly deluded, if you're sat in the saddle your still putting weight on your back foot. So the not "pulling up" only actualy loses you about 5%, the rest is through squidgey soles and crank/pedal flex.
Posted 2 years ago # -
The not pulling up loses you nothing at all, since at best you only unweight the back foot slightly. What loses you more is having to recruit extra muscles to keep your foot in place.
Posted 2 years ago # -
flat pedals lose about 15%-20% efficiency depending on the rider/shoe/pedal combination.
evidence, or just hand waving?
Posted 2 years ago # -
look you get the gist of what i'm saying......if you have carbon soled shoes with uberstiff soles then all is good.
thisisnotaspoon ...dont get me started on tyres ;).
flatties rely on a flat sole to grip the pedal...so confuisus shoes with no grip maketh a man fall over in mud.
BrucePosted 2 years ago # -
I love internet 'truth'
Posted 2 years ago # -
flatties rely on a flat sole to grip the pedal...so confuisus shoes with no grip maketh a man fall over in mud.
they also have pins - cant say i've ever had a real problem.
flatties are superb in the mud - much better than SPD's when its really claggy
Posted 2 years ago # -
The not pulling up loses you nothing at all, since at best you only unweight the back foot slightly
Curious, not sure how I manage to pull my shoe out of the cleat on steep bits by slightly unweighting my foot!
Posted 2 years ago # -
It's hilarious that people genuinely believe that pulling up "saves" energy and the belief that pulling up doesn;t in itself use energy. Having flatties and NOT pulling up saves more energy ffs..
Posted 2 years ago # -
Curious, not sure how I manage to pull my shoe out of the cleat on steep bits by slightly unweighting my foot!
Because you're not pedalling efficiently.Posted 2 years ago # -
Enfit - the pulling up uses different muscles. Not that it does not use energy but you are using more of the total muscle mass to provide thrust. Hence greater efficiency.
Only a minor effect tho for sure
Posted 2 years ago # -
Not pulling up does not save energy, because your trailing leg weighs quite a lot, and if you fail to lift it your front leg has to do that.
Posted 2 years ago # -
Because you're not pedalling efficiently.
What has efficiency got to do with it? How is it possible to pull your foot out of the pedal cleats if you are not pulling up on the pedals?
Posted 2 years ago # -
What has efficiency got to do with it?
Everything, since we're discussing how much less efficient flats are
Posted 2 years ago # -
Just resurecting it for an argument on a friday.
My masters dissertation was on putting sensors in sports gear so I read arround this stuff.
In summary-
Pedaling 'perfect circles' is more about keeping the tension in the chain as constant as possible, than actualy pulling up as hard as you push down.Just try it, attach a 25kg weight to your foot (a 25kg sack of spuds maybe?) and try and lift that leg up as if your were pedaling.
A sprinter can put down arround 8x that force (arround 200kg per leg)!
If you could pedal a perfect circle you would detatch your lower leg from your upper leg with the strain on the ligaments.
SPD's are more efficient, but only 20% ish, 10-15% of that is down to shoe design, if you put 5.10 rubber on a set of SPD shoes you get back most of that loss. the remaining 5% is in lifting the dead weight of your foot, shoe and leg. But in most situations SPD riders are doing just the same and not pulling up.
Anyone on a tandem? If you try and ride with the pedals in phase and the second person is significanlty weaker than the other, they feel like the pedals are falling away from them, this is what your back leg experiences when you try and pedal perfect cicrcles, at best it barely adds anything to the torque, normaly it just lifts a fraction if its own weight.
Posted 2 years ago # -
n.b. those figures were based on running shoes which are soft and squidgy.
A stiff BMX shoe will be much closer to the hypothetical 5.10/cycling shoe combo.
Posted 2 years ago # -
since you resurected it and i'm in a taiwan hotel at the mo, the daftest thing i've seen this week are those stepper bikes. again. every f-in trade show you get people 'cruising' the aisles (ie as popular as riding your bike on a busy pavement at rush hour!) on bikes that use up-down motion steppers with a sprung ratchet chain to crank the wheel
kind of fun in a way but someone's really trying to sell them, still. someone must have deep pockes to promote them cos show space isn't cheap and i've seen them at shows since year dot, but i've never seen one being used outside a show hall.
optimism can be both wonderful and a bit sad ) anyone ever seen one that may have been bought for real £??
Posted 2 years ago #
Topic Closed
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