S
Spacey Spade
Guest
Moved over from rec.bicycles.soc:
>>>Dear Sheldon Brown,
>>>
>>>Thank you so much for your web pages devoted to cycling.
>>>
>>>I would very much like to see a torsional test on bicycle frames where the frame is held by the
>>>wheel axles, and the deflection measurements are at the bottom bracket due to loads on the bottom
>>>bracket. [paragraph cut, continued below]
>>
>>Then you would like to see Bicycling magazine's frame test jig, AKA "the tarantula". Back in the
>>1980's, when Gary Klein and then Canondale were becoming popular, Bicycling published BB
>>deflection for all bikes and frames they tested. Now they assume the readers are illiterate, so
>>bike tests have lots of pictures, few words, and fewer numbers. You might get more info on
>>rec.bicycles.tech, this topic seems to be more suited for that group. Mitch.
>
>Unfortunately Bicycling Magazine no longer tests bicycles. Now days they only publish puff pieces
>or thinly veiled press releases. They don't want to pissoff their advertisers with any level of
>criticism. Ken
>
>>>This would be a simple simulation for in-saddle hammering (when arms are not used). Is there some
>>>test results published already?
>>>
>>>For the test you could use a 1" steel bar in the steerer as in a previous test of yours, making
>>>sure to afix the bar on the axis where the front axle would be (and not allowing it to rotate
>>>there, but allowing rotation in the steerer tube... either that or use the same forks on all
>>>frames hehe!). You could even put weights on the saddle and on the handlebars to make it even
>>>more lifelike.
>>>
>>>Having owned a Schwinn Premis, now a Cannondale, I really appreciate the torsional stiffness from
>>>the Cannondale. On the Schwinn I used to look down and see the bottom bracket swinging from side
>>>to side under load (and the chainring would rub the front derailleur to the same tune if I didn't
>>>have it adjusted right). Spacey
Would anyone with access to bikes be interested in doing some non-destructive tests?
Regards,
Spacey
>>>Dear Sheldon Brown,
>>>
>>>Thank you so much for your web pages devoted to cycling.
>>>
>>>I would very much like to see a torsional test on bicycle frames where the frame is held by the
>>>wheel axles, and the deflection measurements are at the bottom bracket due to loads on the bottom
>>>bracket. [paragraph cut, continued below]
>>
>>Then you would like to see Bicycling magazine's frame test jig, AKA "the tarantula". Back in the
>>1980's, when Gary Klein and then Canondale were becoming popular, Bicycling published BB
>>deflection for all bikes and frames they tested. Now they assume the readers are illiterate, so
>>bike tests have lots of pictures, few words, and fewer numbers. You might get more info on
>>rec.bicycles.tech, this topic seems to be more suited for that group. Mitch.
>
>Unfortunately Bicycling Magazine no longer tests bicycles. Now days they only publish puff pieces
>or thinly veiled press releases. They don't want to pissoff their advertisers with any level of
>criticism. Ken
>
>>>This would be a simple simulation for in-saddle hammering (when arms are not used). Is there some
>>>test results published already?
>>>
>>>For the test you could use a 1" steel bar in the steerer as in a previous test of yours, making
>>>sure to afix the bar on the axis where the front axle would be (and not allowing it to rotate
>>>there, but allowing rotation in the steerer tube... either that or use the same forks on all
>>>frames hehe!). You could even put weights on the saddle and on the handlebars to make it even
>>>more lifelike.
>>>
>>>Having owned a Schwinn Premis, now a Cannondale, I really appreciate the torsional stiffness from
>>>the Cannondale. On the Schwinn I used to look down and see the bottom bracket swinging from side
>>>to side under load (and the chainring would rub the front derailleur to the same tune if I didn't
>>>have it adjusted right). Spacey
Would anyone with access to bikes be interested in doing some non-destructive tests?
Regards,
Spacey