john schmidt

Ok only one more email from me today.. (I probably reached my weekly

quota anyway?) But heh its Monday and it was looking boring?



First, I personally don't care too much if I ride with people with

flaps and fenders or not. It was just a tip to make it less daunting

and time consuming. (a front flap though really does help keep the

chain cleaner, I was amazed at the difference it made on my bike..)   I

would much-much rather have people come out and group ride, then not

because they are worried about not having flaps or fenders. (now I

would change my tune if we were riding on wet roads covered in cow

manure.)



Second, I want to clarify the use of Zip ties (I forgot the Zip and

was calling them plastic ties). If you are going to use them in

"critical" situation, probably use the higher quality zip ties. The

ones made in china are great for most uses and they are cheap, but

sometimes the ratchet isn't formed well enough and they slip.   The high

quality ones actually have load ratings and will not slip.   Also don't

skimp, use multiple ties just in case one has a defect and fails. Also

probably never use a plastic tie where only it is the load carrying

member. unless you are sure and it has really good safety factor or it

is non critical if it breaks..   For example on my ski rack, the

plastic ties just hold the ski rack down against an interface, the

interface carries most of the load / force.   use common sense.. and

then inspect occasionally too !!    



AND Finally Weight Issues. When I was talking less weight, I did NOT

mean to make the bicycle lighter, that is to let you climb faster...



What I meant was less weight down low like that on the fender, lessons

the chance of the fender breaking!!   First , less weight simply means

less force. And second, less weight means higher natural frequency and

thus less chance of resonance and vibration. Things that resonate, that

aren't designed to resonate, usually break. (e.g. galloping gertie).

Actually my front fender broke on Saturday. We got on this one chip

sealed road and the bumps on the road caused an excitation frequency

that must have nearly matched my fender's natural frequency, a mile down

the road, the fender broke. It was kind of cool watching the fender

flutter... wow just like a humming bird? yeah and I actually thought

it would last till home where I had already planned to add some

stiffness.. (natural freq = square root of stiffness over mass, so to

get higher frequency either decrease mass or increase stiffness or do

both)   



But look all this talk of fenders made the sun come out !





rick martin wrote:

 

Here's a good plan... shed 5lbs off yourself & use as many bolts,

rivets, ect. As you want!    too funny     -ricke-