Shimano freewheel, max coasting RPM?

On Friday, July 18, 2014 11:00:55 AM UTC-7, JoeRiel wrote:
AMuzi writes:



John Doe wrote:

I just bought a Shimano SF-1200 freewheel. What is the maximum

coasting RPM for such a freewheel? If you don't know the

specification, can you give me a ballpark estimate?



Clive George clive xxxx-x.fsnet.co.uk wrote:

I can't see why there would be such a maximum specified. However 60mph

is about 700 rpm on a 700c wheel so they'll easily cope with that.

What speed are you thinking of?



On 7/18/2014 11:32 AM, John Doe wrote:

If you must know... I'm building a racing bike for a beloved and

unusually talented midget friend. The wheels are tiny but (in

spandex) he can pedal up to 2000 RPM.





Something's not right, either a typo, an error or a falsehood.



I do not believe there is _anything_ a human can do at 2000 rpm= 33

times per second given tour standard issue nervous system. Certainly

not move a crank that fast.



He's concerned about the rpm of the wheel, not the crank.

Presumably it's a small diameter wheel.



--

Joe Riel

Yes, but let say he has a 20" wheel, 2,000 RPM would yield about 120 mph. Assuming he has a 53/12, he would have to spin at about 650 RPMs, which I can do, but not for more than maybe half an hour. I think the subject of the post needs this: http://tinyurl.com/oadu73j The pictured rider is in wool, however, and the subject of the post may need a different front ring if he is wearing Spandex, particularly if it is purple.


-- Jay Beattie.

jbeattie writes:

On Friday, July 18, 2014 11:00:55 AM UTC-7, JoeRiel wrote:
AMuzi writes:



John Doe wrote:

I just bought a Shimano SF-1200 freewheel. What is the maximum

coasting RPM for such a freewheel? If you don't know the

specification, can you give me a ballpark estimate?



Clive George clive xxxx-x.fsnet.co.uk wrote:

I can't see why there would be such a maximum specified. However
60mph

is about 700 rpm on a 700c wheel so they'll easily cope with
that.

What speed are you thinking of?



On 7/18/2014 11:32 AM, John Doe wrote:

If you must know... I'm building a racing bike for a beloved and

unusually talented midget friend. The wheels are tiny but (in

spandex) he can pedal up to 2000 RPM.





Something's not right, either a typo, an error or a falsehood.



I do not believe there is _anything_ a human can do at 2000 rpm= 33

times per second given tour standard issue nervous
system. Certainly

not move a crank that fast.



He's concerned about the rpm of the wheel, not the crank.

Presumably it's a small diameter wheel.



--

Joe Riel

Yes, but let say he has a 20" wheel, 2,000 RPM would yield about 120
mph. Assuming he has a 53/12, he would have to spin at about 650 RPMs,
which I can do, but not for more than maybe half an hour. I think the
subject of the post needs this: http://tinyurl.com/oadu73j The
pictured rider is in wool, however, and the subject of the post may
need a different front ring if he is wearing Spandex, particularly if
it is purple.

Being a midget and all, there might be chafing issues with the size of
that chain ring---a kevlar skinsuit seems in order. A skateboard-sized
wheel may be more practical, though attaching the freewheel to it could
be challenging.

--
Joe Riel

'ahhhh a midjet ! off corso...

question: pedaling a transmission output shaft to 2000 is possible ?

No Shimano's work isnot good for high speeds. Bicycle engineering at cycle speeds and temps.

Bearing races, pressures, lubricants are no high speed systems. For 1912, outasight.

wait what abt 100 mph behind a railroad car ? I dunno ask him.

On Friday, July 18, 2014 5:59:58 PM UTC-4, wrote:
'ahhhh a midjet ! off corso...



question: pedaling a transmission output shaft to 2000 is possible ?



No Shimano's work isnot good for high speeds. Bicycle engineering at cycle speeds and temps.



Bearing races, pressures, lubricants are no high speed systems. For 1912, outasight.



wait what abt 100 mph behind a railroad car ? I dunno ask him.

LLLLLLLLLLLLLLLLLLLLL

no argument on that position ?

On Friday, July 18, 2014 10:28:25 AM UTC-4, John Doe wrote:
I just bought a Shimano SF-1200 freewheel. What is the maximum

coasting RPM for such a freewheel? If you don't know the

specification, can you give me a ballpark estimate?



Thanks.

-9 on the Troll Meter.

off-topic Google Groups spam/troll...

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Subject: Shimano freewheel, max coasting RPM?
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On Friday, July 18, 2014 10:28:25 AM UTC-4, John Doe wrote:
I just bought a Shimano SF-1200 freewheel. What is the maximum

coasting RPM for such a freewheel? If you don't know the

specification, can you give me a ballpark estimate?



Thanks.

-9 on the Troll Meter.