UK Karting - Notice Board (General Karting) : Re: Can someone weigh & measure their rim?

Notice Board (General Karting)

Re: Can someone weigh & measure their rim?
Posted by 'itpro' on 01 Jun 2009 @ 16:50

| View Message Thread | Reply to this message |

itproJoined: August 2001
Total Posts: 6
[ View User Profile ]

Tangler

You may know the maths but I don't.

However, I DO suspect it's complex. Why? Imagine two types of (logically daft) rims. 1 set has 99% of its material pressed within 1cm of the axle and a 'featherweight, filligree' beading area. The other is the reverse with 95% of the mass in the 'beading area' and almost NOTHING near the axle. They could BOTH have the identical weights (mass) BUT the energy needed to rotae the former would be less than the latter, even thoigh they have the IDENTICAL mass. The distance from the centre of the mass is important when calculating rotational energy and I can't see how we measure that, simply!

My point is that we'd need to know a HELL of a lot about the contruction of the rim to calculate it!

However, it's blatantly OBVIOUS that the 'tread' of the tyres is HEAVY and it is LONG way from the rotational centre and thus it needs MUCH more energy to rotate THAT bit than the 'wheel'.

That's testable at home. Simply mount a rim on a smooth running axle: spin them and 'feel' how much force is needed to spin/stop it and take the time needed to slow from a fixed rotation speed. Now fit a TYRE to that rim and check it again.

If you do the test, you'll find it's VERY hard to tell if a rim is even MOUNTED on the axle..... but you will EASILY feel the rim and tyre! That should tell us a lot!

Now try it with your ENORMOUS disk brake mounted! The difference between a mounted, vented cast-iron disk and a skinny Magura can be EASILY felt..... However, you simply CANNOT detect the differences between a Mag and an Ally mounted in that scenario.

The Rotational mass is NOT a significant issue, here! It's all MUCH to small when taking everything else into account!

All thopse who scream 'it's the thermal properties' of the metal don't seem to give a THOUGHT about the effect that, needing to make the Mag wheel THICKER measn that it may have a smaller air-volume under the tyre. They are SO certain that it's the thermal properties of the metal that thyey don't CONSIDER any other reason!

Ian

Message Thread:

Mag Wheels2 by 'PaulMRotax' (30 May 2009 @ 20:39)

Re: Mag Wheels2 by 'PaulMRotax' (30 May 2009 @ 20:42)

Re: Mag Wheels2 oh dear, again! by 'itpro' (31 May 2009 @ 23:16)

Re: Mag Wheels2 oh dear, again! by 'PaulMRotax' (01 Jun 2009 @ 7:22)

Re: Mag Wheels2 oh dear, again! by 'itpro' (01 Jun 2009 @ 11:08)

Re: Mag Wheels2 oh dear, again! by 'NJB' (01 Jun 2009 @ 14:22)

Re: Mag Wheels2 oh dear, again! by 'itpro' (01 Jun 2009 @ 14:31)

Re: Mag Wheels2 oh dear, again! by 'AndyJay' (01 Jun 2009 @ 15:42)

Re: Mag Wheels2 oh dear, again! by 'NJB' (01 Jun 2009 @ 16:54)

Re: NJB by 'AndyJay' (01 Jun 2009 @ 17:45)

andy by 'NJB' (01 Jun 2009 @ 18:53)

Re: andy by 'AndyJay' (01 Jun 2009 @ 20:47)

NJB.. "Mags allow the tyres to keep cooler".... by 'Chad' (01 Jun 2009 @ 23:42)

Re: NJB.. by 'NJB' (02 Jun 2009 @ 9:02)

Re: NJB.. by 'Chad' (02 Jun 2009 @ 9:14)

Re: NJB.. by 'AndyJay' (02 Jun 2009 @ 9:31)

Re: NJB.. by 'NJB' (02 Jun 2009 @ 9:35)

Re: NJB.. by 'AndyJay' (02 Jun 2009 @ 9:37)

andy by 'NJB' (02 Jun 2009 @ 9:47)

Re: andy by 'AndyJay' (02 Jun 2009 @ 10:31)

Re: NJB - AndyJay by 'John' (02 Jun 2009 @ 11:07)

Re: NJB - AndyJay by 'NJB' (02 Jun 2009 @ 11:20)

Re: NJB - AndyJay by 'itpro' (02 Jun 2009 @ 11:50)

Re: NJB - AndyJay by 'buzzinrussell' (05 Jun 2009 @ 22:33)

the driver by 'BanzaiBoy' (02 Jun 2009 @ 12:03)

Re: NJB - AndyJay by 'AndyJay' (02 Jun 2009 @ 11:27)

Re: Mag Wheels2 oh dear, again! by 'QuickOldTimer' (01 Jun 2009 @ 16:08)

Re: Mag Wheels2 by 'AndyJay' (30 May 2009 @ 21:30)

Re: Mag Wheels2 by 'PaulMRotax' (30 May 2009 @ 22:11)

Revolution Revelation ! by 'DavyBoy' (30 May 2009 @ 21:49)

Re: Revolution Revelation ! by 'PaulMRotax' (30 May 2009 @ 22:17)

Re: Revolution Revelation ! by 'DavyBoy' (30 May 2009 @ 22:28)

Re: Revolution Revelation ! by 'AndyJay' (30 May 2009 @ 22:59)

Re: Revolution Revelation ! by 'PaulMRotax' (31 May 2009 @ 17:26)

Re: Revolution Revelation ! by 'DavyBoy' (31 May 2009 @ 19:05)

Re: Revolution Revelation ! by 'itpro' (01 Jun 2009 @ 1:59)

Re: Revolution Revelation ! by 'PaulMRotax' (01 Jun 2009 @ 7:11)

Re: Revolution Revelation ! by 'itpro' (01 Jun 2009 @ 11:15)

Re: Revolution Revelation ! by 'Inter61' (01 Jun 2009 @ 13:56)

Re: Revolution Revelation ! Inter by 'itpro' (01 Jun 2009 @ 14:35)

Re: Revolution Revelation ! Inter by 'andrewf' (01 Jun 2009 @ 16:44)

Re: Revolution Revelation ! Inter by 'Inter61' (01 Jun 2009 @ 18:00)

Re: Revolution Revelation ! Inter by 'andrewf' (01 Jun 2009 @ 18:08)

Re: Revolution Revelation ! by 'PaulMRotax' (01 Jun 2009 @ 20:49)

What about other Mag components ? by 'DavyBoy' (01 Jun 2009 @ 20:58)

Re: What about other Mag components ? by 'AndyJay' (01 Jun 2009 @ 21:02)

Re: What about other Mag components ? by 'DavyBoy' (02 Jun 2009 @ 9:46)

Re: What about other Mag components ? by 'AndyJay' (02 Jun 2009 @ 10:43)

Re: What about other Mag components ? by 'DavyBoy' (02 Jun 2009 @ 11:06)

Re: What about other Mag components ? by 'AndyJay' (02 Jun 2009 @ 11:19)

So..... to sum up! by 'itpro' (02 Jun 2009 @ 11:21)

Re: So..... to sum up! by 'AndyJay' (02 Jun 2009 @ 11:34)

Re: So..... to sum up! by 'PaulMRotax' (02 Jun 2009 @ 18:51)

Re: So..... to sum up! by 'itpro' (03 Jun 2009 @ 12:28)

Re: So..... to sum up! by 'PaulMRotax' (06 Jun 2009 @ 11:18)

Alloys ..more "kitchen "science !.. by 'Chad' (31 May 2009 @ 5:07)

Re: Test Test Test by 'pccsystems' (31 May 2009 @ 16:22)

Re: Test Test Test by 'NJB' (31 May 2009 @ 18:59)

Re: Test Test Test by 'Chad' (01 Jun 2009 @ 1:01)

Re: Test Test Test by 'itpro' (01 Jun 2009 @ 14:48)

Can someone weigh & measure their rim? by 'TanglerTKM' (01 Jun 2009 @ 15:19)

Re: Can someone weigh & measure their rim? by 'itpro' << You are here!

Re: Can someone weigh & measure their rim? by 'TanglerTKM' (01 Jun 2009 @ 18:22)

The test has been done before .. by 'Chad' (01 Jun 2009 @ 23:58)

Chad by 'itpro' (31 May 2009 @ 23:20)

Re: Chad by 'AndyJay' (01 Jun 2009 @ 0:57)

Andy ..Tensile properties.. by 'Chad' (01 Jun 2009 @ 1:15)

Re: Andy ..Tensile properties.. by 'AndyJay' (01 Jun 2009 @ 10:07)

Re: Andy ..Tensile properties.. by 'Chad' (01 Jun 2009 @ 12:45)

Re: Andy ..Tensile properties.. by 'AndyJay' (01 Jun 2009 @ 15:33)

Re: Chad by 'PaulMRotax' (01 Jun 2009 @ 7:14)

Re: Chad by 'itpro' (01 Jun 2009 @ 13:54)

Post a Reply:

You may post a direct reply to this message which will appear in this thread.
To post a new or unrelated message use This Form. Top of Page
Notice Board Index

[ UK Karting Main Index ]


News	Karts & Karting	Notice Board	Market Place	Companies Directory	Tracks Directory	Events Calendar	Race Results	Photo Gallery	Links