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Re: Mag vs Ali rims ...itpro
Posted by 'SimonS' on 11 Feb 2009 @ 11:05


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SimonS
Joined: December 2004
Total Posts: 4
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It cannot be 'that simple' unfortunately.

You cannot separate the material from the design, because the design is often affected by the material.

Aluminium for example is weaker than steel for the same thickness but stronger than steel for the same weight.

However, a wide design is often inherently stronger than a 'narrow' design. A piece of wood 3 inches wide and 1/4 inch thich will flex a lot in one direction but little in the other.

The extra thickness of the mag wheel compared to the ali will also change the wheels design characteristics. You wouldn't build an ali wheel that way because it would become too heavy.

When modelling 'stiffness' in wheels, the effect is the same as being 'out of balance'. It causes an eccentric deviation from the centre of rotation of the axle. If you understand what this does in the way of handling (what one might call experience, comparing theoretical results with what one experiences on the track then one can make an educated guess as to what setup will work on a track and why. You can also predict what other changes may need to be done to the setup to compensate for the downside of those changes.

For example, if the track is hot and grippy, then a stiff setup may work because it:

Uses less energy in eccentricity
Recovers faster leaving corners
Causes less tyre stress

but:

It also creates less 'grip' at the rear because the tyre no longer conforms to the track so well.

This means that you need to be on the right side of the curve between 'advantage' and 'disadvantage' to be faster.

It may also mean that you have to adjust the front configuration to rebalance the kart.

Or you can just go out and test, and test and test until you find out a configuration that works without knowing why. Not everyone has that advantage of a race team that will share data and the sheer time needed to eliminate all the 'wrong' adjustments. (eg: We have discussed on this forum the way to calculate tire pressures. In F1 we know that they change pressure by as little as 0.01 of a bar and teh difference between a good performing tyre and a bad performing tyre is as little as 0.2 bar. If you tested your tyres at 0.01 increments the tyre wear would outweigh the advantages long before you found the 'right' pressure.)

Message Thread:

Mag vs Ali rims ...NJB  by 'Chad'   (10 Feb 2009 @ 3:53)
Re: Mag vs Ali rims ...NJB  by 'itpro'   (10 Feb 2009 @ 9:36)
Re: Mag vs Ali rims ...NJB  by 'NJB'   (10 Feb 2009 @ 10:58)
Re: Mag vs Ali rims ...  by 'John'   (10 Feb 2009 @ 12:07)
Re: NJB...i with you on this one  by 'Avago'   (10 Feb 2009 @ 14:26)
Re: NJB...i with you on this one  by 'itpro'   (10 Feb 2009 @ 17:06)
Re: NJB...i with you on this one  by 'BD'   (10 Feb 2009 @ 20:52)
Re: NJB...i with you on this one  by 'NJB'   (10 Feb 2009 @ 21:58)
Re: NJB...  by 'itpro'   (10 Feb 2009 @ 23:08)
Re: NJB...  by 'NJB'   (11 Feb 2009 @ 9:07)
Also  by 'NJB'   (11 Feb 2009 @ 10:28)
Re: Also - NJB  by 'John'   (11 Feb 2009 @ 11:33)
Free Test Day  by 'NJB'   (11 Feb 2009 @ 15:33)
Re: Free Test Day  by 'John'   (11 Feb 2009 @ 16:01)
Re: Free Test Day  by 'itpro'   (11 Feb 2009 @ 18:24)
Re: Free Test Day....now over subscribed  by 'NJB'   (12 Feb 2009 @ 9:52)
John  by 'NJB'   (11 Feb 2009 @ 15:48)
Re: Also  by 'itpro'   (11 Feb 2009 @ 11:37)
Why dont F1 teams use different wheels ?  by 'Chad'   (11 Feb 2009 @ 13:05)
Re: Why dont F1 teams use different wheels ?  by 'itpro'   (11 Feb 2009 @ 13:27)
Re: Also  by 'NJB'   (11 Feb 2009 @ 15:25)
Re: Also  by 'itpro'   (11 Feb 2009 @ 18:37)
Re: Also  by 'NJB'   (11 Feb 2009 @ 19:06)
Re: Mag vs Ali rims ...NJB  by 'KenE'   (10 Feb 2009 @ 10:02)
" Mags will generally reduce grip relative to Alu  by 'Chad'   (10 Feb 2009 @ 23:05)
Re: Mag vs Ali rims ...NJB  by 'itpro'   (10 Feb 2009 @ 23:21)
Re: Mag vs Ali rims ...itpro  by 'NJB'   (11 Feb 2009 @ 10:25)
Re: Mag vs Ali rims ...itpro  by 'SimonS'  << You are here!
A perfect example of using 'theory', there!  by 'itpro'   (11 Feb 2009 @ 11:28)
Re: Mag vs Ali rims ...itpro  by 'davidmc'   (11 Feb 2009 @ 11:45)
Re: Mag vs Ali rims ...itpro  by 'itpro'   (11 Feb 2009 @ 11:24)
Re: Mag vs Ali rims ...itpro  by 'chriskasch'   (11 Feb 2009 @ 12:34)
Re: Mag vs Ali rims ...itpro  by 'davidmc'   (11 Feb 2009 @ 13:05)
Re: Mag vs Ali rims ...itpro  by 'chriskasch'   (11 Feb 2009 @ 13:11)
Re: Mag vs Ali rims ...itpro  by 'KenE'   (12 Feb 2009 @ 19:59)
Re: Mag vs Ali rims ...itpro  by 'DavyBoy'   (15 Feb 2009 @ 10:01)
Davy....  by 'itpro'   (15 Feb 2009 @ 12:54)
Re: Davy....  by 'DavyBoy'   (15 Feb 2009 @ 14:21)

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