Vixen wheel weight ?

[Moto]

Anyone know the weight of the standard Vixen alloy 'fin' wheel. I could weigh mine but it would mean removing and refitting the tyre.

Thx

Moto

[phillpot]

Weigh a tyre and subtract from total weight?

I could weigh a T slot, would it be vastly different, how accurate do you need it?

[Moto]

phillpot said:

Weigh a tyre and subtract from total weight?

Same issue. To weigh the tyre I'd have to take it off the rim.

I was hoping some one may have a rim lying around that they could weigh to save me having to split & refit.

Moto

[nwarner]

The tyre is off my spare at the moment but I haven't got any scales. If you don't get a answer by Saturday I'll see if I can borrow some at the weekend and weigh it for you.

Nige

[phillpot]

Moto said:

Same issue. To weigh the tyre I'd have to take it off the rim.

I thinking more like take your scales to a tyre place and see if they'll let you weigh a similar sized tyre?

Just how accurate do you want it, and why?

[Moto]

As accurate as possible really, say to within 0.1 of a kg would be fantastic.

Nigel, that would be really appreciated, thx.

I'm trying to calculate (to see what reduction is possible) the unsprung weight.The starting points are wheels & tyres. Just wanting to compare a standard Vixen fin rim weight compared to a new Minilite rim or other forged rim.

Moto

[nwarner]

Just borrowed a neighbours scales and it weighs 7.7kg

Nige

[tyracious]

The fins are way cool but it's evident they are quite heavy - as has been commented on before and from personal experience.
For such a light car, the unsprung mass is detrimental if one goes by the usual theories.
A five spoke Revolution wheel is around 8 lbs.
The fins are over twice as heavy.
If and when fitting a light wheel - how much impact does that have on spring rates and shock settings?

[Moto]

Thx Nige. That's really useful.

Moto

[Mr Plow]

Moto said:

I'm trying to calculate (to see what reduction is possible) the unsprung weight.The starting points are wheels & tyres. Just wanting to compare a standard Vixen fin rim weight compared to a new Minilite rim or other forged rim.

Moto

I'd be interested to understand other areas you've identified where weight can be saved. One of my primary goals is to rebuild the car as light as possible. But still retain reliability and adhere the blue book regulations.

[Moto]

Mr Plow said:

I'd be interested to understand other areas you've identified where weight can be saved. One of my primary goals is to rebuild the car as light as possible. But still retain reliability and adhere the blue book regulations.

FWIW, my view is that blue book regs are inherently about adding weight ie you have to add something such as a roll cage/bar or fire extinguisher, etc. The reg's may also define things you can't do which also inherently means you can't take certain weight out.

The common practices fit into 'easy to do' - such as swap a cast iron component for an alloy equivalent such as head, bell housing, gearbox casing, diff casing etc. Also consider replacing glass with poly carb items. 'Hard to do' items are primarily lightening the body work by replacing existing with thinner glass fibre items. This is obviously high cost work. These are all sprung weight items so if you run in a handicap championship like me, there's little or no benefit as power and weight are usually the key handicap elements in any handicap calculation.

More beneficial can be reducing unsprung weight as it is claimed to offer greater benefit per kg saved. I've seen stated anything from 4-15 x multipliers. You can do this replacing rear brake hub covers with alloy or fit lighter rims or tyres. Obviously this may also increase or decrease other important elements such as grip, tyre roll, braking, acceleration etc.

It is a bit of a black art and very much based on complex physics or a combination of experience and testing. All good fun though.

Moto

[tyracious]

tyracious said:

A five spoke Revolution wheel is around 8 lbs.
The fins are over twice as heavy.

Duh .. pounds/kilos/pounds/kilos.
Had to correct my silliness.
A five spoke Revolution wheel is around 8 KILOS.
Guess the fin is really not that heavy at 7.7kg.
Maybe I got something besides air inside mine cause they do seem to weigh a lot.

[Moto]

The conclusion I came to was that there's not much opportunity to reduce weight from the standard wheel / combination. Alloy hubs, calipers & drums seems to be the main unsprung weight saving opportunities.

Moto