Now, this may be controversial

[jpp]

To reduce unsprung mass and hopefully improve smoothness and performance a little has anyone tried higher profile tyres on a smaller rim.......runs away from the thread

[jrb43]

Are you certain that tyre rubber is less dense that lightweight alloy? I'm not sure actually you would lose weight.

Now, I'm going on a celery and watercress diet, and although that's sprung mass; my logic is irrefutable

Edited by jrb43 on Wednesday 17th November 19:31

[OatSy]

Put 16" spiders on and you will feel a huge difference in handling. I have both 16 and 18" spiders for the TAM and much prefer the 16" rims over the 18"

[nightSpirit]

If you really wanted to save some weight (would compromise the car) you could remove trim that's not needed, strip the interior fit some buckets, remove the speakers etc. TVR have done a pretty good job, usually when I buy a car I can instantly see atleast 100kg of st I don't need (that's 2 seats in my Golf R32) but on the Tam I look at it, have a thought then realise it's been done...so look again and very little can I touch.

[Mattt]

I was surprised at how heavy the 18" Spiders are.

[JR]

jrb43 said:

Are you certain that tyre rubber is less dense that lightweight alloy? I'm not sure actually you would lose weight.

For the same rolling radius of tyre smaller dia wheels are always lighter.

OatSy said:

Put 16" spiders on and you will feel a huge difference in handling. I have both 16 and 18" spiders for the TAM and much prefer the 16" rims over the 18"

I was wondering that also: save weight in comparison to what? The T-series chssis was designed with 16" wheels.

nightSpirit said:

If you really wanted to save some weight (would compromise the car) you could remove trim that's not needed, strip the interior fit some buckets, remove the speakers etc. TVR have done a pretty good job, usually when I buy a car I can instantly see atleast 100kg of st I don't need (that's 2 seats in my Golf R32) but on the Tam I look at it, have a thought then realise it's been done...so look again and very little can I touch.

But all of that it sprung weight which is not as useful as saving on unsprung weight of which rotating unsprung weight is where the greatest gains can be had.

[jpp]

In my Elise I certainly noticed a performance gain on track using the original rims rather than the wider bigger victory rims I used on the road. However the width certainly improved traction and they looked much better. I'm not looking to lose much traction with a 350, but there's just a tendency to tramline with the 18s even after a geo by Dom and they do seem quite heavy, so it's interesting to hear about experience with 16s.

[DonkeyApple]

Weight differences aside, I did often wonder whether a T car would be a better general driver onsmaller rims and higher profile tyres.

I'm not an enormous fan of the recent craze to go as low profile as possible.

I'm sure such tyres are better onthe edge butmost people don't drive on the edge but use the cars in a more conventional manner.

What's the general consensus?

[fredd1e]

Apparently the differences between the 16 and 18 spiders handling aren't due to rim diameter but more due to offset particularly at the front where the 16" had optimum offset but the 18" was compromised to get the wheel/tyre under the wheelarch. See the tuscan spacer thread for more details.
Obviously a higher sidewall will give a more compliant ride (when comparing the same tyre model) but will probably also give a softer turn in feel.

[JR]

fredd1e said:

Apparently the differences between the 16 and 18 spiders handling aren't due to rim diameter but more due to offset particularly at the front where the 16" had optimum offset but the 18" was compromised to get the wheel/tyre under the wheelarch. See the tuscan spacer thread for more details.

The Tuscan spacer thread was about the differences that a small change in ET can make. This is minor compared to the very major differences between 16" and 18" dia rims.