Wider wheels advantages

[bamberjim]

Hi all,

Can anyone tell me if say running a 9 or 10” wide rear wheels with say a 255/35 has any advantages over running an 8.5” with a 255/35 on...

Logic says the 8.5” would be lighter... so better to
Use or are there something I’m missing apart from looks

only reason I am asking is I have both widths

Cheers Jim

 

[Anonymous]

If you look at this.. https://www.tyresizecalculator.com/charts/tire-width-for-a-wheel-rim-size-chart

Then you will see that for any tyre size there are really only two rim sizes that are preferred.

If you really want to push it and probably incur some handling anomalies then the chart shows the absolute upper / lower bounds

 

[bamberjim]

Thanks, the question I guess was really about wheel width and not tyres to be fair... let me try a again

18x10 with 265/35 vs a 18x8.5 with 255/35

Is a lighter wheel (8.5”) with 10mm less tyre width a better option than a 10” with 10mm more tyre width

 

[Anonymous]

Different question...all things being equal a wider rim equals a wider tyre which helps cornering grip and braking...

This is offset by the need for appropriate steering geometry and suspension.

There is a general mantra about unsprung weight which should be as low as possible to improve the handling..

So a smaller rim and smaller tyre reduces unsprung weight equals ‘better’..

However given that the wheel n tyre is but one part of the unsprung weight...discs,hubs,calipers, major parts of the steering and suspension linkages are all part of that so without being silly using inappropriately heavy alloys the benefit of wider alloys and wider tyres is a greater benefit...

If you look at Boxsters they have always ran bigger wheels/tyres than the equivalent Z and are perceived to have ‘better’ handling..

So tyre sizes/wheel widths increase as a function of time..

 

[M1k3yC]

If you look at Boxsters they have always ran bigger wheels/tyres than the equivalent Z and are perceived to have ‘better’ handling..

Wouldn't the mid-mounted engine of the Porsche have a much greater effect on handling than the different wheel and tyre sizes if you're comparing the two cars?

 

[Anonymous]

If you look at Boxsters they have always ran bigger wheels/tyres than the equivalent Z and are perceived to have ‘better’ handling..

Wouldn't the mid-mounted engine of the Porsche have a much greater effect on handling than the different wheel and tyre sizes if you're comparing the two cars?

Hello, like all handling discussions, many factors contribute to the final solution..

I think its well recognised that mid engined cars well executed are better handling than those that aren't primarily as there is less angular momentum around the central point.. a spinnng dumbell has a greater inertia / momentum than a mass centrally placed equivalent to the two balls on the dumbell..

so for sure that helps the Boxster, however having bigger tyres means that more cornering forces can be tolerated before slip..so in theory it should be able to go around corners faster than a car with narrower tyres..

Thinking it through the mid engine's greatest benefit is in the initial desire to turn..once the car is turning at a steady rate the mid engine doesn't offer an advantage..of course most of the time initial turn in is more important than being able to maintain a rate of turn for several seconds..

 

[groovy_hippy]

Boxsters generally have more power to put down than Zeds too. IIRC the 2.5 986 Boxster had 260bhp, with the S and future generations having more. Only some Zeds (and Z4Ms) come close/had more in pure horsepower...

 

[Smartbear]

Boxsters generally have more power to put down than Zeds too. IIRC the 2.5 986 Boxster had 260bhp, with the S and future generations having more. Only some Zeds (and Z4Ms) come close/had more in pure horsepower...

Looks like 201bhp? https://en.wikipedia.org/wiki/Porsche_986
Rob

 

[M340]

Boxsters generally have more power to put down than Zeds too. IIRC the 2.5 986 Boxster had 260bhp, with the S and future generations having more. Only some Zeds (and Z4Ms) come close/had more in pure horsepower...

Boxster 986 generation started out with a less than desirable 2.5 and 204BHP. That’s the one you can get for £3k. The later 2.7 was better and the 3.2S the one to have, with 260BHP ish. Later 987 models had a 3.2S and 3.4S option depending on year, the latter pushing 295BHP. Porsche never offered the more basic 2.0/2.2 type options. All are expensive when they go pop.

But....you’re comparing a front engined car with a mid engined one. I’ve had both. The 986 destroys the E85/6 in terms of handling all day long. 3.0Si and 986 3.2S about on a par performance wise. Z4M is quicker, of course but (by design) much more lairy...on a track, I think a 3.2S would run it close.

 

[sars]

Thanks, the question I guess was really about wheel width and not tyres to be fair... let me try a again

18x10 with 265/35 vs a 18x8.5 with 255/35

Is a lighter wheel (8.5”) with 10mm less tyre width a better option than a 10” with 10mm more tyre width

The other point apart from an increase in unsprung weight, is that increasing the wheel diameter, 265/35 R18 vs 255/35 R18 makes it harder to rotate the wheel, ergo the torque at the axle acts on larger wheel radius thus reducing force, you know the thing that causes a mass to accelerate. Simply, fitting a bigger diameter wheel makes your car slower to accelerate.

 

[bamberjim]

Decided to go with 8.5 on the rear as doesn’t seem to be any advantage trying to squeeze the 10” under

Will have
18x8.5 et38 front BBS RX507 225/40/18
18x8.5 ET22 rear BBS RX502 255/40/18


Just need to get them polished up and hopefully be looking like these

 

[sars]

Very nice, now you have to decide on tyres, Tyre Reviews is a great place to start

[youtube]2_utfLrFaOM[/youtube]

 

[Stevo1987]

*** Non PC humour alert *** You can pull more birds with wider wheels. I thought everyone knew that. Well, those who were young in the 1980's.