Huge E30 rims

[Guest Spargo]

18" rims fit, thats fine.

How wide can I go front and rear. I'm prepared to roll arches, but what sort of offsets am i needing to run x9" rears?

TIA

[bumpstop325 0]

the wider you go, the more surface area on the road you will have.

but remember that the wider the tyre dosnt mean the more grip you will have. If you go too wide, you will end up with less grip.

9" rears would be over kill.

on the other hand....wide body kit. with dish.

Also, my Zs mag that got burnt will be out of the shop soon. :thumb:

[*sic 1]

truck time!

[petone 0]

the wider you go, the more surface area on the road you will have.

but remember that the wider the tyre dosnt mean the more grip you will have. If you go too wide, you will end up with less grip.

9" rears would be over kill.

on the other hand....wide body kit. with dish.

Also, my Zs mag that got burnt will be out of the shop soon. :thumb:

surface area has nothing to do with friction force (or grip)

its the whole friction equation- friction force = friction co-efficient x normal force

or in our case- grip = goodness of tyre used x weight of car on wheel. so according to that wider tires don't give you any more grip... but I'll let you guys prove me wrong

Getting real wide tires will make it way easier to aquaplane, but look f**king cool

[Guest Spargo]

Most obviously, the selection of tyres is decisive to cornering grip. Car engineers have nothing to do with the friction of the tyres, which is determined by the compound and texture. However, they can choose the most suitable tyres for their cars. 

In the past decade, increasing tyre's diameter and width is a common trend shared by all car makers. Do you still remember the Lamborghini Countach employed 15-inch tyres? Today's exotics; Ferrari, Porsche and Viper have 18 to 19-inch rubber! Larger diameter accompany with larger width increase the contact patch area (that is, the area of the tyre contacts with the ground), thus result in more grip. However, this also result in poorer wet road grip because the pressure acting upon the contact patch (that is, the car's weight divided by contact patch area) is reduced thus the tire becomes easier to "float" on the water. Therefore the texture also need to be improved for better water clearance. 

Low profile tyres are also fashionable in these days. Since the thickness becomes thinner, it is more resistant to side wall deflection under substantial cornering force. However, this is not much related to grip. 

It must be mentioned that wide tyres are not always good. Especially are front tyres, the wider they are, the more resistance generates when they are steered. This create a heavy and insensitive steering feel, also more tyre roar and wear. If you want to modify your car by using wider tyres, always consider the drawback first. In my opinion, most well-sorted European cars have already equipped with the most suitable tyres. 

http://www.autozine.org/technical_school/h...2.htm#Tire-Grip

So based on what you've told me, scrub the 18" idea on anything wider than 8 inches, unless someone can actually answer the question I first posed.

Next question, how would a staggered setup, ie: 7.5"F / 8.5"R affect understeer, how easy would it be to dial this out using camber plates?

OT: Tim, did you have your wheels x-rayed for cracks / stresses that might have occoured during the barbeque?

[Guest Andrew]

the wider you go, the more surface area on the road you will have.

but remember that the wider the tyre dosnt mean the more grip you will have. If you go too wide, you will end up with less grip.

9" rears would be over kill.

on the other hand....wide body kit. with dish.

Also, my Zs mag that got burnt will be out of the shop soon. :thumb:

surface area has nothing to do with friction force (or grip)

its the whole friction equation- friction force = friction co-efficient x normal force

or in our case- grip = goodness of tyre used x weight of car on wheel. so according to that wider tires don't give you any more grip... but I'll let you guys prove me wrong

Getting real wide tires will make it way easier to aquaplane, but look f**king cool

your correct - the kinetic friction equation doesn't apply to rolling tyres - so you have the correct static friction equation.

I'm sure if i whip out the maths book we can calculate how much "grip" a tyre can theoretically resist.

[Guest Andrew]

Next question, how would a staggered setup, ie: 7.5"F / 8.5"R affect understeer, how easy would it be to dial this out using camber plates?

e30s understeer anyway -

i would dial it out with swaybars - not camber.

[Ghost 0]

surface area has nothing to do with friction force (or grip)

its the whole friction equation- friction force = friction co-efficient x normal force

or in our case- grip = goodness of tyre used x weight of car on wheel. so according to that wider tires don't give you any more grip... but I'll let you guys prove me wrong

Getting real wide tires will make it way easier to aquaplane, but look f**king cool

Wider tires do have more grip.

The friction co-effieient takes into account surface area. Its a force over area relationship.

Normal force in this case is vertical.

google it.

[dave 2]

sam, these guys dont have a clue...

modifymycar.com disagrees!!

20's yo!

[E30-323ti 66]

Do you need 18x9's with 200hp??

I think not.

Some nice 16x7.5 or 8's with 225/45's would be just right.

Wheels are still reasonably light, tyres are wide enough to not need any body work and give plenty of grip. (could run 245/45's with some fender rollling etc...)

Quite a few OE 5er wheels are that size, so could look v.tasteful.

[bmwsparkle 3]

or u cud buy my 3 peice BBS RS 16x8, 16x9, make me an offer

[E30-323ti 66]

or u cud buy my 3 peice BBS RS 16x8, 16x9, make me an offer

Got any pic's Sparkle???

Offsets??

[kiwipetrolhead 1]

sam, these guys dont have a clue...

modifymycar.com disagrees!!

20's yo!

Them are very nice wheels for a 635csi.

As for wheels though I agree with some, you can go too big in both width and diameter. It all comes down to the weight and dimensions of the car and the horsepower. Them 3-series boy racer cars you see around with oversized chromes look crap and I bet they don't handle all that well either. And of course, the bigger the wheel the more drag and the more weight. So you'll slow your car down, and then you won't need as much grip. Wide wheels are a problem in the wet too, as someone else already pointed out. And in NZ we have wet roads a lot. Also, note that F1 cars use 13" wheels with high profile tyres, yet the have massive grip (due to the combination of the tyres and the aerodynamics) but F1 cars prove that you can corner hard with smaller wheels and high profile tyres. Why do they use this setup? A: It is the rules. But of course, F1 cars are very light, so you can't compare them to road cars really. As someone pointed out, Euro car makers work out the best wheel sizes for their cars, so stay close to the OE for best results. Another good way to help is to look at the Targa Rally cars. They use sensible wheels and tyres for the best performance on NZ roads.

[bmwsparkle 3]

Got any pic's Sparkle???

Offsets??

nah im gonna keep them, was only stirring

20et, e34 etc offset, normal lookin bbs rs 3 peice with the centrecaps that come out, shud have them in bout 2 weeks

[Ghost 0]

My current set up is 225/35/17 on the front and 245/40/17 on the rear from the PO. This stagged set up gives me understeer, the general consensus on s14.net (which is useful in your case with your M3 set up) is 225's all round is a good bet. Anything wider, like in my case, and you have to play with camber plates etc etc. (you can get away with 235's...)

My personal opinion is 17's are the perfect size for e30's if you looking for bling while considering performance. I'll be changing my tyres (when my current tires die) to a more neutral setup.

The 245/40/17's on the rear further reduce acceleration (when combined with my heavy style 5's), with a larger rotational diameter. Just another consideration.

As we have low torque motors, rim and tyre weight are that much more important- to the point were the butt dyno will notice.

When I track, I'll throw the 16's back on.

Ash

[Guest Spargo]

Okay, i've decided on my setup; 17x8" allround, with a possible 7.5/8.5 split if it came to that.

The main reason for bigger rims is wanting to run 300mm or so discs up front, not because i'm over powering my measly 200hp.

Ash, i've missed two sets of style 5's on TM (my dream BMW rim), but... we'll see what next week brings me

I've only ever seen two E30's manage 18" rims; Jordo's on CSL reps, and that silver -tec II I posted running 18" konig Holes wheels.

Okay final quesion, 17x8" allround, which offset and rubber?

[conrod 1]

Got any pic's Sparkle???

Offsets??

nah im gonna keep them, was only stirring

20et, e34 etc offset, normal lookin bbs rs 3 peice with the centrecaps that come out, shud have them in bout 2 weeks

Didn't buy them off trade me, from a punter in Hamilton by any chance?

[bmwsparkle 3]

nope,

[bumpstop325 0]

OT: Tim, did you have your wheels x-rayed for cracks / stresses that might have occoured during the barbeque?

OT: my mags will pwn faces when when all four are on. mind you it does already with only 2 on.

Its costing 120+gst to get reparied. I didnt see an xray machine there. Mind you i dont really know what one looks like.

[E30-323ti 66]

OT: Tim, did you have your wheels x-rayed for cracks / stresses that might have occoured during the barbeque?

OT: my mags will pwn faces when when all four are on. mind you it does already with only 2 on.

Its costing 120+gst to get reparied. I didnt see an xray machine there. Mind you i dont really know what one looks like.

I hope you put some decent sized tyres on this time Tim!!!

Some 225/45's at least.

Looking forward to seeing it.