new wheels

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kal

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i'm planing on getting a new wheels, so i'm thinking of getting 19" wheels but i still don't know which tires should i get RFT or regular !!

and the size of the tires r 235/35-19 Front/Rear is that size ok ?! i like the 19" wheels but what i don't like is sometimes the tires becomes too thin !! r all 19" like that ?!!

my friend is telling me to get RFTs so that it well protect the wheels from getting bent !! and i want to try the difference in driving in regular tires like every body is suggesting here that it's much better than RFTs, he is bugging me on not getting regular tires he's telling me ur not going to tracks to put them and feel the difference, and if u had a flat tire what u gonna do u don't have a spare, or what if something happened to ur wheels what u gonna do !! he really made me sick of all these questions and arguments :headbang:
so what should i do ?!!
 
kal

Some of your friends arguments seem illogical. I see no reason why you would bend the rim, you won't need to track a car to feel the difference and if you do not have run flats then you just carry a tyre repair kit and small airpump (That's what the ///M do anyway)

19" seems too big a rim to me and will adversly affect the Z but I'll let the tyre specialists chip in there.
 
Got 19's on mine and love them.

Look great and run great.

I'd ignore your mate, get some non-RFT's and a repair kit!
 
19" non run-flats will be fine. Get 19" run-flat tires only if you feel like experimenting repositioning your internal organs. :D
 
Let me qualify my comment about the 19" rim in that standard is 16" or 17" and you expressed concern over thin tyres. Invariably if you add 2" to the rim the tyre becomes much lower profile to maintain the same overall radius.

I agree though that they look really good with certain rims
 
I do spot a nasty nick on Senwar's wheels though in his picture :evil:
 
I agree about the run flat tires completely. Took mine off which had a lot of treed on them and replaced them ASAP. :) But I am not sure if putting a larger wheel, is a good idea. I did that on my Mercedes and it messed up everything on the internal computer as far as calculations on mileage etc. Wouldn’t the speedometer also be off? :? Just a question so you had better find out about this stuff first. Maybe there is a way to tell the vehicle the size of your wheels, I do not know. :driving:
 
CJ10Jeeper and Wazzzman are both correct.


CJ10 talks about PLUS sizing, were you take your wheels from the stock size up to the next size but adjust the tire so as to maintain the same outer diameter. This then keeps the speedometer correct and your DME works like it is supposed to.

Plus sizing is this. You start with a stock 16" wheel, like what I had. I had 16" with 225 50/R16's RFT and went up two inches (Plus 2+) to an 18" wheel. The tire size I used to keep the speedometer correct is 225 40/R18. 1.8” wider but the same outer circumference as stock.

If I would have gone with 235 40/R18’s (an even wider tire) the outer tire circumference would have been greater than stock and my speedometer would have been 4% slower.

(There are several web sites that have tire/wheel calculators so you can do your own research. Search this site. I and others have posted those sites on this forum. )

By going with a Plus size, you reduce the sidewall thickness.... Normally, reducing the sidewall thickness will increase the ride harshness, BUT if you remove the RFT's and go with a non-RFT you will notice increased ride comfort even though you reduced the sidewall thickness....

Another thing to worry about is the weight of the wheels... The heavier wheel you get, over the stock wheel weight, the slower the car accelerates and handling can be affected.

Do your own research before you decide. I took two months and almost pulled the trigger on two different types of wheels before I bought the ones I now have.
 
225/50r18 The first number (225)is the width of the tire at the widest point in the sidewall. It is called the section width. The second number(50)means it is 50% as tall as it is wide. This is called the aspect ratio. The third number is the rim size. There is a mathmatical formula that you plug in the numbers and it will tell you the radius of any size you can think of. I dont think I have it here at the house, but I will bring it home from work tomorrow night and post it for you. Keep in mind section width and tread width are two seperate things, and dont go hand in hand. You would need to check the spec chart on the tire you are considering to get the correct number for the tire. Hope this helps
 
Ok, here is the formula.

section width divided by 25.4=x
x times aspect ratio=y
y times 2=z
rim size + z=overall diameter

Here is how it looks on a real size. 275/55R20

275 divided by 25.4=10.8
10.8 x .55=5.95
5.95 x 2=11.9
20 + 11.9=31.9

so the overall diameter of a 275/55R20 is 31.9"

This will work on every size tire. Just remember this does not give you tread width, most manufactures are close, but they all very somewhat.

I hope this helps.
 
ok well i'm confused :? isn't there anybody here who have 19" on there Z4 non M ?!

the weight on these wheels are 26.0lbs and 26.5lbs is that too heavy for 19" ?! don't compare it with samller size wheels.
 
kal said:
ok well i'm confused :? isn't there anybody here who have 19" on there Z4 non M ?!

the weight on these wheels are 26.0lbs and 26.5lbs is that too heavy for 19" ?! don't compare it with samller size wheels.
Click to expand...


Your stock wheels from BMW are most likely 22lbs each.

I my opinion, I would not go to a 26 pound wheel.

If you are fully aware of all the issues, and still like the look, go for it.... It's your car...
 
Stock Z4 wheels are usually around 24.5~26lbs. 26lbs isn't too bad for 19" wheels. But be careful of the source that claims the wheel weights. A certain company has continously advertised their 19" CSL replicas to be 26lbs despite everyone who has ever bothered to weigh those wheels got 29lbs~31lbs. For 19" wheels, the closer they are to 20lbs the better. Go with the reputable brands like BBS, Volks, O.Z..
 
BBS is too pricy and the other 2 i didn't like, i went to a tire place they told me to fit 18" better coz 19" wont fit my car and they have to raise it or something like that i didn't exactly understand.

http://www.europeanautosource.com/product_info.php?cPath=67_203_204_293_297&products_id=1468

i saw these wheels and liked them they r the new style of the csl or same brand something like that.

but there is no 18" !!
 
kal said:
BBS is too pricy and the other 2 i didn't like, i went to a tire place they told me to fit 18" better coz 19" wont fit my car and they have to raise it or something like that i didn't exactly understand.

http://www.europeanautosource.com/product_info.php?cPath=67_203_204_293_297&products_id=1468

i saw these wheels and liked them they r the new style of the csl or same brand something like that.

but there is no 18" !!
Click to expand...

Ignore the tire place. They don't know sh!t.

Go for 18" if ride comfort is a concern. But those 19" V715's will fit your Z4 just fine. And if you go with 19" wheels, you might want to consider lowering the suspensions, especially since the V715's have deep dish lips so the wheel gaps will look more pronounced and thus visually they'll make your Z4 look like a 4x4.
 
yeah that's what i'm going to do get me some coilovers to lower the car, but is it ok to go with the 19" aren't they heavy !?
i really like those wheels but i'm confused 19 or 18 !! :?

and which one i get first the coils or the wheels ?!
 
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