225/45/17

ZoomVT

Glorified Newbie
Contributor
:
2008 | BMW e90 |
Do you guys think i will have trouble putting this size on my sedan and dropping it with the EIBACH Pro Kit?
Would you recommend a different size?
The wheels that im getting are:

-17X7.5 +50mm offset
or
-17X7.5 +48mm offset

I actually wanted to get 225/45/18 but i was told that i would had to mees up with more stuff because my car came with 16s and it was too much difference.
is that true?
if not then i would get these same rims but in 18" and both rims are
18X7.5 with +48mm offset

All the help and comments that you can give me would be greatly appreciated.
If you want to see the wheels, they are in a thread name Kazera

Thanks!
 
ZoomVT said:
Do you guys think i will have trouble putting this size on my sedan and dropping it with the EIBACH Pro Kit?
Would you recommend a different size?
The wheels that im getting are:

-17X7.5 +50mm offset
or
-17X7.5 +48mm offset

I actually wanted to get 225/45/18 but i was told that i would had to mees up with more stuff because my car came with 16s and it was too much difference.
is that true?
if not then i would get these same rims but in 18" and both rims are
18X7.5 with +48mm offset

All the help and comments that you can give me would be greatly appreciated.
If you want to see the wheels, they are in a thread name Kazera

Thanks!

Here is the deal. According to the data found on www.tirerack.com your OEM tire has around 837 revs per mile.

Based on the number of revs per mile you can find the overall diameter of your wheel/tire combo. Here is how you do it (I used my OEM tire because it is listed on the website):

63360 inches/mile divided by 821 = 77.17 inches of circumference
77.17 / Pi (3.1416) = 24.5 inches of diameter

You need to stay within 3 % of this number. 3 % of 24.5 is 0.735 inches. Why is it important to stay within 3 % of that number??? It's because you want your speedometer to give you a correct speed. If you increase the overall diameter of your wheel/tire combo you will go faster than your speedometer will indicate, if you decrease it, you will go slower than the speedometer says. (It changes a little bit with each tire model, but usually the variation is within accepted percentage of variation)

Sorry for all that mathematical stuff but I studied mathematics for a long time so I'm comfortable with all these numbers.

Let's check with the size you were talking about. I chose the AVON TECH M550 A/S Ultra High Performance All-Season tire. The revs per mile is 800.
If you do the math you get 25.21 inches which is inside the 3% variation. It should work well. If I can suggest though, you would be closer to the OEM specs with a 225/40/18 tire at 827 revs per mile.

P.S.: I'm not a mechanic pro so if anybody else thinks I'm wrong, feel free to correct my explanation.
 
WOW. Pretty interesting stuff.
Now i have a question though, i asked the guy at tirerack to give me the 225/40/17 cause i ended up going with the 17" wheels. He said that he couldnt do it because that was a race tire.
According to your math, is it a problem to get 225/40/17?
By the way the tires im buying are Kumho ASX
 
ZoomVT said:
WOW. Pretty interesting stuff.
Now i have a question though, i asked the guy at tirerack to give me the 225/40/17 cause i ended up going with the 17" wheels. He said that he couldnt do it because that was a race tire.
According to your math, is it a problem to get 225/40/17?
By the way the tires im buying are Kumho ASX

I went on the Tire Rack website and looked at the offered sizes for the KUMHO ECSTA ASX which I think is the same tire you are talking about and the size 225/40/17 is not offered. In fact, when you do a search for all available tires of this size you get nothing. The guy from Tire Rack is probably right. You will have to go for a 225/45/17 or a 215/50/17 like I have on my car as OEM, but if you pay for new rims ( by the way, if you install 225/45/17 your rim width needs to be between 7" and 8.5" with a best width of 7.5") I wouldn't go with the OEM size, I would go bigger. You should look at the AVON TECH M550 A/S for practically the same price the reviews are better for the AVON. I have never had this kind of tire before so I can't tell you if they are really good, but I need to change my tires on my car and I'm gonna go with the AVON.
 
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hmm interesting, i must have missed them.
i already ordered the 225/45/17s and the rims do have a width of 7.5 so i think i'll be all set.
thanks for taking the time to look it up for me bro.
now about hose AVON, how is the wet traction? thats my main concern, roads here in VT are in bad shape and a lot of grooves collect a lot of water, i hydro all the time with my stock tires.
 
ZoomVT said:
hmm interesting, i must have missed them.
i already ordered the 225/45/17s and the rims do have a width of 7.5 so i think i'll be all set.
thanks for taking the time to look it up for me bro.
now about hose AVON, how is the wet traction? thats my main concern, roads here in VT are in bad shape and a lot of grooves collect a lot of water, i hydro all the time with my stock tires.

According to the Tire Rack results and survey, they are suppose to be excellent. In the online survey they are number 1 out of 17 high performance all season tires and they have the best wet traction of all equal with the Pirelli PZero Nero M&S. In Tire Rack private testing they are second. Only the Bridgestone Potenza RE950 were considered better. You can see all of that on the Tire Rack website.
 
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