# (suspension) how low to drop on 18"...



## Sublime_intervention (Oct 5, 2005)

Sup brothers... how u guys doin...

2005 Altima SE V6 (Auto) Middle East spec. 

i just got a set of 18X8 Front and 18X9 Rear rims, Front tires are 40 profile and Rear are 35, for some reason... i always thought that they should be the same profile but i have been told otherwise... any how after putting the new shoes on my Altima, it became obvious that the car needs a major drop...

A suspension upgrade has always been on my mind, now with the new rims it has become now more important then ever...

The point of this Thread is:
How low can i safely lower my car ? 
Eibach has the Pro-kit 1" drop and the Eibach Sportline 2" drop, 
B&G has a 1.6"front and 1.2" drop, Nismo has the 0.9" Front and 0.4 Rear set up... the rear of the car looks ok... but the front looks like there is an elephant sitting on the back end of the car...

so plz share with me your personal experiences on this topic... plus is it really ok to have different tire profiles ? 

Thnx for your time guys..


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## Smitty 3.5 (Dec 13, 2004)

To this day I have yet to hear of another person that put 9” wide wheels on an 3rd gen Altima, but it may be possible with the perfect offset. It is not necessary to have the same aspect ratio (profile) on all 4 tires; many cars have wider tires in the back requiring a smaller aspect ratio in order to maintain the same diameter as the front tires. The aspect ratio on the tire is actually means how tall the sidewall of the tire is in relation to its width. If someone were to tell me that they have a 35 profile tire; that means absolutely nothing to me without also telling me the width of the tire as well. For example a 2001 BMW 740i has a 235/50R18 in the front and a 255/45R18 in the rear, which have overall diameters of 27.04” and 27.25” respectively. Both tires have different section widths and aspect ratios but are nearly identical in overall diameter.

As far as lowering your car it is hard to tell if you will have proper clearance without knowing your wheel offset and tire sizes. I have had the Eibach pro-kit with 245/35/19 tires on 19 x 8” wheels with a 35mm offset for 3 years now with no problems except for bottoming out every once and a while. It depends how low you want to go and depends on the road conditions in your area, I know if I was much lower I would not be able to travel very far in my city. The Eibach Pro-Kit is a 1.3” drop in the front and 0.8” drop in the rear. The Eibach Sportlines a 1.8” drop in the front and 1.0” in the rear.

Hope this helps.


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## AltibOi02 (May 30, 2005)

^^
There is a guy that has 10.5" wide wheels on his 3rd gen altima but did do modification to fit them on....
now, yes cars have different tire profile sizes like BMW's might have a 40 side wall and a 35 sidewall on the rears. but a 35 sidewall on a 18" wheel is def. going to be way off...it should be more like 40-45 side wall and also depends slightly on the width of the tire....as for lowering I would lower minimally if you're going to keep that tire/wheel combo just to be on the "safe" side...your car is slightly lower than stock because of that combo....but its really your choice...


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## Smitty 3.5 (Dec 13, 2004)

AltibOi02 said:


> ^^
> There is a guy that has 10.5" wide wheels on his 3rd gen altima but did do modification to fit them on....
> now, yes cars have different tire profile sizes like BMW's might have a 40 side wall and a 35 sidewall on the rears. but a 35 sidewall on a 18" wheel is def. going to be way off...it should be more like 40-45 side wall and also depends slightly on the width of the tire....as for lowering I would lower minimally if you're going to keep that tire/wheel combo just to be on the "safe" side...your car is slightly lower than stock because of that combo....but its really your choice...


I don't think you understand how tire sizes work, by using the term sidewall it seems you are unclear what the numbers on a tire indicate. It does not depend slightly on the width of the tire; it depends only on the width of the tire. Here is what the numbers on a tire mean:

For example a 235/50R18
-The 235 means the section width of the tire in millimeters (mm) 235mm is approximately 9.25"
-The 50 means that the height of the sidewall of the tire is 50% the width of the tire section. To calculate the sidewall height, multiply the section width by 50% (0.50). 
-The last number is obviously the wheel size in inches.

Calculations for a 235/50R18
235mm * (0.50) = 117.5mm this is the sidewall height in mm
117.5mm / 25.4 = 4.63" converted to inches
The sidewall height now needs to be multiplied by 2 and added to the wheel diameter in order to calculate the final diameter

(4.63" *2) + 18 = 27.26" This is the final overall tire diameter

A 255/45R18
(255*.45) = 114.75mm
114.75mm / 25.4 = 4.52"
(4.52" *2) +18 = 27.04"

This shows how two tires with different aspect ratios (or sidewall as you say) can have nearly the same overall diameter. No two tire sizes are going to have the same diameter because tire sizes increase in multiples of 5. Like I said before the aspect ratio (or sidewall) means little wihout knowing the width of the tire and there is absolutely no other way to calculate tire size because they were manufactured using these equations.


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