[James330I]

it is my understanding that when we upgrade to 19s or so, the wheel gap actually increases, and therefore makes our car look like a 4 X 4. Is this not the case?

My friend and I are having a debate. He says when you upsize, it will fill the wheel well up, and you really don't have to lower. I ofcourse disagree, and just with pics of BMWs on 19s alone, they do look raised.

Can ne1 give a technical and good explanation of exactly WHY it gives the car a raised look? I can't quite seem to put my explanation into words.

 

[Cyric]

I'm not an expert by any means, but I have picked up some basic info by reading these boards the last two weeks.

I believe it works like this - if you alter the outside diameter of your wheel/tire combo the speedometer and odometer will read incorrectly, because they are calibrated for the original outside diameter.

When people switch to 19s the profile of the tire decreases, while the size of the wheel increases. Therefore, the same outside diameter is kept. So because of the lower profile tire, the gap is actually increased.

I could be totally wrong on this, so someone else please add to this or correct me if I'm wrong.

 

[PhilH]

So because of the lower profile tire, the gap is actually increased.

I could be totally wrong on this, so someone else please add to this or correct me if I'm wrong.

You're totally wrong. :tongue: Since the outside diameter of the tire is exactly the same as stock, the wheel gap is exactly the same. Unless you go with a tire that is the wrong size, it's a fact.

As for why it looks like a 4x4, the way I figure it, when you see a 18" or 19" wheel, you expect a sportier and lower car. It's jarring to see a car with big wheels at stock ride height. It's not a technical explanation, but it makes perfect sense to me.

 

[James330I]

You're totally wrong. :tongue: Since the outside diameter of the tire is exactly the same as stock, the wheel gap is exactly the same. Unless you go with a tire that is the wrong size, it's a fact.

so, since it's hard to find an exact match of tire with the perfect profile you're lookin for, and most of the time, upgrading rims plus low profile tires will be slightly bigger (my 19s with 235/35 is about an inch bigger than the stock 17s), that would be why it would raise the car then, right??

 

[PhilH]

My old E34 with stock suspension (which was very high in the front from the factory) looked like a 4x4 with 16" wheels and tires with the factory outside diameter, so it's not just bigger tires on the 19s that cause that look.

Because of how nearly all cars are designed, people expect to see a wheel gap that is the width of the tire or less. When you go with a lower profile tire, it generally looks like you have to lower the car just to make it look "normal".

BTW, nice wheels! Do you have a Dinan suspension? impin:

 

[James330I]

no Dinan susp...too much $,not enough lowering. (

I decided to go with Eibach/Bilsten combo instead.

 

[PhilH]

no Dinan susp...too much $,not enough lowering. (

I decided to go with Eibach/Bilsten combo instead.

I figured it wasn't Dinan from the drop. Looks great.

 

[Choson1]

The only thing you need to look at is the overall diameter of the tire. If it's smaller than stock, you will have more wheel gap, and vice versa if it's larger. The reason getting 19's without a drop looks like a 4x4 is that you have less sidewall on the tire, and it gives the illusion that the gap increased. Stock tires have plenty of sidewall (which is black and mixes in with the gap), and thus it looks okay.

 

[huyner328]

the car does sit lower with stock wheels.

when i had my 19s for the summer, i could get over speedbumps fine, and now that i have the 16s, i can't even get into my garage....

 

[IDLOOK2]

The only thing you need to look at is the overall diameter of the tire. If it's smaller than stock, you will have more wheel gap, and vice versa if it's larger. The reason getting 19's without a drop looks like a 4x4 is that you have less sidewall on the tire, and it gives the illusion that the gap increased. Stock tires have plenty of sidewall (which is black and mixes in with the gap), and thus it looks okay.

Well said:thumbup: