pros/cons running bigger wheel in rear

RiyadYar

Supramania Contributor
Nov 20, 2007
384
0
16
NY
hey guys, I currently have 16" n/a mkiv rims on my 89 supra. i like the look of a bigger wheel in the back so I was thinking of putting 17" TT mkiv wheels in the rear, and keeping 16's up front. what would be the advantages /disadvantages to a setup like this . (ie fuel economy, handling, speedo not accurate etc) Thanks.
 

Enraged

A HG job took HOW long??
Mar 30, 2005
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Victoria, BC, Canada
disadvantage: it would look stupid imho. either run 16s, or upgrade to 17s. Don't stagger diameters.

as for speedo, etc, as long as the diameter of the tire is the same, it will be fine. you can google tire size calculators to figure out what tire you would need.

If anything I would stagger the other way, 18s on the front for big brakes, 17s on the back for more sidewall for tires.
 

Poodles

I play with fire
Jul 22, 2006
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Enraged;1937587 said:
disadvantage: it would look stupid imho. either run 16s, or upgrade to 17s. Don't stagger diameters.

as for speedo, etc, as long as the diameter of the tire is the same, it will be fine. you can google tire size calculators to figure out what tire you would need.

If anything I would stagger the other way, 18s on the front for big brakes, 17s on the back for more sidewall for tires.

Yep, that's how many have done it (Duane for instance)
 

joel903

New Member
Apr 6, 2005
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If you're able to get a full set of TT 17" rims, then just use those. N/A MKIV 16" rims looks silly compare to the TT rims.

The Con of a wider tire in the rear is that they're expensive to replace.
The Pro of it would definately be the looks and the added rubber.

To me the best tires sizes on TT rims are:
245/45/17 for the fronts
275/40/17 for the rears
 

Enraged

A HG job took HOW long??
Mar 30, 2005
1,843
21
38
Victoria, BC, Canada
if you get MKIV TT wheels, get a good quality set of hubcentric spacers for the front (I run 25mm), otherwise the front wheels are tucked way in and it looks bad.
 

Dan_Gyoba

Turbo Swapper
Aug 9, 2007
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Alberta
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If you want to run a larger diameter tire in the back, then you'll have speedo issues. It'll change the caster on the front a bit as well, but whether significant or not, I can't say.

If you're planning on keeping the same rolling diameter front and rear, then this is backwards. You'd want the smaller sidewalls on the front, since the point of smaller sidewalls is supposed to be more rigid wheels to resist turning stresses. Or for brake clearance for larger brakes, which would mean larger diameter rims to the front.

I suppose that the con would be that it'd look like you were setting the car up as a FF drag car. :p
 

DeMoN2318

New Member
May 24, 2012
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Arizona
If you are looking for a rake look then you should get wider tires in back with the same (or larger) profile rating. but wider tires are expensive

Larger wheels are usually heavier which means more rotational inertia which will make them harder to get rolling so you may lose some acceleration performance.
 

kanji1jz

kanji
Jan 16, 2008
103
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0
tampa fl
Just get a good set of drag radials for the rear and you will get all the rake you need and want. I have seen Mustangs with a 19 in front and a 20 in rear (I know that isn't the sizes you are going to be running but just as an example) and I didn't think that it looked too terrible. His coil overs were set so that the tires filled the wheel well and gave it a pretty nice rake.
 

Grandavi

Active Member
Sep 25, 2008
2,663
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Calgary, Alberta, Canada
Old school way to do your car really.. we used to do that a lot in the 70's. With our car, I like equal height with more width in the back. Do your car styling with coilovers.. my front is dropped slightly more than the rear.

we used to use "shackles" on our leaf springs too... would really throw the suspension dynamics out of whack... but made the car look faster... :p



hmm... just thinking about it.. car suspension has changed a lot since the 70's...
 

jetjock

creepy-ass cracka
Jul 11, 2005
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I know of a car that came from the factory that way but almost nobody notices. It had to have larger wheels/tries in back because of the rear weight bias or it would easily swap ends. Seems pointless on a MKIII though.
 

Rollus

New Member
Jun 2, 2011
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Paris, France
jetjock;1938162 said:
I know of a car that came from the factory that way but almost nobody notices. It had to have larger wheels/tries in back because of the rear weight bias or it would easily swap ends. Seems pointless on a MKIII though.

Please post a pic of that car ;-) I'm just curious
 

Grandavi

Active Member
Sep 25, 2008
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Calgary, Alberta, Canada
Taller rear vs smaller front is almost purely aesthetics. Raise the backend and it looks ready to pounce. Flat = boring.

Its something a lot if us older folk did to our 500 buck cars to make them impressive.
 

jetjock

creepy-ass cracka
Jul 11, 2005
9,439
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Redacted per Title 18 USC Section 798
Rollus;1938285 said:
Ho YES, thanks, I remember that, as at this time I own a Renault which shared common parts with Lotus Europa and DMC DeLorean IIRC

Right. Other than the doors and body panels the Delorean was designed by Lotus and has an Esprit chassis. The tranny and parts of the engine are Renault.

Enraged;1938335 said:
What do you mean?

It's obvious to me but I speak Nick. :icon_razz
 

destrux

Active Member
May 19, 2010
1,183
10
38
PA
The Chevy Corvette has been running different wheel diameters for years. They ran a 17" front with an 18" rear for a while then stepped up to a 18" front with a 19" rear.

When you increase diameter of the overall tire you also increase the length of the contact patch. The goal is to make the handling more predictable as it makes the contact patch less prone to change due to road surface irregularities.

The reason for changing the wheel diameter to do this rather than just changing the sidewall height is because cars like the Corvette are designed to go very fast for a very long time. If they just threw tires with a taller sidewall on the rear not only would it look noticeable but it would also generate more heat from flex at high speed. So they upsize the rear wheels to keep the sidewall roughly the same side as the front.

Do we need it on our MKIII's? Sure, why not? The longer contact patch idea would work well on any car.

This also applies to the front tires I suppose, but I'm sure there's some reason they don't do that (maybe it's just looks? maybe aerodynamics? maybe handling dynamics?). I never asked an engineer why they don't make the fronts bigger too. Maybe I should.