Wheel Width - Is it a Critical Issue?

[Ian Butt]

Hello 356 Forum,

I'm in the 7th inning restoring my Light Ivory 1964 356C Coupe, and my mechanic is encouraging me to widen my original ventilated chrome wheels to 5.5" from their current 4.5" while we are re-chroming them. His rationale is a wider selection of tires that are better and less expensive than the vintage recreations available, and visually the change is so small that you really can't see any difference.

I think this is sound reasoning because while I'm trying to keep the car in totally original spec, this change would improve drivability and the ownership experience without any real downside--which I'm generally comfortable with. But, my concern is an audience for this car that tends to be very persnickety, and may view such a "modification" as inexcusable. So, what does everyone think? Is this a critical issue when it comes to authenticity and originality at a concours event or on the auction block? Or is it considered an "acceptable" change to the car?

Thanks in advance for the input!

Ian

[David Jones]

Quick answer is that it is a waste of money for a street car in my opinion. I have 4.5J wheels on my "C" with 185's which is about as wide as you should go. Go wider and a number of things happen.
Steering effort at low speeds goes up.
Front tires rub on the inside of the wheel wells on full lock.
Spare tire will not fit in trunk, I have a 165 for a spare.
For street use I doubt you could improve the handling much over the 185's. My earlier cars have 165's and feel much better than they did when I once tried 185's.

[Edwin Ek]

Address all of David's concerns by running 4.5" rims in the front and 5.5" rims in the rear, with 165 and 185 tires.

You don't affect the steering feel, which is the best part of a later 356. There are no problems with rubbing. You cut down on oversteer, which is why Porsche itself did that later when it figured out what was going on. You soften the on-stilts look of the rear. Plus it is a very subtle modification which can be reversed in ten minutes. Put together a set of 7 wheels if you are concerned about showing the car, so you can go with 5 4.5" rims if you want.

The Vredestein Sprint Classic HR-rated tires come in both sizes, and it seems now that the Pirelli CN36 VR-rated tires do also: 165-80 and 185-70.

[Ian Butt]

Thanks guys, that's really helpful. I wasn't aware of the spare/trunk issue (mechanic was) and that's good to know regarding the steering feel. These few issues are already pushing me towards keeping the original 4.5" wheel width all-around (and 165's). It's original, they're all interchangeable, and there are no issues whatsoever. I like simple.

[Mike Wilson]

Ian: if they are the original rims, however, I wouldn't modify them. I'm running 5-1/2" Mangels with 185's and like the handling. The original rims are in storage. I, too, have a 4-1/2 rim with a 165 as a spare.

[James Belisle]

Depending on the level of originality you're going for with your restoration, the 5.5s could alter the overall look of your car because you'll likely have to go with a shorter sidewall aspect ratio. I have a set on my car, with 195/60s, that were installed by a PO. They rub a little at full lock, but not terribly. I'm not running out to change them back to stock, but I probably wouldn't pay to have an original set widened, either.

[Geoff Fleming]

Having owned 356s with stock 4.5 rims, and 165 tires, then using 185 tires on 5.5 rims I can state that I have never felt any real difference in handling, ( for better or worse), regardless of the tire width. The steering may feel a bit heavier with the wider rims/ tires and of course, you will be increasing the rotating weight at each axle somewhat but not enough to cause any real problem. I do know some owners who run 195 series tires , front and rear, and tend to like the feel they offer. It really is a personal choice.
For the past twenty years I am back to 165 series tires but use 3/4" spacers on the wheel hubs, since the car came to me with them installed. For regular street and highway driving the car seems to feel about right.

[Edwin Ek]

Depending on the level of originality you're going for with your restoration, the 5.5s could alter the overall look of your car because you'll likely have to go with a shorter sidewall aspect ratio. I have a set on my car, with 195/60s, that were installed by a PO. They rub a little at full lock, but not terribly. I'm not running out to change them back to stock, but I probably wouldn't pay to have an original set widened, either.

The goal is to choose an aspect ratio so that the overall diameter doesn't change. That means the height of the sidewall and the look don't change also.

[C J Murray]

The stock wheels and tires work much better on a basically stock car. If you build an Outlaw with significant engine and suspension modifications then larger wheels and tires are useful but David is correct about the negative effects to the feel of the car. Also, if you have your original dated wheels they are too valuable to butcher by widening them.

[Doug McDonnell]

When restoring my C I found that all 5 of my chrome wheels were original per COA. I kept them stock size when I had Boltons rechrome them. It rides and handles very well. Stock 165/80/15 tires all around.

[Mark Roth]

Two points:

I tried the 165 with 4.5 rims on the front and 185 with 5.5 rims on the on the back route. Steering was light but the balance was off on long sweeping turns. Could have been the different brand tires. I then went to 185 all around. Been that way for over 20 years.

This conversation got me thinking about 165 on 5.5 rims. How would that handle?

[Edwin Ek]

Mark, I think we traded a couple of posts about this in a different thread. From several reports, and Porsche's experience with later cars, that combo works fine. The poor handling you felt was no doubt due to mixing make and model of tire, not sizes.

165-78 tires on 5.5" rims would effectively shorten the sidewalls, making the ride a little worse. Normally when you shorten the sidewall, handling gets crisper. In this case, I am not so sure it is clear cut, because you still have as much rubber, it is just being deployed at a different angle. In other words, you get more lateral squish. Vertical squish also affects handling (negatively), but at least ride is improved.

[Mike Horton]

Two points:

I tried the 165 with 4.5 rims on the front and 185 with 5.5 rims on the on the back route. Steering was light but the balance was off on long sweeping turns. Could have been the different brand tires. I then went to 185 all around. Been that way for over 20 years.

This conversation got me thinking about 165 on 5.5 rims. How would that handle?

Mark, the '68 & '69 900 cars, came from Porsche with the 5.5" rim width, and the 165 radials... 912, & 911, and there have been many of those on roads for decades...

...were you at HCR this year?

[Mark Roth]

Thanks guys.
I may go back to the 165s next round.

[David Campbell]

I have a 61 Coupe and it came with a set of new chrome (in the box) 5.5" wheels. It sits on old rusted chrome 4.5" rims now.
I am not tied to the vintage tread look, so any recommendations for aspect ratio? The Continental, Dunlop and Kuhmo brands are in my price bracket at 185/65/15 and look to be 24.5 inch diameter and 7.4" section width, with 6.1" tread width. If anyone has photos of a similar set up please post. Thanks in advance.