6 X 15 vs 7 X 15 Big Handling Difference?
 

I need some advice from those in the know. I have a new set of tires arriving soon and I need to decide which wheels to use, I have a set of polished 6 x15's Fuchs and a set of the black repo 7x15's. The tires are Dunlop Sports and they are 195/65/15 they are going on a stock 76 911. I like the look of the polished Fuchs but I'm thinking the 7'' wheels are going to give me better handling? Looking for opinions. Thanks

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My guess is the stock will handle better than the repos if for no other reason on weight difference alone.

There must be a lot of guys here who switched from 6's to 7's, there has to be someone who has an opinion about the differences in handling? dramatic?, good?, not noticeable?
Thanks

The weight difference is so dramatic the extra width means nothing. The extra width just allows better usage of wider tires......

It depends!
 

If you have a tire stretched onto the 6 inch rims that isn't all sloppy vice a 7 inch rim with a sloppy tire! Then the 6 inch might out handle the 7 inch rim!

For every tire is a minimum and maximum recommended rim. Therefore if you take a tire and mount it on the maximum width rim recommended, that would basically net you the best handling. And the other way, would net you less in return!

PS cornering is affected by suspension, weight, road conditions etc. etc. etc. etc. Without getting all scientific on you, a heavy suspensioned car with rims and tires sized properly might not handle as well on street as a softer sprung, and more street oriented setup, but then would be blown away on the track by the heavy suspensioned car!

I think you already got good feedback. Without knowing which model of Dunlop Sport, I'm going to assume the SP 5000 since it's the only one that shows up in that size at TR. It lists rim width as 5.5 to 7.

The weight difference in the rims is going to make the car more agile, therefore better handling in most cases.

Excellent response, sincerely!
 

To add, the weight difference "potential" in rims can make the car more agile if the shocks and spring rates or torsion bars are set appropriately for the change of weight!

What would be the approx. weight difference in these two wheels any ideas? Thanks

Found these tires on Ebay, they seemed like a good deal. 480 tread wear, A traction, A temp, H rated, good reviews....... Dunlop Sport LM703

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Really? You have the wheels correct? Weigh them or just lift them up. Why does a number matter to you?

The 195's fit very well on the Fuch 6", they look 100% better and they are correct for your car if that matters.

Looking at the eventual development of the Torsion bar chassis .Wouldn,t it be an option to consider using 6,s on the front and 7,s on the rear? (Paint one pair or polish the other.)

+1

or

6s for the street and 7s (w 205s) for the track.

BTW I used to have 7 x 15 repos on my car and they were great. I can't imagine that you could tell the difference between the weights of those wheels when you are driving.

The wider wheels will make the car feel more stable and planted. It's hard to say, however, if the "handling" would be better with the 7s, since that is a subjective term.

Yes I have the wheels and they all have different tires mounted so weighing them isn't going to tell me true weights. If the difference is only a pound or two I would think the 7 inchers would give me better handling but that's what I'm trying to figure out.

Thanks everyone for the input.

Butt dyno says that factory 7's with 205s handle better than factory 6s with any size tires....but with the size tires you are buying...I think the 7's are a waste and are likely too wide.

+1 on what flinstone said. I think it has more to do with the purpose of the car and the caliber of the driver. On an autocross/track car with an experienced driver, the 7's will make a difference. On a street/highway cruiser with the 195's, the polished 6's will be fine and look much better, as what 911s55 said.

I'm betting that in a blind test you could not detect any difference between 6s and 7s running the same tires in the same size - and nor could I or 99.9% of drivers? Nor would they be able detect the difference between real and repo wheels due to weight.

Agree with Laurence. I'm guessing that only one of us out of several hundred could detect any difference at all between your setups. Lots of us will however claim that we can. And you didn't tell us if you track the car. If the setup is for the street, the argument is truly meaningless. Do whatever you feel like.
For the record I have never gone as fast at Willow Springs with 7's as I did with 6's all around on a nearly stock 74.
Now if you were going from 6's with 185's to 8's and 9's with 245's...

My car had 16x6 205's in the front and I switched to 16x7's with 205's. Both tire sizes the same, but they were different tires.
I switched them for looks to fill out the wheel well. The biggest difference (that I could feel) on the street was the difference between the two different tire brands, not the weight, nor the width of the rims.

The other thing to think about is what kind of repro is that? What is it's history? Is it pressure cast or gravity cast? Unless I knew what it was, I might feel safer with the forged fuchs.