I'm looking to upgrade the tires on my 1984 300ZX turbo. I want to keep the stock wheels, they currently have the stock size 215/60/15 tires on them.

Question is, how much wider can I go with tires for the stock wheels? 225? 235? And should I go to a 40 or 50 series tire instead.

I figured some of you have been down this road before, so I look for your sage advice...thanks!

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John Taddonio
1970 240Z
1977 530Z
1984 300ZXT
zcarnut@hotmail.com
FB: Zccr zcarclubofrochester

John, do you know the width of the stock wheels? The selection of 15 inch tires is slowly dwindling down.

I use the TireRack.com website when trying to answer this question for my Z. I use the specs tab to determine the stock tire size diameter. In your case with 215/60 R15s, is 25.2 inches. I then look through the other sizes to see what ratios come close to the original diameter. The chart also shows recommended wheel widths for each size.

http://www.tirerack.com/tires/TireSearc ... iameter=15

http://www.tirerack.com/tires/tires.jsp ... mpare1=yes

You can use this screen to view the various sizes based on the wheel size.

http://www.tirerack.com/tires/sizes/res ... iameter=15

_________________
Phil
1981 280zxt - Now in the care my son!
2014 370Z Sports Touring Roadster

A 225/50R15 would be a good size for that Z. Could go 215/50R15, or swap. 225's in back and 215's up front. I was on tire rack last night, (yes Phil, good Idea, lots of tire info,) and for my 15x8's Im looking at 225/45's for the rear and 205/50's for the front. It's about time I use those rims I got of Tom W. years ago.

I've been scouting around the tire rack site, good info for sure.

I'm thinking I may stay with the 60 series tires and go just a bit wider at 225. I never liked the "rubber band" look of low profile tires on older Zs....

_________________
John Taddonio
1970 240Z
1977 530Z
1984 300ZXT
zcarnut@hotmail.com
FB: Zccr zcarclubofrochester

You guyz are a wealth of information. What a great Club.

....and staying with the 60's % going a little wider will = a better ride.

As an option, I have a set of stock Z32 wheels with new Khumo 245/50/16 high performance tires. They came off of a wrecked Z31, so I know they will bolt onto my '84. Too big a tire?

_________________
John Taddonio
1970 240Z
1977 530Z
1984 300ZXT
zcarnut@hotmail.com
FB: Zccr zcarclubofrochester

that size will fit fine. Z31's can comfortably handle about a 255 up front and a 285 width in the rear though there are limiting factors to take into account (year, body style, wheel offset, suspension type/condition). Some have stuffed larger in there but that's a bit off topic.

Having had several different sizes on the stock 15" and 16" wheels I would recommend at least a 225 and a 50 a/r. That size is far from a rubberband look and still has plenty of sidewall for potholes and relative comfort. 60's allow too much sidewall flex and squirm and in my opinion visually don't do anything for the car...look too tall and kinda 80's. But considering it is an 80's car it may be just the look one is trying to achieve.

Keep in mind that the same size tire in different brands may actually be very different in size when installed on the car. Found this out the hard way on more than one occasion.

I like the look of Z32 wheels on a Z31, just don't forget the 1" adapters!

What 1" adapters are you referring to? My '84 is a turbo with 5 lugs.

_________________
John Taddonio
1970 240Z
1977 530Z
1984 300ZXT
zcarnut@hotmail.com
FB: Zccr zcarclubofrochester

It depends on the exact wheels you have: are the Z32 wheels from a turbo or non turbo? You may need a pair of 1" adapters for the front/rear to get the wheels to sit flush. Twin Turbo rear wheels are wider with a lower offset and bolt right up. Fronts will need adapters regardless as they are the same for both n/a & TT.

Adapters instead of spacers, this way no vibration and a margin of safety.

1" seems like a lot. I'd be reluctant to take it out that far with the Z31 genders.

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John Taddonio
1970 240Z
1977 530Z
1984 300ZXT
zcarnut@hotmail.com
FB: Zccr zcarclubofrochester

1" is kind of the norm in the Z31 world. Due to their extremely low offset it makes fitting any aftermarket wheels a necessity as very few are made with +10 or lower offset (very few that aren't double the cost of the car that is!).

I personally run a 25mm (1") up front with a 15mm in the rear of my 86T and have had no issues whtsoever. Just be sure to purchase quality adapters and not Chinese knock-offs, this is an important item. Also be sure that they are hubcentric to eliminate any imbalance issues, IIRC Z31's are 66.1 but I could be wrong on that.

I just got a set of 4 adapter for my Z31 to allow u sof Z 32 or 35 wheels.
6061 T6 billet aluminum
CNC machined
pressed-in studs included
open end lug nuts included
Cost was ~ $175 delivered for all 4 corners from these guys so send them an email
sales@ezaccessory.com

Not in use yet as while installing the adapters... I found I need to do brakes all around (including new front discs - Ouch #1) as well as new boots for front struts (Ouch #2) before putting new sneakers on. So a project in the works at the moment.

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'87 Z31 5 spd N/A in Red Pearl (~stock)
'90 Z32 5 spd N/A in Azure Blue Pearl (~stock)
'91 Z32 TT 5 spd in White Pearlglow (enhanced)
'03 Z33 Touring 6 spd Chrome Silver (~stock)
'09 GT-R Super Silver... Lusty Enough As Is!

Sorry - too many typos- I should have proof read before send...
that was suposed to read Z32 or Z33 (vs 35?) wheels. I'm sure the GTR wheels won't fit... but wouldn't that be a sight? An '87 Z with Godzilla's feet and sneakers!
Z32's need 1" though Z33's only ~ 2/3" but all should be fine with 1" adapters.

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'87 Z31 5 spd N/A in Red Pearl (~stock)
'90 Z32 5 spd N/A in Azure Blue Pearl (~stock)
'91 Z32 TT 5 spd in White Pearlglow (enhanced)
'03 Z33 Touring 6 spd Chrome Silver (~stock)
'09 GT-R Super Silver... Lusty Enough As Is!