Hello everyone. I have ’70 914/6 GT tribute. The wheels on the car are Fuchs (7x15 and 8x15). I’m thinking of going 8”/9” and hoping you can give me your opinion on what backspacing and tire size works best. I'd like to hear what you GT owners think, what you're running, etc.

I'm also toying with going with 16” and have the same questions.

Any input and pictures would be really appreciated.

-Dave

Just like narrow body cars, not all flared cars fit the same and some tires are wider than others even when sized the same.

I built 2 -6 GTs. Given tire choices today, I would choose 16" Fuchs.

For width, I'd stick with 7 and 8s. You really don't need the extra tire. The car feels entirely different with too much tire.

In fact, my next -6 conversion will run 6x16 Fuchs all around, no flares, and a 2.4 six without the front cooler. Lighter and simpler next time, if third time's the charm.

Roblav1,
What size tires on the 16” wheels?

Just a question on this. When I got my car it had 155's on it, I liked the way it handled but it would go into a four wheel drift pretty easy. So I went to 165's, better but 205's (the biggest I could fit) were great. Still with more speed in the corner the drift came back. So for this phase I was going up to 225's. With smaller tires and no flares, most are running the same size tire all around, but with bigger tires and flares I see more people running smaller tires in front. Not all but it appears most do. If the 225's fit in front, why are you fella's running smaller tires? Is there something I'm missing.

My car has 16x8 & 16x9 Fuchs w/930 rear spacer all the way around. 225/50 in the front 245/45 rears. Front tire barely starts to rub inner fender at full lock. I have 993tt brakes on my car, 15s won’t clear the calipers.

My narrow body (914-4 w/approx 150 to the wheels and under 2000 lbs) rear flares were stretched to fit 225s, but always ran 205s on 7x15 cookie cutters, loved the handling, nimbleness of that car, felt that 225s might have taken some of that away. Ran Bridgestone re71, 205/50x15 is the same as spec Miata, so tire choices are a little better.

^ I'd love to hear more on this, too. The best/most fun/most confidence-inspiring 914 I've driven in terms of backroad fun was a GT-look car running square with 225/50R15 all around. Might have been slightly off square with 15x7 and 15x8. There are a lot of great tires in that size, particularly the Toyo RA1—which looks "right" on a 914 with its simple sidewall and tread pattern and lasts a long time for an R-compound tire.

If you like 16s on a 914, and I do, it's hard to argue with 205/55R16 on 16x6-inch Fuchs on a narrow 914. Some fender rolling may be required, but there are many good tire choices, and tire choice > tire size IMO. There are also good 225/50R16 and 245/45R16 options for those with GTs. If I had a flared car, I'd probably want a set of 16x7 and 16x8 to run with 205/225 or 205/245, but I prefer 15s on more "period look" cars, and there are more good choices than we've had, between Pirelli P6000 & CN36 and Avon CR6ZZ for tall tires plus some 205/50R15 and 225/50R15 tires if the shorter OD is okay.

I've been mulling 185/70R15 front with 215/60R15 rear Avons for a long time, or just going 215/60R15 all around. I've been on 185/70R15 CR6ZZs for several years, but was spoiled by 205s in the past. The move to 215/60 includes some big commitments between widening deep sixes (or—gulp—real 911R wheels) and rolling fenders (at the least). Feels risky, but then I look at pics of this car on 215/60R15 square—and a sticky 215 is probably plenty of tire for a 2000-2200~lb 914. I wonder how much pulling/rolling was involved in getting these in…

https://bringatrailer.com/listing/1970-porsche-914-25/

I have noticed a big feel difference between 205s and 225s as well as by brand. Hard to say how any sane combination is going to play out. I would say the bigger the tire the heavier the feel is going to be, but the grip is real. I run 225/50/16s all the way around. I believe they are the 8x16 and 9x16 Fuchs (doubt they are real). The offset pushes the rears out a little more than stock I believe. I could easily go for 255s in the back I bet and maybe 245s in front, but I suspect it would kind of suck to drive on the road.

If I had a narrow body I think I would head towards a 16 for options and then go with a 205. I have 205s on another car and I think it is a really good spot. Great road feel, lightness of steering, reasonable grip.

Click to view attachment

205’s keep the lively feel. 225’s start to feel a bit heavy.

Just my opinion.

As usual, everything is a compromise. On my next 914, I'll run 205/55 -16, since that's my particular sweet spot between ultimate grip and feel.

Now... I first started driving SWB 912's with 4.5" rims. Grip was not so hot but it was fun wagging the tail coming out of corners, even with the underpowered engine. It taught me driver control, especially in sand, ice, and snow.

A few years later, moved to SWB 911's on 6x15 Fuchs on 195 or 205/15 tires. That, to me, is the sweet spot. The steering is still light and the grip is very good, especially for a street car.

My current GT, which I'm selling, has 7 and 8x15 Fuchs on Toyo Proxes 205/50 and 225/45. Poxes are similar to the racing rain tires I used on the track. The grip is phenomenal.

Soo... I built the GT I thought I wanted... but actually don't because it doesn't have the old Porsche "feel" on the street. My car would be great for track days, but having raced formula cars for 15 years, I no longer want to do that.

It's all about your personal compromise.

Anyway, I'll soon be looking for another 914 to convert.

Thanks Guy's for the responses.

I’m not a fan of 16’s but if I was going to use them, I would paint them up to look like 15’s. To my eyes, it helps retain the classic look.

Toyo R888R 225/50x15 on all 4 corners

Can't argue with a Dancing Banana. Square it is, thanks again

Advantages to a "square" set up? easy tire rotation front/rear and side to side.

Advantages to a "staggered" set up, smaller in front, is
1) lighter steering feel
2) inherent understeer

Going from 155s to 185s to 205s to 225 etc.. will do two things:
1) Move the point of no return higher (that "oh shit.. I was going to fast and ran out of talent to correct/save myself)

2) input significantly more g-force into a suspension that was originally designed to cope with 165 tires as their option size(185's on a /6) - which leads to stressing out other parts of the car.

Today's "sticky" 205 autocross tires are nearly 9" wide.. the stock 165? not so much. heck that sticky 205 is likely grippier than a then new Goodyear Race slick was in 1970.

As for the OP, go with the combo that provides tires that fit and a look you like.. since almost all GT builds are built with appearance in mind.

Keep in mind, factory GT cars ran pretty small wheels depending on the class rules at the time of the running. For instance, the 1970 86hr Marathon GT cars ran in two classes.. The "slow" car ran with 6" wheels all around.. the other 2 cars ran "up" a class, running 7" rims on the rear - all under GT flares.

I've machined those bil's I got from you and spindles will be going up. So I need 16" or 17". I never saw the 16's painted like this, that is much better to my eye.

@Racer

I went to 205's all around in 1983, so I'm used to that feel. 225 seems like the natural progression for me, the car would feel foreign with a different size in the back only. I'm shooting for a sticker version of my old friend. Suspension and tub are also getting some love, but I'll keep a closer eye on the stress points. Thanks

Has to be a hoot…

Thanks everyone…great feedback!

@SirAndy-What are your rim widths?

I'm running 205/55R15 with cookies on my narrow body, this size doesn't look as odd as the 50's
The wide body I will be building I'll likely use an aftermarket 16 or 17" wheel, OE's are getting too expensive.

I pulled the trigger on the Tokyo R888R tires. Fronts are 15x7 with 205/50 and the rears are 15x8 with 225/50. Here it is: