83 308 GTB QV Tire Size Questions

Hi David,

The early USA market 308 QV's were delivered with Metric TRX wheels , 165 TR 390 ( 15.5 inches) and 220/55 VR 390 tires.

220/55 VR 390 tires will work fine, just be prepared for the heart attack at the price when the tires need replacing!

Grim

 

David,
You could buy an entire set of proper 16" wheels AND a set of 16" staggered wheels for the same price as a set of the TRX tires...

Superformance in the UK sells the well regarded OEM option size replacement wheel set (2 of 16"x7", 2 of 16"x8") for £845.00 (http://www.superformance.co.uk/308/wheels.html ), or roughly $1,056 USD. Tire Rack lists 33 sets of tires available in the proper 2x205/55-16, 2x225/50-16 staggered size, ranging from $299.80 for 4 tires (Riken Raptor) to the extremely good Contenental ExtremeContactSport (a far better tire than the TRX; well most of the listed tires will be also!) for $501.96 USD.

The TRX from Longstone https://www.longstonetyres.co.uk/classic-car-tyres/ferrari/308-gts-qv/220-55wr390-michelin-trx.html are £342.00 each, or £1,368 = $1,710 USD.

So for $1,056 for wheels plus $501.96 for tires, $1558 USD total, you could have a much better wheel/tire combination for $152 LESS than just a set of TRX tires. Then the next time you need to buy tires in 5 or 6 years or so (when performance tires should be replaced due to age hardening), you'll only have to spend $501.96 for another set of Continental ECS instead of $1,710 for another set of the TRX...

 

The above is exactly why I have repro 16" wheels on my car and a set of metric wheels and tires tires rotting away in the shed in the backyard.

 

My car (84 308 GTS QV Euro) came from the previous owner with a TRX wheel and ancient tire for a spare, even though it has the factory 16" wheels - I suspect a prior owner misplaced the original spare and someone, somewhere, picked up a cheap TRX wheel/tire from eBay. I bought a Volvo space saver wheel and skinny tire from eBay, the Volvo bolt pattern is also 5x108 and I trust a 5 year old spare tire much more than a 30 yr old TRX tire if I ever had to use it! The skinny Volvo spare tire also leaves a bit of stowage space in the front trunk on top of the tire as well.

 

Don't think the 8" wheel/tire will fit under the front bonnet. The SPCs show 308 that came with 16" wheels used a 7" wide for the spare.

The wheel bolt length differences are related to the brake disc design (not the wheels) -- i.e., putting a 7" or 8" wheel on the rear = use the shorter wheel bolts, and, likewise, putting a 7" or 8" wheel on the front = use the longer wheel bolts.

 

I agree that the 8" wheel won't fit in the frunk space. So if you do get a flat in the rear you'd better hope that you were alone. If not, you're leaving something or someone by the side of the road. I've never tried mounting a rear wheel on the front, there might be interference issues with fenders or suspension parts.

I did not need to change wheel bolts moving between metric and repro wheels. They are different lengths already.

On the 308 the rear hub diameter is bigger than the front. The repro wheels are designed with the rear's hub diameter for both front and rear. The spacer makes sure the fronts are centered when you bolt them up. This design does allow the front wheels to be mounted front or rear so you could use a repro front as a spare. That's what I have. Superformance will sell you one (or five). But I also would use a 30 year old TRX as a spare if that was my only option. I wouldn't use it at high speed or for very long, but I would use it to get to the next town if I needed.

 

I had Superformance repro 16" rims. I sold them: they are not original (you can clearly see the rear ones are different from the originals) and they weight much more than the original TRX metric rims.
A tip: buy an original set of Cromodora 16" rims (even if they cost a lot, 4-5 k, but you won't lose your money) or buy a TRX set. The TRX are very strong and durable tires, they can last ten years without problems: I drove several times my former 1983 Ferrari 208 GTS turbo with factory original TRX tires, 34 years old (up to last year). I didn't go over 80 mph (120 km/h), but they still worked.

I hated to see my car with not original rims, so I spent the money and (on my 308) I put back the TRX rims with fresh TRX tires and I got a spare of 16" Cromodora factory option rim set.

ciao

 

Forgot to mention, further to the Volvo spare, a few details and key considerations: - I used an S80 spare, size 125/80-17. It's the same diameter as the 308's 16" tires. This photo compares to the similar diameter TRX tire

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The wheel required drilling a few holes to accommodate the brake disc centre fixing screws that project from the hub of the brake disc. See here (that's the rear brake, but the fixing screws are the same):

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Here's a picture of the holes drilled in the spare wheel to give clearance to those disc fixing screws:

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The steel wheel hub area is much thinner than the alloy centre of the Ferrari wheels, so the regular wheel bolts are too long - they would bottom out if you tried to use them with the Volvo spare, and leave the wheel wobbling! The Ferrari wheel bolts are 14x1.5 diameter and pitch, which is the same as several European cars use - Audi, for example. I bought a set of 5 shorter bolts from ECS Tuning specifically for use with the spare - they have them on sale right now for $0.42 each! https://www.ecstuning.com/b-ecs-parts/ball-seat-wheel-bolt-14x15x255mm-priced-each/ls17d25f~ecs/


Also, the centre hub flange of the Ferrari front discs is smaller than the centre flange of the rear discs - which is why the Superformance replica wheels require a hub ring in front, as they have the same centre bore profile front and rear (The OEM 1Ferrari front wheels have a stepped bore - larger diameter to fit the shallower, larger flange on the rear disc, but a deeper narrower bore to fit the deeper front flange). That also means that the Volvo spare wheel fits on the front hub, but does NOT fit on the rear hub. The solution, should you have a rear flat tire, is to install the Volvo spare on the front position, and move the front tire to the rear to replace the flat rear tire. A bit of extra work, but it will still get you on the move.

Here's the Volvo spare mounted to the front hub (car is on jacks, so the suspension is not loaded):

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The spare tire compartment with the full size TRX wheel/tire in place:

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And with the Volvo space saver spare in place

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how much was the total with the discount applied?

 

The Volvo spare is a great idea; a fresh space-saver spare for cheap. I paid $40 for mine which I found in a crashed Volvo in a junkyard.

I had test-mounted my Volvo spare on my front wheel and had thought that it fit with the factory bolts. I've been driving around with the Volvo spare in the front trunk for a couple of years! Thanks for the tip. I just ordered a set of bolts from ECS Tuning.

 

Yeah because the original owner (moron) did not order the optional wheel back in '83. I was in the exact same position as you when I bought my car in '01 and it was on my top priority to refurb the suspension bushings, shocks and put 16inch rims to run real rubber to enjoy the car - I really like enjoying the handeling of a car. Never looked back. Still have the set of beautiful TRX rims with very nice looking tires sitting in the back of the storage unit for all those platinum awards ;-).

I just could never waste that much money on a tire which has been crap for well over 25 years.

Anyway, hope you drive it more the the prior owners, they are loads of fun on nice country roads with a couple buddies in the mirror or out in front.

 

Holy frack.... I guess I'll say... hope you're happy with them?

 

WOW! $$$

A the opposite end of the scale, my research has led me to purchase Firestone Firehawk Indy 500s for my '89 328.

 

I’m using Firestone Indy 500s on my 2018 Alfa Giulia and I love them!!


Sent from my iPhone using FerrariChat.com mobile app

 

You have not even include the mount and balancing cost.