Extremely pleased to say, thanks to the power of FerrariChat, we now have a set of correct mag wheels, and straight eared spinners. Thank you daytonaman & 500tr
I have a single, slotted mag that was/is the spare for my GTC. Excellent paint and chrome trim disc. Tire (newish sumitomo) mounted. PM if interested. steve
I have a source for new-reproduction centers for the knock-offs. These have the raised Ferrari horse and the arrow. They really are quite nice.
Correct reproductions for the straight-ear centers should also have the step ridge inboard of the perimeter.
We discussed this a while back. Please could you clarify exactly what the aspect ratio would be on the M series Dunlop R7 tyres as it does not say in the sizes marked on the tyres. Was it the case that tyre manufacturers only started quoting and marking the lower profile tyres with their aspect ratios as they became prevalent? Snip of a 275 GTB/C build sheet referencing the wheel and tyre sizes. Image Unavailable, Please Login
Steve: As per the Dunlop Racing Tire Catalog, a 550Mx15 is a 58 aspect ratio and a 600Mx15 is a 56 aspect ratio.
Thank you very much, Dyke? Would you know what aspect ratio the Dunlop R5 tyres used on the 250 GTO in sizes Front 6.00 - 15 and Rear 7.00 - 15 was?
Steve: 250 GTO's that used Dunlop R5's had fronts of 600x15 aspect ratio of 79, the rears 700x15 is no longer made, but a 650x15 has an aspect ratio of 74, so I would expect a 700 to be in that range. Today we use the "L" Series Dunlops on the GTO's and a 600Lx15 has a 68 aspect ratio and a 700Lx15 has a 66 aspect ratio. The "L" Series appeared in the early 60's and GTO's raced with them.
Thank you again, Dyke. Pourret's 250 Comp book actually sates that the 250 GTO used Dunlop R 5 and R 6, Yellow or Green Spot in 600 L x 15 Front and 700 L x 15 rear, so was it the case that the R5 tyre was also an L tyre and the GTO always used the lower profile L tyres rather than a taller 79 aspect ratio tyre?
Steve: You are starting to ask questions to which I do not know the answers. R5 refers to a "tread pattern". Today, the "L" Series tires use a CR65 "tread pattern", while the "non-letter" (and taller profile) use a R5 "tread pattern". As for Jess' book, remember, he was not a racer and I would not depend upon his book for accurate comments about tires of the period. With that said, if you look at photos of GTO's racing early in their career, the tires appear to be very "skinny", ie, the narrow tire Dunlop today refers to as the R5. I am pretty sure that, based upon period photos, GTO's raced on BOTH the "non-letter" and "L" Series tires.
Digging up this old thread with a similar question - do some (any? or all?) of the 330GTC Speciales sport 15" rims? In looking at some photos, it appears that one or two might have 15's, but perhaps I'm delusional. If yes, then are these RW4011's- on the assumption that they have size 32 hubs? For kicks, I've test-fit an RW4011 on a GTC just to see if it would work - it does fit and the wheel turns (BARELY, while stationary only), but the diameter of the tire that it was wearing was about 1" too tall, so I was unable to test it while driving. (btw I know the RW4010s are narrower, but I don't care for the look of the outside spokes).
I believe the only GTC car that had 15" wheels, Star Campagnolos with straight 3 eared knock off spinners, (and 42 spline hubs?) was the 330/365 CTC Prototype Speciale #10581 built for Leopold Pirelli. IIRC, Seth, @intrepidcva11, a former long term owner of this car has said that the wheels fowled the wheel wells when turning.
Any knowledge as to the width of those one-off rims (7 or 7.5, perhaps?) and the size of the tire? Depending on where it rubbed the well, Its also possible that they didn't get the offset exactly right.
Seth @intrepidcva11 has the build sheets for the carl See here. So perhaps he will be kind enough to check them to find both the width of the wheels and size of the Pirelli tyres?