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Post by Calvin on May 13, 2013 16:05:46 GMT -5
One thing the frustrates the heck out of me about this era in indycar racing is Tire size.
I wished we had a list of what size of tire were run on what car or year.
Like for example what size did the 63 Winner have or the 65 Winner 69, 70, 71, 72, and the rest of the 70's into the 80's.
Its never been clear to me what some of these sizes are.
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Post by mjjracer on May 13, 2013 18:09:39 GMT -5
Excellent question Calvin!
I've been wondering if Michael's new '63 Lotus/Watson tires would work for the '64 Lotus of Bobby Marshman - just got some of those decals off of eBay.
MJ
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Post by Patrick on May 14, 2013 10:23:23 GMT -5
If the list could include examples of 1/25 tire resources (that were applicable) which were broken down into years that would be great (what a mouth full!). This could be a standard that we all measure our cars by.
Does anyone know what I mean?
Patrick
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Post by indy on May 14, 2013 12:27:59 GMT -5
I think we've run the same tire size for the last few decades, right??
F 10.0/25.8R15 or 305/35R15
R 14.5/28.0R15 or 415/40R15
If we can get a list together then I will organize it and put it up on a sticky on the forum.
Jordan
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Deleted
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Post by Deleted on May 15, 2013 12:18:13 GMT -5
I am new here so I hope I am not stating the obvious but if you know the wheel size and have a profile or near profile race day photo, you can calculate the heighth of the tire and then in turn use that number to scale down to the model you are building. For instance, the '63 Lotus ran Halibrand 15" wheels on the rear at Indy on race day. The wheel on a race day photo of the car that I have measures 20 mm. (I use metric because the math is easier). The tire measured from one side to the other directly through the middle measures 35 mm. Since we know the wheel is 15 inches represented by the 20 mm in the photo, the heighth can be found using ratios. That is , the 35 mm in the photo comes out to a 26 inch tall tire in 1:1.
To apply that to the model is another ratio problem. The AMT Halibrand wheel measures 17 mm which is slightly larger than 1/25 but the model seems to be proportioned with the wheel so if 17 mm represents 15 inches in 1/1, then 30 mm equals 26 inches. If you look at the AMT ERTL plastic front tire, it measures a little more than 30 mm. It is not wide enough but it has the correct Firestone lettering and crossed flags. If you have an undistorted photo of the car from the from the front or rear, you can find the width using the heighth that was just found by the same method.
If there is no useful photo, then you have to resort to research. The book "Team Lotus, the Indianapolis Years" has the tread width of the rear 1963 Firestone race day tires as 8.25 inches so using 17 mm = 15 inches, it is found the model tire tread width should be around 9 mm. This seems like a wide tire for 1963 but it is believable because the Halibrand wheel was 9 inches wide. The additional width can be made up using plastic card rings.
The front tires of the 1/1 come out to about 24 inches. The AMT front tires are too tall by 2 mm but they are the right width. By sanding them with a drill chuck I was able to remove 1 mm which makes them 1 scale inch too tall but they look convincing.
I hope this was helpful.
This method will work on any car and it will give you the dimensions of the after market tire you are looking for. I hope you find this helpful
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Post by indy on May 15, 2013 13:13:10 GMT -5
Isn't the rim measurement the inside of the tire? So the 15" does not include any lip on the rim. Or am I off base?
Jordan
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Post by Deleted on May 15, 2013 13:43:32 GMT -5
No you are not off base, I originally thought the difference would be negligible, so the tire heighth would be inaccurate this way. However, using a photo and measuring the ratio between the wheel lip diameter and the tire diameter can still be accurately transferred to the model because in the photo you are measuring the wheel lip diameter which is what is being compared to on the model. It's really not necessary to know the 1:1 tire height to do this. I have stared at the AMT Lotus 29 for a long time trying to make the kit tires work as they were and recently I came up with this idea of photographic ratio comparison. I mocked up a set of tires this way and photographed it in the same position and when compared, it looks nearly identical to the 1:1 photo.
I did not mean to mislead anyone because as Indy indicated you will not have the correct tire size unless you account for the depth of the lip on the wheel, but the method of correctly sizing the model tire for the model works. You are just transferring the proportions from one size to another.
Again, I apologize.
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Post by indy on May 15, 2013 14:20:09 GMT -5
I think you have a decent idea. If you had a rim and from measurements thought it to be accurate size-wise in scale then you could extrapolate the tire size from measuring a picture. You'd just modify the procedure above you lined out above only slightly to get at a fairly accurate number.
It is nice to have you here, I appreciate you jumping on in. Please feel free to keep chiming in.
Jordan
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Post by Calvin on May 15, 2013 22:08:15 GMT -5
Does anyone know if the 1968 Winner tire size is the same as the 1969 Winner? I know its Goodyear and Firestone....But is the size the same? I dont know maybe not?   |
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Post by alwaysindy on May 16, 2013 9:57:37 GMT -5
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Post by Calvin on May 16, 2013 22:46:59 GMT -5
Thanks Tim!
Lots of different shapes and sizes back then.
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Orso
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Post by Orso on May 17, 2013 2:27:40 GMT -5
I've been wondering if Michael's new '63 Lotus/Watson tires would work for the '64 Lotus of Bobby Marshman This picture is interesting, it is Bobby with the 1963 and 1964 wheels: www.flickr.com/photos/lightning72/3997831245/Björn |
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Post by mjjracer on May 17, 2013 10:22:50 GMT -5
I've been wondering if Michael's new '63 Lotus/Watson tires would work for the '64 Lotus of Bobby Marshman This picture is interesting, it is Bobby with the 1963 and 1964 wheels: www.flickr.com/photos/lightning72/3997831245/Björn Wow! That answers that question. Thanks! MJ |
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Post by indycals on May 17, 2013 10:59:07 GMT -5
I've been wondering if Michael's new '63 Lotus/Watson tires would work for the '64 Lotus of Bobby Marshman This picture is interesting, it is Bobby with the 1963 and 1964 wheels: www.flickr.com/photos/lightning72/3997831245/Björn There should be an asterisk on that photo. In 1963 there were two sets of wheels in use - the larger, skinnier wheels used for the previous decade, and new 15" wheels allowing for lower profile and wider tires. There were not enough 15" wheels to go around so some teams got them, others had to stick with the older wheels. Jones and Clark had the new 15" wheels and that is what my new tires replicate. Hurtubise who was on the front row had the older wheels as well as Marshman. This photo looks like a 1963 FRONT tire and a 1964 REAR tire as if the 63 was a rear tire, it should be considerable taller than the 64 tire, but in the photo it is only slightly taller. The height of my rear 1963 tires is about the same as the height of the front kit tires that they replace. But in either case, by the mid 60s tires were changing pretty much every year, so no, my 1963 tires wouldn't work on a 1964 car. Lance's 64 Watson tires would be better. Plus the 63 tire was the last year before Firestone introduced the gold ring. here's a pic of the 63 front row where you can clearly see the difference in wheels/tires between Jones and Hurtubise. www.imscdn.com/gallery/indycar/indy/1963/19630101-nphotographer/med/1963_front_row.jpg |
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Post by mjjracer on May 17, 2013 13:43:34 GMT -5
There should be an asterisk on that photo. In 1963 there were two sets of wheels in use - the larger, skinnier wheels used for the previous decade, and new 15" wheels allowing for lower profile and wider tires. There were not enough 15" wheels to go around so some teams got them, others had to stick with the older wheels. Jones and Clark had the new 15" wheels and that is what my new tires replicate. Hurtubise who was on the front row had the older wheels as well as Marshman. This photo looks like a 1963 FRONT tire and a 1964 REAR tire as if the 63 was a rear tire, it should be considerable taller than the 64 tire, but in the photo it is only slightly taller. The height of my rear 1963 tires is about the same as the height of the front kit tires that they replace. But in either case, by the mid 60s tires were changing pretty much every year, so no, my 1963 tires wouldn't work on a 1964 car. Lance's 64 Watson tires would be better. Plus the 63 tire was the last year before Firestone introduced the gold ring. here's a pic of the 63 front row where you can clearly see the difference in wheels/tires between Jones and Hurtubise. www.imscdn.com/gallery/indycar/indy/1963/19630101-nphotographer/med/1963_front_row.jpgThanks Michael, very helpful. Now, if they had only known, they could have taken those taller wheels, put some super low profile tires on and kicked some butt. If only we knew then what we know now. MJ |
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Post by Calvin on Jun 11, 2013 16:04:00 GMT -5
Does anyone know when the front tire sizes increased in the 70's?
When I look at the tire sizes in pictures from 1977 and compare them to 1978 the 1978 tires look bigger slightly.
Really my main question is would the front tires from the AMT PC-6's be too big for anything prior to 1978?
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Post by indycals on Jun 12, 2013 3:18:30 GMT -5
I tried overlaying some photos from 77 and 78 and I can't detect any discernable difference in tire size.
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Post by Calvin on Jun 12, 2013 8:18:56 GMT -5
I guess my eyes are just tricking me, they just look slightly smaller on Foyt's car?   But I DO Know that Front AMT PC-6 Tires with 1988 AMT rear tires are perfect for the Chaparral 2k! I know that for sure just because I have all the specs imaginable about the Yellow Submarine! LOL  To my eyes the front tires on the Chaparral look bigger than the fronts on Foyt's Coyote IMO. |
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Post by smbrm on Jun 15, 2013 18:19:33 GMT -5
Does anyone know if the 1968 Winner tire size is the same as the 1969 Winner? I know its Goodyear and Firestone....But is the size the same? I dont know maybe not? They are not the same size. The size was increased after the 1968 Indy 500 for the Telegram Trophy race at Mosport. I believe the wider tires in the MPC Olsonite Eagle Kit reflect this change. The reference is from Auto Racing Magazine December 1968 Telegram Trophy 200 race report: "...Another sidelight of interest was the introduction by USAC of extra-wide wheels and tires and the "historic" sight of rain treads in the pits." Not sure if I have info on the dimensions of either. cheers Stephen |
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