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1930 Indy tire size


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#1 m9a3r5i7o2n

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Posted 24 February 2006 - 16:04

I am asking about the wheel sizes of the old Indy cars that ran in 1930 as the people who are rebuilding these cars can’t find the make, probably Dayton, sizes and spoke numbers,.
The pictures I have show that they are spoke with the knock off wheel nuts and narrow Firestone slick tires. But I can’t read the tire sizes. The best counting of the spoke number is 80, but this could easily be wrong as the picture is not very clear!
I have called Dayton and their record doesn’t go back to 1930 except for just knowing that they are sure that the wheels are Dayton.
Someone answered this question I believe before but I have unfortunately lost the information over a period of time on this useful piece of information. The person at Dayton (Derrick Ex. 111) tried to be helpful but appeared to be at a loss for old information of this type.
However he was sure that they had the wheels of nearness to the old ones.
It is amazing how much has been written on the old Oakland in Atlas F1.
M. L. Anderson :clap:

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#2 A E Anderson

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Posted 25 February 2006 - 10:00

Originally posted by m9a3r5i7o2n
I am asking about the wheel sizes of the old Indy cars that ran in 1930 as the people who are rebuilding these cars can’t find the make, probably Dayton, sizes and spoke numbers,.
The pictures I have show that they are spoke with the knock off wheel nuts and narrow Firestone slick tires. But I can’t read the tire sizes. The best counting of the spoke number is 80, but this could easily be wrong as the picture is not very clear!
I have called Dayton and their record doesn’t go back to 1930 except for just knowing that they are sure that the wheels are Dayton.
Someone answered this question I believe before but I have unfortunately lost the information over a period of time on this useful piece of information. The person at Dayton (Derrick Ex. 111) tried to be helpful but appeared to be at a loss for old information of this type.
However he was sure that they had the wheels of nearness to the old ones.
It is amazing how much has been written on the old Oakland in Atlas F1.
M. L. Anderson :clap:


Marion,

6:00-20 rims and tires were pretty common in Speedway racing in 1930, I believe. I don't think Firestone was making any variety of tire sizes that year--their racing tires seem to have been passenger car casings, with racing treads (or the lack thereof?)

Art Anderson

#3 D-Type

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Posted 25 February 2006 - 15:36

Marion,

You could try asking the same question over on Trackforum - that lot know all there is to know about Indianapolis history.

#4 m9a3r5i7o2n

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Posted 25 February 2006 - 18:16

One would think that if a firm advertises a product from 1930 to this date they would know the answer. It just isn't so. I have applied for membership at the aforementioned Trackforum it would not surprise me that one of those people know more about it than the men in the business. The man at Dayton did his best but I imagine that they likely get 20 questions a day that are just about impossible to answer unless you get ahold of the person who is in charge of that particular subject.

I also believe that the size is nominally 6.00 X20, but this doesn't answer the question about the wheels. There are just too many variables as,"What size are the knock off hubs. Some are made with differing numbers of spokes, etc,etc.

Thank You, M. L. Anderson :wave:

#5 dbw

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Posted 25 February 2006 - 20:37

ok..i think i answered this a long time ago- so i'll give it a try....as of 1930 the rim dia was beginning to shrink..the 20" rims were used in the mid '20s but as of 1930 19's were quite popular..the rims themselves were manufactured by various companies but were pretty much all straight side -flat base -lock ring type.[and i might add stayed alarmingly narrow..3-4"]..the hubs might vary a bit but all the serious guys all used a 52mm rudge long nose [or "speedway"] hub...most often attached with a two eared open face knockoff... the spoke count also varied but 72 seemed to be the standard...[this is where i'd have to go way into the dark damp files]...but as i recall a triple cross pattern with two rows on the rim was common..the wide flat surface of the lock ring rim allowed for a pretty wide spacing for nipple holes..the long nose hub allowed a wide latitude of rim offset when lacing the wheel...i don't know if that helps...however..

from 1930 things at indy moved fast...by 1932 bigger cars [such as the studebaker factory cars] ran 18's[still lockring] on rudge speedway hubs..."balloon" tires began to appear..[these had a bigger overall section than the standard speedway tire] the '35 miller fords used 18" lock ring rims / rudge hubs.. in '37 miller used 16" [!] drop center rims [!!!]with the ever present rudge speedway hubs on the fwd gulf cars...but i digress...

i can't speak as to what present day restorers are doing for wheels...i'm currently in the gp bugatti world and that pretty much limits my choices of wheels [wheel]...there are, however a large number of indy cars now being restored/partially recreated/totally created...a visit to the miller site might help...jim stranberg at high mountain classics in colorado has restored several millers..phil reilly in northern calif has also done quality miller and indycar work...the late chuck davis probably had the most connections [and parts i might add]..buck boudeman might also know of sources for wheels...this is a long time ago but when bob sutherland was really into millers he had several people in the uk making-ah-restoring cars and parts...it might be worth a look over there....

i would rather think that a small speciality house will be of more help than the dayton folks....hey try corky coker at coker tire..i'll bet he's up on current suppliers...

best of luck :wave:

#6 A E Anderson

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Posted 26 February 2006 - 06:02

Originally posted by dbw
ok..i think i answered this a long time ago- so i'll give it a try....as of 1930 the rim dia was beginning to shrink..the 20" rims were used in the mid '20s but as of 1930 19's were quite popular..the rims themselves were manufactured by various companies but were pretty much all straight side -flat base -lock ring type.[and i might add stayed alarmingly narrow..3-4"]..the hubs might vary a bit but all the serious guys all used a 52mm rudge long nose [or "speedway"] hub...most often attached with a two eared open face knockoff... the spoke count also varied but 72 seemed to be the standard...[this is where i'd have to go way into the dark damp files]...but as i recall a triple cross pattern with two rows on the rim was common..the wide flat surface of the lock ring rim allowed for a pretty wide spacing for nipple holes..the long nose hub allowed a wide latitude of rim offset when lacing the wheel...i don't know if that helps...however..

from 1930 things at indy moved fast...by 1932 bigger cars [such as the studebaker factory cars] ran 18's[still lockring] on rudge speedway hubs..."balloon" tires began to appear..[these had a bigger overall section than the standard speedway tire] the '35 miller fords used 18" lock ring rims / rudge hubs.. in '37 miller used 16" [!] drop center rims [!!!]with the ever present rudge speedway hubs on the fwd gulf cars...but i digress...

i can't speak as to what present day restorers are doing for wheels...i'm currently in the gp bugatti world and that pretty much limits my choices of wheels [wheel]...there are, however a large number of indy cars now being restored/partially recreated/totally created...a visit to the miller site might help...jim stranberg at high mountain classics in colorado has restored several millers..phil reilly in northern calif has also done quality miller and indycar work...the late chuck davis probably had the most connections [and parts i might add]..buck boudeman might also know of sources for wheels...this is a long time ago but when bob sutherland was really into millers he had several people in the uk making-ah-restoring cars and parts...it might be worth a look over there....

i would rather think that a small speciality house will be of more help than the dayton folks....hey try corky coker at coker tire..i'll bet he's up on current suppliers...

best of luck :wave:


the 20" diameter rim and tire combination was very, very much there on new production cars of 1930, for example, the Duesenberg Model J used them out to the end, except for the 17's mounted on JN models in '36-37. At Indianapolis, believe it or not, the front-drive Novi and the Blue Crown FD (pretty sure about the Blue Crown cars) used 10" rims from 1946 on, the Novi receiving 10" diameter cast alloy Halibrands for its last attempt to qualify in 1955 (those wheels were on the car until it's re-restoration in the late 1980's).

Balloon tires arrived at Indianapolis in 1925, replacing the older, straight-sided hard, high-pressure tires which dated back into the early 'teens. The 1931 Cummins Diesel Special still stands on 17" rubber, which I believe is the tire size it ran when built. Those tires are beyond balloon, they are virtually "donuts", they are that fat in cross section--but then, there's something on the order of 1000lbs of cast iron diesel truck engine up front, mounted in a fairly stout Duesenberg Model A luxury car chassis left over from the late 20's.

Also, throughout the 30's, there was very little, beyond tread thickness and pattern, between medium-duty truck tires, and their same-size luxury car tires, and I'd bet that Firestone did little more than create new vulcanizing molds to make those into racing tires back then.

Art

#7 dbw

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Posted 26 February 2006 - 09:25

yes..at indy wheels got big again after the war [20" mags were pretty standard in the 50's]..but they did get wide...the dusies were a big heavy car and a 20" rim/tire made sense...altho the l-29 cord had 18's and it was no lightweight...dayton had to specially make the monster dental drive front hubs to fit the fwd guts inside.

#8 m9a3r5i7o2n

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Posted 26 February 2006 - 19:40

Art stated; I'd bet that Firestone did little more than create new vulcanizing molds to make those into racing tires back then.

From what I have been able to glean from statements of other people I’d state that you are right, Firestone didn’t seem to have a lot of interest in pushing the envelope further into the future until Goodyear got back into the business of making racing tires sometime ago.
It is probably almost an accident that they made the Balloon Tire about 1925. From pictures I have seen in the book, “The Miller Dynasty” and Ludvigsen‘s book, “Indy Cars 1911-1939, the tread on those looked about 3 inches wide. As near as I can tell the Balloon tire came out in 1925. The picture on page 70 definitely shows the White letters on each tire as, “Firestone Balloon“. The Firestone picture on page 49,1925, seems to have Balloon on it but not in White lettering. This was the time that the tire pressures dropped from about 100 p.s.i.g. to around 30 p.s.i.g.. So this seems to confirm that the Balloon tire came out some where around the 1925 period. After that there were none that I can find that weren’t Firestone of one type or another. There are no Dunlop pictures after 1926 in evidence in either book.
The 1935 cars had 6.000-18 written on them, page 113 of Ludvigsens book.
Also on page 111 there is a picture and a statement of “an example of the classic full-floating “safety” hub using a 310 series ball bearing. The axle may break, or be replaced ,without affecting the wheel hub itself. This pattern was used on nearly all American racing cars until the open tube rear end came into general use after WW2. The picture shows a 52mm RW Hub. It surely does not look very strong. No wonder the open tube replaced it.

Tomorrow, Monday, I will try some of the places mentioned especially Coker and see what happens.
Yours, M.L. Anderson :clap:

#9 A E Anderson

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Posted 26 February 2006 - 20:31

Originally posted by dbw
yes..at indy wheels got big again after the war [20" mags were pretty standard in the 50's]..but they did get wide...the dusies were a big heavy car and a 20" rim/tire made sense...altho the l-29 cord had 18's and it was no lightweight...dayton had to specially make the monster dental drive front hubs to fit the fwd guts inside.


No,

20" mag wheels were not standard at all in the 50's. By 1950, AAA Championship cars were running 18" rear, 16" front wheels and tires, with Novi retaining the 20-inchers as much for the added tire "footprint" as anything else, along with the much greater weight of the car.

Art

#10 A E Anderson

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Posted 26 February 2006 - 21:24

Originally posted by m9a3r5i7o2n
Art stated; I'd bet that Firestone did little more than create new vulcanizing molds to make those into racing tires back then.

From what I have been able to glean from statements of other people I’d state that you are right, Firestone didn’t seem to have a lot of interest in pushing the envelope further into the future until Goodyear got back into the business of making racing tires sometime ago.
It is probably almost an accident that they made the Balloon Tire about 1925. From pictures I have seen in the book, “The Miller Dynasty” and Ludvigsen‘s book, “Indy Cars 1911-1939, the tread on those looked about 3 inches wide. As near as I can tell the Balloon tire came out in 1925. The picture on page 70 definitely shows the White letters on each tire as, “Firestone Balloon“. The Firestone picture on page 49,1925, seems to have Balloon on it but not in White lettering. This was the time that the tire pressures dropped from about 100 p.s.i.g. to around 30 p.s.i.g.. So this seems to confirm that the Balloon tire came out some where around the 1925 period. After that there were none that I can find that weren’t Firestone of one type or another. There are no Dunlop pictures after 1926 in evidence in either book.
The 1935 cars had 6.000-18 written on them, page 113 of Ludvigsens book.
Also on page 111 there is a picture and a statement of “an example of the classic full-floating “safety” hub using a 310 series ball bearing. The axle may break, or be replaced ,without affecting the wheel hub itself. This pattern was used on nearly all American racing cars until the open tube rear end came into general use after WW2. The picture shows a 52mm RW Hub. It surely does not look very strong. No wonder the open tube replaced it.

Tomorrow, Monday, I will try some of the places mentioned especially Coker and see what happens.
Yours, M.L. Anderson :clap:


Marion,

The period 1925 to 1941 wasn't known for significant advancements in tire technology by anyone, frankly--not Firestone, not Goodyear, not BF Goodrich, not anybody. Tire sizes got smaller and wider through about 1935-36, finally standardizing at 16" diameter by then, which remained pretty constant until 1948-49. The rubber used was natural latex rubber, synthetic rubber would wait until the necessity of the Second World War, and then expand into mass-produced civilian tires after the war--although civilian tires were made during the war--ever see the characters S-1, S-2, and S-3 on old tire sidewalls? Those denoted synthetic rubber on wartime tires. Nor had synthetic fibers made it to tire casings, until the need for massive numbers of high pressure aircraft tires during the war--enter nylon tire cording. Until then, every US tiremaker was using cotton cord for making tire casings.

Tire tread width (or the lack thereof) did not a balloon tire make or break--but rim and casing width did. The balloon tire concept stems from the near-circular cross section of the inflated tire casing, not tread witdths. Race cars of the teens through the early 20's ran on tires with much more an "oval" cross-section, more tall than wide, hence the term "straight-sided tire", with a "clincher" rim, which gripped the tire casing by virtue of the rim having been rolled into almost a C-clamp configuration, the tires themselves running upwards of 90-95psi pressure. Also, those early tires were much, much narrower in cross section, and were measured, not by rim diameter, but by tread diameter and rim width. Racing tires, at least in Speedway racing, continued having a narrower tread in comparison to the width of their casings, all the way to the eve of US entry into WW-II, pictures clearly show that, along with the tires on cars at Indianapolis Motor Speedway's Museum. (One of the perhaps little-known things about the Musuem is that Firestone built up a pretty fair supply of older racing tire sizes for the Speedway Museum in the late 50's/early 60's, before they began disposing of old tire molds--such was the relationship enjoyed by Tony Hulman Jr. (one of the pioneers of the antique car hobby, a founding member of AACA in 1936, BTW, and Firestone Tire & Rubber in those years). I had the opportunity, once, about 1977 or 1978, to have a tour of the "supply building" used by the two men responsible for restoration and maintenance of the Museum's growing collection--rack after rack of old-style Firestone racing tires, nicely wrapped from the factory, in all manner of old sizes.

Balloon passenger car tires of the 1930's, such as would have been on your favorite car, the Oakland, ran a lower pressure than the old high-pressure "clincher" tires (those clinchers require about 79-75psi) or in the range of 45-50psi. It wasn't until the coming of the really low-pressure 15" tires of 1948-49, along with nylon and rayon casings that tire pressures on passenger cars dropped to 35psi. Tire treads on passenger cars could, of course, be built up at the edges, for a wider tread, simply because they weren't running the incessant high speeds of a race car. so heat buildup in the treads coupled with centrifugal force wasn't nearly the problem it would have been in racing. Where a passenger car tire of the 30's, built with 6, and in some cases, 8 ply casings, might be more than an inch thick at the center of the tread, race tires were, just as they are today still, far thinner, probably no more than 1/2" thick at the center of the tread. Wide tread, built up thickly at the edges on a round cross-section casing, simply would not have held up, certainly not vulcanized natural latex rubber, although race tires did get some buildup of the tread edges by the late 30's.

In 1994, at the first Miller Race Car Reunion at Wisconsin's Milwaukee Mile, one of the 1938 Burd Piston Ring Specials showed up, an all original car, down to a set of tires which had been the last tires mounted during a pit stop at Indianapolis in 1938, Firestone gum-dipped cotton cord racing tires! This car, regardless of intelligence or the lack thereof, was run that weekend, in 100-degree July weather, until the owner had to pull it off the track due to the breaker strip showing. Chris Etzel and I measured and photographed this car extensively (it was a 2-man car, memory tells me that it dated to about 1931-32, with updated bodywork) I seem to recall its tire sizes as having been 6:00-18 rear, 5:00-16 front, with the rear tread width being 5", or just about 1/2" narrower than a comparable 16" passenger car tire of the day. I believe we read on the sidewall, the legend: 8-ply, again quite consistent with larger passenger car tires of the period. Firestone Tire and Rubber, with the development of their balloon tires, had developed, and patented, a process whereby they soaked the cotton cord in clear gum rubber, before winding it into tire casings, which ostensibly reduced the wear of the plies of cotton cording rubbing against each other as the tire casing flexed in passenger car use. Whether or not it was significantly effective or not, I cannot tell, as my father, who was on the road daily in his job in the years 1937-69, constantly reminded me that until the postwar years, he could not get more than 10.000 miles out of a set of tires before the war, which seems to have been pretty much the norm with those old cotton tire casings. Dad used Firestones, as well as other makes of tires back then--he bought on price, not on brand.

Tire technology, just as with much of the rest of automotive technology, developed but slowly in those years, frankly.

Art

#11 m9a3r5i7o2n

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Posted 01 March 2006 - 23:56

Have spent the last two days trying to find someone who sells the 52mm long nose Rudge-Whitworth Hub, so far the only one I can find is in Germany and am now composing a letter in English to send to them and hope they have someone who speaks and reads English.
Some of the interesting things one finds.

OCT 6, 1923 Ford Archives Letter from Harvey Firestone to Henry Ford:
"Your interest in balloon tires started me actively testing and developing them and they are giving service far beyond my expectations. At this time several large automobile manufacturers are active in their experiments on this tire and I believe will adopt it as optional equipment.
Cole booklet with a notation made by Mr. Edison. You will see that he is strongly sold on the balloon tire."

1922 Trial Balloon
Firestone introduces balloon tires. These low-pressure tires dramatically improve riding comfort, and they are less susceptible to blowouts. Within five years, more than half of all tires manufactured in the United States are balloon tires.
1922, Sig Haugdahl a Norwegian immigrant, the first man to balance the wheels and tires on his race car. :up:
M.L. Anderson :clap: