Inner tubes

what you understand under "innertube"?
I understand this "thing" where you put air in. and when I translate it says the same. but you not may put this in without the nipples of the spokes are covered. may be you also say to this innertube? even it is no tube. it is a molded rubber, at the outside thinner as in the middle.
and you write you refuse to fit them without innertubes. so then the air just will come out at all holes. could you please explain for me better what you mean? thanks

 

as an aside. only use michelin inner tubes. also, will nitrogen filled tires maintain their pressures longer?

 

Romano, ”inner tube” is the soft inflatable rubber tube with valve stem you place inside a tire in many oldtimer cars, especially those with wire wheels to hold the air.
Many oldtimer car spoke or wire wheel also require tube protectors, also known as “flaps”, which are soft rubber rings you place inside the wheel, on top of the spoke nipples so they don’t puncture the tube.

Most cars made since 1950’s don’t require or use either, as they commonly have wheels designed for (modern style) “tubeless” tires.

P.S. Looks like Dougal posted a picture of an Michelin “inner tube”.

 

Not necessary but preferred in some applications. I’ve installed/used “other” brands in several cars tens of thousands of of miles and currently still do (remember, I probably enjoy driving 50-100 y.o. vintage cars far more than most, at least 4K-5K miles annually).

Personally, I’ve never used/tried any nitrogen, but OTOH, haven’t had any pressure failures with good, old fashioned compressed air either.
While I haven’t researched or tried the use of “nitrogen” in tires, I think the “marketing” for its use might be based on some (claimed ?) minimal lower temperature “improvements”(?), but how much and/or how scientifically were the results achieved/verified and how accurate they may be in real world applications.
A lot of clients and friends have asked me if they should use it, especially in new/modern cars that might’ve come with it and I’ve always tell them above, but if they feel more confident by using it, I won’t try to stop them.

 

thank you very much timo for this explanation. so I also have known this and tried to write

sorry dougal, I missread your post I was reading you refuse to use an innertube. sorry again

this of course is not state of the art

but you as a tire specialist, why you not explained this so as timo did about 5 minutes after your post?

 

This 1974 document seems to be "off" as the "original" tire specification for the 330 GT is listed as 215/70 -15, which is definitely incorrect. The original tire size was 205-15 (before aspect ratios were a "thing" ). 215/70-15 is definitely a valid alternative to use, and maybe is all Michelin offered in 1974, but listing that size as "original" is incorrect.

Also, I don't really read that document as saying tubes being compulsory, but rather, "if you require a tube, this is the size to use".

All of those models except the Dino still had Borranis as an option, so it is probably speaking to that configuration. Some Dino had Borranis fitted after buying them, though not ever from the factory I don't think.

It is extremely unusual that they have the "365P" model included as that is a one-off 3-seat, center driving position prototype

I believe the Dino 206/246 and 330GTC/365GTC sections are just showing that both models share the same tubes, not that tubes are excluded for the 246GT and 365GT. Where there are two lines in a section, it is only for tire pressure, which is most likely for for normal and high-speed use -- otherwise, I think the all data specified applies to all the models listed in each section.

Although magnesium is porous, properly zinc-chromate-primered Campagnolo wheels should not leak air. I would be opposed to unnecessarily adding tubes, not for cost reasons (per Michelin document), but to avoid additional unseeded weight on the periphery of the tire/wheel.

 

Yes. The molecules are bigger, so they will definitely hold air longer with pure nitrogen. Also tire pressure is more stable over differing temperatures with nitrogen, so that can make a significant difference on track where tire temp varies a lot and 1 or 2 PSI can make a significant difference in handling. Also (probably more of interest to vintage car use) pure Nitrogen is less likely to contain moisture than air from pumps, which means it will reduce long-term degradation of tires.

There's nothing wrong with using air (which is 78% nitrogen anyway), but Nitrogen is a bit better from every perspective. Costco includes Nitrogen fills for free when they install tires and the "air pumps" in the Costco parking lots are Nitrogen also. You can go to any Costco location and fill your tires with Nitrogen for free. You are supposed to be a member to use it, but there isn't any card swipe necessary, so you can fill even if you aren't a member.

One good place to use Nitrogen is to fill the "mini-donut" spares on modern cars. I checked the air pressure on my 996 mini-donut, and it was 4 PSI -- instead of the recommended 60 -- so it would have been useless if needed (near-zero was the "norm" when I posted about that to Rennlist, so those donuts drain air over time). It's a good idea to fill the mini-spare any time you fill the main tires (or at least every few times you fill them). It's even better to use Nitrogen for those so they leak more slowly over time.

 

I agree about what we call here safety wheels but its such an old term many do not know it. A safety wheel is one with the "bump" designed to keep beads seated with air loss.

As far as what Ferraris position was in the 67/68 period parts books were changing from all tires with tubes to going tubeless on alloy wheels. .
Maybe they were having trouble with alloy wheels leaking? Or maybe there were still people (I still run into them) who feel having a tube was safer. One of the reasons the industry went away from tubes was it was resoundingly proven tubeless is safer.

 

Parts book for 330 shows tubes on both type wheels.

 

Very interesting. The plot thickens ….

 

Long story but I did a history of Ferrari valve stems for the IAC/PFA. Queen Mother parts book is the 1st one that shows a valve stem for tubless tires.

By the way. The Schrader Valve is evidently the oldest technology still in use in the auto industry.