MTFCA Forum

I recently had the pleasure of seeing some new Blockley tubes. They are heavy duty, and will not require flaps. The problem is, the valve stems are horrible! We need to get together and tell Blockley to address this problem. My suggestion is to have them supplied to us with the correct size valve stem opening and no valve stem, or at least a rubber stem that we can cut off as I've been doing for years, so I can install the proper metal valve stem.

They are excellent tubes in all manner which pertains to them holding air and keeping the car the requisite height off of the ground.

To suggest that they should be improved by leaving the stem off, such that every purchaser had to go out and find and install a set of original, separate stems, well, no one asked for an opinion on that, so I won't give one...

Simple FYI. I bought a bunch of them about a year ago. Yes, the stems are a bit too big. But that doesn't really bother me. I am just so glad to get what appear to be good well made innertubes instead of the past several I bought that were pure junk, and cannot even be reliably patched if one picks up a nail (or has to patch over a factory flaw failure!).
Yes, the stems are larger. However, I have two late brass era model Ts that I could not mount tires onto because I had no tubes! Eight wood felloe wheels, four of them the larger stems slipped into the original factory holes snug but easily. The other four, the stems would not quite slip through without a bit of effort. Only one was actually difficult. Others simply carefully running a barely big enough drill bit through the original steel sleeve for the valve stem expanded the steel sleeve enough for the valve stem to slip through! Running the drill bit through didn't even do serious harm to the factory original steel sleeves! Even the one I had to first expand with a succession of tapered punches to round it out a bit, I managed to keep the factory original steel sleeve intact and in place.

I can live with that.

However, I do see Larry's point. If one wants to use the right valve stem covers? They won't fit easily. I wonder if the outside of the valve stem could be rethreaded enough smaller to accept the original valve stem covers?

I wonder if the outside of the valve stem could be rethreaded enough smaller to accept the original valve stem covers?

No. The 724/725 size is too big to be rethreaded down to 777/888 size. I use the bigger size because it was all I had when I started installing my own stems. All the reproduction dust covers fit the larger size, and it's not hard to find originals that do too. I continue to use the big stems because all my covers, new and old, fit them.

I don't doubt that Blockley tubes are superior, but I have found Hartford tubes quite adequate. So I still buy Hartford rubber stem tubes for about $20 and install my own metal stems.

I must be a bit of a dill! If you can avail yourself of a set of period correct Dill sliding fit valve cap/covers, who cares what valve stem they totally hide?

Allan from down under

I agree with the above statement. I use Dill too. I'm working with a lad named Julian that is trying to help me with this matter. I'm going to keep my fingers crossed. If he can help, I told him they will sell thousands of those tubes if done correctly! Not only that, but we will not have to use flaps any longer!

The problem is, the valve stems are horrible!

Is there something wrong with the stems other than being the incorrect size?

By the way, I'm not making the same comment Scott's not making.

I'm still communicating with Julian at Blockley. He is a very nice man, and is trying to help me. The problem for now is they use the metric system, and I don't understand that. The large diameter valves work, but are too big in diameter for our application. I prefer the 2 3/4 inch length as opposed to the 3" length that Ford used, because they still do the job, and do not show with the proper dust cover.

Larry,

Why not send Julian one of your valve stems so they can get the exact measurement you are looking for.

perry kete wrote: ↑

Mon Apr 24, 2023 6:26 pm

Larry,

Why not send Julian one of your valve stems so they can get the exact measurement you are looking for.

The ideal thing would be to make the new stems to the original, smaller size with the correct threads.
Certainly the volume of tubes being made would justify this relatively minimal change.

There isn't any real reason to send an original valve, but it's a nice thought...

No need to reinvent or reverse engineer the correct stem. Everything about it is standard and known in industry: the correct 777 stem is 3" tall and has 10V2 threads on it's body, with standard 8V1 threads at the end (as do all valves even to this day)

They're not a particularly difficult turning project but for what anyone would pay for them, I never offered any for sale. Made with CNC equipment (which I do not have), they'd be a snap to make.

The problem may be that the majority of tunes for other sized tyres have the far more common larger sized stems and fittings. I can understand why they are also used on 30 x 3.5" tunes, in these days of shrinking inventories.

Allan from down under.

I worry that tubes that have been retrofitted with original Schrader 777 and 888 stems will continue to be thrown away when our cars inevitably change hands and the new owners don't know any better.

I haven't heard from Julian today. I'm still hopeful Blockley can supply us with a tube that has a removeable stem, or better yet, a tube with the correct size hole in it to insert our own valves. I'm impressed with the quality of the tubes I saw, and have no idea what the valves were for, and that is why I called them horrible. If Blockley can supply us with what we need, there will be no need for cheap tubes any longer, or flaps!

...have no idea what the valves were for...

Probably for Packard, Case, Pierce, Locomobile, Stoddard, and other larger cars and trucks. With only two stem widths, both were used on many different vehicles. I bet Ford was not the only car that came with 777 sized stems.

This info is on the Blockley website, under tech, seems they use a metal stem that is 12mm in dia. with O.D. thread of 26tpi.? The product page on the 3 1/2" and the 3" tubes only state nickel plated metal stems, but don't give a size.

Valve stem diameters and uses
For most "old car" applications the valve stem hole in the wheel rims come in 3 sizes, which are nominally:

- 8mm diameter, observed on some small and Voiturette cars (as well as motorcycles which often had the same tyre sizes). This 8mm size hole will have an inner tube with what is called either a "TR4" or "TR6" metal stem, both of these stems being virtually identical. At Blockley we use the TR6 stem because the patch that attaches to the tube has a larger surface area, and we like this.

- 11.5 mm (0.453") diameter. The most common size we all know on our cars. This hole size is for use with rubber stem ("TR13") or the metal stem ("TR11") valved inner tubes.

- 16 mm (0.635") diameter , the largest of the sizes. This fits a rubber TR15 stemmed inner tube. Popular on tractors and some post war cars of the 1940's and 1950's. We supply a well fitting adapter / grommet / collar that slips over the TR13 stem to increase it to the bigger TR15 size making it a snug fit in the hole in the wheel, for use in these wheels that have the 16mm hole. This plastic adapter also has the advantage of additional protection for the rubber stem from any potential sharpness at the juncture of where the hole exits the rim.

The valve stem terms mentioned above TR4, TR6, TR11, TR13, TR15 etc were the numbers assigned to the different valve stems by the company Schrader, who started up in the 1890's with their invention that is still going strong! TR refers to the Tyre and Rim Association that was set up in the USA in 1903 to set the standard dimensions for these items, based on what already existed, as apart from Shrader there were many other companies producing valve stems such as Dill, Bridgeport, Michelin and so on. Each company had their own numbering system but after the agreed standardisation, the same TR number meant teh same thing irrespective of manufacturer.

All metal valve "TR11" valve stems used on our thick butyl Blockley Superior tubes are nickel plated, just as they were in period. We have not yet found an unplated original stem on an original period tube. And this is also the case with early veteran tubes. The nickel plating avoids the brass tarnishing and is just another bit of attention to detail, the way we like to do things at Blockley!

And finally mention should be made of the screw on valve cap, which should always be used to stop the ingress of dirt. At Blockley we supply all inner tubes with metal valve caps with a washer inside that will keep air in the tube, even if the valve fails. Having this good seal prevents the dirt as well as moisture contaminating the valve core.

"As a postscript, there are also another valve stem sizes (3/8", 12mm etc) , used on Veteran and Edwardian cars and some into the 1920's using beaded edge tyres, or as they say in the USA "Clincher" tires, which carried on to the Straight Sided tyres that came after which were in use up to the later 1920's, all of which had an "on centre" valve stem position. The most popular stem had a diameter of 12mm with a outside thread of 26 tpi and Blockley uses this dimension stem today (Nickel plated as they were all originally in period) on most of the beaded edge range of inner tubes we produce."

For the T originally used the 777 that is 3" tall, and these were O.D. .406" or 10.3mm. Without measuring a Blockley, unless someone has, it appears they use a modern-like metal 12mm stem on their clincher tubes? Don't know for sure.



Other sizes are larger O.D. for the bigger tires over 3" wide

Dan

the larger/largest stem(s) are 12V1 threads

Scott_Conger wrote: ↑

Tue Apr 25, 2023 5:18 pm

Dan

the larger/largest stem(s) are 12V1 threads

Thanks Scott, that is what the Blockley website stated for the 'straight side' or for us Americans the clincher tire tubes they mfg.

Got this off the internet:

The Valve Stem Threads (external where the Nut is screwed) are known as 12V1.
Major Dia. is between 12.03 & 12.24 MM.
TPI : 26.

I haven't heard from Blockley yet. I still don't have a satisfactory answer to my question. I want to be able to order a tube with the valve stem hole in it, so I can use my own valves. I have enough originals to last me forever. If I have to order Blockleys tubes with their valves that's fine, but would still like to know if their valves are copies of originals and are of the 777 dimensions, and not the larger Pierce Arrow size. Additionally Dan McEachern is currently making the correct rims nuts for early cars that are round, and have the correct knurl @ $20.00 each.

...would still like to know if their valves are copies of originals and are of the 777 dimensions.

No. They are TR11 size. See Blockley's notes posted above by Dan Treace.