I am on a NHTSA email list for recalls. Every time there is a new recall, I get a notice. I always read them to see if there is anything interesting. And in December I did get one that is interesting.

82,000 tires are being recalled in various sizes going all the way back to 2016. The problem? The DOT code is too long.

It seems the tire manufacturer (in Indonesia) used a 6 digit option code, instead of the max allowable of 4. NHTSA said consumers couldn’t enter the DOT code into the registration database, so the tires had to be recalled. I assume that is just a justification, because other recalls have been done because of non-compliance with DOT code problems of an even lesser condition.

Ya’ see, the DOT code has to have the following format:

Plant code = 3 digits (Before 2015 it was 2 digits, but starting 2015, it could be 2 or 3 and by April, 2025, 3 was manditory)

Size code = 2 digits

Optional code = max of 4, and none is acceptable.

Date code = 4 digits.

That is the DOT code can have as little as 9 digits, but as many as 13. Most tire manufacturers have settled on 13, so there is no confusion.

And, of course, things have changed over time. I go into great and gory detail here.

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At the final Formula 1 race for the year – Abu Dhabi – Pirelli mandated a pressure increase for the front tires after the first practice secessions. They said it was to prevent “graining”, which is where the tread rubber loses grip with the track surface and has trouble getting “into” track surface. Increasing the pressure does the reduce the size of the footprint, so the tire is more likely to penetrate into the track macrotexture.

Always fun for a tire engineer when Pirelli mandates changes in F1.

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I received another email from NHTSA announcing another recall. This time it was for a Firestone tire with a belt edge insert out of position. They took 2 weeks to discover this and another 2 weeks to do all the paperwork. Many of the tires were in the warehouse, but some had been shipped. They had not tested any, but must have picked it up by looking at tires in production. (How exactly?) I can imagine a couple of ways this could happen and the explanation given to NHTSA doesn’t provide enough info to be sure.

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Tire Technology International Magazine has reported that Sumitomo is going to rebrand all its brands at a later date – Jan 1, 2026? The report says that everything will become Dunlop – and that’s because they now own the naming rights in Europe, North America, and Oceanna (which means Malaysia, and other countries in the islands off SE Asia and Australia). The branding changes includes Falken.

I was aware that Sumitomo bought the rights in North America, but I was unaware that there was a problem in Europe, and also not aware that they had bought the rights from Continental in Oceana. There is also the issue of India, where the name is used by someone else for bicycle and motorcycle tires.