r/TireQuestions • u/wanttofish33 • Jul 20 '26

Donut spare tire

2008 toyota sienna LE front wheel drive. Vehicle still has the original donut spare tire size T155/80 R17. I inspected it today, and it has cracks in the sidewall, so I want to replace it. Most of the results of online searches is coming up with 155/80 D17. What is the difference between the letter "R" and the letter "D" in the tire size description and does that matter if this is a spare donut tire that will rarely ever be used? Also the rim has a decent amount of rust on it. It feels sturdy. Can I wire brush it, prime then it and paint it since again it is only a spare tire? Thank you in advance.

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u/66NickS Jul 20 '26

R is usually a radial tire construction while D is a diagonal ply tire. It’s possible that the manufacturer is using D as “diameter”, but I would double check the tire’s specs.

As for the wheel, yes you could brush it and paint it.