Tire Sizes Explained

A simple explanation of Tire sizes, what all the numbers mean and where to find them

Tyres & Tires Explained

I've been playing Car Mechanic Simulator for a while and have a very limited amount of knowledge about tires and what the numbers on the sidewalls actually mean. So I was a bit shocked when someone asked me how do I know which tires to match to which rims and what will fit the actual vehicle in the game.

Firstly I'll start by saying the choice of tire and rim combination is entirely up to you! I mean that's the way the game was designed. You choose the style and repaint them if you want. Make them bigger or smaller it's all entirely up to your personal preference. I'm guessing that you already know how to buy tires and rims, how to pain rims, and how to put them together and balance them ect. So I'll not cover that.

BUT

If like me you like to find and restore the junkers and rust buckets it might help if you can find the right tire size. To do this is easy, go to the car in question and click the job sheet (Car info screen)

Make sure you are on the Car Information tab and if you look down the list it will tell you the size of the tires placed on the car by the factory as well as the style of rim it used by default.



As you can see in the info I've used as an example the car has two sets of tires. 245/50R21 and 275/50R21. All this means is the car has slightly larger back tires than it has on the front.

Let me explain the sizes

The first Number which is 275 is the width of the tire, that's from edge to edge it's actually measured in millimetres but anyway it's the bit of the tire that actually has tread on it and touches the road shown in the image with a red arrow. The second number is 50, this is the width of the tire wall from the hole in the middle to the edge. Basically this is the size or depth of the side of the tire. The bigger this is the more side profile the tire has oh and I've shown that in yellow. Finally the R21 is the radius of the tire so its overall size shown as the blue circle.


With all this in in mind I know my wider tires (the 275/50R21) is the rear tire and the slimmer 245/50R21 is my fronts. Since my tires have a Radial or R size of 21 that means whichever rims I choose I know need to be R21. I'm not sure what the ET:0 size thing is about but then I've never had to adjust it.

Anyway, I know its just one of those small things but I hope someone else finds this useful.

[Bloky]

THANK YOU ive been here for almost an hour trying to get the right size and you saved possibly another hour

[KJ]

Still doesnt make sense

[megatr0n]

Bro thank you so much!!!!

[Wuhbzz]

I am only here to mention, in the screenshot that shows the factory tire size and rim, the car is 1 mile away from 69,420. That's pretty epic.

[TheCatweazle]

I found that the info given is not quite correct.

Width and Profile are both correct.

Size: This one's wrong. A tire's size of a tire does not refer to its exterior diameter, but to its interior one - the hole in the tire. If you have a rim with a size of 20 inches, the interior diameter of the tire also needs to be 20 inches, or you won't be able to wrangle the rim into the tire.

R: This tells us that we're dealing with radial tires which, in real life, have all but replaced all the other kinds of tires (like cross ply or belted bias tires).

ET: This is the industry-standard abbreviation of the German word "Einpresstiefe" and refers to where the hub-mounting (that's where the bolts go in) is situated in relation to the rim's centerline. You can move the hub-mounting closer to the rims' outer side or closer to the inner side, while the rest remains the same.

Hope this helps.

[BrianLee1551]

Excellent guide. Thank You for taking the time to help out. It is appreciated.

[ccthetrucker33]

well im confused about finding the right size,cuz im not using mods,i playing it on sandbox mode,and at times i have trouble matching the sizes of tires mainly because when i try the number options to match the old ones they wont stay set when i find 1 Of the numbers it doesnt stay set trying to find the rest,to match them,so i get fustrated because if i try putting it on car it tells me it doesnt match,so i get stuck and fustrated,another thing is the gameplay option unreaslistic tire sizes so what does that mean/do and does it help at all

[Edinhu!]

top

[dave's games]

thank for the tip i always write down the tire sizes

[Colonel Action]

ET is offset from center. A higher ET will push the center of the rim closer to the car and move the tire further away from the axle, effectively giving the car a wider stance and wider track width