Wheel and Tire Fitment
by Pat Goss
This time we're going to talk about how the professionals figure out which tires and wheels will fit on your car. And for that information we have Matt Edmonds our tire expert. Matt, welcome back to Goss’s garage.
MATT EDMONDS: Pleasure to be here, Pat.
PAT GOSS: All right now aftermarket tires and wheels and so on very popular.
MATT EDMONDS: They are they are something that people can do you can upgrade your vehicle make your vehicle look nice make it personal a lot of people many times will say wheels are like jewelry for your car and that's really what they are there's something something that really makes it yours and makes it stand out from the crowd.
PAT GOSS: OK, but there’s tens of thousands of wheels out there. How do you figure out what's going to fit?
MATT EDMONDS: Well that being said they’re jewelry, they’re very technical as you can imagine. We have to make sure that with the tire and wheel off we see all of these components that are behind it the brakes… the suspension. Things that we have to make sure that we clear properly. So one of the things you have to do is go in and use what's called a faro-arm to really digitize this area and once it's been digitized you can then virtually fit wheels on it. That makes sure that we clear everything but before that we have to make sure that the wheels have the right load carrying capacity. They have the right bolt circle… the center bore.. the proper offset very important to make sure that all those technical aspects are taken care of.
PAT GOSS: Now this is faro arm that you're talking about for certain automotive engine things and so on… use a unit that has a little pointer… you touch all these different spots and it gives you the readings. Is it something like that?
MATT EDMONDS: Well that was the original faro arm the new version of the faro arm that we now use has a sonar on it so it’s actually taking tens of thousands of points of information and gives you a model that really looks 3D and you can actually take it and spin it… rotate it and virtually place these tires and wheels onto this area of the vehicle shall we say.
PAT GOSS: Okay now different manufacturers even though the tire may be the same dimension as far as the numbers are concerned the actual dimensions are different.
MATT EDMONDS: They do. The profile changes so what we do is within a size of tire we’ll take the extreme. Whatever is the largest a variant of that and we will then virtually place that on the wheel section so that we make sure that the tire clears for instance a suspension point up high that might give it an issue on turn in and then pay special attention to the suspension point to see if it moves so that we know we have those clearances.
PAT GOSS: Okay so it's science not guesswork.
MATT EDMONDS: Absolutely, it's just not a bunch of numbers and looking at pretty wheels although that's really the best way as a consumer to shop for it so you want to make sure you work with someone that has done the science behind it.
PAT GOSS: Matt, thank you and if you have a question or comment drop us a line right here at MotorWeek.