Visualizing a new tire size

[theholycow]

Tirerack.com can show you what new, different-sized wheels will look like on your car. You choose your car and it shows you a picture, and shows you pictures of new wheels on it. However, it can't show a different size tire; whatever the OEM outside diameter is, that's what it shows.

I'd like to put taller tires on my VW to lower the engine RPM at any given speed. I tried using Google Images to find photos and then paint.net to paste new tires over the existing ones, but I'm not confident that I've done it accurately. Does anyone know of a tool I could use to visualize the change without having to actually get a tire and install it?

[GasSavers_maximilian]

I assume you used a tire size calculator for the size difference? If you give me the raw sizes and your pics I'd be happy to double check your results.

[GasSavers_BEEF]

so did you decide to keep the VW instead of getting something different?

I may be a little behind

[theholycow]

Yeah, it's most likely that I'll keep it. Even if it weren't for practicality and reality concerns, I don't see me actually doing all the work of getting rid of it and getting another car. I'm realistic about my laziness.

OEM size on car now: 195-65-15
Size I'm considering: 205-70-15

The miata.net tire size calculator shows you crudely-drawn circles to represent the difference but that doesn't tell me how out-of-place it would look on the car.

I used this photo of a Rabbit:
http://z.about.com/d/cars/1/0/5/0/1/...abbit_side.jpg
(it's 4 door but that shouldn't change the tire size results)

...wait a minute, I just realized what the problem was and why the result didn't seem right. That picture doesn't have the same size tire/wheel combo as my car, that one has 16 inch wheels!

Ok, anyway, here's the tire I used for a 205-70-15:
http://static.howstuffworks.com/gif/...rofile-480.jpg
I extracted just the tire itself from the photo, then scaled it until it fit on the VW rim, but of course I scaled it to the wrong rim.

Ok, here's a couple photos that have the same wheels.
http://images03.olx.com/ui/2/39/71/f_17443871_1.jpeg
http://image.europeancarweb.com/f/12...+side_view.jpg

[GasSavers_maximilian]

The Miata calculator is the one I use too (1st hit in Google). It says the diameter would go from 25" to 26.3".

I'm a little confused by the 16" business and want to make sure I do this right. Can you give a real world dimension to add some scale to that picture you want to use? Just pick a straight line feature (the bottom of the rear door window would work great).

[theholycow]

The 16" business is because the car I used had 16" wheels, which screws everything up. Just don't use the car at the about.com link and everything will work fine. The last links are to cars with the correct size (15") wheels.

Will any of the dimensions at
http://www.vw.com/rabbit/completespe...us/#dimensions
help? I don't know where to get dimensions for a 4 door (mine's the 2 door so I can't just measure it). Maybe after work I'll take straight-on pictures of my car and measure some stuff...

[GasSavers_maximilian]

The length of the Rabbit is 165.8" and the image of the car is 1184 pixels long. That picture's got some angle on the wheels so you see the top and side a bit, so I tried to account for it. Got about 190 pixels, so 26.6". Scaling the tires to 26.3" would shave only a couple pixels (literally) off of them. Unfortunately the blueprint site I found doesn't have plans for the Rabbit, so I couldn't pursue that angle for a dead-on view. The specs page one is a little small.

Cute car, BTW!

[theholycow]

Yes, it certainly is "cute".

[GasSavers_maximilian]

Oh yeah, 25" inch wheels would measure up at 178.5 pixels on that image. I'd say that it's a pretty good estimate for you as-is. Don't know about hub cap size or anything.

I drove a Vespa inspired scooter for years, so I'm not one to disparage a cute vehicle!

[theholycow]

Now I'm confused...