Plus sizing?

[69chargerboy]

Does anyone know how to "Plus Size" wheel/tire combos? If I were to increase my wheel size from a 14" stock to a 16" or greater, how would I calculate the best wheel/tire combo so my speedometer to read a correct speed when I'm driving? Thanks!

[Mass_Mopar]

The only way to keep the speedometer accurate is to maintain the same overall diameter (tire diameter) which is unlikey if you're starting from 14" wheels.  You'll probably end up having to change the speedometer gear in the transmission, which isn't as hard to do as it sounds.

[Troy]

It's mostly a ball park figure but the way I always understood it is something like this: Try dropping down in aspect ratio (the part between the '/' and the 'R') by 10 and going up in width by 10 for every inch in rim diameter. For example, a "Plus 1" from a 195/80R14 series tire is roughly a 205/70R15 and a "Plus 2" is about 215/60R16.

An easier way is to use a tire calculator like this one:
http://www.1010tires.com/TireSizeCalculator.asp

Put in your original tire size in the top set and the tire size(s) you're interested in down below. Once you submit the form you'll get a chart showing the differences in your selections. The key part is "Revs per Mile" (which is directly related to diameter).

Troy

[Musicman]

Here's a real nice calculator//comparetor for you... http://www.rims-n-tires.com/rt_specs.jsp

[0X01B8]

Here's a real nice calculator//comparetor for you... http://www.rims-n-tires.com/rt_specs.jsp

That's a good one.  Another one, in the same general topic --> http://vexer.com/68rt/speed.html  Under tires, click on 'profile.'

[l8rg8r]

What size 14" tires are you running now

[69chargerboy]

What size 14" tires are you running now

Well, I'm not running anything right now, but the car is currently being restored, I'm looking to buy new wheels and tires....

[l8rg8r]

OK if i had a tire size i could tell you what size 16 is the same diameter

[basarowich]

Does anyone know if there are any threads regarding replacing the seals on the speedometer gear?