Tire size calculator

[Hog Chain]

Very useful information! Thanks!!!!

[RoverGGM]

Will this be a "sticky"?

[MissFJ]

RoverGGM previously said:

Will this be a "sticky"?

It was stuck awhile ago

[prasbros]

Thanks a Million!!!

[Apexbasher]

Very good sheet, KLD. That will help a great deal with tire selection.

[tuqk4u]

This is another really useful link for all those who are contemplating tire/wheel changes.

Tire/Wheel Combination Calculator

[uphill]

How do you adjust the speedometer to compensate for the change in tire diameter? Is there an "easy" way to do this (oh, I doubt it but I thought I'd ask)?

[Prof T]

Kansas Law Dog previously said:

The attached spreadsheet (Excel) will calculate and graph true vehicle speeds at different engine rpm and in different gears (transmission) for the MT and AT FJ Cruisers. This assumes the tire, in revolutions per mile from 1010 tires (Tire Size Calculator - tire & wheel plus sizing), is correct. Changing the tire selection will recalculate speed values. Feel free to copy this file to your own hard drive. The forum has limited download sizing, so the Excel file is in a zip format. Sorry it seems to be the only way.

The spreadsheet consists of seven (7) worksheets: 2 sheets that the users can input their selections into, 4 sheets with graphs (AT – High Range, AT – Low Range, MT – High Range, and MT – Low Range), and 1 datasheet used to generate the graphs.

Tire-Data: this sheet lists most standard tires sizes that fit rims 16” to 22” that FJ owners have considered for modification. The stock tire, 265/70R17 is always the first tire, because true speed of selected tire can be compared to the stock tire at 60 miles per hour. Should the user wish to select another tire, pick the tire you want from rows 14 through 52, and locate the number (column “A”) corresponding to your tire selection. Input this number in cell “A6”.

Gear-Ratio: this sheet numerically shows the gear ratios for transmission, transfer case, axle differentials, and final ratio calculation as data, Tables 1 and 2. As presented, the stock tire (265/70R17) is listed by the “1” in cell “D19”. To change to the tire of your choice, input “2” into cell “D19”. Only a “1” or “2” will work. If you want another tire go back to the Tire-Data worksheet and select another tire. See above. If you want to see the vehicle speeds Table 3 and 4 for a particular engine rpm, input a difference rpm number in cell “D30”. If you want to see speeds in kilometers per hour (Table 3) and meters per second (Table 4) change the number in cell “D32” from “1” to “2”.

Graphs AT-Hi, AT-Lo, MT-Hi and MT-Lo are self explanatory. The graphs are only in miles per hour (sorry), and the upper limit is 110 miles per hour, because the FJ Cruiser has a speed governor set for 109 miles per hour. Changing your tire selection will reposition the lines on the graphs, but the data labels (1st, 2nd, 3rd, etc) don’t move.

The last worksheet – Plot-Data – is the data source for the graphs and should not be altered.

EXCELLENT. A great download.

[FJimmyCruiser13]

Wow, I should have clicked on this a long time ago, but I was so busy looking at all the other cool stuff. My wife INSISTS that I will be going faster than what the speedometer says, but according to all the calculations, I will actually be doing ~55 instead of 60. So as long as I keep it 4 or 5 miles over the speed limit, I should be ok. Not that anyone could push me out of the way when I'm done with it anyway.

[Big-T]

so what is everybody doing to correct there speedo/oddo?