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-   -   Tire size change speedo change? (http://www.wranglerforum.com/f282/tire-size-change-speedo-change-263101.html)

JeepJT04 08-15-2013 08:25 PM

Tire size change speedo change?
 
Alright so I went from stock 29s on my 97 to 31s. Speedo should be off correct?
When I check it with a speed app on pho e it's dead on so far up to 35mph... But I know I know at 65 it's off.

wwch99tj 08-15-2013 08:28 PM

Speedos aren't 100% accurate from the factory sometimes with 31's it makes them read correct... :confused:
Mine, 4 cyl 5 speed was off by about 9% (slower) with 31's...

Budplz 08-15-2013 08:40 PM

Good question. I run 33s and speedometer also seems correct???

Water Dog 08-15-2013 09:11 PM

Speedo's are going to run off at a percentage, and not a fixed number. 10%= 1mph off at 10mph, and 10mph off at 100mph etc. so you're going to see a larger amount off at 65mph than at 30mph.

Steeljag 08-15-2013 09:22 PM

With the tires in my sig I'm off 7 mph at 57 mph. With GPS reading 57, speedo reads 50mph.

Mctim35 08-15-2013 09:38 PM

I used this chart after I got the lift in. Cheap enough and installs in about 5 minutes. I checked it with the GPS and it's spot on now. Plus my MPG's don't look so horrible.
http://www.jeep4x4center.com/jeep-speedometer-gears/

VTBalla34 08-15-2013 09:50 PM

Quote:

Originally Posted by Mctim35 (Post 4083669)
I used this chart after I got the lift in. Cheap enough and installs in about 5 minutes. I checked it with the GPS and it's spot on now. Plus my MPG's don't look so horrible.
http://www.jeep4x4center.com/jeep-speedometer-gears/

+1. Instant mpg increase! LOL

Neil F. 08-16-2013 05:07 AM

Quote:

Originally Posted by Budplz (Post 4083391)
Good question. I run 33s and speedometer also seems correct???

Unless the PO changed the speedo gear, it will be off with 33

RnEmOvr 08-16-2013 05:12 AM

If you have a smart phone download a speedometer app and check it accordingly

JeepJT04 08-16-2013 06:42 AM

Quote:

Originally Posted by Mctim35 (Post 4083669)
I used this chart after I got the lift in. Cheap enough and installs in about 5 minutes. I checked it with the GPS and it's spot on now. Plus my MPG's don't look so horrible.
http://www.jeep4x4center.com/jeep-speedometer-gears/

I don't know my gears :s

wwch99tj 08-16-2013 08:28 AM

If its still stock check the 9 o'clock position on the rear diff for a tag with the gear ratio on it

I've highlighted mine on here
http://i1228.photobucket.com/albums/...1676381685.jpg
Regular pic
http://i1228.photobucket.com/albums/...ps6d2b99f5.jpg

JeepJT04 08-17-2013 07:03 AM

Think my tag is gone :s

wwch99tj 08-17-2013 08:27 AM

http://www.jeepforum.com/forum/f9/fa...-ratio-615380/

Neil F. 08-17-2013 01:53 PM

Quote:

Originally Posted by JeepJT04 (Post 4088788)
Think my tag is gone :s

Check the front. It will have a tag also

JeepJT04 08-17-2013 01:56 PM

Did not know that!


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