4bangerjp.com
General Forums => The Mess Hall => Topic started by: Alacran on January 18, 2008, 10:10:20 AM
-
Sorry if this seems terribly simple but I'm new at this and need all the help I can get. I read the FAQ'S but it left me confused as ever. I have a 94 JY 4cyl with 5 speed. I put 31" BFG AT's on it (actual diameter 30") and I want to recalibrate the speedometer. Am I correct in assuming that I have 4.10 gears? In the Quadratec catalog there is a chart that shows That if I have a 30'' tire and 4.10 gears I need to use a 37 tooth speedometer gear. Does this sound about right to you folks? Thanks for any help!
-
Here is a great site that will make quick work of your problem: http://www.jeeptech.com/javaAps/Speedo.html (http://www.jeeptech.com/javaAps/Speedo.html)
-
Sorry if this seems terribly simple but I'm new at this and need all the help I can get. I read the FAQ'S but it left me confused as ever. I have a 94 JY 4cyl with 5 speed. I put 31" BFG AT's on it (actual diameter 30") and I want to recalibrate the speedometer. Am I correct in assuming that I have 4.10 gears? In the Quadratec catalog there is a chart that shows That if I have a 30'' tire and 4.10 gears I need to use a 37 tooth speedometer gear. Does this sound about right to you folks? Thanks for any help!
You have to know your stock gear ratio. It should be 4.10/4.11 BUT you might want to check your axles for the ID Tag and see what's in there. The ID tag is on the differential cover, held on my two bolts at the 2 o'clock position usually.
-
Thanks for the help guys! This forum is loaded with information.
-
IF (BIG IF) you have 4.10 gears (you probably do, but check anyway), then yes, it sounds about right. I have a 38 tooth speedo gear on 31's, and the speed on the dash is almost always on par with the speed on my GPS (sometimes the difference is 1 mph when I am doing 65~70 mph, but that is negliagable).
-
Sorry if this seems terribly simple but I'm new at this and need all the help I can get. I read the FAQ'S but it left me confused as ever. I have a 94 JY 4cyl with 5 speed. I put 31" BFG AT's on it (actual diameter 30") and I want to recalibrate the speedometer. Am I correct in assuming that I have 4.10 gears? In the Quadratec catalog there is a chart that shows That if I have a 30'' tire and 4.10 gears I need to use a 37 tooth speedometer gear. Does this sound about right to you folks? Thanks for any help!
I would go by advertised height and not actual height, stick with 31" in the charts as I believe that's how they are set up. Yes, I know there are a lot of variances between tire manufacturers but I think 31" will get you the closest.
-
I would go by advertised height and not actual height, stick with 31" in the charts as I believe that's how they are set up. Yes, I know there are a lot of variances between tire manufacturers but I think 31" will get you the closest.
Yes, Terry uses advertised height not actual height in his calculations, which is why it's not perfect.
-
OK.... Well I went ahead and ordered the 37 tooth. I'll let you know how it turns out.