XL's and the speedo

[pghjeeper]

Can anyone running xl's on a stock 715 tell me how far the speedo is off? Today is the first day I have driven my truck since bringing it home and it seems to be having trouble breaking 30mph on the speedo.

[Roy]

We usually just use a GPS unit as a reference while we operate the vehicle at different speeds to determine the variation(s). Some owners request correction. This can be achieved via an electronic programmable speedo, or a mechanical gear driven unit installed in-line in the speedo cable for us OE-type speedo gauge afficianados.

[randyscycle]

I generally use a GPS unit myself, as the percentage the speedo is off changes the faster you go.....There is a calculator somewhere I have seen online to figure this out, and I am sure someone will be along shortly to post it up.

[brute4c]

If you can access a gps, you can run on a back road at different speeds and figure where you are...51 is 55 or whatever...could make a chart from 5 to 60, every 5 mph if you want...

Some newer speedos have a built in way to set themselves...if you go with a non stock one...you hit a button, drive 1 mile exactly and hit the button again...a gps would be very helpful there too.

Occasionally you see a device on ebay that hooks to the speedo cable mount on the tcase and allows for ratio changes to be made...not sure if it will actually fit on an np200 case or not...


If you were running 55~60 mph before and can only do 30 now something is certainly wrong...I would expect about 5-7 mph change at 55...less speed, less change.

[porkchop]

My stock speedo with the XL's are correct at all speeds. I didn't think it was possible but it is. I tested it with a GPS.

[brute4c]

GPS shows my stock speedo to be off 2 mph at 60...reads 60 but really going 62.

[pghjeeper]

I don't know how to descibe best what the 715 is doing its like its in low range at 30 mph she is screaming. I've shifted it into and out of low range and I can feel the diferance. In fourth the truck is either screaming or kind of sputtering along. I'm going to try and change the air cleaner, clean the carb, and change the fuel filter and see if that helps any.
I know this truck was running perfect for kwai down in Texas but she just doesn't seem to be running right now.

[Barrman]

12% is what my speedo and odometer is off with the XZL tires. So, running 48 mph on the speedo gives me 54 actual. My gps shows this to be true. Pistolnut can too since he has followed me for darn near 1000 miles now.

As all the above post show, stock speedometers are not exactly instruments of precision. Your results will probably vary.

[kwai]

Tim has it right. The speedo showed around 48 when I was doing 55 to keep up with traffic.

[robsgp]

Less scientific but easy, I found one of those police radar trailers in my neighborhood and kept going around the block and coming up on it at different speeds from 20 to 40 (25mph zone). Stock speedo was showing same thing as the radar.