2nd Gen Non-Engine/Transmission speedometer change

[parttime]

Is there anything that can be done to calibrate the speedometer to read normal after installing 285/75/16 in place of the 265's? Just had them installed and speedo is off 2. 5 mph. It isn't anything big but just curious more than anything else.

 

[vssman]

24V trucks no longer have a vss sensor. Instead they use the ABS sensor for speed. You need to install a "converter box" to correct the speedo. Not sure where to get one but I'm sure one of the vendors under "links" can help.

 

[work2muchplay2little]

Here's a couple of links for you:



If you have 4 wheel ABS : TruSpeed

If you have 2 wheel ABS: Abbott ERA

 

[parttime]

Thanks vssman and work2muchplay2little for the information and the links. I will check them out.

 

[clong]

If there is a dealer that you trust... you can have the speedometer recalibrated by them using and ODB-111 programmer. I have the same size tires on my truck and with the setting at the minimum setting it is off by less than 2%.

 

[dcava]

Speedo

Been down this road with a very good dealer. The DRB-III

was used and we entered the fewest revs per mile possible. Best we could do was 2. 5 mph slower than actual speed. DRB-III won't let you enter any lower revs per mile value.

 

[parttime]

I went to my dealer and tried using the DRB III. That is true, you can only put in a minimum of 647 revs/mile and this tire needs 632. The links from work2muchplay2little were interesting but looked like a $150 fix. I'll probably live with the 2. 5 mph error. Thanks for the information.

 

[athompson]

I have a brand new TruSpeed that I decided not to use. If you're interested, PM me.

 

[Udaloy]

Originally posted by work2muchplay2little

Here's a couple of links for you:



If you have 4 wheel ABS : TruSpeed

If you have 2 wheel ABS: Abbott ERA

I just bought an ERA correction box but now I don't know if I should try using it on my '02 with 4WALB. I've read a lot of posts on the issue but they all seemed to be rather old. Is the Abbott box still not compatible with 4WALB's? Anyone have success with it? Thanks.

 

[Mundgyver]

parttime



I just installed my Abbott Electronic Ratio Adapter yesterday and it works like a charm. The speed is dead on with the GPS. I have the 285s on vice the 265. The 265 were 1 1/5 mph below acutal speed and the 285 were 2 1/2 mph above actual speed. Now I have actual speed indicated which will give me a true mileage.



Connector 130 on page 8W-30-37of the 2001 supplement shows the circuit and page 8W-80-12 shows the connector to use. Pin 33.



The ratio for your tires will be 1. 025 on the 12 switches and the 4 dip switch for system type will be set to the Three-Wire VSS position.



With this box installed I can run any size tires I want.

 

[Udaloy]

Mundgyver,



That's great but do you have 4WALB or just RWALB?

 

[Mundgyver]

I have the 4 Wheel Anti-Lock. It should not matter which system you have, because the Abbott is installed on the primary veichle speed sensor before the Computer Asst Brake module or any of the computers. Took me about 3 hours to install it. I'm a little on the picky side for how I wire things up.