Date: Sun, 3 Jul 2016 14:55:56 -0700
Reply-To: Stuart MacMillan <stuartmacm@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Stuart MacMillan <stuartmacm@GMAIL.COM>
Subject: Re: Speedometer is off
In-Reply-To: <CAEwp_cRnwHEnf10oXGTj=DxzbkY39e49i1BpeqTtsoKYe9oGgA@mail.gmail.com>
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Marc,
Per Bentley, the later speedos (model years '86-'91) are supposed to read +3 mph (Bentley p. 90.30), but I've seen them 5+ mph higher at 60-70 mph. The DOT required that speedometers read higher than actual, at least in that era. Odometers are -1% to +3.5% per FTC. If your odo is within spec per gps on a flat road, then the fix is to remove and replace the needle about the distance of the error on the dial farther counter clockwise. Move the needle over the stop pin and mark where it rests before you remove it.
Removing the needle is tricky, I use the two spoon pry method, but be sure to lay a tissue over it so it doesn't fly off, which will be across the room and off the wall, resulting in total destruction. Be sure the spoons are up against the drive pin.
'83 to '85 speedos like mine had +6.2 mph plus 5%, ridiculously off. I've replaced it with an '87 model, but I use an inexpensive dedicated gps to monitor my speed, and it also shows the speed limit which is useful. https://www.amazon.com/Garmin-2597LMT-Portable-Bluetooth-Lifetime/dp/B00AXX0I88/ref=sr_1_1?ie=UTF8&qid=1467582653&sr=8-1&keywords=garmin+automotive+gps
Stuart
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Marc Perdue
Sent: Sunday, July 03, 2016 12:35 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Speedometer is off
Hi all,
I have an '87 Westy, auto, with Yokohama LT 195/75R-14 Y356 D tires.
Being as they are bigger than the 185s, I always figured that the speedometer was a few mph off. When I picked up my van yesterday, something felt very wrong to me. I felt like I was pushing the van really hard to get up to Interstate speed, 70 mph, and I was passing a lot of people at 63-65 mph.
Today, I had my wife download a speedometer app to her phone and we checked our actual speed against what my speedometer was reading. We found it was off by 5 mph at lower speeds and off by 7 mph at higher speeds.
So, I assume that I have three options here:
1) Adjust my speed according to what I know the discrepancy to be;
2) Change the gearing so that my speedometer is accurate once again?;
3) Change the size of my tires.
Since I just bought 2 new tires, that last option is not one that I'm going to pursue any time in the near future, but may consider when the time comes to replace tires.
In any event, I thought this information might be useful to anybody who's running this size tires on their vans.
Drive safe, y'all!
Marc Perdue
PS--This was a real eye-opener for me when I considered the time or two when I actually thought I got up to 85-90 . . . =8^O
