Melissa,The OE tire size for Vanagon was about 25.4" diameter and your current tire is very close at around 25.5", so it isn't too likely that your tire is messing with your top end speed error, if there is one. These vans have speedo error anyway. The way I found out what my exact error was was to use a GPS. I happened to own one now but is it possible to borrow one from someone and take it for a ride. I'm not so sure than any tire-size calculation can be of much help when the basic Van speedo setting is off anyway. You've already mentioned the use of the highway mile markers and that would be an estimate as well, not actual. Tire Rack has a bunch of information about technical tire stuff here: http://www.tirerack.com/about/techcenter.jsp I don't have any information about that cable modification. I simply know now that I have a speedo error and come across so many of those roadside speed indicators in special speed zones, and they so consistently tell me I'm going faster than my speedo says, that I have pretty much memorized the speed difference at various speeds. I usually just use the 10MPH increments, knowing I need to adjust up 2-3 mph at 30 indicated, and 4-5 at 50 indicated, etc. until I get to 70. Not a very technically accurate system I've developed but it has resulted in no speeding tickets in 10 years. I'd suggest using this tire size speed calculator if you're curious and want to mess with it/one: http://www.syncro.ca/tiresize/ bob '87 Syncro Westy On Mon, Oct 12, 2009 at 5:40 PM, Melissa Mourkas <westywoman@mac.com> wrote: > I have come to the conclusion that I am not driving as fast as my > speedometer indicates as people are racing around me and my speedo > says I am doing 70 mph (and I thought this 1.9L was just really > peppy!). I have 15/65/205 tires/wheels. I have been unable to > conduct a test using mile markers as they are nearly non-existent > around here and, no, I do not own a GPS. (I like maps). My shift > points seem about 5 mph off the marks on the speedometer as well. I > followed a thread on the Samba regarding this disparity: > > http://www.thesamba.com/vw/forum/viewtopic.php?t=345224 > > They were claiming as much as 10 mph under at 70 mph (actually > traveling at 60 mph). Has anyone on this list experienced this and > have you tried this ratio-adjusted speedo cable shown in that thread? > > The vendor for the adjusted cable is: > > http://www.tacomaspeedometer.com/index/index.php? > option=com_content&task=view&id=15&Itemid=28 > > I apologize if this has been covered ad nauseum in the past. I will > try to come up with something more original next time. In the > meantime, thanks to all who choose to reply. > > > Melissa Mourkas > '84 Westy Honey Bee > Sacramento, CA > |
Please note - During the past 17 years of operation, several gigabytes of
Vanagon mail messages have been archived. Searching the entire collection
will take up to five minutes to complete. Please be patient!
Return to the archives @ gerry.vanagon.com
The vanagon mailing list archives are copyright (c) 1994-2011, and may not be reproduced without the express written permission of the list administrators. Posting messages to this mailing list grants a license to the mailing list administrators to reproduce the message in a compilation, either printed or electronic. All compilations will be not-for-profit, with any excess proceeds going to the Vanagon mailing list.
Any profits from list compilations go exclusively towards the management and operation of the Vanagon mailing list and vanagon mailing list web site.