Vanagon EuroVan
Previous messageNext messagePrevious in topicNext in topicPrevious by same authorNext by same authorPrevious page (June 1998, week 2)Back to main VANAGON pageJoin or leave VANAGON (or change settings)ReplyPost a new messageSearchProportional fontNon-proportional font
Date:         Wed, 10 Jun 1998 01:13:33 EDT
Reply-To:     Modl6971@AOL.COM
Sender:       Vanagon Mailing List <Vanagon@vanagon.com>
From:         Michael Modl <Modl6971@AOL.COM>
Subject:      Re: tire size vs. rpm.  the real answer
Comments: To: carl_hansen@ieee.org, vanagon@vanagon.com
Content-type: text/plain; charset=US-ASCII

In a message dated 98-06-09 14:02:55 EDT, carl_hansen@ieee.org writes:

<< Well, sorta, but not quite. Let's take Michael's example of a van on jacks, and extend it a bit. Imagine the van is a NON-Syncro, attach rubberbands, big ones, so that the rear wheels drive the front tires, and the tires front and back are the same size. You will again get a speedometer reading, and no matter what size the wheels are (as long as front and back are the same), at 4000 RPM, you will get the same reading.

So what did that prove, well, nothing actually, IN EITHER CASE.

The actual effect of larger or smaller tires CAN ONLY be tested on the road. And as Gary noted, bigger tires, means 70 mph comes up at a slower RPM, and with smaller tires, 70 mph comes up at a higher RPM. It doesn't matter is you have a 1, 2, 3, or 4 wheel drive vehicle, it doesn't matter if you attach to a driven wheel, or an undriven wheel, the same is true.

Now if you are a rally diver, you might care about undriven vs. driven because of wheel spin. I can remember a REAL deap and muddy flat section that I knew was no longer than 1/2 mile long, but Tom and I had an indicated 1.2 mile on the odometer. Lots of wheel spin, and a little fear that we wouldn't get to the other end and would have to have some farmer pull us out.

Ch '89 SyncroBeast Prior Lake, MinneSnowta well, ok, it's summer Land of Sky Blue Waters

>> Hi Ch. Well now that I thought about it, you are right. Whether or not the speedo drive is coming from the front diff or the left front wheel the speedo will always read the same. I dont know why I thought it would make a difference. I wasn't feeling very well last night. I guess if someone with a REAR wheel drive vanagon wants to make the RPM lower without having to recalibrate the speedo, they will have to put 28" diameter tires in the rear only. RPM at 4000 RPM would equal 78 MPH, (3600 RPM = 70 MPH) and the speedo will show that speed, since nothing was done at front , right. Michael Modl. 87 syncro


Back to: Top of message | Previous page | Main VANAGON page

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.