Go Back   iRV2 Forums > iRV2.com COMMUNITY FORUMS > Just Conversation
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
Thread Tools Search this Thread Display Modes
Old 10-30-2015, 06:48 PM   #1
Senior Member
HHIDan's Avatar
Join Date: Mar 2011
Location: Ottawa Ontario Canada
Posts: 1,235
Tire size metric or imperial

My tire size is 305/70R22.5
which is 305 millimeters
70 percent as high as it is wide (213.5 mils or 8.4 inches)
22.5 inch rim size, total diameter 22.5 + (8.4x2)= 39.3 inches

Now my question: Why would they mix metric and imperial??

'06 Mountain Aire 4309, ISL 400-CM850, Spartan MMGT
'16 Jeep Wrangler
HHIDan is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 10-30-2015, 08:27 PM   #2
Senior Member
Skip426's Avatar

Join Date: Apr 2011
Location: Powell River, B.C.
Posts: 11,954
I think the North American auto industry was too attached to the Imperial rim sizing ( inches ) . If memory serves , Ford tried metric rim sizing in the 80's and when customers went looking for replacement tires there was a real up-roar.
Same thing happened when they tried metric sized plywood sheets.

99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
Skip426 is offline   Reply With Quote
Old 10-30-2015, 08:58 PM   #3
Senior Member
92TNTRacing's Avatar
Country Coach Owners Club
Join Date: Jun 2013
Posts: 437
Re: why are tyres measured in metric/imperial??
1997 Country Coach Intrigue Horizon 36' (The Dinosaur Burner)
92TNTRacing is offline   Reply With Quote
Old 10-31-2015, 08:15 PM   #4
Join Date: Jul 2002
Posts: 66
Interesting article but I think he had this bit backwards, a smaller diameter tire would make more revolutions causing an odometer to read higher.

However, this 3% difference in diameter did cause some problems for the general
public in the US because standard automobile odometers indicated less mileage
using the reduced diameter of radial tires. The general public thought that the
radial tires were reducing their car’s fuel economy.
Wilber1 is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Change Tire Size grthigpen Monaco Owner's Forum 1 08-13-2015 07:53 PM
Changing tire size on 22.5 rims garyvont Class A Motorhome Discussions 20 07-30-2015 06:05 PM
Help with new tire size for RR8R chassis Chef Guy Roadmaster Motorhome Chassis Forum 3 05-09-2015 12:29 PM
Tire size for 89 Winnebago Chieftain M23RC IamJerryP Winnebago Industries Owner's Forum 4 01-08-2015 05:53 PM
Tire size 2nomads Workhorse and Chevrolet Chassis Motorhome Forum 16 03-15-2014 02:28 PM

» Virginia Campgrounds

Reviews provided by

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 03:33 PM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.