Speedo/tires/radar - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
VN750 General Discussion

 
LinkBack Thread Tools Display Modes
post #1 of 4 (permalink) Old 06-16-2008, 02:07 PM Thread Starter
Senior Member
 
liljd's Avatar
 
Join Date: Jan 2008
Location: Knoxville, Tn
Posts: 476
iTrader: (0)
 
Speedo/tires/radar

I've read several threads about tire size and speed, and how a gps puts it a bit over or under the true speed.

I went over to the east district today due to curiosity and had one of our officers clock me in the lot and found my speedo to be correct with my 100/90-19 front tire. How much will it be off if I go with a larger front? Anyone have any ideas????

James
1985 vn700 (T'Plana)
Gremlin bell
HD-O shield
saddlebagged
custom made supports
tool bag
extended backrest
Protac backrest
Highway pegs
custom mirrors
custom grips
V&H cruisers
lever covers
DieHard AGM
Kuryakin battery gauge
and LED taillights
marbled

____________________

VROC #27169
Tn VROC #134

www.youtube.com/thetrueliljd
liljd is offline  
Sponsored Links
Advertisement
 
post #2 of 4 (permalink) Old 06-16-2008, 02:36 PM
Senior Member
 
Join Date: Mar 2005
Location: Channelview, TX
Posts: 748
iTrader: (1)
 
Quote:
Originally Posted by liljd View Post
I've read several threads about tire size and speed, and how a gps puts it a bit over or under the true speed.

I went over to the east district today due to curiosity and had one of our officers clock me in the lot and found my speedo to be correct with my 100/90-19 front tire. How much will it be off if I go with a larger front? Anyone have any ideas????
Correct at what speed? The speedo gets more inaccurate the faster you go; i.e., with the stock 100/90-19 tire, mine was off [email protected] indicated, 64 actual, and ~1mph (give or take) more for each 8-10mph indicated above that. At 127 indicated, I was actually doing ~115. Haven't gone near that since putting a 110/90-19 on the front, but at 70mph indicated, I'm doing 70mph actual. Tire brand, compound, and tire air pressure all have some effect, too; no two are necessarily gonna be exactly the same.

Jim

J.D.
Kerrville, TX
'95 Vulcan 750 "Therapy II",
aka "Raggedy Ann"
'95 VN750 project
'03 VN800B "The Little Black"
'04 VN800E Drifter project
'93 VN1500A custom project
VROC #16185
GCVROC #33

Photo album: http://www.flickr.com/photos/leekayd/sets
J.D. is offline  
post #3 of 4 (permalink) Old 06-16-2008, 02:40 PM
Senior Member
 
Vulcaneyez's Avatar
 
Join Date: Aug 2007
Location: Virginia
Posts: 103
iTrader: (0)
 
Speedos seem to be off by a percentage (around 10%) rather than a fixed number (like 5mph). I used a Garmin GPS on my bike this weekend and found it was off 10%. So at 50 indicated I am really doing 45; at 70 indicated I am doing 63 to 64.

I believe that larger tires will show a slower speed than you were actually going and smaller tires will register higher speeds. So, if your speedo is accurate now and you put a larger tire on it, it will now read slow.

Vulcaneyez
Vulcaneyez is offline  
 
post #4 of 4 (permalink) Old 06-16-2008, 02:51 PM Thread Starter
Senior Member
 
liljd's Avatar
 
Join Date: Jan 2008
Location: Knoxville, Tn
Posts: 476
iTrader: (0)
 
I don't have a gps so can't say bout that but it was tested at 55mph. I was thinking bout going a bit bigger with the front tire and was curious. But I don't want to get a tiket either LOL. How much do the gps things run?

James
1985 vn700 (T'Plana)
Gremlin bell
HD-O shield
saddlebagged
custom made supports
tool bag
extended backrest
Protac backrest
Highway pegs
custom mirrors
custom grips
V&H cruisers
lever covers
DieHard AGM
Kuryakin battery gauge
and LED taillights
marbled

____________________

VROC #27169
Tn VROC #134

www.youtube.com/thetrueliljd
liljd is offline  
Sponsored Links
Advertisement
 
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

Once registered, your User Name"cannot be changed". We can make exceptions within 7 days, but after that, it is set in stone.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome