Fordmods Logo

Surely wheel width is relevant to speedo accuracy? 

 

Page 1 of 1 [ 10 posts ] 

 
 Post subject: Surely wheel width is relevant to speedo accuracy?
Posted: Thu May 07, 2009 10:00 pm 
Getting Side Ways
Offline
User avatar

Age: 31

Posts: 11103

Joined: 15th Nov 2004

Ride: AU III XR8 Pursuit 250 ute

Location: Hobart
TAS, Australia

I was playing around with a speedo calculator this afternoon, and afterwards I was thinking that it didn't ask me the width of the wheel that the tyre is on. Surely this effects the calculations somewhat?

 

_________________

Heaps of performance EF/L parts for sale, including supercharged VCT motor!

2002 Ford AU Series III Falcon XR8 Pursuit 250 ute - 5.6L of V8 Windsor!

Top
 Profile  
 
 
 Post subject: Re: Surely wheel width is relevant to speedo accuracy?
Posted: Thu May 07, 2009 10:05 pm 
Getting Side Ways
Offline

Age: 33

Posts: 6746

Joined: 13th Mar 2006

Gallery: 10 images

Ride: NCII Fairlane

Location: Bathurst
NSW, Australia

Width i wouldn't think so as it is the height that really makes or brakes it cause as the width of the tyre is more related to the traction i'd say

feel free for fellow members to correct

 

_________________

R.I.P Tobias my son.

Top
 Profile  
 
 
 Post subject: Re: Surely wheel width is relevant to speedo accuracy?
Posted: Thu May 07, 2009 10:14 pm 
Fordmods Addict
Offline
User avatar

Age: 31

Posts: 7958

Joined: 1st Jun 2005

Gallery: 13 images

Ride: Falcon

Power: 237 rwkw

Location: Melbourne
VIC, Australia

twr7cx wrote:
I was playing around with a speedo calculator this afternoon, and afterwards I was thinking that it didn't ask me the width of the wheel that the tyre is on. Surely this effects the calculations somewhat?

yeah if you stretching the tyre a massive amount on the rim then it will definately have a smaller rolling diameter.
But that would be an extreme, and still probably not a massive amount of difference.
I mean if you stretch a tyre onto a rim enough that it is going to affect rolling diameter THAT much, it's probably not gonna seal anyway!!

 

_________________

ED XR8 Sprint - S-Trim, V500, 249rwkw
BF MKII F6 Tornado - 237rwkw

Top
 Profile  
 
 
 Post subject: Re: Surely wheel width is relevant to speedo accuracy?
Posted: Thu May 07, 2009 10:25 pm 
Getting Side Ways
Offline
User avatar

Age: 28

Posts: 4326

Joined: 30th Oct 2006

Gallery: 18 images

Ride: Envi EF

Location: Grafton
NSW, Australia

Tyre size is 235, width/ 35, height in a percentage of width /18 rim size.
So yes, to be accurate you should have to put in all the details.

 

_________________

>>>EF Futura T build<<<

Top
 Profile  
 
 
 Post subject: Re: Surely wheel width is relevant to speedo accuracy?
Posted: Thu May 07, 2009 10:54 pm 
Getting Side Ways
Offline
User avatar

Age: 31

Posts: 11103

Joined: 15th Nov 2004

Ride: AU III XR8 Pursuit 250 ute

Location: Hobart
TAS, Australia

Steady ED wrote:
twr7cx wrote:
I was playing around with a speedo calculator this afternoon, and afterwards I was thinking that it didn't ask me the width of the wheel that the tyre is on. Surely this effects the calculations somewhat?

yeah if you stretching the tyre a massive amount on the rim then it will definately have a smaller rolling diameter.
But that would be an extreme, and still probably not a massive amount of difference.
I mean if you stretch a tyre onto a rim enough that it is going to affect rolling diameter THAT much, it's probably not gonna seal anyway!!


What about the opposite of putting a tyre that is wider than required for the rim?

 

_________________

Heaps of performance EF/L parts for sale, including supercharged VCT motor!

2002 Ford AU Series III Falcon XR8 Pursuit 250 ute - 5.6L of V8 Windsor!

Top
 Profile  
 
 
 Post subject: Re: Surely wheel width is relevant to speedo accuracy?
Posted: Fri May 08, 2009 12:10 am 
Getting Side Ways
Offline

Age: 66

Posts: 2548

Joined: 18th Mar 2006

Ride: EF-XR8chaser

Location: wollongong
NSW, Australia

twr7cx wrote:
I was playing around with a speedo calculator this afternoon, and afterwards I was thinking that it didn't ask me the width of the wheel that the tyre is on. Surely this effects the calculations somewhat?

no,the circumference of the tyre,air pressure,wear on tread==linear roll length per revolution of the wheel,to determine the gear ratio to speedo.to do a check use a gps for speed.thats why the rims are 15,16,17 and will fall into the speedo limits,i havnt tried over 17s,but the cop speedo may compensate enough over 17s as the rims get bigger and the tyre wall profile reduces to keep the dia. the same,unless the tyre is larger in dia, over stock one or it distorts larger with speed like a dragster tyre.then a gps will pick it up at higher speeds.

 

_________________

R.I.P HANS HARTMAN

Top
 Profile  
 
 
 Post subject: Re: Surely wheel width is relevant to speedo accuracy?
Posted: Fri May 08, 2009 7:54 am 
Fordmods Addict
Offline
User avatar

Age: 31

Posts: 7958

Joined: 1st Jun 2005

Gallery: 13 images

Ride: Falcon

Power: 237 rwkw

Location: Melbourne
VIC, Australia

twr7cx wrote:
Steady ED wrote:
twr7cx wrote:
I was playing around with a speedo calculator this afternoon, and afterwards I was thinking that it didn't ask me the width of the wheel that the tyre is on. Surely this effects the calculations somewhat?

yeah if you stretching the tyre a massive amount on the rim then it will definately have a smaller rolling diameter.
But that would be an extreme, and still probably not a massive amount of difference.
I mean if you stretch a tyre onto a rim enough that it is going to affect rolling diameter THAT much, it's probably not gonna seal anyway!!


What about the opposite of putting a tyre that is wider than required for the rim?

Still the same, the sidewalls are going to 'lay over' and slightly reduce rolling diameter, but again, you are talking a massive mismatch in rim vs tyre width to make a significant difference.

P.S. I am the only person who understood your post :lol:

 

_________________

ED XR8 Sprint - S-Trim, V500, 249rwkw
BF MKII F6 Tornado - 237rwkw

Top
 Profile  
 
 
 Post subject: Re: Surely wheel width is relevant to speedo accuracy?
Posted: Fri May 08, 2009 8:53 am 
Getting Side Ways
Offline
User avatar

Age: 31

Posts: 11103

Joined: 15th Nov 2004

Ride: AU III XR8 Pursuit 250 ute

Location: Hobart
TAS, Australia

Steady ED wrote:
P.S. I am the only person who understood your post :lol:


I noticed. :D :shock: :?

 

_________________

Heaps of performance EF/L parts for sale, including supercharged VCT motor!

2002 Ford AU Series III Falcon XR8 Pursuit 250 ute - 5.6L of V8 Windsor!

Top
 Profile  
 
 
 Post subject: Re: Surely wheel width is relevant to speedo accuracy?
Posted: Fri May 08, 2009 10:24 am 
Getting Side Ways
Offline

Posts: 6166

Joined: 8th May 2007

i think your worrying about nothing.... what are we talking about, maybe 0.5 or 1.0km difference at the most?

you should be worrying about the different shapes & sizes of tyres from different brands, even though they have the same size markings on them
Top
 Profile  
 
 
 Post subject: Re: Surely wheel width is relevant to speedo accuracy?
Posted: Fri May 08, 2009 12:56 pm 
Getting Side Ways
Offline
User avatar

Age: 28

Posts: 4326

Joined: 30th Oct 2006

Gallery: 18 images

Ride: Envi EF

Location: Grafton
NSW, Australia

twr7cx wrote:
Steady ED wrote:
P.S. I am the only person who understood your post :lol:


I noticed. :D :shock: :?


HA I get it now.

RIM width doesnt matter, for a calculator at least.

 

_________________

>>>EF Futura T build<<<

Top
 Profile  
 
Display posts from previous:
Sort by  
 Page 1 of 1  [ 10 posts ] 

Who is online

Users browsing this forum: No registered users and 10 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

 

 

It is currently Fri Dec 15, 2017 4:19 am All times are UTC + 11 hours

 

 

(c)2014 Total Web Solutions Australia - Australian Web Hosting and Domain Names