| Author | Topic |
|---|
Location:
Melbourne
Registered:
December 2004
|
|
Bigger wheels, will they effect speed reading? how to adjust the speedo
|
Mon, 30 May 2005 10:58
|
 |
Hey guys
Did a search couldnt really find much that helped
Baiscally what has happened is that ive got a sprinter (4ac) and ive uped the rim size to 15inch rather then the standard 13inch, this has also change the tire dimaiter, as I havnt dont have lower profile tyres, now when I drive it is has felt that the speedo is not reading write as the car feels that it is going alot faster then what the speedo is reading. Ive got my brother to drive the car as well to see what he thought and he agreed that the speedo is not reading right.
what I want to know, is it possible to adjust the reading of the speedo, I know that you can do it in other cars ie HZ holden as it has a small gear that uses different teeth, I know this cause my brother change his one on the week end, but he wasnt sure about my car as he is a holden person.
any thoughts?
thanks
julz
|
|
|
I supported Toymods
Location:
Perth, WA
Registered:
May 2003
|
|
Re: Bigger wheels, will they effect speed reading? how to adjust the speedo
|
Mon, 30 May 2005 11:02
|
|
stock - not adjustable
can get speedo gear thingy that fixes it
or get the corresponding 15" tyre that has the same rolling diameter
|
|
|
Location:
sydney
Registered:
May 2002
|
|
Re: Bigger wheels, will they effect speed reading? how to adjust the speedo
|
Mon, 30 May 2005 11:10
|
|
|
if your speedo is out it will cost $220-$240 to get it fixed properly.That is the price I got quoted 2 weeks ago
|
|
|
Location:
Melbourne
Registered:
December 2004
|
|
Re: Bigger wheels, will they effect speed reading? how to adjust the speedo
|
Mon, 30 May 2005 11:17
|
|
|
shit I didnt think it would be that bad $200 + I think I may have to contact toyota or something to see if I can get the gear thing if not Ill just change the tyres, there giving me trouble anyways (rubbing all round)
|
|
|
I supported Toymods
Location:
Perth
Registered:
May 2002
|
|
Re: Bigger wheels, will they effect speed reading? how to adjust the speedo
|
Mon, 30 May 2005 23:51
|
|
|
The simplest option is just to make sure you maintain the same overall rolling diameter with your wheel/tyre combo. There are laws for this.
|
|
|
Location:
brisbane
Registered:
October 2004
|
|
Re: Bigger wheels, will they effect speed reading? how to adjust the speedo
|
Tue, 31 May 2005 01:25
|
|
there are laws to the rolling cirumference for a reason, so it doesnt affect your acceleration/speed and the speed readings - eg qld is 10% difference in wheel diameter, and also so the bigger wheels dont foul the wheel arches and suspension!
therefore you may have larger rims with lower profile tyres to maintain the same diameter within 10%.
to go to the next rim size (+ 1 inch) you must have a step down in the profile (-15 or so),
or + 2 inch up = -30 in tyre profile etc, these are called plus 1, plus 2 plus 3 fitaments.
the other option is to correct the speedo system, 3 options :
correct the speedo, older cable ones use a magnet and can be calibrated.
newer cable ones that cant be calibrated you would use a mechanical speedo correcter, its a ratio box about $120
newer electronic ones, you use a digital speedo correcter, about $130 or $60 for a jaycar kit.
but dont band aid the problem if you can avoid it, instead of changing the diff / correcting the speedo, you are still running a bigger wheel which affects the car, fix that problem and you wont have the rest of the problems - ie lower profile tyres, cheaper now because the have become common.
good luck
[Updated on: Tue, 31 May 2005 01:26]
|
|
|
Location:
Vic, AU
Registered:
September 2004
|
|
Re: Bigger wheels, will they effect speed reading? how to adjust the speedo
|
Tue, 31 May 2005 09:14
|
|
I call shananagan's!!
First off, getting a speedo corrected should not cost that much... I got mine FIXED AND adjusted, in a VH Commodore, for under $100. Speedo place in Ringwood did it, if that helps. 
Secondly, it's not just changing tyre profile that will affect your speedo. Diff changes will do it as well.. It's not that difficult to adjust it accordingly. Refer to above statement. 
PS. Just found this; http://dairally.net/daihard/chas/MiscCalculators/D aiTyreSize.htm
Should help you figure out how much faster it'll be.
|
|
|
