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Re: 17 inch to 20 inch wheels
[Re: Aspen7695]
#2441232
01/26/18 10:31 PM
01/26/18 10:31 PM
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Joined: Jan 2008
Posts: 3,886 Lost and Spaced
bboogieart
master
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master
Joined: Jan 2008
Posts: 3,886
Lost and Spaced
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Absolutely nothing so long as the tire is the same outside diameter. It isn't the rim but the tire height that would effect the speedo...
I have mechanical Aptitude. I can screw up anything.
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Re: 17 inch to 20 inch wheels
[Re: Aspen7695]
#2441591
01/27/18 04:55 PM
01/27/18 04:55 PM
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Joined: Jan 2003
Posts: 15,976 Chilliwack B.C. Canada
RUNCHARGER
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 15,976
Chilliwack B.C. Canada
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Are you sure they are a lot different? I changed the 17's to 20's on my 15 and there wasn't a big difference in circumference. The speed went from reading 2% slow to reading about 1% fast. When it is showing 60MPH the truck is actually doing about 61MPH according to radar anyway.
Sheldon
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Re: 17 inch to 20 inch wheels
[Re: Aspen7695]
#2441633
01/27/18 06:04 PM
01/27/18 06:04 PM
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Joined: Jan 2005
Posts: 12,423 Kalispell Mt.
HotRodDave
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I Live Here
Joined: Jan 2005
Posts: 12,423
Kalispell Mt.
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It is easy for someone with a real scan tool to reprogram it. I am not talking the little code readers but a real scanner like my mac mentor or snap on solus or the one the dealer has. If you were in my neck of the woods I wouldn't even charge for it because it's so easy.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: 17 inch to 20 inch wheels
[Re: HotRodDave]
#2444941
02/01/18 11:41 PM
02/01/18 11:41 PM
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Joined: Jan 2008
Posts: 3,886 Lost and Spaced
bboogieart
master
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master
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Posts: 3,886
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OK so we are looking at a tire diameter change, (29 or 32 or 40?) it doesn't really matter... You can reprogram as stated above, or do it the way I do....
Put the new wheels & tires on and have a friend with a cell phone follow you. They can then make sure you are traveling a specific speed. Test it on the highway and in the city at slower speeds. Now it's just math. The speedo is "X" m.p.h. off. Not as precise as the above but will give you real world accuracy. Drive accordingly.
I have mechanical Aptitude. I can screw up anything.
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Re: 17 inch to 20 inch wheels
[Re: Aspen7695]
#2445224
02/02/18 03:27 PM
02/02/18 03:27 PM
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Joined: Jan 2005
Posts: 12,423 Kalispell Mt.
HotRodDave
I Live Here
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I Live Here
Joined: Jan 2005
Posts: 12,423
Kalispell Mt.
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the problem doing it that way is you have to figure a percentage off not just X MPH as it will be different at every speed. Its good math excercise for your brain though.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: 17 inch to 20 inch wheels
[Re: HotRodDave]
#2445595
02/03/18 12:59 PM
02/03/18 12:59 PM
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Joined: Jan 2008
Posts: 3,886 Lost and Spaced
bboogieart
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master
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Posts: 3,886
Lost and Spaced
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Good stuff. Didn't know that. Hurts my brain thinking about it.
I have mechanical Aptitude. I can screw up anything.
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