Jump to content

ForScan and inproper tire size from original


Recommended Posts

With ForScan, the tire size was 2437mm in the system ...  the original tire oem is 265-65-18 and is supposed to be 2517.... wth......???

Also, if you change the tire size, it will send a DTC code for AWD...  You will need to relearn the PCM and then, delete/reset the AWD dtc code...


Am I the only one with a improper tire size registered?  Is this normal or I should change it to proper size for the oem tire?

Screenshot_20230217_164420_Chrome.jpg

Edited by Watchdog
Link to comment
Share on other sites

Tire size was a great frustration when picking winter tires for my 22 Explorer Limited (20" rims) when I decided to switch to 18" rims like on the XLT. I went with Blizzak DMV2's. On line sites would show they would not fit. Costco would not warranty or install them. When compared to the 20" DMV's there is negligible difference. The 18" diameter, (P255 65 18) is 31.06" with 671 rotations per mile v/s the 20" (P255 55 20) 31.02" with 672 rotations per mile. When these numbers are close how could there be a problem. Of course load and speed ratings need to be close as well. The dealer I purchased my Explorer from ordered and installed the DMV's for me on some aftermarket wheels I supplied. There was never any concern over fit or computer recalibration. If there is a larger difference in the numbers for revolutions per mile it could make small difference in your speedometer reading but just a few mph. Hope this helps clear it up some for you.

 

  • Like 1
Link to comment
Share on other sites

4 hours ago, ohsown said:

Tire size was a great frustration when picking winter tires for my 22 Explorer Limited (20" rims) when I decided to switch to 18" rims like on the XLT. I went with Blizzak DMV2's. On line sites would show they would not fit. Costco would not warranty or install them. When compared to the 20" DMV's there is negligible difference. The 18" diameter, (P255 65 18) is 31.06" with 671 rotations per mile v/s the 20" (P255 55 20) 31.02" with 672 rotations per mile. When these numbers are close how could there be a problem. Of course load and speed ratings need to be close as well. The dealer I purchased my Explorer from ordered and installed the DMV's for me on some aftermarket wheels I supplied. There was never any concern over fit or computer recalibration. If there is a larger difference in the numbers for revolutions per mile it could make small difference in your speedometer reading but just a few mph. Hope this helps clear it up some for you.

 

I have the same tire however,  when I look with ForScan, the original setting shows 2437mm circumferences but the original tires are 2517.  Is this a Ford Tire gate??????    Were these specs done with the spare tire?  How come, when I try to add, it says maximum tire size,  This means the tire I have 255-70r18 with a 2558 circ. is to big, speed and mileage wont be proper!    

 

 

Link to comment
Share on other sites

You may have the same tire, a Blizzak DM-V2,     but,    you do not have the same size. You show you have a 70 series, 255/70/18 where I have a 255/65/18.  Your size has a 1.07" larger diameter, requiring only 649 revolutions per mile. This will change you speedo slightly, 23 tire revolutions over a mile shouldn't be that big but I dont know the math for how much. It will show you going a bit slower than you actually are. As for the forscan system, computer and drive system I don't know impact on them.

Link to comment
Share on other sites

3 hours ago, ohsown said:

You may have the same tire, a Blizzak DM-V2,     but,    you do not have the same size. You show you have a 70 series, 255/70/18 where I have a 255/65/18.  Your size has a 1.07" larger diameter, requiring only 649 revolutions per mile. This will change you speedo slightly, 23 tire revolutions over a mile shouldn't be that big but I dont know the math for how much. It will show you going a bit slower than you actually are. As for the forscan system, computer and drive system I don't know impact on them.

Yes, I knew there would be a slight speed difference but in ForScan, the tire size in circumference is not even close to the original tire size.  2437 vs 2518. That's who I was wandering where does this size come from?  In summer, I will put back the original tire Dueller 265-65r18 but in winter I prefer tinner tire.

Link to comment
Share on other sites

6 hours ago, akirby said:

I was right - the circumference of the loaded tire is slightly less.

 

https://www.ranger5g.com/forum/threads/forscan-tire-size-wiki.10139/

Great info....  Si if I get it straigt, my new tires are 255-70R18 = 2558mm * 0.967 = 2473mm  to input in Forscan.   And when I will put back the OEM tire 265-65r18  = 2517 * 0.967 =  2434 instead of 2437 original settings.

 

S

Link to comment
Share on other sites

Squash factor, well I've been schooled! Am I ever glad I didn't know about this when I was looking for winter tires. I'd still be looking. I would have liked a narrower tire for winter as well but even the ones I bought show as not fitting my vehicle. Phone calls to Bridgestone were of no help either.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...