Center Bore

SASK_RT · February 16, 2019

I have a buddy that just bought a 2019 Ram 1500 and upgraded the wheels on day one. I'm in the market for a second set of wheels for my truck. My question is will the 2019 Ram wheels with the following specs fit my GM product since the bolt pattern is now the same? It looks like the center bore of the Ram is 0.3mm smaller that my GM truck? Does anyone know if I the ram wheels with smaller bore would work on my truck? My buddy would give me a good deal if hey would work for me. I am only really concerned about the center bore. If I can't get the wheel on the hub, I'm outta luck. Any input on bore sizes?

Here are the specs that I can find about Ram and GM stock specs:

RAM

275/55R20

9Jx20 ET19.1

6x139.7

Center Bore: 77.8 mm

GM

275/55R20

9Jx20 ET27

6x139.7

Center Bore: 78.1 mm

Any help would be appreciated>

Edited February 17, 2019 by SASK_RT

Yeomama · February 16, 2019

Check the rim's backspacing for compatibility.

Edited February 16, 2019 by Yeomama

SASK_RT · February 17, 2019

32 minutes ago, Yeomama said:

Check the rim's backspacing for compatibility.

Isn't offset basically the same thing? It looks like there is only 8mm of difference.

Thanks for the reply

Darmichar · February 17, 2019

14 minutes ago, SASK_RT said:

Isn't offset basically the same thing? It looks like there is only 8mm of difference.

Thanks for the reply

Plug the specs in here:

https://www.wheel-size.com/calc/?wheel1=265-65-18X8.5ET25&wheel2=315-50-20X10ET-23&fcl=50mm&wcl=30mm&scl=50mm

It will let you visualize what they'll ultimately look like.

SASK_RT · February 17, 2019

26 minutes ago, Darmichar said:

Plug the specs in here:

https://www.wheel-size.com/calc/?wheel1=265-65-18X8.5ET25&wheel2=315-50-20X10ET-23&fcl=50mm&wcl=30mm&scl=50mm

It will let you visualize what they'll ultimately look like.

I am not worried about clearance anywhere but the center bore. Will the smaller bore of the Rams wheel at 77.8mm fit over the hub center of the GM. It is 0.3mm larger at 78.1.

Darmichar · February 17, 2019

6 minutes ago, SASK_RT said:

I am not worried about clearance anywhere but the center bore. Will the smaller bore of the Rams wheel at 77.8mm fit over the hub center of the GM. It is 0.3mm larger at 78.1.

I truly think you'd just have to try them. I'm sure there's a tolerance on that bore +/- a certain amount and .3mm (.1 inch) isn't much in the grand scheme of things.

SASK_RT · February 17, 2019

3 minutes ago, Darmichar said:

I truly think you'd just have to try them. I'm sure there's a tolerance on that bore +/- a certain amount and .3mm (.1 inch) isn't much in the grand scheme of things.

Thanks again. I agree its not much...I'm hoping someone with more knowledge and experience would have a more concrete answer.

JCKustoms · February 17, 2019

It’s actually only .012” difference, 3.062 to 3.074. I highly doubt 12 thousandths will make any difference! I’d do it. [emoji16]

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SASK_RT · February 17, 2019

11 minutes ago, JCKustoms said:

It’s actually only .012” difference, 3.062 to 3.074. I highly doubt 12 thousandths will make any difference! I’d do it.

good point. I guess I was over thinking the 0.3mm. I might give them a try.

Darmichar · February 17, 2019

11 minutes ago, JCKustoms said:

It’s actually only .012” difference, 3.062 to 3.074. I highly doubt 12 thousandths will make any difference! I’d do it.

Sent from my iPhone using Tapatalk

You're right, I did a quick conversion in google and didn't realize it dropped the decimal before the 3. I'd definitely give that clearance a shot.

dieselfan1 · February 17, 2019

Can't you just try one and see if it fits instead of all the speculation ?

SASK_RT · February 17, 2019

35 minutes ago, dieselfan1 said:

Can't you just try one and see if it fits instead of all the speculation ?

That would be ideal...but with no workshop and -25 temps, not something I was willing to attempt.

dieselfan1 · February 17, 2019

1 hour ago, SASK_RT said:

That would be ideal...but with no workshop and -25 temps, not something I was willing to attempt.

I'm getting sick of winter too.

We are on pace to break the record snowfall for the month of February here just north of Minneapolis with two more snowfalls predicted in the next 6 days. At least we are above zero this week.