Wheel offset when replacing alloys

[Deepreddave]

My son has a 2010 mk7 diesel Fiesta with the 1.4 engine and needs some new alloy wheels. His looks to be the only model in the range with an offset of 41.5 with the majority having 47.5. My Ford dealer confirms 47.5 will fit fine so can someone please explain why the original spec would be 41.5? Is it because that engine is a slightly different size to the others in the range?
Ford alloy wheels look to have been susceptible since the start but finding replacements with the added limitation is pricing a PITA 🙂 Thanks in advance.

[Duhh]

All engine sizes of that age of Fiesta have an option of 16 inch alloys with 41.5 offset (6.5j wheels). 14 inch alloys have 37.5 offset (5.5j wheels),and 15 and 17 inch alloys have 47.5 offset (6j and 7j wheels).
Its not that one particular engine size needs a bigger offset to make room for bigger brakes or similar, the options are available from Ford across the board so your son's car will be fine with any of the above.

edited to add handy website
[URL] https://www.wheel-size.com [URL/]

Edited by Duhh on Tuesday 22 May 09:11

[Deepreddave]

Duhh said:

...so your son's car will be fine with any of the above.
edited to add handy website
[URL] https://www.wheel-size.com [URL/]

Great thanks and really appreciate the response. Sorry if this is dim but why the difference in offset? I'd just like to understand why the 16" on the 2008-2012 are 41.5 but the later 2012--> are 47.5.

Edited by Deepreddave on Tuesday 22 May 10:01

[Duhh]

Wider wheels need to be further away from the inner wing so they don't scrape while turning hence the smaller offset on the 16s (smaller offset means the wheels are further from the bodywork).
That doesn't really explain the bigger offset on the 17s though, guess there's other factors with them, but I don't know .

[stevieturbo]

Deepreddave said:

Great thanks and really appreciate the response. Sorry if this is dim but why the difference in offset? I'd just like to understand why the 16" on the 2008-2012 are 41.5 but the later 2012--> are 47.5.

Edited by Deepreddave on Tuesday 22 May 10:01

probably a wider rim, which can negate the offset as the centreline still remains the same, or outer edge remains the same etc etc. Depends where they want the wheel placed.

[Deepreddave]

Thanks both. There must be a reason why the pre-facelift models were all specced 16" rims with this offset, even if it was just rims they had as part of their range. The later post facelifted models all had 47.5 so unless they changed the chassis/bodywork I'm struggling to see why changing to 47.5 would be an issue.

[E-bmw]

As above it probably won't.

[Deepreddave]

Thanks again. Ford dealer has advised he foresees no problems but wheels would need geometry reset given 6mm inboard.
He wondered if the 41.5 was down to brake disc clearance on wider wheel but didn't see a problem in that respect so not totally clear.
Ford customer service are so far resisting answering the question at all so that's less than ideal.
Will update idc although I appreciate it may only be of real interest to me!

Edited by Deepreddave on Tuesday 22 May 19:23

[Deepreddave]

Just a thought, presumably I could fit a spacer to decrease the offset from 47.5 nearer to 41.5 but would say 5mm mean I required longer bolts? Anyone had experience in this regard?