Wheel Offset

[DaveB]

Struggling with wheel balance and needing new rubber, I'm planning to spend some hard earned reddies on 15" Minilite wheels with +15mm offset from Midland Wheels; before going ahead I wanted to understand offsets, tyre sizes and how they may affect clearances.

Current - 185/80 R14 on standard 5.5J alloys ET32.
New - 195/65 R15 on 5.5J Minilites ET15 would give about 12mm extra clearance from the front suspension but would be about 22mm nearer the wheel arches.

After some head scratching I've come up with the following diagram which would suggest there should be no problem (if my understanding is correct ???) and looking at the current clearances there should be no problem with the extra width, especially as the slightly smaller overall diameter with the 195/65s would help with rear wheel arch clearance and I'm not worried about a small difference in speedo reading. Not sure though about front inner wheel arch when on full lock; any thoughts


Tyres & Wheels Sizes.jpg









































Dave

[ChasR]

FWIW, my split rims are effectively ET33 6.5Jx15" at the moment with 205/60R15s. Rear do not catch even with the car loaded up and the fronts clear the struts in addition to the inner wheelarches on full lock. On 195/65s I doubt you should run into issues .

With the rear, remember that the camber change of the rear suspension design will help with the wheels clearing the outer wheelarch (although naturally, there is a element of trial and error to that).

[Dieter H. Marschall]

Hello Dave,

I have put on the following rims: Appliance Industries, Harbour City, California (« Wolfrace »-Design) 6x14, ET +19.
This adds 16mm all together to the width of both axles.

Kind regards,
Dieter.

[milothedog]

Struggling with wheel balance and needing new rubber, I'm planning to spend some hard earned reddies on 15" Minilite wheels with +15mm offset from Midland Wheels; before going ahead I wanted to understand offsets, tyre sizes and how they may affect clearances.

Current - 185/80 R14 on standard 5.5J alloys ET32.
New - 195/65 R15 on 5.5J Minilites ET15 would give about 12mm extra clearance from the front suspension but would be about 22mm nearer the wheel arches.

After some head scratching I've come up with the following diagram which would suggest there should be no problem (if my understanding is correct ???) and looking at the current clearances there should be no problem with the extra width, especially as the slightly smaller overall diameter with the 195/65s would help with rear wheel arch clearance and I'm not worried about a small difference in speedo reading. Not sure though about front inner wheel arch when on full lock; any thoughts


[ATTACH=CONFIG]16506[/ATTACH]









































Dave

Have a look here Dave. http://www.carbibles.com/tyre_bible_pg4.html

Ian

[DaveB]

Thanks guys; a great help. The carbibles info certainly make it all much clearer. Searching the forum I've come across different opinions on the standard Stag alloy offset, 32mm or 28mm ??

cheers

Dave

[mike@thenook]

Hi Dave,

195/65 on any 15" (or 14" if you could get them) would leave you with no advantage in tyre contact area. I run 195/70 x 14 on 6" rims (same as HRS racer) the standard stag wheels are only 5.5" so with a 15" wheel 5.5" wide there would be no extra tyre contact at all - I would go for 6" and proabably the 205 width as ChasR runs as anything less will leave no improvements and probably the car willl look under tyted due the lwoer profile - bear in mind the original XVS/XAS tyres are an 80- section....

Cheers,

[ChasR]

I shall be honest here and say that I now believe the offset is ET28. Most of the information I initially read pointed towards the wheels having an offset of ET32 (the MG gurus and the information on here).

When I performed some measurements on the wheels (backspace, centreline, total width etc.) in addition to looking at the values on the wheels themselves (I believe it says 5.5Jx15"x1.12 on the wheels from memory) they all pointed towards an offset of ET28 .

[mjheathcote]

I believe the standard alloy wheel to be ET 28.
....can't remember where I got that info from though now!