Ideal offset for 275/40R20 on 20x9.5 for 14 SQ5

[tastic]

I have a 2014 SQ5 and have picked up some 20x9.5 wheels and 275/40R20 rubber.

The wheels have a native offset of +35. What would be the ideal offset? Get 10mm all around and make them +25?

Will be lowered but not slammed on H&R coils.

Thanks in advance!

PFA pre lowering




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[riceboy22]

et25 should be about right. These were 20x9.5 et29 with 5mm spacers added, 275/40r20 Michelins, and dropped 2”.

[base14]

+2 on the et25. Its pretty darn flush with that setup! 10/15mm F/R spacers on your setup would be better than 10 all around

[tastic]

et25 should be about right. These were 20x9.5 et29 with 5mm spacers added, 275/40r20 Michelins, and dropped 2”.

That looks great! When you have a moment, do you have any other shots handy? Perhaps a similar angle from the front and a side shot?


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[riceboy22]

I don’t have those wheels anymore, but here are a couple of different angles I had taken photos.

[tastic]

Thanks! Much appreciated! Where did you source the ecodes? I’m allergic to amber as well.


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[base14]

If it helps, these are 20x9 et25. I put 5mm spacers in the back (not pictured here) and it looked perfect to me but had vibrations so I removed them. It’s easier to space 10-20mm BC they have the hub centric lip which the 5ers did not.



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[buggravy]

Everyone else beat me to it, but I feel like ET25 has basically become the reference point for all non OEM fitments. Works perfectly with tires from 255 to 295, with no clearance or poke issues across the board.

[riceboy22]

Thanks! Much appreciated! Where did you source the ecodes? I’m allergic to amber as well.


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If you’re interested shoot me a PM and I can share info. I got them from a somewhat unique source.

[SQive]

Everyone else beat me to it, but I feel like ET25 has basically become the reference point for all non OEM fitments. Works perfectly with tires from 255 to 295, with no clearance or poke issues across the board.

Now hold on there, Wilbur. . .the 10.5" wheels do poke a little at +25, but it looks damn good on the gen.1 SQ5's.

[kellin]

Now hold on there, Wilbur. . .the 10.5" wheels do poke a little at +25, but it looks damn good on the gen.1 SQ5's.

20x10 et25 is probably one of the best fitments for the S/Q5. Look at Mops@Nemesis’ posts and you’ll see what I mean.

[tastic]

Ended up having to go with 12mm spacers up front to clear the caliper (10mm didn’t fit). For the rears, I used 15mm. So final net offset is +23 front +20 rear. Camber is -2.0 front and -2.2 rear. Stock arms. Lowered on H&R coils.








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[Silver_Bullet]

Ended up having to go with 12mm spacers up front to clear the caliper (10mm didn’t fit). For the rears, I used 15mm. So final net offset is +23 front +20 rear. Camber is -2.0 front and -2.2 rear. Stock arms. Lowered on H&R coils.

I did a quick calc a little while back, and an additional 1 degree of negative camber will move the top of the wheel in by 6.4mm (all else being equal). Something to keep in mind if you are running a lot of camber and comparing the look to those running a more stock camber.

[stapan]

I did a quick calc a little while back, and an additional 1 degree of negative camber will move the top of the wheel in by 6.4mm (all else being equal). Something to keep in mind if you are running a lot of camber and comparing the look to those running a more stock camber.

This is great info. Something many people don't think about when selecting wheels that can make a big difference in final fitment.

Anyone have data on how much camber drops with every inch of lowering?

[stapan]

I did a quick calc a little while back, and an additional 1 degree of negative camber will move the top of the wheel in by 6.4mm (all else being equal). Something to keep in mind if you are running a lot of camber and comparing the look to those running a more stock camber.

How did you get 6.4mm? Using this calculator and a 29.1 diameter, I get 0.51 inches (approx 12-13mm) per degree:

http://www.gtsparkplugs.com/Camber-O...alculator.html

[Silver_Bullet]

How did you get 6.4mm? Using this calculator and a 29.1 diameter, I get 0.51 inches (approx 12-13mm) per degree:

http://www.gtsparkplugs.com/Camber-O...alculator.html

I like that somebody did a calculator! But this is basic trig. I get the same number but divide by 2. If you look at their drawing they are showing the change over the diameter - from the top of the tire to the bottom of the tire. If you assume you are roughly pivoting around the drive axis/wheel centerline, then half the move is in at the top and half the move is out at the bottom.

But this has got me thinking here, so into the rabbit hole we go! It will not pivot around the drive axis specifically because the control arms set the suspension and I assume the drive axle will float to adjust horizontally. Maybe the system pivots more around the lower control arms, which seem to attach to the knuckle maybe 4-5 inches under the drive shaft. In that case, add 4 inches to the radius = 14.55 + 4 = 18.55. Top Offset per Degree = 18.55 *25.4* sin (1 degree) = 8.2mm. So maybe a little more than 6.4mm.

But now deeper into the rabbit hole. I'm thinking this works with the change from your original setup to your lowered setup with the camber measured PRE-ALIGNMENT. Once they align it, they will be shortening the lower control arm to pull in the bottom of the wheel to get camber back in spec as much as possible. So the post alignment top offset change would be the calculation above plus the amount shortened on the lower control arm in mm during alignment. I would use your pre-alignment camber numbers as the best estimate since the upper control arms are so high - the top of the tire will not move that much with the shortening of the lower control arm on the bottom.

I hope my logic is on target but feel free to trash it if I'm off base here. I have no relevant domain knowledge on suspensions, just trying to noodle this out!

[stapan]

I like that somebody did a calculator! But this is basic trig. I get the same number but divide by 2. If you look at their drawing they are showing the change over the diameter - from the top of the tire to the bottom of the tire. If you assume you are roughly pivoting around the drive axis/wheel centerline, then half the move is in at the top and half the move is out at the bottom.

But this has got me thinking here, so into the rabbit hole we go! It will not pivot around the drive axis specifically because the control arms set the suspension and I assume the drive axle will float to adjust horizontally. Maybe the system pivots more around the lower control arms, which seem to attach to the knuckle maybe 4-5 inches under the drive shaft. In that case, add 4 inches to the radius = 14.55 + 4 = 18.55. Top Offset per Degree = 18.55 *25.4* sin (1 degree) = 8.2mm. So maybe a little more than 6.4mm.

But now deeper into the rabbit hole. I'm thinking this works with the change from your original setup to your lowered setup with the camber measured PRE-ALIGNMENT. Once they align it, they will be shortening the lower control arm to pull in the bottom of the wheel to get camber back in spec as much as possible. So the post alignment top offset change would be the calculation above plus the amount shortened on the lower control arm in mm during alignment. I would use your pre-alignment camber numbers as the best estimate since the upper control arms are so high - the top of the tire will not move that much with the shortening of the lower control arm on the bottom.

I hope my logic is on target but feel free to trash it if I'm off base here. I have no relevant domain knowledge on suspensions, just trying to noodle this out!

Love it! Thanks for sharing with the community. I was surprised how hard it was to find an accurate estimate of this effect.

You seem to really know your stuff - how much does lowering an inch equate to in negative camber change? That'll help us get to the end goal lowering amount -> offset change.