17x9.5 vs 17x8

[scottw]

I was looking at the Black Rhino Overland wheels. They come in 17x9.5 and 17x8.

The 9.5's have a smaller backspace (4.5 inches vs 5.7). Besides backspacing (and offsets) is there any particular reason to choose one over the other? (the tires can handle 7.5 to 9.5-inch wheels and recommend 8).

Thanks,
Scott

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[Arterius2]

less sidewall bulge on the 9.5, more actual diameter being used so you actually get more height from the tires than 8.

Also less chance for your tire to miss a bead when off-roading with the 9.5 (less breaking angle or whatever you call it between tire bead and the wheel rims due to less sidewall bulge)

 

[irishtim7]

less sidewall bulge on the 9.5, more actual diameter being used so you actually get more height from the tires than 8.

Also less chance for your tire to miss a bead when off-roading with the 9.5 (less breaking angle or whatever you call it between tire bead and the wheel rims due to less sidewall bulge)

FWIW it's the opposite on losing a bead when aired down.

Rim width relative to tread width has an effect on bead retention when aired down and on the overall tire profile. In general a narrower wheel (from within the manufacturers guidelines) will result in a more rounded profile with a slightly smaller footprint but with slightly greater protection of the wheel. Narrower wheels also may retain the bead marginally better when aired down than will the wider wheels. Wider wheel provide a flatter tire profile and greater footprint. Since the rim is wider it will not be as protected from the rocks as would a narrower wheel with the same tire. The tire carcass will exert less pressure on the wider width bead when aired down and a wider wheel may thus be marginally more likely to lose a bead when pressures are low. Wider wheels, with less sidewall bulge, may reduce the rubbing of large tires on the springs at full turn.

 

[Arterius2]

FWIW it's the opposite on losing a bead when aired down.

Rim width relative to tread width has an effect on bead retention when aired down and on the overall tire profile. In general a narrower wheel (from within the manufacturers guidelines) will result in a more rounded profile with a slightly smaller footprint but with slightly greater protection of the wheel. Narrower wheels also may retain the bead marginally better when aired down than will the wider wheels. Wider wheel provide a flatter tire profile and greater footprint. Since the rim is wider it will not be as protected from the rocks as would a narrower wheel with the same tire. The tire carcass will exert less pressure on the wider width bead when aired down and a wider wheel may thus be marginally more likely to lose a bead when pressures are low. Wider wheels, with less sidewall bulge, may reduce the rubbing of large tires on the springs at full turn.

OK, but if tire is too wide for the rim, during tire deformation (while turning or off-roading) wouldn't that create enough pressure and cause tire burping to disengage the bead's breaking-point? Basically the same reason why you'd lose a bead if you air down too much? Wider wheels allow you to air down more without being in the danger zone of losing a bead. (tire deforms until rim edge digs into the outer sidewall bend and pushes the bead out from underside)

 

[irishtim7]

OK, but if tire is too wide for the rim, during tire deformation (while turning or off-roading) wouldn't that create enough pressure and cause tire burping to disengage the bead's breaking-point? Basically the same reason why you'd lose a bead if you air down too much? Wider wheels allow you to air down more without being in the danger zone of losing a bead.

Well, what is too wide? As long as you're within spec for wheel width I think it's fine. For street driving you may be right, narrow would be more apt to lose a bead during hard cornering. But, who drives like that in a Jeep on the road? That's not even a concern in a street situation TBH. The info I posted above was for being aired down offroad. If one is taking corners like a M3 while aired down offroad, there's going to be more problems than just losing a bead. It's probably even negligible anyway with 8" vs 9.5". Personally, I would go narrow for the greater wheel protection mainly.

 

[Arterius2]

Well, what is too wide? As long as you're within spec for wheel width I think it's fine. For street driving you may be right, narrow would be more apt to lose a bead during hard cornering. But, who drives like that in a Jeep on the road? That's not even a concern in a street situation TBH. The info I posted above was for being aired down offroad. If one is taking corners like a M3 while aired down offroad, there's going to be more problems than just losing a bead. It's probably even negligible anyway with 8" vs 9.5". Personally, I would go narrow for the greater wheel protection mainly.

I see, I'm mostly just a geeky theory guy without much off-road experience, thought I'd chip in on what I know mathematically-wise , but yea, cheers!

 

[scottw]

Thanks @Arterius2 and @irishtim7 for the insights.

 

[blnewt]

Are there any other wheels you like in an 8.5 or 9 width w/ backspacing around 5? What tires were you planning, and are you lifted or planning to lift?

 

[scottw]

Are there any other wheels you like in an 8.5 or 9 width w/ backspacing around 5? What tires were you planning, and are you lifted or planning to lift?

I am actually now leaning towards the BR Glamis (https://www.quadratec.com/p/black-rhino/glamis-wheel-07-17-jeep-wrangler-jk). I didn't notice the Overland has an -18 offset which I think will cause the tires to stick out a little more than I would like. The Glamis (or may be Sidewinder) is a -12 offset. (I like what I saw in this thread: https://www.jlwranglerforums.com/forum/threads/285-75r17-on-sahara.3609/)

For the tire, I am going with the Nitto Ridge Grappler (285/75/17). I like the look of it and it is one of the few in that size that has a load range of C. As a bonus, there are a couple of places doing 10% off the Nittos.

Where you curious or does something I am thinking about sound off?

 

[irishtim7]

For reference this is 17x9 -12 with a 37x12.5" tire. A 285 will look a little different and won't stick out as much.

 

[Rkobel]

Hi all, a little newer to the Jeep community but would love some advice.
Running a 2023 Willys 4xe with a 2.5 inch Metalcloak True DR Lift w/redrock shocks. The lift calls for an aftermarket wheel with a MAX backspacing of 4.5 - OR, if keeping stock Jeep wheels, a 1.75-2.00” spacer is required to clear the shock relocation bracket.
For financial reasons, I opted to keep the stock wheels and toss on the 1.75” spacers. The lift is great but I am still riding on the stock 255/75r17 tires(~32”) that came with it - which doesn’t look awful IMHO, but could look way better with larger tires. Here is where I need the advice.

For wheels: would 17x9 or 17x8 be a better choice?
I’ve noticed finding 17x9 with the appropriate offset/backspacing (-12 to -19ish/4.25-4.50 BS required is a little tough. There seem to be more options with the 17x8.

For tires: just looking for a bit larger, either 285/70r17 or the larger (preferably) 285/75r17.

I do very light off-roading with the family, nothing too extreme. Also not looking to re-gear the Willys which I think comes standard with a 3.73, to accommodate a larger 35” or 37”.

I would appreciate ANY advice and expertise! Much appreciated!!

 

[2nd 392]

[QUOTE="Rkobel,
For wheels: would 17x9 or 17x8 be a better choice?
I’ve noticed finding 17x9 with the appropriate offset/backspacing (-12 to -19ish/4.25-4.50 BS required is a little tough. There seem to be more options with the 17x8.

For tires: just looking for a bit larger, either 285/70r17 or the larger (preferably) 285/75r17.

I do very light off-roading with the family, nothing too extreme. Also not looking to re-gear the Willys which I think comes standard with a 3.73, to accommodate a larger 35” or 37”.

I would appreciate ANY advice and expertise! Much appreciated!!
[/QUOTE]
Question- why so much negative offset ? I have -1 mm (8.5”, 4.75” BS) and 12.50’s tread is about even with the XR extensions, much more the tires will be throwing crap on the Jeep. 0 offset with an 8” will be 4.5”, an 8.5” -6, that likely isn’t made so -12 (4.25” BS)etc, the wider the wheel the more - offset needed

 

[Rkobel]

2nd 392 - thanks for the reply.
The reason for the large negative offset was because when I looked at 17x9 wheels that that have a BS of 4.5 or less, the offset is usually between (-12 and -15) the -19 wheels I found were in my price range and the BS was 4.25 (well within the recommended max of 4.50 that Metalcloak says is needed for no interference w/suspesnion components) I’d prefer to have the least amount of negative offset as possible, just want to make sure I clear the suspension. I noticed that it was easier to find appropriate BS with the 17x8 and 17x8.5 wheels w/much less negative offset. So that being said, would the smaller wheels be better with the offset closer to zero? Just want to make sure they will still accommodate the 285/70r17 or the more desirable 285/75r17. Thanks!

 

[2nd 392]

2nd 392 - thanks for the reply.
The reason for the large negative offset was because when I looked at 17x9 wheels that that have a BS of 4.5 or less, the offset is usually between (-12 and -15) the -19 wheels I found were in my price range and the BS was 4.25 (well within the recommended max of 4.50 that Metalcloak says is needed for no interference w/suspesnion components) I’d prefer to have the least amount of negative offset as possible, just want to make sure I clear the suspension. I noticed that it was easier to find appropriate BS with the 17x8 and 17x8.5 wheels w/much less negative offset. So that being said, would the smaller wheels be better with the offset closer to zero? Just want to make sure they will still accommodate the 285/70r17 or the more desirable 285/75r17. Thanks!

I just took a close look, you could likely go 8.5” -12mm, 4.25” BS without going (or slightly) past the extensions with 12.50’s. 285’s are just ~11.50’s tread, but fit for 12.50’s, you will probably want to upgrade in the (near) future.

psssst- with the lift 285/70 or even 285/75 will look too small . The factory 33’s looked small on mine with the factory 1.5” lift. Save money in the long run and get light 35/12.50’s. I got 59 lb Toyo AT3, the lightest 35/12.50 - 315/70
3 peak. They have proven to be a terrific tire. … do also consider wheel weight when choosing. My 8.5” wheel 35/12.50 combo is 2 lbs lighter than the factory 7.5” 285/70 combo
Edit- brain fart, if your Willys doesn’t have the wide axles no sweat with the -12-19 mm. Sorry, I don’t know the axle width difference.

 

[Rkobel]

Thanks for the info. I’d love to run 35” right out of gate. So if I were to run the 35/12.50/17, would a 17x9 be the way to go over a 17x8 or 17.8.5? And would the 4.5” BS still be enough to clear all components of Metalcloak 2.5” lift with that tire size? The metalcloak rep said that the 2.5 lift was designed to accommodate 35” tires - but obviously finding the right wheel size/backspace and offset with the right tire/size is key. My thought would be the 17x9 wheel with -12 offset/~4.5 BS, with a 35/12.50/17 or 315/70r17. (But would going with a lightly more negative offset and lower BS be safer with the larger/wider tires?) thanks again all, I truly appreciate your input!

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