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Wheel Specs?

72651 Views 85 Replies 20 Participants Last post by  DGatzby
Basically all I know is they are 20 x 9.5

Anybody know where I can find our stock wheels
Backspacing
Offset
Lug Spacing
Weight

Thanks
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Thanks
Ill take that.

Now just need to know backspacing.
I can weigh them if I have too, but I'm sure somebody already has, so hopefully they'll know.
Oh, also, by chance do you guys know what the SRT wheel center cap diameter is?

Thanks again
Cool didn't know the convert method. Thanks.

So it works out to be:

9.5 (inches)
divided by 2
= 4.75
+ offset of 18.5 mm (which equals .728346 inches)

4.75 + .728346 = 5.478
Thanks, I have been familiar with offset for years, but seems only in recent years is the term "backspacing" coming into play (does this refer to how deep dish the wheel is?).
So I really didn't know what that was or how to measure it.
Just wanted to make sure the aftermarket wheels I'm looking at will look good and fit properly without rubbing issues.
OK, I've researched a bit more.
this backspacing and offset thing seem to be two ways of finding out the EXACT same information. So why did they start to talk "backspacing" in the past couple years.

Backspacing is the distance from the back of the wheel to the back of the mounting hub
Offset, as has been the standard forever, is the distance in millimeters OUTWARD or INWARD from centerline of the wheel to the mounting hub.
So to me, what's the point of measuring backspacing, it just causes confusion, and here's a perfect example.

I'm looking at wheels for the Hellcat that will look aggressive and not "cheesy aftermarket looking" so I can take off and store the forged OEM wheels, so if/when it comes time to sell the Hellcat, the OEM wheels will be immaculate, adding to the value of the car.
I'm also wanting to find 20x10 wheels so if I decide to put 305's on the car, it's within the recommended rim size and I don't have to worry about ballooning or anything putting 305's on a 9.5 inch wide wheel.

The wheel I am looking at is a
20 x 10
says it has a offset of 25 mm
Which is perfect compared to stock. Wheel won't stick out any further than current OEM wheel, but actually the face of the wheel will sit inward a measly 1 millimeter, but because the wheel is 1/2 wider the additional 1/2 inch is all on the inside, meaning it's wider inward toward the suspension and tucking under the wheel wells.
However, this same wheel says it has a backspacing of 6.50"
Well, how in the heck can it have a 6.50" backspacing but have an offset of 25mm from the centerline of the wheel. There is a 1/2 inch discrepancy there.
So either the wheel has a 25 mm offset and a 6.00 inch backspacing or
the wheel has a 6.50" backspacing or a roughly 38 mm offset

So unless I'm missing something with this backspacing stuff, I don't know which to believe on this wheel.???
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^ I am with ya. Let me guess that is the Bravado site? If so I agree those numbers are so strange I moved on. I am at about at my wits end. I have been shopping for three hours for ANY manufacturer that offers anything not custom in a 9.5" front and a 11" rear that works! I think I have changed my mind, may want black and not chrome but I can't find anything that works at least off the shelf. I know those Bravado's works because there is a thread where a member used them. I have a question or two out on email now.

FYI, I do think that 25 mm may be close to the magic rear offset for an 11". We know a 21mm offset works with a 315, because that is the Bravado thread. I am about to pull the trigger, but can't find anything to buy!!

No it wasn't the Bravado, but I did JUST see that thread and looked at them.
I wouldn't want 20 x 11's
I saw that coldheartid went with them, and they stick out to far for my tastes.
If they made them in 20 x 10.5 that would be better. Even 20 x 10's.
My thing is, I don't want wheels that have an offset that makes them stick OUT from under the wheel well any further than the stock ones.
I'd like wheels that are 1/2 to 1 inch wider, but basically all of that width inside under the wheel well.
So the more positive offset the more it sets back into the car. I have the 305's mounted up. Keeping the same offset at 18.5 mm with a wider wheel keeps the tire in the same realitive place. Notice that there is 5/8" distance from the face of the 9.5" wheel to the outside edge of a 305. Coldheartid has a 21mm offset, shifting it in just a bit. He reports even with those huge 325's he still has some room at the critical spot inside. I think I am going to go with 305 rears. So IMO a 25mm offset will work with either a 10.5 or an 11" and tuck the package in as far as we dare. On the backs only now.
My issue is that we need 315/35/20 tires to have the same overall outside diameter of the stock 275/40/20 tires.
305/35/20's make the tire 2.2% smaller. This means a smaller sidewall and bigger wheel well gap. To most they won't notice, but on your own car, the tire looks short. Further, this lowers the final drive ratio, which means it spins easier. So though you will have more tire on the road, the tires are going to turn 2.2% faster (and therefore harder, which means more tire spin).
Ideally, we have 315 tires. Even more grip (tire on the road) and the same overall diameter so we can launch harder when needed and less chance of tire spin, if going say, 40 mph and you get hard into the throttle.

Issue for me is, 315 size tires are "recommended" on 10.5 inch or wider wheels, which there aren't many of, with an offset of around 30 mm, so they don't stick out any further than what our stock wheels do now.
305's are ok for 10 inch wide wheels
295/40 tires would work best on 10 inch wide wheels, but here we give up some width of the tire on the road, but it's also a taller tire than stock, which means we raise the final drive ratio. This is good for being able to launch harder and keeping revs lower, but the issue is there is basically ZERO choices in 295/40 tires.

I just don't know why Dodge choose to put 9.5 inch wide wheels and 275 inch wide tires on the rear of this powerful of a car.
They SHOULD of just gone the staggered route.
And put 10.5 inch wide wheels with 315/35/20 tires on the rear, and all would be perfect.
But like what we are running into, they probably couldn't find a maker of staggered wheels that looked good, and they didn't want to pay for the R&D for a company to make them.
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A wider wheel with the same offset as stock will push your wheel outside of the body, 1" wider with same offset means 1/2" of wheel outwards, if you go 1" wider and want the wheel in the same location as stock your offset should be around 31mm
Yup.
I just put 30 mm offset because it's a round number and close enough. :)
DGatzby,

We may in fact be saying the same thing.

To make sure I'm going to reiterate here as to what I want.

Our stock wheels are 9.5 inches wide with an offset of 18 mm

In order to get a 10.5 inch wheel that doesn't stick OUT away from the car any further than the stock wheel
you need to get it with an offset of roughly 30 mm (31mm to be exact)
However, because the wheel is 1 inch wider, that 1 inch has to go somewhere, and in this case with a 30-31mm offset it, that one inch of wheel will be 1 inch closer to the suspension.

Unless you are saying we do not have 1 inch of space in there, which it looks like we do, except the plastic wheel well cover, which we can mold or cut away, I don't see how a 315/35 tire on a 10.5 inch wheel in the rear would rub.

Now I'd be worried about going with anything wider than a 10 inch wheel in the front as there doesn't seem to be a lot of room there near the top of the wheel, where there is a black angled suspension bar about a fingers width away from the stock tire already.
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DGatzby,

You may be right about the 30 mm offset on a 10.5 inch wide rear wheel not working with 315 tires, that may in fact be cutting it too tight.
The only reason I said I think it would was because of Coldheartid's post.
He made a 11 inch wheel with a 21 mm offset work with the 315 tires and said there is plenty of room?
That's a wheel that's 1/2 inch (13 mm) wider but the offset is only 9 mm difference.

But it wouldn't matter anyway, as I haven't found one single 20 x 10.5 wheel with a 30 mm offset. Most are 20-24 mm.
So if I had too, I'd go with a 24 mm offset. That would push the wheel about 6-7 mm further out away from the car.

But again, the issue is, the wheels I've found that I like the best are 20 x 10's and have a 25 mm offset.
Which is actually perfect, but pushing the limit for a 315 tire, where a 10.5 inch wheel would be best for a 315 tire.
But I haven't found a 20 x 10.5 inch wheel that I like with an offset even at 24 mm.

So it's a conundrum right now.
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Thanks.
I have never used a spacer before on any of the numerous aftermarket wheels I have boughten.
However, I've never owned a car with so few wheel choices that fit/work.

Unless the wheel he is using a 10.5" rear wheel that has an offset of like 15, he shouldn't need a 25 mm spacer.
I'm apt to think a 10.5" rear wheel with a 20 mm or high offset will work based on the clearance I see in the rear.

It's the fronts that are tight. The wheels I like that come in 20 x10 or 20 x 10.5 size all seem to have a front wheel that is
20 x 9 or 20 x 10
So I feel if I could put a 20 x 10 up there, it would be great.
But it would be REALLY close to hitting the suspension part.
But I wouldn't want to use a spacer up front unless it was a small one like 7 mm (about 1/4").
Anything more and it will force the front wheels out too far for my liking.
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What wheels are you trying to use IA CAT? And what sizes front and rear?
Driver, someone may have answered this but if not, a 20x10 wheel is 10 wide at the tire mounting lip, but backspacing is measured from the outer lip and the accepted thickness of the outer lip is 1/2 inch on each side of the rim, therefore the backspace of a 20x10 rim would be 5+1/2+offset (if positive) measured from the outer rim lip.
Yeah, but isnt backspacing is a more recent term when talking wheels, but it's kind of a duplicating information?
If you have the offset of the wheels, that's really all you need. You can do the math to find the backspacing from that, because the offset is the same thing, tells you how far from the centerline of the wheel the mounting surface is.

So a 20 x 10 wheel with a 25 mm offset is going to have a wheel that sticks in toward the suspension 13mm (1/2") more than the stock 9.5" wheels with 18 mm offset.
The 20 x 10 wheel with a 25 mm offset will also stick out toward the road 1 mm more than the stock wheel too.

That's my dilemma. Look at the space between the top of the stock wheel/tire and the suspension assembly on the FRONT WHEEL. Turn your wheel all the way and then try to get a finger between them. It has at most just over 1/2" clearance.
So a 20 x 10 wheel with 25 mm offset will have a wheel that's almost touching that suspension assembly. There may be 1/8" inch clearance. Not enough for comfort in my book. But it the 20 x 10 wheel had an offset of 20-22 mm that would bring it away from the suspension assembly another few mils which would give the piece of mind I'd be looking for.
The only reason I'm considering 20 x 10 up front is because the wheels I like don't come in a 20 x 9.5 like stock. It's 20x10 or 20x9.
The 20 x 9 may look a bit small and the "deep dish" look to it is a bit lost on the 9 inch wheel compared to even the 9.5 and especially the 10 wide wheel.
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What's the best wheel spacer (brand) to get if I need to use a 1/8" inch (4-5 mm) spacer for the front wheels?
I would think the place that sells the wheels would be able to provide the spacers too and know the ideal diameter for the car.
The problem with the front is the small casting boss at the top of the spindle arm hitting the tire with a wider rim and the upper ball joint bolt hitting if using a taller tire, i measured approx .525 inch between the spindle casting boss and .4 inch between the ball joint bolt clearance with the stock tire and wheel combo. No problem with tire height if still using 275x40 but the wider rim will place tire approx .309 inch closer to spindle arm , so if clearance is approx .525 inch, he would have approx 1/4 inch clearance between the casting boss on the spindle arm and the tire with the 20x10 rim. The rim would have no problem on rear with the 275x40 tire. The best thing would be to measure his clearance between the casting boss and compare the clearance to see if a tire .309 inch more to the inside will fit.
Yes your measurements seem to fall into what I've noticed and said, that there is about 1/2 inch clearance up front.
And if I do go with the 20 x 10 up front, I'd keep the 275/40 tires on, so the tire should not be an issue, just the rim being a bit closer. It will for sure make it close, as it's pretty close stock to that spindle arm. I just think it will look bad going with a 20 x 9 wheel up front, as few wheels are made in 20 x 9.5 for the front and 20 x 10 for the rear. So I'd just go 20 x 10 in front and rear, or 20 x 10.5 in rear if I can get the right offset in a 20 x 10.5 rim.
I'd ideally like to go with 315/35/20 tire in the rear, as it keeps the same O.D. as the stock tire, it's just wider.
I know 315's on a 20 x 10 wheel is pushing the limits of that size, and ideally the 315 tire has a 10.5 inch rim to put it on, but again, few choices in 10.5 inch wide rims that will fit on our cars.
Driver, I mounted 22x10.5 , +20 offset, and there is no rim interference at the front or rear on mine, clearance problems on front will be at the top of the spindle arm with the tire sidewall and as you know, a wider rim will Increase your tire section width
Really, so you put a 10.5 inch wide wheel with a 20 offset on the FRONT and it cleared that top spindle arm?
I took the plunge with Triumph. Same rear as you, identical 9.5" front to the OEM.
What Triumph wheel did you get?
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