21 replies to this topic

[sigmfsk]

Is anybody using Mopar OEM style rims other than the stock 5.5" or optional 6.5"?

For the rear, I'd narrowed down my tire options to
255/70R15 : 29.0" diameter
275/60R15 : 28.0" diameter
325/50R15 : 28.0" diameter

I test fit a 255/70R15 BF Goodrich, Radial T/A on the 6.5" wide police rim with 4.25" backspacing.

In both the rear left and rear right wheel well, there was almost exactly 2" clearance between the tire and fender-lip, and between the tire and spring (both in front and behind the axle).

This tells me that I might be able to fit in a 325/50R15, but it would be a tight fit, and I think it would look more drag-car-like instead of police-car-like. A 275/60R15 should fit nicely, with lots of space around it, and I don't think it will look un-bluesmobile-like from the side or back.

With a 28" diameter 275/60R15 rear, I'll get a 28" diameter 235/70R15 front. I would prefer having a 29" diameter tires all the way around, with a 235/75R15 front, but in order for a 275 width tire to have a 29" diameter, it would need to be a 275/65R15, and nobody makes one that size.

Here are some pics showing clearance, and comparisons between the 215/75R15 and the 255/70R15.

I'm thinking of getting Mopar OEM style 15x8 wheels with 5" backspacing. For what its worth, that is the same width and backspacing recommended by this fellow for his '69 Fury that runs 275/50-17s:
C-Body DryDock: Forums / Performance Tech / Wheel & tire upgrades, '69 300

I see these places make custom Mopar OEM style wheels:
The Mopar Dude-Sales of Classic Cars and Muscle Cars. Burlington, Kansas
Mopar Wheels - Stockton Wheel

For the fronts, I'll keep the stock 6.5" wheels and 235/70R15. Wider wheels and tires are harder to fit up front, and I'm more concerned about getting the power to the pavement.

your friend in measure twice, buy custom rim once,
arthur

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[bluzman]

Wheel and tire combos can definitely make or break the look of your ride. I have a 77 Royal that I am running Wheel Vintique 15x10 steelies on the rear with a 5 inch backspacing. I have a pair of 295 65 15 Mickey Thompson drag radials on them. They look killer and will clear the factory wheelhouse lip..tight but does not contact the lip....., but if your suspension travels a lot..the sidewall will hit the the lip. I cut about 3/4 of the inner wheelhouse lip away..Blended just where tire will contact....so I would not ruin the tires or quarter panels. Also running a set of the WV 15x7s on the front with Toyo 235 75 15's. Currently building a 74 Bluesmobile...too. I love these cars...cause there are hardly any around where I live.

[bluzman]

Oh yeah..I am also running the Monroe Coil over shocks on the rear...

[sigmfsk]

bluzman said:

I have a 77 Royal that I am running Wheel Vintique 15x10 steelies on the rear with a 5 inch backspacing. I have a pair of 295 65 15 Mickey Thompson drag radials on them.

Wow; that's a big tire! Did the wheel well size change much between 74 and 77? I estimated that a 8" wide wheel with 5" backspacing would be perfectly centered with about 2" on each side (of a 275/60R15 tire). I think a 10" wide wheel with 5" backspacing would push out the wheel too far. Maybe there's a difference in axle widths (I have a 9.25" axle of unmeasured width). I hope to have my new rear tire/wheel combo within a week or so and will post some pics.

thanks,
arthur

[bluzman]

Well ....the 77 has an 8.25 rear, but I just purchased a 9.25 rear from ebay that supposedly has the same measurements...we'll see when it shows up. I really did not want a drag radial..(kinda soft)..but they only make the 295 65 15 size in the drag radial. The tire is about 11.3 inches wide and 30 inches tall. Looks great ...but I can tell ya first hand....totally suck when its raining..drive slowly! Hey... at least I can look cool while driving/fishtailing trying to maintain the power from the whopping 150 HP 318.

[sigmfsk]

This thread
http://www.bluesbrotherscentral.com/forum/bluesmobiles-sale/8477-usa-1974-monaco-sedan-california.html
shows a '74 with four 15x8 wheels with 245/60R15 tires.
They're 1.5" smaller diameter than 235/75R15 tires, but it does show that a 8" rim can fit up front. And if an 8" rim fits, and 245/60R15 fit, then a 255/70R15 might fit. And if a 255/70R15 fits, then a 255/55R18 on a 18x8 rim will fit. And then, per
http://www.bluesbrotherscentral.com/forum/bluesmobiles/9490-z-rated-tire-wheel-questions.html#post113204
I can have a Y-rated tire with sufficient load capacity at speed

[sigmfsk]

I just received (2) 15x8 wheels, each with 5" backspacing from
Mopar Wheels - Stockton Wheel

Stockton seems to be known for quality, and for taking a long time, and that's exactly what I got. I got some nice wheels, and sure am glad I wasn't in a rush.

I measured for the wheels carefully months ago, expecting a perfect fit in the rear, and maybe a fit in the front. It's close, but I think I hit paydirt!

pic1: 215/75R15 on 15x6.5 cop rim on left, 255/70R15 on 15x8 on right.
pic2: 215/75R15 on left front
pic3: 255/70R15 on right front

one thing to examine was the full lock stop.

pic4: this is the right knuckle with the tire straight ahead. the two pieces indicated touch when at full right lock.

pic5: right knuckle at full right lock.

pic6: right knuckle at full right lock with the 255/70R15 installed. Notice that there is a slight gap - the tire hits the frame rail so that the stop never hits. The gap is slight and I don't think I'll miss the tiny bit of reduced turning radius. And, even at this angle the front rubber brake hose is very taught - more taught than I think is reasonable. I probably won't go through the effort of welding on a spacer to the knuckle so that it hits before the tire hits the frame. I'll just make sure I don't go to full lock and goose the throttle while grinding the tire against the frame.

pic7: left knuckle at full right lock with 215/75R15 on stock 6.5" police rim. Just to get an idea of the spacing between the rim & the upper a-arm.

pic8: right knuckle with 255/70R15 at full right lock at ride height. Man its close, but I can't see any way that the rim would hit the a-arm. If something bends or breaks such that the rim hits the a-arm, I figure I'm already in big trouble.

pic9: right knuckle with 255/70R15 at full left lock at ride height.

pic10: showing clearance between brake caliper and rim

pic11: steering linkage

and the rear is just anticlimactic after that (pic 12 and 13).


I could get different backspacing for front & rear, but I'm thinking of just getting all the same size for easier tire rotations.

If I had to do it all over again, I'd get 15x8 rims with 4.75" backspacing instead of 5" backspacing. It would provide some clearance in the front, and the rear has more than enough room to move outboard without problems. But being that I already have 5" backspacing, I don't think it's worth changing now. I'll do more tests when I have the torsion bars out of the front and can easily move the front suspension through its complete range of motion.

your friend in meaty tires,
arthur

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[sigmfsk]

I finally found a screen shot of the bluesmobile with a clip-on wheel weight on the outside of the rim. The 1 mm clip thickness could be an important factor for those of us trying to roll with 1.5 mm of clearance between the rim and a-arm.

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[sigmfsk]

sigmfsk said:

pic6: ... I probably won't go through the effort of welding on a spacer to the knuckle so that it hits [the lower a-arm stop] before the tire hits the frame. I'll just make sure I don't go to full lock and goose the throttle while grinding the tire against the frame.

I just received the Feb 2011 issue of Mopar Action, which had this Q&A (page 93)

> Q: RE: My '68 Charger 440. How do I tell which power steering box is a close ratio?...
>
> A: There is NO SUCH THING as a Mopar fast ratio steering box. The quicker ratio was
> (and is) achieved via a longer pitman arm - simple as that. The boxes designed for the
> fast-ratio pitman arm relocated the stops to prevent tires from rubbing on the frame rails
> and had "T/A" cast in the side in large letters.

I called Mopar high performance suspension products, Mopar high performance torsion bars, Mopar high performance sway bars, Mopar suspension kits, Mopar steering kits, Mopar tubular upper control arms, Mopar leaf springs, Mopar high performance suspension and and spoke with Dick and asked about relocated stops (for his Stage 1 power steering gear) so that my wider tires didn't hit the frame, and he said that by far the easier and better solution was just to beef up the knuckle/a-arm stops. And I'm thinking he's right, and that I should go through that small effort.

[sigmfsk]

Here a guy is selling (or offering for sale) '74 Monaco with 24" rims:
http://www.bluesbrotherscentral.com/forum/bluesmobiles-sale/11322-usa-1974-monaco-2-door-donk-tennessee.html

I called the seller today and asked about the wheels & tires. He was polite and said I was welcome to come look, but he really didn't know much about them.

He said that the tires were probably 275/25R24.
He knew the rims were 24" diameter, but he didn't who made them, what the width was, and wasn't familiar with the terms "backspace" or "offset". He said that the rims would fit any car. I just held my tongue and asked more questions. I eventually got out of him that the rims were for a 2004 745 BMW. That initially sounded strange, but it looks like they might be Status Dystany rims - that have a variety of bolt patterns:
STATUS DYSTANY S822 - STATUS WHEELS - MANUFACTURER OF STATUS, RUFF RACING, ELEMENT, & NAKAYAMA WHEELS FOR CAR AND SUV
20x8.5 inch Status Dynasty wheels - SaturnFans.com Classifieds
STATUS WHEELS DYSTANY BLACK/CHROME INSERTS - Wheels and Rims from Performance Plus Tire

This ad
24"STATUS RIM/WHEELS MAGNUM,CHARGER,300C MARQUISE BMW - eBay (item 270547089824 end time Dec-09-10 12:52:24 PST)
shows 24" rims with 5x114.3 (Monaco 5x4.5) bolt pattern. I'll ask them if they are hubcentric and try to get a backspace measurement.

A 275/25R24 tire is 29.413" in diameter.
Car / SUV / Van / Light Truck Tire Calculations
just a little larger in diameter than a
275/35R15 (29.0")
and a
255/55R18 (29.0") - the smallest diameter z-rated tire I can find with a load rating that can handle a 74 Monaco at speed.
http://www.bluesbrotherscentral.com/forum/bluesmobiles/9490-z-rated-tire-wheel-questions.html#post113204

Of course, I don't know if this guy's tires aren't rubbing, but it will be interesting to see where this guys inner and outer rim lips are located compared to my 8" wide 15" diameter rims.

your friend in tires that don't rub,
arthur

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Edited by sigmfsk, 04 December 2010 - 01:05 PM.
add pic

[sigmfsk]

sigmfsk said:

This ad
24"STATUS RIM/WHEELS MAGNUM,CHARGER,300C MARQUISE BMW - eBay (item 270547089824 end time Dec-09-10 12:52:24 PST)
shows 24" rims with 5x114.3 (Monaco 5x4.5) bolt pattern. I'll ask them if they are hubcentric and try to get a backspace measurement.

Heard back that they are +15mm offset.
A 9.5" rim is 10.5" wide, so that means backspacing is
10.5 / 2 + 15/25.4 = 5.84"
Here's a good page on backspace / offset
https://www.rsracing.com/tech-wheel.html

So these rims/tires stick in 0.84" further than my 5" backspacing rims that just clear the upper a-arm. This makes sense in that the rims are so much larger diameter the upper a-arm is actually inside the rim.

But my tires rub the frame at full lock. With an extra 0.84" further in, this car must have a turning radius of 500 feet.

your friend in keeping the turning radius small for the 2011 Steam CEVS EVOC challenge,
arthur

[scatpack01]

one thing I noticed was the Ford Ranger pick ups use a 225/70r15 tire. Which is what a stock Monaco cop car tire size is. Kinda funny....

[sigmfsk]

This 77 monaco
Dodge - eBay (item 260726085859 end time Jan-29-11 07:17:01 PST)
has
> a new set of P255/60 R15`s all around and a brand new spare.





The for-sale thread is here:
http://www.bluesbrotherscentral.com/forum/bluesmobiles-sale/11554-usa-1977-royal-monaco-isp-clone-kentucky.html#post120226

I e-mailed the seller asking if the rims were original civilian, or cop rims, or custom cop-looking, and if they all had equal backspacing. 255/60R15 is a spicy meatball!

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[sigmfsk]

It looks like a 1977 c-body monaco had the same wheel sizes as a 1974. 5.5" width standard. 6.5" wide width for wagons and police.

1977 brochure in pic 1 from
Directory Index: Dodge/1977_Dodge/1977_Dodge_Monaco_Brochure
from
http://www.bluesbrotherscentral.com/forum/bluesmobiles/10114-brochures-1974-monaco-custom-brougham.html#post109217

But it looks like this car is not using standard Monaco rims, civilian, police, or wagon. It's using the slotted police rims like those in pic 2 from
MOPAR DODGE PLYMOUTH POLICE WHEEL SET COP CAR 15X7 NICE - eBay (item 330519913762 end time Feb-14-11 17:49:23 PST)

Those rims are 7" wide, which is greater than the 6.5" minimum rim width for a 255 tire.
BFGoodrich Radial T/A

Did all mopar 7" cop rims come with the same backspacing? If I can get the backspacing of those rims for sale on e-bay, and the backspacing is the same as what's on this e-bay car for sale, we'll have a reference for how a Monaco looks with 255 tires on rims with a particular backspacing.

And then I can just add 1/2" to either side to get an 8" rim for a 255 tire that will be centered at the same point. 8" is the measuring rim width for a 255/55R18 tire that I'm planning on using sometimes:
http://www.bluesbrotherscentral.com/forum/bluesmobiles/9490-z-rated-tire-wheel-questions.html#post113204

your friend in rubber meeting the road,
arthur

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[sigmfsk]

From Aug 2010:

> If I had to do it all over again, I'd get 15x8 rims with 4.75" backspacing instead of 5"
> backspacing.

It looks like Mopar 7" cop rims have backspacing
> just a tic over 4 1/4" inches.
Moparchat - Home of MOPAR enthusiasts worldwide! - View Single Post - Backspacing on Cop Car Wheel or Rallye Wheel.

This corresponds with this e-bay ad
4 RECOND MOPAR COP 15 X 7 DEEP SLOT WHEELS W NEW TRIM - eBay (item 190455937687 end time Feb-09-11 12:47:40 PST)
which has this posted response:
> The offset is 4.25 inches.
I think they mean backspacing, not offset.

So consider a tire on a 7" rim with 4.25" backspacing. Keeping the center of the tire in the same location, an 8" rim would need 4.75" backspacing.

And that's what I thought would be a nice choice after checking my 5" wheels. It still doesn't mean my 5" backspacing wheels won't fit up front; I still need to
> do more tests when I have the torsion bars out of the front and can easily move the
> front suspension through its complete range of motion.

On a related note, I see pic 1 here:
Plymouth Gtx Suspension Photo 20
Where it says:
> Be sure to allow for wheel balancing weights that will be in this area of the rim as well.

Bah; clearly the bluesmobile had wheel weights on the outside of the rim (at least the passenger rear wheel).

Anybody near Lawrenceburg,Ky? It would be interesting to see if there was any evidence of the tires rubbing the wheel wells. I'm sure that the tires rub the subframe at full lock, but that's easy to prevent.

your friend in wide tires that don't rub,
arthur

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[sigmfsk]

Just heard back from this seller of 15x7 mopar cop rims:
MOPAR DODGE PLYMOUTH POLICE WHEEL SET COP CAR 15X7 NICE - eBay (item 330519913762 end time Feb-14-11 17:49:23 PST)

> hi, the backspace is 4 1/4" thanks

So I think hits home what the '77 monaco was using above. Sweet! I can't imagine anyone wanting more than a 255 width tire, at least in front.

your friend in stuffing the wheel wells, but not to overflowing,
arthur

[sigmfsk]

I was thinking about my suspension geometry and fitting the 8" wheels on the front, and then remembered that Country Bunker is using the 7" wide slotted cop wheels (pic 1). For visible screen shot accuracy, we'd like the outboard lip of the wheel to be in the same place as stock. We'd also like that for clearance from the outboard edge of the tire to the wheel well. We'd also like the inboard edge of the tire to not proceed so far inboard that it hits the subframe, wheel well, a-arm, sway bar or anything else. With stock suspension geometry, we also probably don't want the track width to change (keep the center of the tire in the same place). Lots of conflicting goals. I thought it would be helpful to calculate some of the positions, and highlight in pic 1 the 4.75" backspacing that I think will work best for a 8" wheel.

It also shows the data for the stock 5.5" wheel, the stock 6.5" cop wheel, and the standard Mopar 7" slotted cop wheel (Country's wheels).

My proposed 4 3/4" backspacing 8" wheel will stick out 1/2" further than Country's (which is itself 1/2" outboard than stock), stick in 1/2" further than Country / stock, and the center of the tire will be about the same as Country's (moved 5/16" outboard compared to stock).

The board won't let me upload the original .ods spreadsheet that shows the calculations, but there should be sufficient detail there that one can easily reverse engineer them from the screenshot of it.

your friend in wheels that best meet conflicting goals,
arthur

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[sigmfsk]

I think Bluzman has the record for the board's widest tires on a 74-77 monaco:

> The rear wheels are wheel vintique steelies.. 15x10 witha 5.5 inch backspacing. Tires
> are 295 65 15 Mickey Thompson Drag Radials. Fronts are wheel vintiques 15x7, with a
> 4 inch backspacing with TOYO H/T 235 75 15s.

More info and pics here:
http://www.bluesbrotherscentral.com/forum/bluesmobiles/11999-well-its-not-bluesmobile.html#post125746

[bluzman]

Arthur, yeah I bought these for the green 77 that I had, and pulled them off after a couple of weeks. The funny thing is, I had to cut a little off the inner wheelwell lip for clearance. The red 77 definitely has more clearance than the green 77. The only difference is the green one was a 318, with the 8.25 rear. I mentioned in an earlier posting that the 15x10s had a 5 inch backspacing, they indeed have a 5.5 BS. Damn...I wish Wheel Vintiques offered them in 15x12!

[sigmfsk]

bluzman said:

I wish Wheel Vintiques offered them in 15x12!

Pics 1 and 2 are 1974, 9.25 axle, 255/70R15, 15x8" wheel, 5.0" backspacing, passenger rear (Marin County) from post 1 in this thread.

Pics 3,4,5 are 1977, 9.25 axle, 295/65R15, 15x10" wheel, 5.5" backspacing, driver rear (your red 77) from
http://www.bluesbrotherscentral.com/forum/bluesmobiles/11999-well-its-not-bluesmobile.html#post125743

It's not clear to me that a 15x12 would fit (without mods), but Stockton Wheel custom makes wheels.
Mopar Wheels - Stockton Wheel
Pic 6 shows a car with a 15x14 "bluesmobile" style wheel.

> The red 77 definitely has more clearance than the green 77.
> The only difference is the green one was a 318, with the 8.25 rear.

I don't know what you're getting at. Are you saying that the position of the axle flange on an 8.25 is at a different location than the flange on the 9.25 so that a 15x10 wheel with 5.5" backspacing fits better in a car with a 9.25 axle? Or are you saying that the axle flanges were in exactly the same locations, but the inner wheel well walls, or quarter panel lip, or leaf spring positioning, or something else was different between the cars so that one car (the car with the 8.25) provided less clearance?

your friend in wide wheels,
arthur

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