Educate me about wheels and tires (and hubs and axles)

[Racer-X-]

This for Elvis, the 1947 DeSoto Custom Sedan.

 

Current situation:

 

Front wheels are 15x6" (maybe 6.5" wide, that's what I wrote down when measuring, but it looks like nobody makes that width in this style wheel) with 3.75" backspacing.  The wheels are "chrome smoothies" They fit with the "classic street rod/restomod" character of this car.  Center bore is about 3.25" (probably 3.195"), and the wheels have dual pattern, 5x4.5" (which is what the hub is), and 5x4.75" (unused).  The front hub is about 3" in diameter, and the lugs are 5 on a 4.5" circle.

 

Rear wheels are 15x7" with 4.125" backspacing, with a center bore of about 3.75" (probably 3.71") and a dual pattern with 5x5.50" that we're using and 5x5.00 unused. It looks like I didn't note the hub center diameter for the rear axle in my phone's note taker app. Grrr.

 

All tires are 215/75R15, and another set of brand new tires are in hand and must be installed soon, once we have steering and braking issues fully resolved. I'm not sure if that's the best size for this car, but it's what we have, and there's resistance to any changes to that size right now.

 

Current issues. 

• Bubba the brake guy installed 3/8" spacers behind the front wheels and still had to grind off a bunch of material (too much, the calipers are cracking in places on the outer side) from the brake calipers he installed. 
• Bubba the brake guy installed some front rotors of unknown origin with his "disc brake upgrade" which are hand drilled (slightly off center for one), and the car has the shakes even at 30mph or so. Rotors of an appropriate offset that fit the 5x4.5 stud pattern are needed, and I'm open to suggestions for those. The calipers we have look like late 1990s Dodge Ram 2500 front calipers.
• The front lug nuts have 2 or 3 internal threads exposed because the lugs don't reach all the way through.
• Even with the spacer, the sidewalls are rubbing on the inside (mostly hitting the brake line bracket at the front side), and that's with the stock (ish) steering arms which give a turning radius somewhere between a destroyer and an aircraft carrier.
• Also, on the right front hub, thre of the lug studs are clearly too small. Two of them had 12mm nuts on them (the others have 1/2" nuts) and the studs can be pushed back with your hand, they are not tight in the holes in the hub and one almost spins freely in the hole.  A third stud on that side had a 1/2" nut tightened down on another 12mm loose stud.  That one was nearly impossible to get loose.
• The rear axle seems to be too long. I'm pretty sure that the rear axle isn't original for the car.
• Rear wheels are nearly impossible to get out of the fenders.  There's not enough space between the hub/brake drum and the fenders.
• Rear tires have minor scuff marks where they're rubbing the fenders on the outside sidewall of the tire. 
• TLDR, we'd like the lug pattern to be the same for all 4 wheels. It would be nice if we could rotate the wheels/tires front to rear.  It would also be nice if one spare wheel/tire can be carried and fitted to any position on the car. I'm not saying that a "staggered" setup isn't in the future for this car, but it's not the immediate next step, and when it happens, it will be done in a way that's easy to undo.

 

I'm leaning toward a 3/4 inch or 1 inch bolted on wheel spacer ("adapter" style spacer) for the front.  This would allow more room for unmodified brake calipers, and would keep the tire off the frame and away from the brake line brackets.  Speaking of those ...

 

I'm also considering relocating the front brake line brackets to the holes right behind the shock absorbers that seem like they're made for that bracket.  That's the circled holes in this pic: 

 

That would allow for a shorter brake hose that goes more directly to the calipers and avoids the coil springs. 

 

I'd like to know more about rear axles. Clearly the one in the car now isn't original.  It's likely from a Ram 1500 truck from what I can tell, or maybe some Jeep.  I'd like to get an axle with hubs that match the front hubs, at least for lug pattern.   If that's just not practical, I could also use the front spacer/adapter to allow the front wheel hubs to fit wheels with the same lug pattern as the rear. An axle with rear disc brakes would be a big plus as well.  This one does have the LS1/4L60E combo, so something beefy enough to take that is required.

[Sniper]

Wow, where to begin.  Isn't following up after hack mechanics fun?

 

Some people probably shake their head at me for being pedantic and anal about stuff, maybe I am but geez lol.

 

This is what I did when I put fat tires in the back of my 51, might help you sort out what will work for you in regards to fitment.  For the front's I have a pair of bolt on spacers that should allow me to run a wider tire on a stock Mopar 15x7 pass car rim, if I go with 15's and not 17's in the front.  Go to finish the disc brake swap first, then see what I can see.

 

 

Now I don't know where you are but I have the stock 15" rims I don't need anymore.  Those might, ought to? sort out your front fitment issue.  Heck I have the stock front brakes I don't need anymore either if you have to go back to drums.  As for the rear end, the Jeep rear axle swap is popular here, I don;t have a link but you ought to be able to search and find.  They can be had with discs as well.

 

[Racer-X-]

I appreciate all the information and the offer on the wheels.  I'll talk to the vehicle owner about this and DM you if we decide to go with them.

 

I guess at the front my two biggest questions are:

1. Is 5x4.5" the correct lug pattern for this car?  I'm going to try to stay stock with that pattern, even if we keep the aftermarket wheels
2. How wide were the original wheels (bead to bead width)? and what was the back spacing?   Can you put a straight edge across the back side of the wheel and measure from that to the mounting flange surface? That's where my current front wheels measure 3.75".   I'm just guessing, but I bet it's less on the stock wheels. Knowing what I'm trying to match will help a lot with selecting  an appropriate bolted on wheel spacer up front.

On the more general discussion, the thing that frustrates me most about this one is that it's the first example of a 1947 DeSoto I've ever seen. Which means I don't know what the car was before the previous shop(s) started modifying it. It's also got a somewhat checkered past, including many decades when it lived in Cuba. Then there was the engine swap (LS1 plus 4L60E) and 12V wiring system done by another shop in Miami (also run by Cubans, I'm told).  They did the interior as well, and the wiring.  They were really, really good at interior finish stuff, and it shows.  And not just in the interior.  The wiring definitely looks like it was done by someone who was really good at interior and upholstery stuff.

 

It's also so old and relatively rare that common references that I use don't list the car.  For example, on this topic, wheel-size.com and other online databases about wheel specs, hub specs and such don't list any DeSoto cars, and nothing from the 1940s.

 

I just discovered Scarebird for the brake kit.  I'll be sending them and email today about their brake kits and "Monster Calipers." I don't know why Bubba did his custom stuff for that.

[Sniper]

Pretty sure the bolt pattern is 5 on 4.5".  Looking in the parts book the Desoto should have either 15x4.5" of 15x5.5".  My 51 uses 15x5.5" but a different part number, what's different isn't spelled out though.  I'll measure the backspacing on what I have later today.

 

I've test fit later model Mopar rims, the 15x7 cop car one, on my 51 with it's stock brakes.  They clear, barely, in all spots except at full lock the P255/60R15 tires I have on them hits the upper pivot bolt.   

[Andydodge]

Racer....those two holes you ask about in the chassis ARE for the original brake hose bracket that is held onto the chassis by small self tapping 1/2" AF head bolts, these are a fairly common bolt on mopars and you should find others holding various brackets onto the chassis........

......as for the wheel size 1947 was a transition year......started off with 6.50x16 tyres, finished with 7.60x15 tyres........width would have been probably 5" to start going to 5.5" maybe 6" but doubtful..........I ran 15 x 6 and 15 x 7 Wheel Vintique Chrome Smoothies with their stock backspace and 195/65  x 15 and 235/65 x 15 Coker Classic Radial Whitewalls on this 41 Plymouth Coupe without any issue, cleared front/back,inside and outside and lowered 2"........bolt pattern should be the same as other mopars( and Ford from 1949), 5 x 4.5"..........andyd

Edited November 21, 2021 by Andydodge

[Racer-X-]

@Sniper, great info there. 

 

3 hours ago, Andydodge said:

those two holes you ask about in the chassis ARE for the original brake hose bracket that is held onto the chassis by small self tapping 1/2" AF head bolts,

 Cool.  So my rubbing issue is with parts that shouldn't be where they are now. Someone (Bubba?) moved them to the place where they're rubbing on the tires. And the "mod" I'm considering is actually a restoration step in this area.

 

3 hours ago, Andydodge said:

I ran 15 x 6 and 15 x 7 Wheel Vintique Chrome Smoothies with their stock backspace and 195/65  x 15 and 235/65 x 15 Coker Classic Radial Whitewalls

The Wheel Vintique smoothies in that size have 3.625" back spacing.  Ours are 3.75" backspacing, so we've got slightly more wheel (an extra 1/8") back there, and we're committed to the 215/75R15 all around for this set of tires. Those tires are huge, and look too big for this car to me.  The owner might consider a staggered setup, and/or (a) different size(s) for the next set of tires.

 

Good to see Ford on that list for 5x4.5.  I thought that was a Ford pattern as well as Mopar.  I'm thinking a Ford rear axle may be in the immediate future for Elvis the DeSoto. For the Mopar purists, you already hate me and this car for the LS1/4L60E swap, so I'm just rounding it out with parts from all of the big 3.