Radial tires

[Barry Wolk]

If you have radial tires on your car there are some things you need to know.

The proper P235R15 is a significantly wider tire than the bias plys originally used. This makes your tires rub on the frame and decreases an already humongous turning radius. The Queen Mary has a better turning radius.

Also, the wider aspect ratio puts the sidewall of the tire dangerously close to the upper ball joint. The previous owner of my car installed 1/4" metal spacers behind the wheels to alleviate this problem. That spacer made a common Mark II problem even worse.

How many of you have lost hubcaps on your Mark II. I would lose them all the time. I also noticed a cacophony of sound emanating from my car whenever driving by a wall or pulling into my garage.

The problem was that the wheels lacked the rigidity to accommodate the sidewall flex of radial tires. This constant flexing was what made the wheels creek on the hubcap retainers. This motion would make the cap loosen and pop off. Also, the constant flexing rotates the cap within the rim, bending the valve stem at an obscene angle. After two failures of valve stems I figures out why.

Once radial tires became the norm the thickness of the metal used in wheels was increased to compensate for the lack of a rigid side-wall. New wheels of the same size are 5 pound heavier than the old one. The more metal, the stronger the wheel.

When ordering new wheels I decided to solve a lot of problems at once. First, new wheels would take care of the creaking. Second, I could order the wheels with any back set I desire. You measure the back set by laying a wheel flat and putting a straight edge across the backside of the metal wheel. Now measure from the straight edge to the back of the bolt hole.

This give you the standard back set. I determined that a 3/4" smaller back set would allow them to clear the fender and no longer rub on the frame. This restored the original turning radius, as poor as it is. It also moved the sidewall further from the ball joint. The problem of rotating hub caps was solved with metal valve stems. It holds the cap in position long enough for the tabs to dig in.

In my opinion, it also resolved another problem that I perceive to be a typical design flaw of the 50's. In my opinion the tires on a Mark II are tucked too far into the wheel wells, giving it a rolly-polly look. Adding 1 1/2" to the width of the wheel track gives it a little more futuristic look of the upcoming slab-sides.

In fact, I see an awful lot of styling cues that ended up on the '61.

http://i244.photobucket.com/albums/gg18/barry2952/Irearuswiugcopy.jpg

[Shelly Harris]

Just returned from a terrific 75 mile summer night ride.

So that's why I have lost 2 hubcaps and the only ones that stay on are the ABS plastic set which flex with the wheels. My radials don't hit the frame, but they are only an inch away from the ball joint. I can't afford to lose another original hubcap... they are going for $400+ each

Barry, where did you get your wheels and what are the exact measurement specs for ordering?

[Mad Scientist]

I’m going to need tires pretty soon so I got out my “Coker tire catalog” to see what they have. For those not familiar with this company it appears that if it is round and made out of rubber they carry it. http://www.cokertire.com/

Anyway using their catalog I made the following chart.

For the true purest the original 820-15 bias ply is still available.
For others there is a choice of three radial sizes that are somewhat close to the original size and load rating.

http://i68.photobucket.com/albums/i17/mscientist/MKII%20rebuild/tirechart.jpg


Apparently the P235 will fit in the wheel wells, but it will not fit in the trunk. To be able to close the trunk you need the P225.

[continentalguy]

I have never had any rubbing problems. I have coker white wall radials. They look very good and preform well I will have to check the sizes. We have also only had a hubcap problem once and since then nothing.

[Shelly Harris]

I'm carrying an old wide white wall bias tire in the trunk. When my current radials run bear I hope to find wide white wall radials.

[Barry Wolk]

Mad Scientist,

I have a Coker P235 in my trunk. It's tight, but it does fit with no alteration to the well. I'll measure the back set on the wheel when I get to my shop. They were ordered from Coker.

You could always run 235s and have a smaller tire in the trunk, just like a space-saver.

My car is heavier than a stock Mark because of the steel plating on the frame. It weighs just north of 5400#, almost 5600# with a full tank of gas.

[CarMan]

Coker is expensive. I found a better deal getting classic style tires at Diamond Back classics.
http://www.widewhitewalltires.com/

Last summer I bought redline tires there for my GTO at a much better price than Coker. You'd have to check on the Whitewalls.

[Barry Wolk]

Diamondback are add-on whitewalls. The Coker tires have a raised blackwall border to protect the whitewall from abrasion. I have Diamondback Michelins on my '55 Porsche and they have been easily scuffed.

The raised protection is worth the extra money to me. Tires are one area where I don't try to scrimp.

Just my $ .02.

[Shelly Harris]

Barry:

No rush on this, but I would like your measurement on the backset. If changing out the steel wheels will cure my throwing hubcaps, then it's well worth the change and I'd like to get going with an order. I'll keep my current Avon P235's till I see some thread wear then go for wide white. Would the other specs to the wheel be 15" x (6" or 6.5") 5 lug ? Actually I'm assuming that the wheels I have are originals w/ too much flex. Wonder if there's a way to check for sure, I'd like to know how. This 53 yr old car has plenty of history i don't know about I'm sure and the wheels I have could be from a 1980 Town Car for all I know..

On getting the wheels with a reduced backset in order to move the tire further out, I'm wondering if I really need that. Although close to the ball joint, there's no rub happening. Also the tire deep into the wheel well doesn't bother me ... but I agree on the front wheels it looks a bit too deep... but the rear's don't -- they look ok in relation to the well well opening. Regardless though, if I change they all must change.

[Barry Wolk]

I weighed my old wheels. They are 22 lbs.

The rim measures 7" across for a 6" wide tire chord.

I measured across the back of the original rim at 4.25" to the lug plate.

It's 5 x 5.25 bolt pattern.

The new wheel is made by Wheel Vintiques

Hope that helps.

[Nick DeSpirito]

The purist here is riding on reproduction Firestone 820x15's bias. The mounted spare will not fit in the spare tire well, so I have a smaller tire in there just in case I need a spare. Seems they make the repros wider than the original tire.

[Barry Wolk]

Wheel Vintiques has their own web site. Maybe you can order direct.

http://www.wheelvintiques.com/

[Shelly Harris]

I weighed my old wheels. They are 22 lbs.

The rim measures 7" across for a 6" wide tire chord.

I measured across the back of the original rim at 4.25" to the lug plate.

It's 5 x 5.25 bolt pattern.

The new wheel is made by Wheel Vintiques

Hope that helps.

So I'm not misunderstanding please confirm that your new wheels backset are reduced 3/4", making that length to be 3.5" lug plate to rear rim ( a diameter line of rear rim) ? correct?

[Barry Wolk]

3.5" is correct. Before you order let me check another wheel box just to make double-sure I'm giving you good info.

It's basically a (0) zero offset as that puts the wheel hub an ideal half of the width of the wheel.

[Mad Scientist]

The purist here is riding on reproduction Firestone 820x15's bias. The mounted spare will not fit in the spare tire well, so I have a smaller tire in there just in case I need a spare. Seems they make the repros wider than the original tire.

Interesting! So just for grins I went out and measured my original Firestone 820x15’s.
Compared to the numbers in my previous chart, which are suppose to be a reproduction of the original I found:
The 5” tread width was actually 5.5”.
The cross section was the same.
But the 29.56” dia. Was 30.4”.


Between the sidewall and the upper ball joint there is approximately 7/16” clearance.
When I do the appropriate number crunching for the p235 this tells me that this tire should just barely fit, but with any flexing at all it would rub.

The p225 should have about a ¼” clearance.
I am currently leaning towards the p225 for mine because of it slightly smaller overall diameter. Even though I was trying to measure very carefully:) I don’t want to chance having the tire rub on my exhaust system.

Going with new wheels with the 3.5” back set would definitely eliminate any rubbing problems.

Does anyone have a preference or feelings about Coker’s own brand of tire compared to BF Goodrich?

[Barry Wolk]

7/16" or even 1/4" is too close for me. Any wear on the outer bearing will translate to a lot of movement inward at the top of the tire. Wear in the lower ball joint or A-arm bushings will do the same.

The A-arm bushings are another good subject. Did you know that they act as torsion fittings to bring the suspension back to a normal position? If not set up properly they will make noise and wreck the ride.

[Barry Wolk]

I double checked the wheels, they are a 4.25" back set.

[Mad Scientist]

Just double checking your double check. I know the original wheels are 4 1/4 " set back but are you saying your new wheels are 4 1/4 or 3 1/2"?:confused:

By the way the bolt hole pattern is 5 x 5.5 not 5 x 5.25.

[Barry Wolk]

I measured 5.25" center to center. Is that not correct?

New wheels are 3.5" back set, to move the wheels outboard by 3/4". This lets a wider tire clear the frame and the top ball joint.

[Shelly Harris]

I measured 5.25" center to center. Is that not correct?

Bolt pattern on 5 lugs is measured from the center of one bolt to the outside edge (the edge farthest away) of a bolt diagonally across from it. There's the 1/4" difference. It's a 5.5 bolt pattern.

Thanks for the help. I'm definitely going this route Barry.

[Barry Wolk]

When you order the wheels you can get them as bare metal. I would have them sand blasted and powder-coated with a proper wheel paint. This will make a good base for the matching car color. Ordering them raw saves a lot of sandblasting time.

Thanks for the bolt pattern lesson. What a strange thing. In the lighting business everything is measured as a bolt circle.

Make sure you order long metal valve stems. They will keep the hubcap from rotating. This will also allow the hubcap tabs to dig into the metal of the wheel, keeping it from popping off.

Take it to a shop with the best balancing rig. Big tires are hard to balance. Insist on tape weights as the normal type dig into the whitewall. Tape weights can be installed concealed by the hubcap.

[Mad Scientist]

Thanks for the bolt pattern lesson. What a strange thing. In the lighting business everything is measured as a bolt circle.


As it is everywhere else, the exception being tires and wheels. :confused: There is probably some neat trivia history for that but I'm not aware of it. ;)

[Mad Scientist]

Well I finally got around to buying tires for my MKII for some reason I just didn’t feel comfortable with my 40 plus year old tires even though they still had plenty of tread left.

I decided to go with the 225 width rather then the 235 just to be sure they would fit. The tread of the 225 is just slightly smaller then that of the 235 but significantly wider the original stock tread. It is also slightly smaller in diameter the 235 which should help to avoid hitting my exhaust system.

Went on line and looked up Cokers price but when ordering a fan from JEG’s I noticed that also carry tires and they had the same tire for less money and less shipping. I also went to my local tire store to see what they might have. Of course when I told him that I was looking for whitewall tires for a 50 year old car his eyes sort of glazed over. Naturally none of his suppliers had anything.

So Tuesday I order them from JEG’s got them yesterday and had them mounted today.
They do fit on the front but with very little room to spare, I was expecting to see more clearance. The 235 would definitely not fit without going to a wheel with less back set. In back on the drivers side I have a small problem with the exhaust pipe. But bending it out of the way won’t be a big deal.

But most interesting is these tires will not fit in the trunk! It appears the bracket that holds the trunk latch is preventing it from tilting back far enough to let the trunk lid close. I will probably wind up remaking that bracket.

http://i68.photobucket.com/albums/i17/mscientist/MKII%20rebuild/tire.jpg

[Barry Wolk]

It looks like it was designed to be a latch bracket/tire keeper. I wonder of mine had already been altered as it had P235s when I bought it.

Now you understand why I cautioned against using standard backset wheels with radial tires.

May your new tires give you many miles of driving pleasure.

[Shelly Harris]

Yes, enjoy those new tires and let us known what difference if any you experience from the old bias ply tires?

[Mad Scientist]

Yes, enjoy those new tires and let us known what difference if any you experience from the old bias ply tires?

That might be a bit subjective, since the last time I drove the car was about forty give or take a few years ago. :D

[Shelly Harris]

Oh my.... is it up and running now? How far along are you in your restoration?

[Mad Scientist]

Not quite, but I think I beginning to see the finish line.:)

When you have some time you might be interested in this link to the Lincoln member project forum where I have a long ongoing thread with many pictures taken during its resurrection.

http://www.thelincolnforum.net/phpbb3/viewtopic.php?f=38&t=25436

[Jim Rohn]

Well I finally got around to buying tires for my MKII for some reason I just didn’t feel comfortable with my 40 plus year old tires even though they still had plenty of tread left.


They do fit on the front but with very little room to spare, I was expecting to see more clearance. The 235 would definitely not fit without going to a wheel with less back set. In back on the drivers side I have a small problem with the exhaust pipe. But bending it out of the way won’t be a big deal.



most all tire stores have wheel spacers, buy a set of them to put your wheel s slightly outboard, you should not need more than 1/4" or whatever mm that ~ to

[Barry Wolk]

I beg to differ. I don't think that that's the best advice for a car this heavy. The wheels typically do not have the same contact surface area on a spacer as they have on a drum. They allow the wheel to flex more than normal.

Wheels are cheap. Losing one isn't. You could probably sell you stock Mark II wheels for what new ones cost. The guy I bought my car from had 3/4" adapters on the rear and 1/4" on the fronts. My front lugs were always loosening up. I lost a lot of hubcaps until I replaced the wheels.

[Mad Scientist]

But most interesting is these tires will not fit in the trunk! It appears the bracket that holds the trunk latch is preventing it from tilting back far enough to let the trunk lid close. I will probably wind up remaking that bracket.




Well I have reworked the offending bracket. Cut most of it away, put left a tab sticking down which I then bent into a support for the latch.

http://i68.photobucket.com/albums/i17/mscientist/MKII%20rebuild/trunklatch1.jpg

The tire now is now able to lean back enough to allow the trunk to close. :)

http://i68.photobucket.com/albums/i17/mscientist/MKII%20rebuild/trunklatch2.jpg

[Shelly Harris]

I don't have a bracket problem because my spare is an old bias ply wide white wall with a cover on it. Why modify a bracket and go to the trouble of fitting in a radial? It's only a spare to be used to get you a few slow miles to a tire repair station.

Actually I can't imagine even my changing a tire on the road side --- which is why I have a cell phone to call emergency service. I have a Lexis 430SC which came with horribly riding/handling "run flats". With "run flats" there's no spare at all! When I switched to normal tires I still had no place for a spare -- which is when I decided to always have the cell phone. That was four years ago and I haven't had need for a spare tire yet.

[Barry Wolk]

Shelly, I drive mine as much as 5 hours away from home to go to shows and often come home on Sundays. I can't imagine driving 5 hours on one bias ply and three radials. I am led to believe that that is dangerous. I'm not sure of the technical reason. Anyone know?

[Shelly Harris]

I don't think it's dangerous to carefully drive a few miles to a repair station. To go long stretches full speed is foolish. The handling is definitely compromised. Probably as bad as going full speed for extended miles on the hard rubber small diameter doughnut in most present day trunks.

[Barry Wolk]

I believe that those are rated for 45 mph. I can't keep my Mark II at 45.;)

Maybe I shouldn't be telling my secrets to a judge.

Hey Shelly! Can you set up a poll where people can claim how fast they've driven their Mark II in say, 5 mph increments? It would have to be anonymous, of course. Wouldn't want to incrimnate one's self.

[Shelly Harris]

Sure. Any registered member can create a poll when they upload the first message in a thread, i.e. when the thread is created. Try it. And you can make it secret polling.

As to top end speed on a Mark II, certainly you know that 56's have a speedometer that goes to 140 and the 57s only go to 120. So it's only reasonable to conclude that the 56s must be faster than 57's. (That's a joke folks -- I know 57s have 10 or something more horses)

[Mad Scientist]

I just like the idea of having a “real” spare tire. Granted flat tires are not all that common. But I had one on my truck last summer when calling on a client. The side wall had come unglued and it sprung a leak. That called for a new tire not just a simple patch.

As far as the top speed of the MKII the story that I heard was someone tried to do 140 in a 56 and it wouldn’t quite go that fast, think it was around 130. So naturally he sued Ford for false advertising. Thus Ford dropped the reading to 120.

According to a story my mother told. Apparently one day a girl friend and her were going out golfing. The golf course at the time was way out in the country, which is now about 20 miles from me and it is anything but out in the country. Anyway at one point the girl friend asks “not to alarm you but just how fast are we going?” seems she was talking and not paying attention and had it up to 110. :o She back of quickly. :)