Technical Help with Lowering Front of 41 Plymouth with Stock Tires

Hey guys, I finally worked my way around to doing the front suspension on my 41 coupe, ready to lower it and relocate the upper shock mounts. I’ve read plenty of posts on here regarding the options. And plan to cut one coil from the original springs to hopefully achieve a 2” drop at the fender lip. And use original size 6.00x16 tires on some 37 Plymouth artillery wheels. The tires are 28.5” diameter, so I cut a cardboard to that size and it looks like a tight fit, when cornering, and I haven’t lowered it yet. It seems like the tire will hit the fender lip. The cardboard is pressed against the current 215/70-15 tires, which have a section with 2” wider than original tires. So the outer edge of the original tires will be tucked in tighter by about an inch.
Anyone have experience running the stock tires with a 2” dropped front?

 

First off, your cardboard is sitting outside of the current tire, which you state is already wider then the tires you want to run. The cardboard located where it is, is giving you an improper perspective. The highest point on the tire is going to be near the center of your current tire, not the outside edge. That makes a huge difference as far as tire clearance is concerned.

Secondly, the cardboard cutout does not appear to be centered on the wheel. If that is true, the actual height of the new tire would then be about 1/2 of the height difference between the cardboard and your current tire, at the center of your current tire's width. That would be because 1/2 of the current height difference would be under the wheel center, only leaving 1/2 the difference above the wheel center. As it sits now, you have the entire difference above the current tire.

 

@gene-koning nailed it. Measure the difference between the top of your tire and the top of the cardboard mock up. Then get a block of wood 1/2 of the difference and put that under the tire. That will align the center of the cardboard with the center of the tire and give you a much better idea of how it will fit.

 

I did the same on my ‘46; 1 coil removed, relocated shocks and bigger sway bar. It had 205/15 on 6” rims in stock centers. Worked great.

 

Thanks guys for pointing out my error. I was thinking ahead when it’s lower the hub will come up to the center of the cardboard, then looked at as though that is the current clearance ‍♂️.
Here’s updated photos with a properly sized block under the tire.

 

Probably the best thing to do now is remove the spring, get a 6.00x16 tire mounted, and cycle the suspension from snubber to snubber and check for fender clearance. I bought some lower snubbers that are about an inch shorter than original. It appears they will allow about 2” of down travel, after the car is lowered. Do you think they will work well?

 

The point of a snubber is to keep the front end components from overtravel into destructive angles, along with having a softer stop. Since this suspension doesn't use ball joints, you can safely ignore the first. A shorter bump stop will allow a bit more free travel, but be more harsh when hitting.
If you've driven it in it's current condition, you would be the most familiar on how often it is bottoming out, if ever, unmodified. Lowering it will obviously decrease the available travel before this happens.

 

Good points you made, thanks. I haven’t driven it on the road yet. It’s about ready to drive, other than painting and installing the rf fender and trunk lid. I probably should do that to establish a baseline.
After that I might try the Aerostar front springs that others have used, they should be stiffer and I would hate to cut the original springs, then find out it hits the snubbers too much.

 

Curious, in normal driving-excluding potholes, etc- how much does a front suspension travel? 2-3? Inches up/down?
I’m just curious if anyone knows.

 

Ok, the cardboard is in the recycle bin and I moved fixing my spare from the bottom to the top of the repair list. The wheel is original 16” and tire was shot and not the size I want to fit, so I got a black wall that closely matches the size of the whitewalls I want to put on it.
I have about 4” clearance to the fender lip with the steering against either stop. I got a different set of snubbers that can absorb more shock and easily be lowered a bit if needed.
Lowering the front 2” would tuck the tire in by an inch, and leave me with 2” tire clearance at the stops.
Anyone out there with a similar car with similar clearances that can comment on the tire rubbing on the fender lip?

 

...if somethin doesn't rub, it ain't low enuf...