The bump stop is designed to do this. I don't see a real concern unless its in constant contact. You need to make sure you have a good rate of travel. If you install a spacer to prevent the tire from hitting the body you need to drive it and see if the bumper is hitting too much or all the time. If it does you need to do something else. If it where me and I couldn't get this to work I would change the wheels. Many C3s have had big tires with big flairs and no problems.
I would not go into making major modifications that will affect the safety/handling. Spacing bump stops either front or rear is common.

 

100%...but knowing that the bump stop is going to be used more often...and relied to provide a good stop. It is a fatigue issue over time that I am concerned about....which I agree with you....this is only one part of a modification to keep the tire from hitting the body.

I wish a photo of the rear leaf spring can be provided....that will tell a lot.

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indianriverbound,

Might I have you consider something. And I know how you feel about the parts you have purchased.

Knowing that you have a conflict between the tire and the body...consider the time and effort you are going to have to put into this. Versus...changing out a part or two and selling off what you just bought. When I have to re-work an area that has a problem much like this....I look at the cost of parts if they will fix the problem....and then compute the labor. And then figure in a total custom modification and present that to the customer and see how much money they want to invest. Because ..in some cases...new parts that were custom machined were machined incorrectly due to variables that were not factored in.....and those customers can not swallow the fact that that part has to be redesigned and machined again....and is now an expensive paper weight.

DUB

 

The rear suspension in a C3 is complicated. Not much room to raise or lower and maintain a range of travel. I agree you don't want that bump stop banging all the time. It's not meant to be an active part of the suspension. If spacing is for insurance that the tire doesn't hit the body and it hits all the time it not good. If it doesnt bump with driving and only bumps on irregular surface movements then I would think its ok. If not I would go to a narrower wheel. With those flairs a 15 x 10 is common and it worked. No more than 4.5 back space. I have 18 x 10 with 5" back space with offset trailing arms. Totally different I know.
I always loved the big flairs. Just need wheels that fit.

 

Ok....have had a chance to play with thing thing a little and think I have quite a few problems going on here. Have thought about everyone's suggestion and they seem to all say the same thing....more major money. Well that is OK...but if we are going to spend more major money I want to do it with as little hassle as possible. I have included pics so that everyone may see what I got and give input. To summarize:
1) The tires are 29-15.5-15 on 15x12 SS Cragers....yeah I know I can go to a smaller tire size but they are what makes the car....don't want to change.
2) When I originally put the tires on and the car settled down with everything stock with the flares about 3/4 inch off the wheel....my spring end bolts are 6 1/2 inches long.
3) I measured the extension of the shocks as it sat stock and they are almost all the way extended to about 14 inches....max is 14 1/2.
Alterations done:
1) Shocks: To increase the travel of the shocks I have custom built 2 inch lift blocks for the top of my shock mounts to give the shocks a bit more room for travel. These things are solid and not going anywhere. As it sits now the shocks are extended about 12 inches. Travel distance for the shock is 9.5-14.5 so it is right in the middle. I also changed to monroe air shocks in an attempt use them to jack the back up a bit. Yeah I know this is not the correct way to do it but bear with me....
2) In an attempt to raise the body I also added washers to the leaf bolts in an attempt to shorten them....1 inch worth on each side. Yes I also know this is not the correct way to do it but bear with me.......
Results of alterations:
1) Switching to the air shocks got me about 1/4 inch more lift and stiffened the rear up....I know this makes for a rough ride but is not my everyday driver and really is not that bad. I am at running about 80lbs and the advertised max pressure on the shocks is 150. Anything at about 100 blows the air line out of the shock so 80lbs is about it.
2) Before I added the washers to the spring bolts I did have some arch in the leaf spring. After I added the washers it rose up about and inch...perfect....right where I needed it. After I took it for a drive it settled back down to right where it was in the beginning.
Consideration of alternatives:
1) Travel stops- Upon inspection I noted the car does have travel stops on it...about 2-3 inches high. There is about 8 inches of open air there and travel stops of that size are not practical and would hit constantly putting too much pressure on the trailing arms.
2) Offset trailing arms- a last ditch alternative that will work with major money and cutting of the half shafts. Would like not to go this route unless forced to.
Possibilities:
After I put on the washers, instead of lifting the car up it pushed the spring down so it is nearly flat. I am thinking that since this is probably the stock spring it is weak? In addition the 6 1/2 inch spring bolts....could shorter ones have been put in by the previous owner due to this problem? I don't think more washers will solve this. If I bought a new leaf spring would it help? Which one to buy? A stock 9 leaf would be considerably cheaper but should I spend the money and go with a #340-#355 composite? Also, to clear the brake calipers with the Cragers I had to put in a 5/8 inch wheel spacer. Someone on this forum told me that Wildwood offers a thin caliper that would allow me to get rid of those wheel spacers thus moving the tires in but I can not find the thread indicating which calipers to buy. I already cut off and relocated the emerg. brake cable mount to the top of the arm so I have the room. Do you think the combination of a new spring and calipers will solve my problem.....all I need is a friggin inch!!!! Right now the flares barely hit but you can see in the pic where they do. All input is welcome.




The pancake





The clearance now





The rub

 

PROBLEM SOLVED: After much consideration I decided the cheapest way to try and fix this problem was spring replacement. I bought a 355 composite spring and was pleased to note that the new spring bolts were threaded 2/3s of the way up giving room for plenty of adjustment. After replacement and setting the bolts to 50% of adjustment, it gave me the 1 1/2 inch clearance I was looking for without compromising the angle of the half shafts too badly. On road testing there was no bottoming out on the flares and to be honest with you the ride was really no different than before with one exception...no bouncing, just solid hook up.Plus with the back end jacked up a bit the beast just looks.....nasty. Very pleased with the results.

 

I am having a similar problem, but with a different fix. My recently acquired 68 vert came with 18 x 8 inch ARP rims and 245/40R-18 tires on the front and 20 x 10 inch ARP rims and 295/40R-20 tires on the back. Car has the ZL-1 fender flares but still needed air shocks on the back for clearance and resulted in the back being jacked up like kids did to their cars back in the 1960s. I'm switching the back to 18 x 10 inch rims on the back so the car will be back to its normal ride height and have the drive shaft and differential in the normal angle.