kgreen Posted May 22 Share Posted May 22 I've got the standard tire 7.00x15 bias ply mounted on my spare wheel. Darn thing doesn't fit into the trunk. The interference is the width of the trunk. I can't tilt the tire upwards with the shelving in place either. Is the tire size different on the spare? It's a C body so help with either a Roadmaster or Super would be helpful Link to comment Share on other sites More sharing options...
Pete Phillips Posted May 23 Share Posted May 23 No, the spare tire size is not different from the other tires. Looks like your shelf has been re-covered or changed around some. Are you sure it is the correct width/height/etc. 7.00 x 15 is the correct tire size for a '40 Roadmaster, according to the BCA Judging Manual. 1 Link to comment Share on other sites More sharing options...
Jolly_John Posted May 24 Share Posted May 24 Ken, are you absolutely sure that is the proper, ORIGINAL configuration trunk shelf board for you model? I'd start there, especially if there wasn't one or both in your car when you purchased it. John 2 Link to comment Share on other sites More sharing options...
Grimy Posted May 24 Share Posted May 24 Folks with sidemounted spares (may or may not be appropriate in your case) have learned the hard way that today's repro tires are often larger in both actual diameter and cross-section than the same sizes were when our cars were built, so it's often necessary to (1) drop one size for the spare (e.g., 6.50 vs 7.00) or (2) find a different brand in which the same nominal size has a smaller diameter. 3 Link to comment Share on other sites More sharing options...
EmTee Posted May 24 Share Posted May 24 I have a similar situation with the spare tire in my '38 Century. In my case, it's the width of the tire/wheel that's the issue. I had to fabricate ~1/2" thick wooden shims to raise the luggage deck above the spare compartment to allow the tire to fit. 3 Link to comment Share on other sites More sharing options...
Shootey Posted May 24 Share Posted May 24 (edited) I have a funny but irrelevant story about spare tire space. My 1941 Estate Wagon has a separate spare tire compartment below the tailgate. The spare tire compartment has a wood cover that swings down approaching the rear bumper. My car has the so-called elephant ears on the rear bumper, protective large end pieces. Because of the elephant ears the spare tire cover cannot be fully opened which thus prevents removal and replacement of the spare tire. I have a photo of my car taken in the 1940’s or 1950’s and the elephant ears were present. My executive decision is to keep the elephant ears and store the spare tire in the main rear deck portion of the car. Edited May 24 by Shootey (see edit history) 3 Link to comment Share on other sites More sharing options...
kgreen Posted May 25 Author Share Posted May 25 On 5/22/2024 at 8:49 PM, Pete Phillips said: No, the spare tire size is not different from the other tires. Looks like your shelf has been re-covered or changed around some. Are you sure it is the correct width/height/etc. 7.00 x 15 is the correct tire size for a '40 Roadmaster, according to the BCA Judging Manual. Yes, that's a 7.00x15 tire. The shelf is new as I just made it from the pattern of an old shelf that I got from a Roadmaster coupe. Link to comment Share on other sites More sharing options...
Jolly_John Posted May 25 Share Posted May 25 (edited) Ken, I wonder if the trunk lid of the coupe is wider than the one on your sedan. And, therefore, the coupe spare tire would slide right in, without having to be lifted at an angle. Perhaps an original sedan trunk board is hinged some inches in, so the closest section of the board can be lifted upward, thus enabling the sedan spare tire itself to be tilted so you can get it in. Again, more guessing on my part. Obviously, you need someone with the same year, series, and model BUICK as yours to step forward with the correct info to solve this dilemma once and for all! I'm surprised that hasn't happened yet. John Edited May 25 by Jolly_John (see edit history) Link to comment Share on other sites More sharing options...
nat Posted May 27 Share Posted May 27 If it fits in the pocket with the shelf out of the way the deck needs to be loose or hinged to get the spare in and out. 1 1 Link to comment Share on other sites More sharing options...
kingrudy Posted June 1 Share Posted June 1 Ken, in my car there is a two tool trays. One just inside the trunk and one that is hinged that backs up to the rear seat and a shelf over the spare tire. The shelf over the spare tire was gone when i got my car. My spare is a 7.00 x 16 (correct for the Super). The depth of that shelf makes all the difference because the trunk lid narrows on both sides as you get closer to the base of the trunk. I believe that the trick is to measure the outside diameter of the tire and then find out where the tire will fit at the lowest point of the trunk opening. Make sense? Link to comment Share on other sites More sharing options...
MCHinson Posted June 1 Share Posted June 1 I suspect that it is similar to the 1938. On the 1938, as EmTee stated, the shelf has to be raised to be able to get the modern tire under it. The reproduction tires are wider than the originals, so the trunk shelf has to be raised from its original position to have enough room to get the spare under the shelf. Link to comment Share on other sites More sharing options...
kgreen Posted June 4 Author Share Posted June 4 Good afternoon, sorry, but I thought I wrote back of my solution. I had attached a 1/2-inch aluminum channel under the trailing edge of the shelf. I found by loosening then lifting the shelf that the tire would fit. I had to lift the shelf about 1/2-inch. I created the problem! Once the channel was removed, everything fit just fine. Note the silver colored screw heads along the rear of the shelf. Seems the spare tire provides the support that the shelf needs. All is well in the trunk at this time. Mike, the storage compartment that you have is missing on my car, that is where the folded top fits. Mathew, the tire fits snug so the whitewall will be ruined in short order. Coker essentially gave me a whitewall upgrade when I asked for a black wall. It really is not a struggle to get the spare in or out now. Wondering how the jack was stored though. Having a couple steel chunks tossed into the tool tray would create more noise than a ricocheting emergency brake cable under the car. Does anyone have photos of the proper storage for the jack? 1 Link to comment Share on other sites More sharing options...
Wm Steed Posted June 9 Share Posted June 9 The spare tire fits perfectly into the trunk of my 38 40/48 series 2dr sedan. The spare that is in the truck is a 650x16 original wheel with a very old narrow tire. Wm. 1 Link to comment Share on other sites More sharing options...
kgreen Posted June 10 Author Share Posted June 10 Looks like I have my tire retainer in backwards. Yours looks more correct Link to comment Share on other sites More sharing options...
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