BMW Roadster Tonneau

Pros: Installs Easily, Covers Cockpit, Lightweight
Cons: Requires Boot Cover
Cost: $78.90 (with shipping)

I’ve always been in a love/hate relationship with the roadster’s boot cover. I liked the way the Z3 looked with the boot cover installed over the folded down top, and I recognize the protective benefits of using the boot cover. However it is such a pain to install that I seldom used it except on long drives (when I knew the top was going to stay down). The problem was that I was never comfortable enough to leave the car parked with the top down. The exposed leather interior would be subject to bird bombs, harmful UV rays, dirt/dust, and prying eyes.

Back in highschool I drove an MGB that had this great accessory called a tonneau cover. This thick vinyl cover snapped around the cabin of the MGB on specially designed snaps that were part of the interior. That tonneau cover effectively covered the interior of the car and it was much easier to take on and off than the convertible top was to put up and down. The other really neat feature is that it had a zipper down the middle so you could unzip just the drivers side and drive the car with the tonneau cover still in place. I’ve been wanting a cover similar to that MGB one for my BMW roadster every since I first got the car. However no one made one, and from a development standpoint since the car wasn’t designed for one chances are it would never exist.

M&M Marketing produced a car cover that was very similar to what I was looking for, and I almost got one. Except the M&M design is really closer to a car cover and I never really cared for the looks of it. From a utility standpoint I’m told that the M&M design works well. It stands up okay to the elements and is moderately easy to take on and off. But it just isn’t that attractive to look at (to me it always looked like a small tent had been pitched over the car). I’m told that the M&M cover is actually a Miata cover that happens to fit, but sometimes it looks just a tad too small to me.

Apparently Carter Lee had the same thoughts and undertook a project to design a simple tonneau cover specifically made for the BMW roadster. Carter’s design fits flush with the dash and it is custom made for the Z3’s interior. There are “pockets” designed to go over the seats and dash pod. Carter even designed two different versions to account for Z3s with and without roll hoops. Carter’s design was not the same as the original MGB tonneau I had always wanted, but it was so close that I just had to have one.

My first indication that Carter had gone all out in making these was the very professional packaging that arrived shortly afterwards. However, after admiring his packaging handy work I immediately ripped the bag open, tossed the instructions and went out to the garage to try it out. Initially I fumbled around trying to figure out the best way to install it (guess I should have read the instructions first). But finally decided that I like to slip the custom pockets over the seats, then get the front of the cover tucked in, secure the sides via the velcro straps, and lastly tuck the back of the cover into the crease at the rear of the boot cover. First couple times took me a few minutes but now I’ve got it down pretty good.

Basically there are four places in the design that attach the tonneau to the roadster. The leading edge of the cover has a foam like trim sewn into it, this is designed to be tucked into the area where the windshield meets the dash. The foam slips into the crack with a push but then expands and secures rather well. Around each side mirror the tonneau cover has two velcro straps that secure the tonneau to the mirror. This works well but does require that you leave the windows down. In the back the tonneau cover tucks into the convertible top storage area along the trailing edge of the boot cover. This leaves a nice smooth taught look, I’m told by Doug and Eileen Morgan that it even keeps water out of your interior should you get caught in a quick shower (however it shouldn’t be considered an acceptable cover if you are expecting a rain storm).

With Carter’s tonneau my MZ3 finally had a cover that matched its sleek styling. The tonneau fit nicely over the instrument pod, seats and roll hoops (non roll hoop version available). It seemed pretty secure but I wanted to put this thing to the test. I got out my $30 Sears electric leaf blower and and decided to give it a wind tunnel test, at the same time I was curious to see what the motion sensor on my Clifford car alarm would think of a fluttering tonneau cover. What I found out is that if the cover is properly installed I could not blow it loose. The first time I didn’t get the front tucked in good and was able to get the front of the cover loose but the velcro straps and rear tuck kept the cover in place. Not sure what this says about the motion sensor, but it never went off even the one time the front of the cover came loose.

Needless to say I was pretty impressed with what Carter created, and I knew it was a keeper but I decided to do some additional tests. At the time I got the cover we were in the middle of an extreme heat wave in Texas. Everyday after work it was a race to see how quickly I could drop the convertible top to let off all the heat that had built up in the cabin. For a week I kept a fancy digital thermometer in the car, and every time I parked I would place the additional temperature sensor out side the car in the shade. During that week I found out that on average Carter’s cover kept the interior of the car about 7 degrees cooler than with the top up. I’m sure the color of the tonneau had to do with that (silver vs black) but I suspect the open air made the biggest difference. Carter now makes a version of the cover in black and there is a part of me that wishes I would have ordered the black version, but I’m sure it gets a little hotter.

Removal of the cover is super easy. I just unvelcro the cover from one of the side mirrors and pull, off it comes. A couple of quick folds or more likely just wad it up and shove it into any storage space like the top storage behind the seat (if you have it). I usually shove it in the trunk over the tiny crevice above the power top motor. If you have the trunk organizer it would fit in there as well.

I asked Doug Morgan what he thought of his tonneau cover (he has a black design without the roll hoop pocket), Doug replied

It does keep leaves and dust out very effectively and at least moderate amounts of rain; yes I have tested this out. If you are careful you can even get the water out without getting it on your interior. For those that live in the hotter areas of the country it does a great job of keeping the interior cool. It became an invaluable item on the BAD IV tour to keep the seats from burning your legs when returning from one of the little jaunts (the steering wheel and door edge didn’t burn either). Carter’s tonneau is a must have on the Homecoming Convoy also. The tonneau is make of lightweight water repellant fabric, which makes for great protection without being bulky so it avoids taking up valuable trunk space.

Personally, my only complaint is that it requires the boot cover, without the boot cover it really doesn’t tuck into or get secured in the back. It is still usable but I suspect a strong breeze could blow the back end loose. But considering it is only $78.90 it really is a fantastic cover. I think the fact that it is designed by a BMW Z3 owner tells you that the product is well thought out and functional. I’m very impressed with it and use it quite often, since that initial leaf blower test it has never come loose, and it has still never caused a problem with my car alarm. I guess the motion sensor goes right through the material because the motion sensor still works.

Carter sells the tonneau cover via a web page, and has lots of information about the roadster tonneau at that web site. Carter offers versions designed for Z3s with the BMW roll hoops and for Z3s without the roll hoops. Both versions of the roadster tonneau are available in black and gray. They are made of a strong, lightweight, compact, and water-repellant nylon taffeta. Whichever version and color you choose the total cost including shipping is only $78.90

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