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| Bicycle Tire Scrunch Pads |
Many thanks to the folks at the New England Paddlers Message Board for this information. I reproduce it here as I received it.
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You may have noticed that I have different-looking grunch pads on my solo canoe. They're not the usual Kevlar matting, but look suspiciously like bicycle tires. Well, that's because they are! I have used them on canoes for over 10 years and they work wonderfully well. They have lasted and , being flexible, they do not damage the canoe.
I first heard of this on a paddling forum on the internet, It wasn't difficult to do and the results are exemplary. One cavil if you try this: Use an OLD road bicycle tire with some wear on it. The new materials, especially the knobby mountain bike tires, like to grab kayaks and never let go…
Originally posted as a thread in a Paddling forum, then rewritten as an article in the Paddler, newsletter of the RI Canoe Association. Reprinted here with permission from the editor.
It is being uploaded for several reasons. One -- a member of this forum reported that when his Kevlar skid plate broke, the stem of his ABS canoe split also. Shortly thereafter, a member of the RI Canoe Assn. told me the same thing had just happened to him.
Two -- a couple of years ago a friend did not tie his brand new Dagger Impulse onto a trailer very well, and it got dragged about a hundred feet before he could bring the vehicle safely to a stop. The stem was ground down well into the foam layer. When he called Dagger for help they suggested bicycle tires, and specifically told him not to use Kevlar skid plates; the reason, they said, was that the Kevlar won't flex with the canoe.
Commercially available Kevlar grunch pads are wonderful protection when you drag your canoe across the ground. As protection when crashing into rocks they are counter productive. Kevlar felt, when saturated with resin, becomes inflexible. Unfortunately ABS is very flexible. The two materials do not complement each other; quite the opposite. *Usually* it is the Kevlar that breaks, taking the vinyl layer with it and leaving exposed ABS. Of course, the *whole thing* doesn't break, so now you have to fill in the gaps before you put another Kevlar grunch plate over it. By this time you have something so thick it begins to function as a skeg. Or you can spend hours, if not days, grinding the old pad off.
There are two solutions. One is Kevlar cloth, which is *much* stronger than felt yet remains flexible when saturated with resin. (Actually, the resin never saturates the fibers, just fills in the gaps.) The down side is that nobody sells ready-made cloth grunch pads so you'll have to make your own. Figure on using one razor blade per inch of cut. No joke!
The other solution is a 26-inch bicycle balloon type street tire. ( NOT a knobby.) Not only will the tire and canoe flex together, but the thick rubber will actually absorb much of the shock of the impact. I've used bicycle tires on all my whitewater canoes since 1983 with never a regret.
> Step 1 - cut the tire in half so you have 2 semi circles.
> Step 2 - cut the wire beads off the tire.
> Step 3 - Using extra coarse sandpaper rough up the inside. Sand until the inner cloth belt is slightly fuzzy.
> Step 4 - Trim one end of each tire half so it is rounded (no corners for catching on rocks)
> Step 5 - Trace the shape of the tire onto the boat (only necessary if you're trying to be neat)
> Step 6 - Sand inside the area you've just traced. Again using extra coarse sandpaper.
> Step 7 - Wipe both the tire and the area of the boat that it will cover with acetone. Make SURE you wear rubber or latex gloves when handling acetone! Don't be cheap with the acetone. The purpose is to soften both the vinyl of the boat and the butyl rubber of the tire for proper adhesion. THIS IS A CRITICAL STEP and is even more important than sanding. DO NOT SKIP IT!!!!!
> Step 8 - Coat one surface or the other with a marine grade epoxy, then carefully apply the tire to the boat. You will need to use duct tape to hold the tire in place while the epoxy cures. As you noticed while tracing the tire's shape on the boat, the tire does not conform easily. Wear rubber or latex gloves when handling epoxy.
>Step 9 - When the epoxy has cured and the duct tape removed use an epoxy putty, preferably PC-7, or PC-11, to build a sloping ramp up to the level of the tread. This will prevent the edge from catching and peeling. I forgot this on one canoe once and the tire did start to peel -- from the canoe being dragged on the ground, not from catching on rocks in the river!
That's about it. As soon as the humidity breaks I'm about to do my own latest acquisition (epoxy applied during extreme humidity will never cure, as I learned the hard way). It will be the 7th canoe I've done this to, and basically, the canoes wear out around the tires.
--Alan (I'll never use Kevlar pads again) August -- Editor, the Paddler, R.I. Canoe Association
Joe Pylka
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