Hi All!
With a large tour coming up and an afternoon of reasonable weather, this seemed like a good time to upgrade Sherpa's pannier hook-rack abrasion protection. I use Ortlieb panniers, and with time and vibration, their glass-reinforced nylon pannier hooks are really abrasive to rack powdercoatings. I've seen photos of holes worn in rack tubing by them, and I just got an email from my Dutch friend who is having a similar problem with his Ortlieb/Tubus combo.
I've been using a Trim-Brite automotive product to wrap my racks, and so far it has worked well to prevent any wear. It is a nice, matte-black tape with low-creep adhesive, intended to restore the window trim on automobiles. It even stands up to the abrasion caused by automatic car washes (the kind that removes the original finish this tape is meant to restore).
Though the tape has worked well, I notice the single layer I wrapped is starting to wear, so I sent for a couple packets of the newest Tubus "Schutzfolien" or protectors meant to keep racks happy with Ortlieb bags. Tubus calls it a "foil" but it is really an adhesive-backed, very shiny clear plastic. My guess is it is adhesive Mylar...it is pretty stiff and hard for its thickness. This is a new material for Tubus this year and they claim it far outlasts their earlier protective foils. See:
http://www.tubus.com/product.php?xn=56In their FAQ, Tubus say...
Question: Why does abrasion begin at my carrier through the panniers?
Answer:
The hooks (and sometimes also the border) of modern panniers are made out of plastic with a content of glasfiber. The part of glasfiber was raised, to make the hooks more robust.
These hooks are abrasive and grind the surface of the carrier.
If there is any sand or dirt between the hook and the carrier, this goes even quicker.
Question: How can I avoid the surface-abrasion caused by the plastic parts of my panniers?
Answer: Our carriers are coated with a very strong polyester-based coating with best available technology.
1) Because abraison can appear, we advise to protect the area with our (optional available) protection foil set before using bags.
In 2012 we developed this new, transparent kind of foil, which is tested in-house to its adhesive power, UV- and abrasion resistance under hard conditions and which has performed strongly. It clearly outmatches the former foil.
2) Please check if your panniers fit exactly to the carrier. The inside diameter of the hooks has to be adapted (if necessary with adapters, which should have come with the pannier) to the tube-diameter of our carriers (10 mm). Also the lower hook must fit exactly to the tube (because of the 14 mm tube of TARA/DUO/SMARTI you need an optional available wider hook).
A good matched bag cannot chatter and accordingly makes less abraison.
I figured I'd need a couple sets, since I have two racks (front and rear). I learned I didn't get enough.
I learned a lot more that may help anyone thinking of getting and applying this stuff:
Lesson #1 You don't get much in each foil kit. There is one sheet that has been die-cut into three strips. Each strip is 40mm x 140mm, totaling 120mm x 140mm split three ways.
Lesson #2: Tubus recommend wrapping stressed areas twice (would have been nice if Tubus put these measurements and details in their FAQ:
http://www.tubus.com/de_oe.php?xn=8 ).
Lesson #3: Tubus further state "in case of extreme stressed areas you should wrap three layers of foil round the carrier". That would be under the pannier hooks (2 per bag), plus the area immediately under the hook (2, 1 @ the forward diagonal of each Thorn Low-Loader), 1 spot each at the lower fin and another 1 each at the lower fin backing plate. That's a lot more tape than is included in each kit, so if you want to protect everything, you'll be short. You'll also be unhappy if you spent as much as I did; retail for these kits is USD$8.49. Two kits plus postage from Portland, OR cost me USD$23.
Lesson #4: The first wrap of a 10mm OD rack consumes 35mm of the stuff..about 1 wrap if you wrap the short way. so don't; go lengthwise (linear). Because the foil is fairly thick at 0.09mm/.0035in, it grows with every wrap, so count on using 108mm or so of the available 140mm length if you go for three wraps. I'm thinking a person would need 4 of these kits to do a minimal job on two racks. That's a lot of money, totaling close to USD$40 at the best prices I could find including postage.
Lesson #5: Despite being very careful with my measurements and cutting and employing Ghandian levels of patience and determination, the results look terrible. I wore nitrile gloves to avoid fingerprinting the adhesive, and the racks were clean as clean can be with no surface oils, thanks to a quick wipe of 99% isopropyl I use for solder-prepping circuit boards. There was no rack abrasion thanks to my previous use of the trim tape. I even got perfect registration when wrapping, thanks to using the sun's linear reflection on the rack tubes.
Lesson #6: Though the foil went on crystal-clear and bubble-free, the longer it was in place, the cloudier it became (See photos). After awhile, I looked at the overlap of my wrappings and found they had come loose. Pressing them in place, they held for about three seconds and popped loose. Taping them in place for 15 minutes had the same result. The film is simply too stiff for the adhesive intended to hold it. The cloudiness comes when the wraps try to unwrap and delaminate from each other, stretching the adhesive and causing air gaps.
I removed the lot, which was surprisingly easy since it had already started to uncurl.
Huh.
My second attempt involved going to Pacific Rubber for a length of Gates Rubber Company's 6 LOLA reinforced and corded hard-neoprene-coated synthetic rubber tubing. I wanted tubing that would fit over the rack (10mm) yet fit inside the Ortlieb hooks with the sizing spacers removed (16mm). By happy accident in metric-challenged America, 10mm/16mm equals a hose with 3/8" ID and 5/8" OD.
I cut off come sections using arc'd cable cutters to get a nice, square cut, then sliced the hose sections lengthwise, missing my major arteries. The result looked nice and I was encouraged. The sun broke through the cloudy Ortlieb foil, the birds sang, and life was good once more.
Not.
As soon as the hose was sliced, it expanded, thanks to the release of compressed internal cording. This left a gap that was neatly filed by the lower retention clasp of the Ortlieb hooks, preventing them from locking the bags on the rack. Worse, the hose had enough friction against the inside of the pannier hooks to make intended removal a three-handed operation. Nice try, but it dinna'gonna work.
I think I'll go back to the Trim-Brite windshield molding trim tape, and just wrap it a few times. It was invisible, looked good, didn't try to uncurl, and lasted a while. Best of all, it came on a roll so there was plenty of it. A friend tried electrical tape, and after riding in hot weather, the adhesive crept out from the layers and gummed-up his hooks. He switched to black duct tape with the same but messier results.
So. What do you do to or put on your racks to minimize pannier hook abrasion? Thanks in advance for your suggestions.
Best,
Dan.