Posts Tagged Repairs
Schwalbe Marathon Plus and Michelin Protek vs. Glass Chip
Posted by Ed in Machine Shop, Recumbent Bicycling on 2019-09-14
The rear tire of my bike was flat before our morning ride and pumping it up produced a hissing sound with a spray of tube sealant:
We run Schwalbe Marathon Plus tires on the rear of our Tour Easy ‘bents, because otherwise I’d be spending far too many hours repairing flats by the side of the road. Searching the blog for the obvious keywords will produce many examples of what it’s like to ride a bike in Dutchess County NY.
Schwalbe says the tires have 5 mm of “highly elastic special rubber” and claims “Even thumbtacks can’t puncture it.” They use the term “Flat-Less” in the sense of “flat less often”, rather than “not flatting”, which seems disingenuous at best.
Flatting less often may be true, but they obviously haven’t tested against Dutchess County road debris:
It’s not quite 5 mm in the longest dimension, but it was embedded deep enough in the tire tread to cut through the armor belt and nick the Michelin Protek tube:
Of course, the hole is dead-center between the two bumps that are supposed to compress around the puncture while the goo fills and seals the void.
Before taking everything apart, I tried gently inflating the tire and putting the puncture at the bottom to let the sealant fill the hole overnight. In the morning, the tire was once again flat, although the floor wasn’t covered in goo. Pumping the tire up produced another spray of sealant.
It’s likely the Protek tube got me home with a slow leak on the previous day’s ride, but it definitely didn’t solve the problem and, frankly, I’ve had ordinary tubes do the same thing. Given the trivial size of the puncture and the complete lack of permanent self-repair, I don’t know what kind of damage it’s supposed to cure.
I’ve already discarded two Protek tubes with slow leaks through the valve stem and no punctures, so they’re definitely not worth the hassle. Michelin no longer lists the tubes on their bike tire site, so it seems they agree.
I made up a boot by punching a 5 mm polypropylene disk, sticking it to a small tire patch, then sticking the patch over the puncture on the tire. With a bit of luck, nothing will line up with the gash and punch through the boot.
I recently replaced all four tires on the Forester, slightly ahead of schedule for reasons not relevant here, and it’s worth noting that a Marathon Plus tire costs about a third of what I paid for a car tire; they’re not to be discarded lightly.
Tour Easy: PTT Switch Replacement
Posted by Ed in Amateur Radio, Electronics Workbench, Recumbent Bicycling on 2019-09-09
The PTT switch on Mary’s Tour Easy became intermittent:
It’s been sitting there for least five years, as witnessed by the sun-yellowed hot melt glue blob, which is pretty good service from a switch intended for indoor use. The 3D printed button never fell off and, in fact, was difficult to remove, so that worked well.
I took it apart and cleaned the contacts, but to no avail, so her bike now sports a new switch with a similar rounded dome:
I clipped the wires a bit beyond the terminals and soldered the new switch in place, so it’s the same cable as before.
Now, to see how long this one lasts …
Rail Trail Tree Clearing
Posted by Ed in Oddities, Recumbent Bicycling on 2019-09-08
Trees along the Dutchess Rail Trail fall over for no obvious reason and sometimes block the path:
But my tool hand is strong:
The DPW folks can haul off the trunk, as it’s more than I can move.
Floor Sweepings from eBay
Posted by Ed in Machine Shop, Oddities on 2019-09-07
Ordered 100 stainless steel M3 washers from a “US Seller”, received this:
Yeah, it looked a bit short to me, too.
The chopped and bent washers in the upper right corner suggest the seller got floor sweepings from his source, which is about what you’d expect for a bottom-dollar vendor.
The seller refunded half, which wasn’t particularly generous, but I wasn’t ready to go to the mat for two bucks.
Raspberry Pi “Moster” Heatsink Retaping
Posted by Ed in Electronics Workbench, Machine Shop on 2019-09-06
A pair of colorful laser-cut stacked acrylic Raspberry Pi cases with “Moster” (*) heatsinks arrived, with the intent of dressing up the HP 7475A plotters for their next Show-n-Tell:
Unfortunately, the thermal tape on one of the CPU heatsinks was sufficiently wrinkled to prevent good contact with the CPU:
The seller sent a replacement copper slug with tape on one side. Presumably, they glue it to the heatsink with thermal silicone:
Of which, I have none on hand.
So I did what I should have done originally, which was to drop a few bucks on a lifetime supply of thermally conductive heatsink tape, apply it to the bare side of the slug and stick the slug to the heatsink with their tape:
The blue stuff is the separation film, with the tape being white. It doesn’t match the black tape on the other side, but seems gooey enough to work.
Done!
Despite the heatsink hype, ball grid array chips dissipate most of their heat through their pads (and perhaps a central thermal pad) into the PCB, so sticking a heatsink atop the package is largely decorative, along the lines of hotrod ornamentation.
The epoxy packages used in previous Raspberry Pi iterations had better thermal conductivity to their top surface:
Than the more recent metal-top packages, which surely have inert-gas fill under the lid:
Pix cropped after being pilfered from the Official Raspberry Pi site.
Yes, the heatsink does conduct some heat into the air, even if not nearly as much as you might want.
(*) I’m pretty sure “Moster” was a typo in the original eBay listing which took on a life of its own to become something of an unofficial trademark. All of the search results ship from Duluth, Georgia (USA), regardless of the nominal seller; feel free to draw your own conclusions.
New Utility Pole
After about a month, a replacement for the fallen utility pole arrived:
This is much easier than digging a hole by hand:
Verily, given the right tools, any job becomes do-able:
It was fascinating for me and just another day at the office for everybody else:
They nailed the original pole tag to the new pole, complete with the original 1940 nail:
I expect this pole will outlive me, just as the original pole outlived the folks who built our house.
The most memorable comment came from the person doing the CHG&E damage assessment, who really really wanted this to not be their problem: “Anybody could steal a pole tag and nail it on that pole.” I asked what location their records showed for the pole tag, whereupon the conversation moved on.
Second-place award: no, we were not interested in trenching underground lines 300 feet along the property line, at our expense, to avoid an “unsightly” pole.
For unknown reasons, I was supposed to figure out which telecom utilities had wired the pole, notify them, and wait for them to tack their cables to the new pole. I called both Verizon and Altice / Optimum, got service tickets, and watched them close the tickets without further action. I tried re-opening the Verizon ticket and was told somebody would be there within 48 hours. An Optimum guy showed up, promised a quick return visit from a team with proper equipment, but nothing happened.
I suppose having no customer at the end of the cable removed any motivation to clear their hardware off our lawn, so, after two weeks, I deployed the bolt cutter, rolled up the cables, and scrapped ’em out.
Done!
Michelin Protek Tube: Another Slow Leak
Posted by Ed in Machine Shop, Recumbent Bicycling on 2019-08-21
After a few days of topping off the rear tire on Mary’s bike, with no gashes or debris in the tire, I finally replaced the Michelin Protek tube and autopsied it:
While it’s possible to extract the valve and perhaps even clean / replace it, I think that’s just delaying the inevitable. The rubber shreds may be necessary to fill large punctures, but they seem to wreck the valve seal.
Her bike now has an ordinary (pronounced “cheap”) tube inside the Schwalbe Marathon Plus armored tire. We’ll see how long this lasts.
Blowback