Sunshine on Brass

Just a quick one.  I am experimenting with heavy brass footer under a turntable.  I made up these and the next morning, the sun was shining in and making the brass glow.

 

Flat tire on the side of the road

When it comes to flat tires on the road with a motorcycle, I have been luckier than I deserve. I started riding again more than 16 years ago and, until the summer of 2019, I hadn't had a flat. Its a good thing too. Almost all of my miles have been on dirt bike, spoke rims with street tires with tubes in the tires. To be honest, I don't think I could remove and patch a tube on the side of the road. These stiff road tires on these narrow dirt bike rims make dismounting and mounting a tire into about a half day of hard work in the shop. Nearly impossible on the side of the road.

Realizing that I was pushing my luck, this season I converted the spoke wheels on my KTM to “tubeless” by sealing the spokes with a special 3M sealant tape. You might say that the universe wanted me to practice my tire plug skills by giving me a drywall screw in the rear tire on the first trip I took after going tubeless. And it did take some practice. My first attempt leaked some air, so I ended up plugging it again on side of the road the next day. That one held long enough for me to complete the ride and ride the 500 miles home.

With my new interest in plugging motorcycle tires, I discussed the subject with other riders and got a range of opinions on the reliability of a plugged motorcycle tire. Riding home, I started wondering what the expert opinion of plugging a motorcycle tire might be. And then I remembered that I knew an expert or two that I could ask.

I will tell you up front that, based on my car experience, I was a proponent of plugging tires. I assumed that, like a car tire, a well executed tire plug could last the life of the tire.

When I got home, I got online and found Dunlop's position on plugging tires. They say never use a plug alone to patch a tire and the only acceptable repair is a “plug/patch”.

 

My next stop was to email my friend, Frank. Frank is a retired tire designer of great expertise. Frank was the father of the original BFG Comp TA and spent time at BFG, Michelin, Dunlop, and Kumho.

Frank's response was that a motorcycle and a car tire are very different things. He pointed out that the tread of a motorcycle tire does a lot of stretching and compressing because of the curved crown of the tread. This means that it is much easier for a plug to come out of a motorcycle tire, even when properly installed. His advice was to get the plugged tire off the bike as soon as possible.  Now that's a little scary.

To be frank, I'm still going to use plugs as an emergency road side fix, but I'm also going to be careful of the stress that I put on a plugged tire and get it off the bike as soon as I get home.

I thought it would be interesting to look at the differences in tire construction between a motorcycle and a car tire. There are 2 cut-away sketches of the inside construction of a typical car and motorcycle tire shown below. The casing or body ply of the tire is almost the same in a motorcycle and a car. Cords run straight across from one bead to the other. The car tire shape is flatter in the tread area, but otherwise similar. Both these tires are radial ply.

 

The big difference comes in the belt. The car has two belts (usually steel) that form a cross hatch because of their cord angles. That structure is really strong, even when punctured, and a car tire plug can often live the life of the tire.

On the other hand, the typical motorcycle tire belt is a single cord that is wrapped around the circumference of the tread. When punctured, the belt cord is cut and can pull away from the hole. Also, as the tire rolls through the contact patch, the belt compresses, then stretches making the loss of a plug possible. As you can imagine, high speed and high load are likely to make this situation worse.

So take it from a convert. If you have to plug your tire along the way, take it a bit easy and keep close track of the tire pressure. Then get that tire off the bike as soon as you can.

Attribution - the cut-away sketches were borrowed from Google Images with the motorcycle tire from bareasschoppers.com and the car tire from overdrive.in.  The picture of the rider with a flat on the side of the road is from roadrunner travel magazine.

Southern Grace and Manners

My last trip of this season was down to western Virginia, a favorite area for me. Once again, I had a puncture in my rear tire.  Before the trip, I had installed a tire pressure monitor and it worked.  I looked at the display and found a flashing red light with a rear tire pressure displayed at 19 psi.

I was up in the mountains in a National Forest with no cell signal and very little traffic, but I had the tools to plug the tire and inflate, so it was no worries.  I was lucky to find a wide, shaded pull out on the side of the road and began fixing the tire.  Part way through the process, a car pulled up and sat behind me watching me work.  When it was clear that I was able to fix the tire and was starting to put away tools, the car approached with an older couple inside.  The lady on the right put down her window and said, "sorry for your troubles" as they rolled back to the highway.  It turns out that they had stopped and waited, just in case I needed some help.  Now that is friendly. 

A Funny Flat Story

This is a short but true story about plugging motorcycle tires. A friend of mine vacationed in Cuba last winter, including 2 weeks exploring with a guide and a rented motorcycle.

It turns out that it was the season for crabs to come out of the ocean and lay their eggs on the shore. My friend and his guide came across the place where the crabs were crossing the road and there were so many that they couldn't avoid hitting a few of them. The crabs claws were so sharp that my friends front tire was punctured and they had to try and find a repair place nearby.

A motorcycle repair shop was found, but the mechanic was out of tire plugs. Not to worry, he had a ready solution. It turns out that condom is a useful replacement for the traditional tire plug. The condom plug lasted the rest of the trip.

Two Bikes Redux

About 1 year ago, I wrote a post about how the specs of my KTM 690 Enduro and my Kawasaki KLR650 were almost identical, but they felt very different when riding.  In fact, they required a different riding style to remain confident and have some flow to riding corner to corner.

After 3 seasons, I have 19k miles on the KTM and I have learned how to ride it with confidence and flow.  It is still a very different style than the KLR.  In fact, I took the KLR out for a ride this summer and just couldn't make it work.  My muscle memory has so completely adapted to the KTM that I can't ride the KLR the way I used to.

But this time, I may have the answer to the differences between bikes.  It's said that lateral flex in a motorcycle is a key part of the suspension during cornering.  For example, if you are leaned over at 45 degrees, the force from a bump is split between the direction the suspension works and lateral force trying to bend the forks and swing arm.  So flex from the forks, frame, and swing arm are the only "suspension" for the lateral loads.  In addition, it is thought that the forks stop working because the side load increases the friction in the fork and it "sticks".

This article discusses the effects of lateral flex on Motogp bikes and the effect of tire design on rider feedback and performance.

https://www.motorsportmagazine.com/opinion/motogp/why-motogp-has-gone-soft

I don't claim that either of my bikes nor the rider are anything like a motogp bike, but lateral stiffness may explain the difference in feel between the KTM and the KLR.  For example, the forks on the KLR are 38mm diameter.  The KTM has 48 mm diameter forks.  The KLR has a frame that is not triangulated with only a single down tube and top tube from the steering head.  The KTM has a triangulated trellis frame that  wraps around the engine and uses the engine structurally.  Finally, the swing arm of the KLR is fabricated small rectangular tube while the KTM is cast with large sections, especially the cross brace.  My guess is that the KTM chassis is an order of magnitude stiffer than the KLR.

Finally, a big difference and one which may explain the difference in feel.

The Chain and the Frame

The subject of motorcycle drive has been on my mind lately.  I'm due to change the chain on my KTM after trying the clean but don't lube approach.  And a friend is in the process of modifying an old BMW with a more modern swing arm, so we were talking about shortening his driveshaft.  It's a surprisingly wimpy looking thing that looks more like a steering shaft than a drive shaft to me.
 
Along the way, I was referred to a video of a motorcycle chain during a drag strip run.  It's not exactly your street bike, but it is a view I've never seen before and often wondered about.

https://www.dailymotion.com/video/x2wxgez

Since we are on the subject, there is also this video from Kevin Cameron on how motorcycle frames have evolved over the years.  It's fun to see him explain things with his hands.

https://www.youtube.com/watch?v=id7UZ3iws40

That reminded me of a recent conversation with a fast rider from our club.  He said that most people have no idea what the capability of a modern sport bike really is.  He picked a road I know which has many tight corners marked at 15 and 20 mph and said that he can average 70 to 80 mph over that mountain.  This could be unsupported bragging, but knowing who said it, I suspect it is data based and pretty close to the truth.  In that case, I hope I never find out the true capability of a sport bike.

Northern California Redux

The sidebar.

You may already be aware that Apple products have gotten very expensive.  It came time to replace my computer and I found that the successor model to my old Mac Mini was $1000 higher, more than double, what my 2012 model had been.  So I started looking around for alternatives and decided to give what's known as a hackintosh a try.  This is a computer built with Windows compatible components that is tweaked to run Mac OS.  Alas, Apple is doing a good job of protecting their intellectual property making it very hard to run that Mac OS on Windows hardware. Of course, my skills in this area are poor, so in the end I failed and put Windows 10 on my Windows hardware computer.  Note that this isn't a great solution for Apple or me, as I am now working on the Windows OS instead of Mac.  Oh well.

So Windows 10 is enough different to cause a learning curve, but one interesting thing that they do is offer pretty landscape pictures on their boot-up screen and those change over time.  You even get to tell it which pictures you like so that they tune it to your taste.

That sent me on an internet quest to download some nice free pictures for wallpaper on the Windows box.  With that success, I noticed that my Mac, which I still use, was a little boring in the wallpaper department. So, I went looking through my pictures for interesting alternatives. And that brought me back to my 2011 trip to northern California.  Several of these I had posted earlier, but heck, that was 8 years ago.




Wandering the backroads, I came across several interesting farm trucks.  These were both in the foothills just west of the Russian River Valley.  Both are Fords from a similar, if not the same era.




















I will throw in the traditional ocean shoreline shot and a picture of a Mendocino cottage, mainly for the contrast between the wood and the green grass.

But the thing that got my camera's attention was the moss growing in range of the mist from the ocean.  Enjoy.

 Armstrong State Natural Reserve

 Porter Creek

 

Pine Flats

Moss Fence