The Bicycling Thread

[955i]

Bears, I recently SQUEEZED some 28x700c cheap-ass Amazon tires onto my 1990 Merckx MX Leader. I have about 1mm clearance on each side behind the bottom bracket. These are cheapies and probably stiffer than need be (they do have a nifty reflective sidewall, though). I have not ridden it much since the change over because of my adductor tendinapathy. What little I have ridden gives me the impression that the wider tires make it both slower and more comfortable in equal measure. I look forward to screwing around with different tire pressures.

LOL This bike was designed and ridden originally when 19's were still a thing, 21's were commonly used, and 23's were seen as a compromise used by sissies.

[wildbears]

I think I posted a while back the different actual tire, bead to opposite bead distances over the tread.
Marked difference between different brands.
As I recall, the higher end tires were closer to the stated size while the cheaper ones were maybe larger.
1 mm clearance is really pushing it. Getting a rock jammed between the tire and frame could be dangerous. See my
post from today.

[wildbears]

Depending on where the clearance is minimal, there are some fixes.
For example, wider rims will change the tires configuration, height and width.

[wildbears]

Pulled the back wheel out of the dropouts today while pedalling and putting a lot of torque into the cranks.
The tire hit the bottom bracket and very suddenly stopped rotating.
Fortunately I was going up a very steep hill without much forward speed.
There was immediate personal contact with the pavement. I will be limping for at least a few days.

Additional Info....

The 1983 Trek 970—a top-tier, lugged steel racing bike built with Columbus tubing—features standard semi-vertical rear wheel dropouts. These dropouts angle slightly forward and downward, allowing for easy rear wheel removal while ensuring the axle sits securely under load. [1, 2, 3, 4]

Axle and Skewer Care: Since semi-vertical dropouts slide downward, a properly clamped, high-quality internal-cam quick-release skewer is vital to prevent the wheel from slipping out under heavy pedaling torque. [1, 2]

[955i]

Bummer, Bears. No lasting damage to you or the bike, I hope.

Three weeks ago I crashed into a raised sidewalk while riding across the University lawn. (Don't ask.) I crashed at no more than one to two miles an hour. Barked my shin on either the off-road serrated pedal or the chain ring. Regardless, it was ugly and my scabs were deep and filled with chain lube. The scabs are now gone and oozing wounds are starting to scar over. It will look cool someday.

[wildbears]

Permanent Chainring Tattoo.

[wildbears]

I need to check to make sure the quick release axles do not come close to the outer aspects of the dropouts.
To ensure your quick-release axles are safe, the axle ends must sit slightly inside the outer faces of the frame dropouts so the quick-release skewer can clamp properly.

[wildbears]

Four Secrets For Training

1. BDNF
"Brain-Derived Neurotrophic Factor (BDNF) is a protein that acts like "Miracle-Gro" for your brain. It is a crucial neurotrophin responsible for the survival, growth, and maintenance of neurons. By promoting synaptic plasticity, BDNF is essential for learning, memory, and cognitive function. [1, 2, 3, 4, 5]
Why BDNF Matters
Learning and Memory: BDNF strengthens synaptic connections in the brain, allowing you to encode, retain, and recall new information. [1, 2]
Mood Regulation: Low BDNF levels are frequently linked to depression, anxiety, and stress. Conversely, optimizing BDNF can improve mood and resilience. [1, 2, 3, 4]
Neuroprotection: It shields existing neurons from dying and helps the brain recover from damage. Reduced levels are associated with neurodegenerative disorders like Alzheimer’s, Parkinson’s, and Huntington’s diseases. [1, 2, 3]
How to Naturally Boost BDNF
Aerobic Exercise: Physical activity is one of the most potent and reliable ways to increase BDNF production. [1, 2, 3]
Quality Sleep: Sleep is essential for clearing toxins and supporting synaptic plasticity, which requires healthy BDNF signaling.
Diet and Fasting: Intermittent fasting and caloric restriction have been shown to elevate BDNF. A diet rich in Omega-3 fatty acids (like DHA) is also beneficial. [1, 2, 3, 4, 5]
Sunlight Exposure: Vitamin D synthesis is linked to increased BDNF levels. [1]
Brain Stimulation: Constant learning, new experiences, and cognitive challenges keep your brain active and promote the release of neurotrophins. [1, 2, 3]
Clinical & Scientific Outlook
Because BDNF cannot be easily delivered directly across the blood-brain barrier, medical research is focused on novel treatments. Scientists are actively running clinical trials—such as gene therapy programs and pharmacological interventions—to stimulate TrkB receptors (BDNF's primary binding partner). The goal is to develop targeted therapies to manage severe neurodegenerative and psychiatric conditions. [1, 2, 3]"

2. Alcohol Post Training
Two or three drinks in the hours after training can reduce muscle protein synthesis by up to 37%.

3. Inactivity and Recovery
Twenty days of inactivity requires 1 1/2 to 2 times that period of training for recovery.

4. Bone Mass and Upper Body Muscle Mass
Lack of resistance training leads to loss of muscle strength, mass. And loss of bone. Jogging is better for bone density than cycling. In fact, cycling alone may even be detrimental to bone mass. Inadequate training of all muscle groups can result in cannibalization of protein from the muscles not training if there is inadequate protein intake.

Note: As previously posted, endurance training also builds up cellular mitochondria.

https://www.sciencedaily.com/release...1102132208.htm

[955i]

Amen to all of the above.

[wildbears]

Why This Cyclist Never Made It Off The Mountain

https://www.youtube.com/watch?v=RBi3K1qKHOc

[955i]

Hard to watch, even though I am very familiar with this story.

[wildbears]

Bontrager Flare RT Back Light Switch Repair


An inner tube patch was used to fix a torn membrane-covered switch. Membrane was retained and glued to the bottom of the patch as the patch was glued to the top of the light housing. The correct orientation of the membrane to the interior electronic switch was needed as it is asymmetrical fore to aft.

[wildbears]

Vitamin D and Muscle Mass

"Vitamin D is the primary vitamin that helps prevent muscle wasting and age-related muscle loss (sarcopenia). It plays a direct role in skeletal muscle function, promotes protein synthesis, and regulates the cellular processes responsible for muscle repair.

While it helps maintain muscle function and performance, it must be paired with protein and activity to decrease age related muscle loss."

[wildbears]

One step forward and two steps back.

It appears the current trend for wider tires on carbon fiber bikes is 30 mm for racing and 32 mm for casual. This is probably driven by the need for more forgiving suspensions on carbon fiber frames for any jarring road pavement.

Then there is the need for electronic shifting due to the Shimano's front derailleurs needing a significant amount of effort to change rings. My mechanical 105 R7000 requires an uncomfortable amount of effort whereas my old Shimano 600 shifts like waving a wand in the air.

[wildbears]

Beyond Protein

"6 other nutrients that help prevent muscle loss

"Protein plays in tandem with other macronutrients, micronutrients, antioxidants, hydration status, activity level, and more," adds Meghan Salamon, a preventive medicine and obesity medicine dietitian at Harvard-affiliated Massachusetts General Hospital.
Here are six key nutrients that work along with protein to support muscle health.

1. Carbohydrates
Carbohydrates are the body's preferred energy source, and they play a vital role in muscle maintenance. During exercise, carbohydrates replenish muscle glycogen, the stored fuel that muscles burn during activity. Without enough carbohydrate fuel, your body may break down muscle tissue for energy instead, contributing to muscle decline.

When you choose your carbs, prioritize high-quality ones like whole grains, vegetables, fruits, and legumes.

2. Magnesium
This mineral is involved in more than 300 biochemical reactions in the human body, and many of them relate directly to muscle health. "Magnesium aids proper muscle function, including contraction and relaxation," notes Salamon. Magnesium is also involved in creating proteins and reducing inflammation, which can help boost muscle recovery.

Smart strategies for achieving and maintaining a healthy weight

3. Iron
Iron plays a fundamental role in muscle function by helping deliver oxygen to muscles and supporting energy production. Low iron levels can prevent the body from making enough myoglobin (the protein within muscle cells that stores and transports oxygen), which can weaken muscle performance. Iron deficiencies can cause anemia, a deficiency of red blood cells and hemoglobin, which carry oxygen to the body's tissues.

While most American adults' diets supply enough iron, the incidence of anemia tends to rise later in life, often due to medications, difficulties absorbing iron, or internal bleeding from health conditions like ulcers. One study of older hospitalized patients found that iron deficiency in itself was a risk factor for impaired muscle strength, even beyond the expected effects of aging. Seek out iron in foods like poultry, fish, tofu, red meat, lentils, and fortified breakfast cereals.

4. Omega-3 fatty acids
These "good fats" - found in fatty fish like salmon, sardines, and mackerel, as well as avocados, walnuts, and flaxseeds - have well-known heart-health benefits. But their anti-inflammatory properties also benefit muscles. Chronic low-grade inflammation is a driver of sarcopenia, and omega-3s may help dampen that process.

Research suggests that omega-3 supplements may help increase the body's rate of building proteins and repairing tissues. A 2021 study found that when middle-age and older adults ate two weekly servings of fish, their muscle mass, hand-grip strength, and gait speed increased significantly over a two-month study period.

5. Vitamin D
Vitamin D plays several important roles in maintaining muscle health. Muscle cells contain vitamin D receptors, and low levels of the vitamin have been consistently linked to weaker muscles, slower walking speed, and a higher risk of falls. Vitamin D is also involved in the body's absorption of calcium - a mineral vital to muscle contraction.

6. Water
You might not think of water as a nutrient, but it's the one most essential to life - and it makes up about 76% of muscle mass. "Adequate hydration is also crucial for muscle performance and function, as well as for lowering the risk and progression of sarcopenia," says Dr. Hu. But dehydration is common in older adults because thirst sensation naturally weakens with age. A 2023 study of 190 older adults found that dehydration was significantly linked with greater levels of breakdown of muscle protein.

Fluid needs vary among individuals, but a good rule is to get four to six cups of water daily, and drink fluids of all types throughout the day - including with every meal.

The bottom line
Getting enough protein is a must for supporting muscle strength as you age, but an overall healthy dietary pattern is just as important. "A varied, high-quality diet can help to ensure proper protein intake, as well as other nutrients necessary for preventing muscle loss," says Salamon. "Focus on getting a variety of colors and food groups in your daily eating.""