Upgrade roweru MTB. Skrajne podejścia

[Pepe75]

5 godzin temu, mike21 napisał(a):

Gumy 2.4 w XC? Cholernie duży przeskok z masą jest między 2.2-2.3 a 2.4. 

 

Raceking 2.2 630g

https://r2-bike.com/CONTINENTAL-Tire-Race-King-29-x-220-BlackChili-ProTection-Bernstein-Edition 

Mezcal 2.35 705g

https://r2-bike.com/VITTORIA-Tire-Mezcal-29-x-235-TNT-TL-Ready-Graphene-20-4C-black-anthracite

Nowy Mezcal 2.4 730g

https://r2-bike.com/VITTORIA-Tire-Mezcal-XC-Race-29-x-24-TLR-black-brown

Pirelli XC RC 2.4 735g

https://r2-bike.com/PIRELLI-Tire-Scorpion-XC-RC-29-x-240-SmartGrip-ProWall-TL-Ready

 

~100g na oponie to nie jest chyba dramatyczna różnica ?

 

 

[jajacek]

RaceKing Race Sport 2.2 z odrobiną błota poważyłem 530.
Do mojej ramy nic więcej niż 2,3 cala i tak nie wejdzie.
Natomiast wieść niesie, że Vittoria nigdy nie trzymają rozmiaru i zawsze są węższe.
Zmierz proszę swoje suwmiarką i napisz ile mają mm na jakiej szerokości obręczy.
W dużym stopniu to też dotyczy Speca. Dopiero na obręczy 30 mm te oznaczone jako 2,3 cala mają te 2,3 cala.
Ponieważ szosowe opony Speca są na pewno robione w fabryce Vittoria w Tajlandii, mam podejrzenie że MTB też.

[Pepe75]

Godzinę temu, jajacek napisał(a):

RaceKing Race Sport 2.2 z odrobiną błota poważyłem 530.
Do mojej ramy nic więcej niż 2,3 cala i tak nie wejdzie.
Natomiast wieść niesie, że Vittoria nigdy nie trzymają rozmiaru i zawsze są węższe.
Zmierz proszę swoje suwmiarką i napisz ile mają mm na jakiej szerokości obręczy.
W dużym stopniu to też dotyczy Speca. Dopiero na obręczy 30 mm te oznaczone jako 2,3 cala mają te 2,3 cala.
Ponieważ szosowe opony Speca są na pewno robione w fabryce Vittoria w Tajlandii, mam podejrzenie że MTB też.

Race Sporty to bardzo stara wersja dętkowa, dawno nieprodukowana - miałem kiedyś takie.

 

Mezcal 2.35 na obręczy wewn 30mm: szerokość 61mm

Raceking protection na obręczy wewn ~26mm,  szerokość 56mm

[jajacek]

O, to szerokie te Mecale. Fast Trak na 30 mm mają 57-58 mm. Mam widzę po jakieś 6 mm po bokach. Czyli 2,35 bym zmieścił tak żeby nie dotykały obręczy.

[Pepe75]

11 minut temu, jajacek napisał(a):

O, to szerokie te Mecale. Fast Trak na 30 mm mają 57-58 mm. Mam widzę po jakieś 6 mm po bokach. Czyli 2,35 bym zmieścił tak żeby nie dotykały obręczy.

Sprawdziłem jeszcze wysokość:

- Racekingi ~55mm

- Mezcale 2.35 ~57mm

[jajacek]

Ciąg dalszy opowieści. Tym razem dyskusje z DeepSeek 🙂

Topic: hardtail mountain bike. My case. Slightly overweight. 175 cm tall. 85 kg weight. My bike. Specialized Epic Comp Carbon 2017. Bike weight around 10.5 kg Wheels, Newmen Evolution SL. A30, with 30 mm rims. Weight 1800 grams. Looking for improvements. My typical bike ride is 50 km. 300 metres denivelation Average speed in winter 15-18 km/h. In summer 18-20 km/h Half of my course is completely flat to get to the woods. In the woods a lot of roots, sand, steep, short climbs, rolling terrain. Do you recon carbon wheels would be beneficial? Do you recon that changing butyl tubes to light TPU tubes or going tubeless would be beneficial?
 

Given your weight, riding style, and the terrain you typically ride, there are several improvements you could consider for your Specialized Epic Comp Carbon 2017 hardtail mountain bike. Let’s break it down:

1. Carbon Wheels

• Pros: Carbon wheels are lighter and stiffer than aluminum wheels, which can improve acceleration, climbing efficiency, and overall handling. They also tend to be more durable in the long run if you’re riding on rough terrain.

• Cons: Carbon wheels can be expensive, and while they are strong, they can be more susceptible to impact damage (e.g., hitting a rock at high speed) compared to aluminum. Given your weight (85 kg), you’d need to ensure the wheels are rated for your weight and riding style.

• Verdict: If you’re looking for marginal gains in performance and are willing to invest, carbon wheels could be beneficial, especially for climbing and rolling terrain. However, the benefits might not be dramatic given your current wheels (Newmen Evolution SL A30) are already relatively light at 1800 grams.

2. Tubeless Setup

• Pros: Going tubeless can reduce rolling resistance, improve traction, and allow you to run lower tire pressures for better comfort and grip on roots and sandy terrain. It also eliminates the risk of pinch flats, which is a plus if you’re riding over roots and rough terrain.

• Cons: There’s a bit of a learning curve with setting up and maintaining tubeless tires, and you’ll need to carry a tubeless repair kit in case of larger punctures.

• Verdict: Switching to a tubeless setup is highly recommended for your type of riding. It will improve comfort, traction, and potentially reduce the overall weight of your bike. This is likely one of the most cost-effective upgrades you can make.

3. Lightweight TPU Tubes

• Pros: TPU (Thermoplastic Polyurethane) tubes are significantly lighter than standard butyl tubes, which can reduce rotational weight and improve acceleration. They also tend to hold air better than butyl tubes.

• Cons: TPU tubes are more expensive and can be more fragile than standard tubes, though they are still more robust than going tubeless.

• Verdict: If you’re not ready to go fully tubeless, switching to lightweight TPU tubes could be a good intermediate step. However, given the benefits of tubeless, it might be better to go straight to a tubeless setup.

4. Other Considerations

• Tires: Given your terrain (roots, sand, steep climbs), consider upgrading to tires with better grip and durability. Look for tires with a more aggressive tread pattern and sidewall protection. The right tire choice can make a big difference in traction and comfort.

• Suspension Setup: Ensure your fork is properly tuned for your weight and riding style. A well-tuned suspension can improve comfort and control, especially on rough terrain.

• Drivetrain: If your drivetrain is worn or outdated, consider upgrading to a more modern 1x drivetrain. This can simplify shifting and reduce weight.

• Saddle and Ergonomics: Comfort is key. Ensure your saddle, handlebars, and grips are optimized for your body. A professional bike fit might be worth considering if you haven’t had one recently.

Summary of Recommendations:

1. Tubeless Setup: This should be your first priority. It will improve traction, comfort, and reduce the risk of flats.

2. Tires: Invest in high-quality tires suited to your terrain.

3. Carbon Wheels: If you have the budget and want to optimize performance, carbon wheels could be a good upgrade, but they are not essential.

4. TPU Tubes: Only consider these if you’re not ready to go tubeless, but tubeless is the better long-term solution.

By focusing on these areas, you should see noticeable improvements in your ride quality, comfort, and performance.


 

[jajacek]

Teraz pytania związane z taką pętlą testową:

Full Ride Metrics:

• Total Distance: 51.7 km

• Total Time: 3:27 hours

• Average Speed: ~15 km/h (consistent with your typical winter average)

• Loop Section (Woods): 28 km, 2:02 hours, 218 m elevation gain

• Flat Section (to/from Woods): 23.7 km, ~1:25 hours (assuming similar average speed)

• Temperature: +2°C

Niestety włącza się jakieś zabezpieczenie, które nie pozwala mi opublikować dalszej części tekstu.

[jajacek]

What I want to do is to analyze two scenarios for that specific loop.
1. Losing 3 kg of my bodyweight
2. Upgrading the bike to carbon wheels, which weigh 500 grams less
 

Scenario 1: Losing 3 kg of Body Weight

Impact on Performance:

1. Power-to-Weight Ratio:

   • Losing 3 kg of body weight directly improves your power-to-weight ratio, which is critical for climbing and accelerating.

   • For example, if your current weight is 85 kg and you lose 3 kg, that’s a 3.5% reduction in total weight (including the bike). On climbs, this could translate to a noticeable improvement in speed and efficiency.

2. Climbing Performance:

   • On your loop with 218 meters of elevation gain, losing 3 kg could make climbs feel easier and allow you to maintain a higher speed.

   • For example, if you currently average 10 km/h on a climb, a 3.5% improvement could increase your speed to ~10.35 km/h. Over multiple climbs, this adds up.

3. Flat and Rolling Terrain:

   • On flat sections, weight has less impact on performance compared to aerodynamics and rolling resistance. However, losing weight will still make it easier to accelerate out of corners or after technical sections.

4. Overall Energy Expenditure:

   • Carrying less weight reduces the energy required to ride, which could help you feel less fatigued over longer distances.

---

Scenario 2: Upgrading to Carbon Wheels (500 grams lighter)

Impact on Performance:

1. Rotational Weight Reduction:

   • Reducing wheel weight by 500 grams has a disproportionate impact on performance because rotational weight (especially at the rim) affects acceleration and climbing more than static weight.

   • Losing 500 grams of rotational weight is roughly equivalent to losing 1.5-2 kg of static weight in terms of performance gains.

2. Climbing Performance:

   • On climbs, lighter wheels will make it easier to accelerate and maintain momentum. This is particularly beneficial on short, steep climbs where quick bursts of power are needed.

   • For example, if you currently average 10 km/h on a climb, a 500-gram wheel reduction could improve your speed by ~1-2% (to ~10.1-10.2 km/h).

3. Flat and Rolling Terrain:

   • Lighter wheels improve acceleration out of corners and on rolling terrain, making it easier to maintain speed.

   • On flat sections, the benefit is smaller but still noticeable, especially if you’re frequently accelerating (e.g., after roots or sand).

4. Handling and Ride Quality:

   • Carbon wheels are often stiffer, which can improve power transfer and handling on technical terrain. However, they can also be harsher on rough surfaces, so this is something to consider if comfort is a priority.

---

Comparing the Two Scenarios:

Aspect	Losing 3 kg Body Weight	Upgrading to Carbon Wheels (500g lighter)
Climbing Performance	~3.5% improvement	~1-2% improvement
Flat Terrain	Minor improvement	Minor improvement
Acceleration	Moderate improvement	Significant improvement
Cost	Free (if achieved through diet/exercise)	Expensive (carbon wheels can cost $1,000+)
Other Benefits	Improved overall health and fitness	Improved handling and aesthetics

---

Which is Better?

• Losing 3 kg of body weight will have a greater overall impact on performance, especially on climbs, and it comes with additional health benefits. It’s also free!

• Upgrading to carbon wheels will improve acceleration and handling, but the performance gains are smaller compared to losing body weight. However, it’s a more immediate change if you’re willing to invest.

---

Recommendation:

1. Focus on Losing 3 kg First:

   • This will give you the most significant performance boost, especially on climbs, and it’s cost-effective.

   • Combine a healthy diet with targeted strength training and endurance rides to achieve this goal.

2. Consider Carbon Wheels Later:

   • Once you’ve lost the weight, upgrading to carbon wheels could be the next step to further optimize performance.

   • If you’re eager to upgrade now, prioritize a tubeless setup first, as it will improve traction and comfort on roots and sand, making your rides more enjoyable.

---

Final Thoughts:

Both changes will improve your performance, but losing 3 kg of body weight is the more impactful and cost-effective option. If you’re looking for a quick upgrade, consider going tubeless first, as it will improve your ride quality on technical terrain. Let me know if you’d like tips on weight loss, training, or wheel upgrades! 🚴‍♂️

[jajacek]

What would be the impact if I changed my current hardtail bike with 100 mm of front suspension to light XC downcountry full suspension bike weighting 500 grams more with 120 of front travel?
 

Switching from your current hardtail (100 mm front suspension) to a lightweight XC/downcountry full-suspension bike (120 mm front travel, 500 grams heavier) would bring several significant changes to your riding experience, especially given the terrain you described (roots, sand, steep climbs, and rolling terrain). Let’s break down the potential impacts:

---

1. Weight Impact:

• 500 Grams Heavier:

  • The additional weight of the full-suspension bike will slightly reduce your climbing efficiency and acceleration.

  • However, the impact of 500 grams is relatively small, especially if the bike is well-designed and the weight is distributed effectively.

  • For comparison, the benefits of full suspension (traction, comfort, and control) often outweigh the minor weight penalty.

---

2. Suspension Benefits:

• Improved Traction:

  • Full suspension provides better rear-wheel traction, especially on technical terrain like roots, rocks, and loose sand. This means you’ll maintain momentum better and waste less energy bouncing over obstacles.

  • On steep, short climbs, the rear suspension will help keep your rear wheel grounded, improving grip and reducing wheel spin.

• Comfort and Control:

  • The added suspension will absorb bumps and vibrations, reducing fatigue on longer rides and technical sections. This is particularly beneficial for a 60-year-old rider, as it reduces strain on your joints and muscles.

  • On descents and rolling terrain, the bike will feel more stable and controlled, allowing you to ride faster and with more confidence.

• 120 mm Front Travel:

  • The increased front travel (from 100 mm to 120 mm) will provide better handling on rough terrain and steeper descents. It will also improve comfort on longer rides.

---

3. Terrain-Specific Impact:

• Roots and Sand:

  • Full suspension will make a huge difference on rooty and sandy sections. The rear suspension will smooth out the bumps, and the improved traction will help you maintain speed and control.

  • On sand, the rear suspension will help keep the bike stable and prevent the rear wheel from digging in.

• Steep Climbs:

  • While the added weight might make climbs slightly harder, the improved traction from the rear suspension will often offset this. You’ll be able to power up steep, technical climbs more efficiently.

  • Modern downcountry bikes are designed to be efficient climbers, so the performance penalty will be minimal.

• Flat Sections:

  • On flat terrain, the full-suspension bike might feel slightly slower due to the added weight and suspension bob. However, most modern XC/downcountry bikes have lockout or firm suspension modes to minimize this effect.

---

4. Ride Quality and Fatigue:

• Reduced Fatigue:

  • The full-suspension bike will significantly reduce the physical toll of riding on rough terrain. This means you’ll feel less fatigued after long rides, allowing you to ride longer or recover faster.

  • For a 60-year-old rider, this is a major benefit, as it reduces strain on your back, arms, and joints.

• Confidence and Fun:

  • The added control and comfort will make technical sections more enjoyable and less intimidating. You’ll likely find yourself riding faster and with more confidence on descents and rough terrain.

---

5. Downsides to Consider:

• Cost:

  • A lightweight XC/downcountry full-suspension bike can be expensive. Ensure the investment aligns with your budget and riding goals.

• Maintenance:

  • Full-suspension bikes require more maintenance (e.g., servicing the rear shock and pivots) compared to hardtails.

• Efficiency on Smooth Terrain:

  • On completely smooth or flat sections, the hardtail might feel slightly more efficient due to its simplicity and lower weight.

---

Summary of Impacts:

Aspect	Impact of Switching to Full Suspension
Weight	500 grams heavier; slight penalty on climbs and acceleration, but offset by improved traction and comfort.
Traction	Significant improvement on roots, sand, and technical climbs.
Comfort	Major improvement; reduced fatigue and strain on joints.
Control	Better handling on descents and rough terrain; increased confidence.
Climbing	Slightly harder due to weight, but improved traction often offsets this.
Flat Terrain	Slightly less efficient, but lockout modes can mitigate this.
Fun Factor	More enjoyable on technical terrain; likely to increase your overall riding pleasure.

---

Recommendation:

If you frequently ride on technical terrain with roots, sand, and steep climbs, a lightweight XC/downcountry full-suspension bike could be a game-changer for your riding experience. The improved traction, comfort, and control will likely outweigh the minor weight penalty, especially given your age and the type of terrain you ride.

However, if your rides are mostly on smooth or flat terrain, or if you prioritize efficiency and low maintenance, your current hardtail might still be the better choice.

---

Next Steps:

1. Test Ride: If possible, test ride a lightweight XC/downcountry full-suspension bike on your typical terrain to see how it feels.

2. Consider Your Priorities: Decide whether the improved comfort and control are worth the added weight and cost.

3. Look for Lightweight Options: Focus on bikes designed for downcountry or XC riding, as they prioritize weight savings and efficiency.

[jajacek]

What was the feature on some Epic or Epic Evo full suspension bike where you could switch the geometry of the fork? Was the reviews positive?
 

You're referring to the Specialized Epic and Epic Evo's "Rocket Ron" or "Flip Chip" geometry adjustment feature. This feature allows you to change the bike's geometry by adjusting the head tube angle and bottom bracket height, effectively tailoring the bike's handling to different terrains or riding preferences. Let’s break it down and discuss how it works, its benefits, and what reviews have said about it.

---

How the Flip Chip Works:

• Location: The flip chip is typically located at the rear shock mount or linkage.

• Adjustment: It has two settings:

  1. High Position (Steep Setting):

     • Steeper head tube angle (e.g., 68.5°).

     • Higher bottom bracket.

     • Better for climbing and XC racing, as it provides a more responsive and efficient pedaling position.

  2. Low Position (Slack Setting):

     • Slacker head tube angle (e.g., 67.5°).

     • Lower bottom bracket.

     • Better for descending and technical terrain, as it improves stability and confidence at speed.

---

Benefits of the Flip Chip:

1. Versatility: You can adjust the bike’s geometry to suit different trails or riding styles. For example, use the steep setting for XC races and the slack setting for technical descents.

2. Customization: Riders can fine-tune the bike’s handling to their preferences, whether they prioritize climbing efficiency or descending stability.

3. Ease of Use: Switching between settings is quick and requires minimal tools, making it easy to adapt the bike on the fly.

---

What Reviews Say:

The flip chip feature has generally received positive reviews from riders and testers. Here’s a summary of the feedback:

Pros:

• Improved Versatility: Reviewers appreciate the ability to adapt the bike to different terrains and riding conditions.

• Noticeable Difference: The changes in head tube angle and bottom bracket height are subtle but noticeable, especially on technical descents or steep climbs.

• No Compromises: The flip chip allows the bike to perform well in both XC and trail-oriented settings without requiring a second bike.

Cons:

• Limited Impact: Some reviewers note that the changes are relatively minor and may not be significant enough for riders who want a dedicated trail bike or a pure XC race bike.

• Not for Everyone: Casual riders or those who stick to one type of terrain may not find the feature necessary.

---

Example Reviews:

1. Pinkbike:

   • Reviewers praised the flip chip for making the Epic Evo a more versatile bike, capable of handling both XC and light trail riding. They noted that the slack setting improved confidence on descents without sacrificing too much climbing efficiency.

   • Quote: “The flip chip is a small but meaningful addition that lets you tailor the bike to your local trails.”

2. BikeRadar:

   • Testers highlighted the flip chip as a useful feature for riders who want a single bike that can do it all. They appreciated the ability to switch between a race-ready setup and a more relaxed, trail-oriented geometry.

   • Quote: “The geometry adjustment is a neat trick that adds versatility to an already capable bike.”

3. Singletracks:

   • Reviewers noted that while the flip chip is a nice feature, it’s not a game-changer. However, they acknowledged that it adds value for riders who want to fine-tune their bike’s handling.

   • Quote: “The flip chip is a thoughtful addition, but it’s not going to transform the bike into something completely different.”

---

Should You Care About the Flip Chip?

• Yes, if:

  • You ride a variety of terrains (e.g., XC races, technical trails, or steep descents).

  • You like to tinker with your bike’s setup to optimize performance.

  • You want a single bike that can adapt to different riding styles.

• No, if:

  • You primarily ride one type of terrain (e.g., only smooth XC trails or only technical descents).

  • You prefer a simple, set-it-and-forget-it setup.

---

Conclusion:

The flip chip geometry adjustment on the Specialized Epic and Epic Evo is a useful feature that adds versatility to an already capable bike. While it’s not a game-changer, it allows you to fine-tune the bike’s handling to suit your riding style or local trails. If you’re considering an Epic or Epic Evo, the flip chip is a nice bonus that could make the bike even more appealing.

In which model was it introduced?

The Flip Chip geometry adjustment feature was introduced on the Specialized Epic and Epic Evo models starting with the 2019 redesign. This redesign marked a significant update to the Epic lineup, bringing modern geometry, improved suspension kinematics, and the addition of the flip chip to allow riders to adjust the bike's handling characteristics.

---

Key Details About the Flip Chip Introduction:

• Model Year: 2019

• Bikes: Specialized Epic (XC race bike) and Epic Evo (downcountry/trail-oriented version).

• Purpose: To provide riders with the ability to tweak the bike's geometry for different terrains or riding styles.

---

How It Works:

The flip chip is located at the rear shock mount and offers two settings:

1. High Position (Steep Setting):

   • Steeper head tube angle (e.g., 68.5°).

   • Higher bottom bracket.

   • Better for climbing and XC racing.

2. Low Position (Slack Setting):

   • Slacker head tube angle (e.g., 67.5°).

   • Lower bottom bracket.

   • Better for descending and technical terrain.

---

Why It Was Introduced:

Specialized added the flip chip to make the Epic and Epic Evo more versatile, allowing riders to:

• Optimize the bike for specific trails or races.

• Adapt the bike's handling to their personal preferences.

• Bridge the gap between XC efficiency and trail bike capability (especially on the Epic Evo).

---

Models with the Flip Chip:

• Specialized Epic (2019 and later): The XC race bike with 100 mm of rear travel.

• Specialized Epic Evo (2019 and later): The downcountry/trail-oriented version with 120 mm of rear travel.

---

Reception:

The flip chip was well-received by riders and reviewers, as it added a layer of customization without complicating the bike's design. It’s particularly appreciated by riders who want a single bike that can handle both XC racing and technical trail riding.

---

If you’re considering a bike with this feature, the Epic Evo might be a great choice for your riding style, given its versatility and ability to handle technical terrain like roots, sand, and steep climbs. Let me know if you’d like more details about specific models or features! 🚵‍♂️

[jajacek]

When did Specialized switched to threaded bottom bracket in Epic and Epic Evo models?
 

Specialized switched to a threaded bottom bracket in the Epic and Epic Evo models starting with the 2021 model year. This change was part of a broader trend in the cycling industry to move away from press-fit bottom brackets, which had been criticized for issues like creaking and difficulty in maintenance.

---

Key Details About the Switch:

• Model Year: 2021

• Bottom Bracket Standard: Threaded (BSA standard).

• Reason for Change: To improve reliability, reduce creaking, and make maintenance easier for riders and mechanics.

---

Why Threaded Bottom Brackets Are Better:

1. Reliability: Threaded bottom brackets are less prone to creaking and loosening compared to press-fit systems.

2. Ease of Maintenance: They are easier to install, remove, and service.

3. Compatibility: The BSA threaded standard is widely supported, making it easier to find replacement parts or upgrade components.

---

Impact on the Epic and Epic Evo:

• The switch to a threaded bottom bracket was a welcome change for riders, as it addressed one of the few common complaints about earlier models.

• It also aligned with Specialized’s focus on improving durability and user-friendliness in their high-performance bikes.

---

How to Identify:

If you’re looking at a used or new Epic or Epic Evo and want to confirm whether it has a threaded bottom bracket:

• Check the Model Year: 2021 and later models have threaded bottom brackets.

• Look at the Frame: The bottom bracket area will have threads visible if it’s a threaded system.

• Consult the Specs: Specialized’s website or product manuals will list the bottom bracket type.

---

Conclusion:

If you’re considering an Epic or Epic Evo, opting for a 2021 or later model will ensure you get the more reliable and user-friendly threaded bottom bracket. This change is just one of many updates that make these bikes excellent choices for XC and downcountry riding.

[jajacek]

What geometry for a hardtail bike would be optimum for my test loop?
 

To determine the optimum geometry for a hardtail bike suited to your test loop, we need to consider the specific characteristics of your ride:

• Terrain: A mix of flat sections, roots, sand, steep short climbs, and rolling terrain.

• Distance: 28 km loop (part of a longer 50 km ride).

• Rider Profile: 175 cm tall, 85 kg, slightly overweight, prioritizing comfort and control.

Based on these factors, here’s a breakdown of the ideal geometry for your hardtail:

---

1. Head Tube Angle (HTA):

• Recommended: 67° to 68.5°

• Why:

  • A slightly slacker head tube angle (around 67° to 68°) will improve stability on descents and technical sections (roots, sand).

  • However, since your loop includes steep climbs, you don’t want it too slack, as that can make climbing feel less efficient.

  • A middle ground (67.5° to 68°) strikes a good balance between climbing efficiency and descending confidence.

---

2. Seat Tube Angle (STA):

• Recommended: 74° to 75°

• Why:

  • A steeper seat tube angle positions you more directly over the bottom bracket, improving pedaling efficiency and comfort on climbs.

  • This is especially important for steep, short climbs where you need to maintain traction and power.

---

3. Reach and Stack:

• Recommended Reach (for your height): 440 mm to 460 mm

• Recommended Stack: 610 mm to 630 mm

• Why:

  • A moderate reach ensures a comfortable, balanced riding position that’s not too stretched out or cramped.

  • A taller stack height (higher front end) will reduce strain on your back, neck, and shoulders, which is important for 50+ year-old rider.

---

4. Chainstay Length:

• Recommended: 430 mm to 440 mm

• Why:

  • Shorter chainstays improve agility and make it easier to lift the front wheel over obstacles like roots.

  • However, too short can make the bike feel twitchy, so a middle ground (around 435 mm) is ideal for stability and maneuverability.

---

5. Bottom Bracket Height (BB Height):

• Recommended: 305 mm to 315 mm (unsagged)

• Why:

  • A slightly lower bottom bracket improves stability and cornering grip, which is helpful on rolling terrain and descents.

  • However, you don’t want it too low, as that increases the risk of pedal strikes on roots and rocks.

---

6. Wheelbase:

• Recommended: 1,150 mm to 1,180 mm

• Why:

  • A moderate wheelbase provides a good balance between stability and agility.

  • Too short can feel twitchy, while too long can feel sluggish on tight, technical sections.

---

7. Fork Travel:

• Recommended: 120 mm

• Why:

  • 120 mm of front suspension is ideal for your terrain, providing enough cushion for roots and descents without being overly heavy or inefficient for climbing.

  • If you prefer a lighter setup, 100 mm is also an option, but it will be less forgiving on rough terrain.

---

8. Tire Clearance:

• Recommended: At least 2.4" tire clearance

• Why:

  • Wider tires (2.4" to 2.6") provide better traction and comfort on roots, sand, and loose terrain.

  • They also allow you to run lower pressures for improved grip without risking pinch flats.

---

Example Bikes with Ideal Geometry:

Here are a few hardtails with geometry that would suit your test loop:

1. Specialized Chisel:

   • HTA: 68.5°

   • STA: 74°

   • Reach: 445 mm (size Large)

   • Chainstays: 430 mm

   • Tire Clearance: 2.4"

2. Trek Procaliber:

   • HTA: 69° (slightly steeper for XC efficiency)

   • STA: 74.5°

   • Reach: 450 mm (size Large)

   • Chainstays: 435 mm

   • Tire Clearance: 2.4"

3. Canyon Exceed:

   • HTA: 68.5°

   • STA: 74°

   • Reach: 455 mm (size Large)

   • Chainstays: 430 mm

   • Tire Clearance: 2.4"

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Summary of Ideal Geometry for Your Test Loop:

Geometry Feature	Recommended Range	Why
Head Tube Angle (HTA)	67° to 68.5°	Balances climbing efficiency and descending stability.
Seat Tube Angle (STA)	74° to 75°	Improves pedaling efficiency and comfort on climbs.
Reach	440 mm to 460 mm	Ensures a comfortable, balanced riding position.
Stack	610 mm to 630 mm	Reduces strain on your back, neck, and shoulders.
Chainstay Length	430 mm to 440 mm	Balances agility and stability.
BB Height	305 mm to 315 mm	Improves stability and cornering grip without risking pedal strikes.
Wheelbase	1,150 mm to 1,180 mm	Provides a balance between stability and agility.
Fork Travel	120 mm	Offers enough cushion for roots and descents without sacrificing weight.
Tire Clearance	2.4" or wider	Improves traction and comfort on roots, sand, and loose terrain.

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Final Thoughts:

A hardtail with the above geometry would be well-suited to your test loop, offering a good balance of efficiency, comfort, and control. If you’re considering a new bike, look for models with these specifications, or consider adjusting your current bike’s setup (e.g., stem length, handlebar rise) to better match these recommendations.

[jajacek]

Geometry of my bike:
Size L, 19 inch
HTA 69.8
STA 74
Reach 441
Stack 622
Chainstay length 430
BB height 309
Wheelbase 1128
Fork travel 100 mm (Fox Step Cast Performance Float 32)
Tire clearance 2.35 inch

My proportions: Height 175 cm
Inseam 84.5 cm
Arm span 182 cm
 

Thank you for providing the detailed geometry of your bike and your body proportions! Let’s analyze how well your current bike fits you and whether it’s optimized for your test loop (28 km with roots, sand, steep climbs, and rolling terrain).

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Bike Geometry Analysis:

Geometry Feature	Your Bike	Ideal for Your Loop	Analysis
Head Tube Angle (HTA)	69.8°	67° to 68.5°	Slightly steeper than ideal. This makes the bike quick-handling but less stable on descents and technical terrain.
Seat Tube Angle (STA)	74°	74° to 75°	Good for climbing efficiency. Matches the ideal range.
Reach	441 mm	440 mm to 460 mm	Fits well within the ideal range. Provides a balanced, comfortable position.
Stack	622 mm	610 mm to 630 mm	Slightly taller stack, which is good for reducing strain on your back and neck.
Chainstay Length	430 mm	430 mm to 440 mm	Ideal for agility and stability.
BB Height	309 mm	305 mm to 315 mm	Slightly higher than ideal, which improves pedal clearance but reduces stability slightly.
Wheelbase	1,128 mm	1,150 mm to 1,180 mm	Slightly shorter than ideal. This makes the bike nimble but less stable at speed.
Fork Travel	100 mm	120 mm	Less travel than ideal. A 120 mm fork would improve comfort and control on rough terrain.
Tire Clearance	2.35"	2.4" or wider	Slightly narrower than ideal. Wider tires would improve traction and comfort on roots and sand.

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Rider Fit Analysis:

Your Proportions	Analysis
Height: 175 cm	A size Large (19") frame is appropriate for your height.
Inseam: 84.5 cm	Your saddle height should be set correctly for efficient pedaling.
Arm Span: 182 cm	Your arm span is longer than your height, which means you might benefit from a slightly longer reach or stem to avoid feeling cramped.

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Key Observations:

1. Handling on Technical Terrain:

   • The steeper head tube angle (69.8°) and shorter wheelbase (1,128 mm) make the bike quick and nimble but less stable on descents and rough terrain. For roots, sand, and steep climbs, a slacker HTA (67° to 68.5°) and longer wheelbase (1,150 mm to 1,180 mm) would improve stability and confidence.

2. Fork Travel:

   • The 100 mm fork is adequate for XC riding but less ideal for technical terrain. A 120 mm fork would provide more cushion and control on roots and descents.

3. Tire Clearance:

   • The 2.35" tire clearance is slightly narrow for your terrain. Wider tires (2.4" to 2.6") would improve traction and comfort on roots and sand.

4. Rider Fit:

   • The frame size and reach are appropriate for your height, but your longer arm span might make the bike feel slightly cramped. A longer stem or handlebars with more backsweep could improve comfort.

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Recommendations for Improvement:

1. Fork Upgrade:

• Consider upgrading to a 120 mm travel fork (e.g., Fox 34 Step-Cast or RockShox SID Ultimate). This will improve comfort and control on rough terrain without significantly affecting climbing efficiency.

2. Tire Upgrade:

• Switch to wider tires (2.4" to 2.6") with a tread pattern suited to your terrain (e.g., Maxxis Forekaster or Schwalbe Rocket Ron). This will improve traction and comfort on roots and sand.

3. Handlebar and Stem Adjustments:

• If the bike feels cramped, try a longer stem (10-20 mm longer) or handlebars with more backsweep (8° to 12°) to better suit your arm span.

4. Tubeless Setup:

• If you’re not already running tubeless, switch to a tubeless setup. This will allow you to run lower tire pressures for better grip and reduce the risk of flats.

5. Geometry Adjustment:

• If possible, use an angled headset to slacken the head tube angle by 1° to 1.5°. This will improve stability on descents without requiring a new frame.

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Conclusion:

Your current bike is well-suited for XC riding but could be optimized for the technical terrain of your test loop. Upgrading the fork, tires, and handlebar/stem setup would make the biggest difference. If you’re considering a new bike, look for one with a slacker head tube angle (67° to 68.5°), longer wheelbase (1,150 mm to 1,180 mm), and 120 mm of fork travel.

[jajacek]

I generally don't have any problems on descents. But I have problems with traction and with front wheel lifting off the ground on steep ascents.
 

Thanks for clarifying! If your main challenges are traction on steep climbs and the front wheel lifting off the ground, we can focus on adjustments and upgrades to address these specific issues. Here’s a detailed breakdown of the problem and solutions:

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Root Causes of Your Issues:

1. Traction Problems on Steep Climbs:

   • This is often caused by:

     • Insufficient weight on the rear wheel.

     • Tires with inadequate grip for the terrain (roots, sand).

     • Tire pressure that’s too high.

2. Front Wheel Lifting on Steep Climbs:

   • This is typically caused by:

     • A steep seat tube angle (STA) or short reach, which positions your weight too far back.

     • Insufficient weight distribution toward the front of the bike.

     • A high bottom bracket (BB), which raises your center of gravity and reduces stability.

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Solutions to Improve Traction and Climbing Performance:

1. Tire Upgrades:

• Wider Tires: Switch to 2.4" to 2.6" tires with an aggressive tread pattern designed for loose and rooty terrain. Examples:

  • Maxxis Forekaster (great for loose and wet conditions).

  • Schwalbe Rocket Ron (lightweight and grippy).

  • Specialized Ground Control (excellent for mixed terrain).

• Tubeless Setup: Run your tires tubeless with lower pressures (e.g., 18-22 psi). This improves grip and reduces the risk of pinch flats.

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2. Weight Distribution Adjustments:

• Saddle Position: Slide your saddle slightly forward on the rails (5-10 mm). This shifts your weight forward, helping to keep the front wheel grounded.

• Body Position: On steep climbs, consciously lean forward and keep your chest low to distribute more weight over the front wheel.

• Stem Length: If your bike feels too short, consider a shorter stem (e.g., 10-20 mm shorter). This shifts your weight forward and improves front-wheel traction.

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3. Suspension Setup:

• Fork Sag: Set your fork sag to 15-20%. This ensures the front end stays planted and responsive on climbs.

• Lockout: Use the fork’s lockout feature on smooth climbs to improve efficiency, but open it up on technical climbs for better traction.

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4. Geometry Adjustments:

• Angled Headset: If your bike’s head tube angle is too steep (69.8°), consider an angled headset to slacken it by 1° to 1.5°. This will improve stability and weight distribution.

• Dropper Post: If you don’t already have one, consider adding a dropper seatpost. Lowering your saddle on steep climbs can help you shift your weight forward and maintain control.

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5. Technique Improvements:

• Climbing Technique:

  • Stay seated as much as possible to maintain traction on the rear wheel.

  • Use a smooth, consistent pedal stroke to avoid spinning out on loose terrain.

  • On very steep climbs, shift your weight forward while keeping your elbows bent and chest low.

• Line Choice: Pick the smoothest line through roots and rocks to maintain momentum and reduce the risk of losing traction.

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Summary of Recommendations:

Solution	Action	Expected Benefit
Tire Upgrade	Switch to 2.4" to 2.6" tires with aggressive tread; go tubeless.	Improved traction on roots, sand, and loose terrain.
Weight Distribution	Slide saddle forward; use a shorter stem; adjust body position.	Better front-wheel grip and reduced wheel lift on steep climbs.
Suspension Setup	Set fork sag to 15-20%; use lockout on smooth climbs.	Improved front-end traction and efficiency.
Geometry Adjustments	Consider an angled headset or dropper post.	Better weight distribution and stability on steep climbs.
Climbing Technique	Stay seated, use smooth pedal strokes, and pick better lines.	Maintains traction and momentum on technical climbs.

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Next Steps:

1. Start with tire upgrades and a tubeless setup, as these will have the most immediate impact on traction.

2. Experiment with saddle position and body positioning to improve weight distribution.

3. If the problem persists, consider geometry adjustments (angled headset, dropper post) or a shorter stem.

[jajacek]

Do you really mean shorter steam on the climbs? Wouldn't be longer stem beneficial in shifting bodyweight forward to counter lifting the front wheel off the ground?
 

You're absolutely correct—my earlier suggestion of a shorter stem was a mistake in the context of addressing front-wheel lift on steep climbs. A longer stem would indeed help shift your weight forward, which is exactly what you need to keep the front wheel grounded. Thank you for catching that! Let me clarify and provide the correct recommendations.

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Why a Longer Stem Helps on Climbs:

• A longer stem moves your handlebars farther forward, which shifts your body weight toward the front of the bike.

• This helps keep the front wheel grounded on steep climbs, especially when combined with proper body positioning (leaning forward, chest low).

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Corrected Recommendations:

1. Stem Length:

• Current Stem: Check the length of your current stem. If it’s shorter than 70-80 mm, consider switching to a longer stem (e.g., 80-100 mm).

• Effect: A longer stem will help distribute more weight over the front wheel, reducing the tendency for it to lift on steep climbs.

2. Saddle Position:

• Slide your saddle slightly forward on the rails (5-10 mm). This also shifts your weight forward and helps keep the front wheel grounded.

3. Body Positioning:

• On steep climbs, consciously lean forward and keep your chest low. This moves your center of gravity forward and improves front-wheel traction.

• Keep your elbows bent to maintain control and balance.