Questions tagged [power]

Power meters and all related data analysis. Power meters measure direct force applied to one of the pedals, crankarm, crankset, rear hub, or other methods. They use cadence in conjunction with the force to measure the power or wattage.

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1answer
61 views

Understanding how to calculate Critical Power curves

Hello fellow cyclists, there are services out there that can calculate power curves based on your bike ride (when training with a power meter). This curve shows the time to exhaustion (t) based on ...
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Changing cranks from Praxis to Ultegra (BB advice)

I purchased a Specialized Roubaix Comp 2018 last year, I was not intending to purchase this bike but Evans had a 40% off sale and the deal was too outrageous to pass. I was originally looking at bikes ...
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1answer
85 views

Power output on rollers doesn't seem to match perceived effort

I have a Garmin Vector Power meter (one-side) and I use plain Tac-X rollers with no technical bits on them. My speed and power come from sensors on the bike. My power output seems low relative to my ...
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99 views

Can I achieve good cycling shoe stiffness in winter with a boot insert?

Background: I ride daily in a very cold climate (Fairbanks, AK). My typical winter riding footwear includes a pair of trail running shoes underneath an insulated (NEOS) overboot, as this is a very ...
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4answers
221 views

Estimating climbing speed on climbs with variable grade

There are numerous calculators online which estimate climbing speed based on power and grade or similar. For example: http://bikecalculator.com/ https://www.gribble.org/cycling/power_v_speed.html ...
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1answer
78 views

Replacing Apex 1 crank arm with Shimano 105

I would like to buy a 4iii power meter integrated in a Shimano 105 crank arm. On my bike I currently have SRAM Apex 1. Will this be possible? Thank you!
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59 views

Need advice. SRM Origin alu vs Quarq Dfour [closed]

I am road cyclist willing to participate in local cycling races. I am looking forward to buying a new powermeter. Currently I have 4iiii left crank only and I want more accurate device to be more ...
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1answer
192 views

Can pedal-based power meters be used as flat pedals?

I would like to collect as much data as possible about my daily road rides so recently I am considering pedal-based power meters such as Faveor Assioma or Garmin Vector 3. However, I don't want to ...
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434 views

How much resistance comes from each part of a bicycle? [closed]

How does one decide which part of a bicycle is the best candidate to upgrade or tune if the goal is higher speed for the same energy? For example, should one upgrade wheels, or tyres, or change to ...
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1answer
54 views

Is SRAM RED AXS Power Meter, 48/35T compatible with Tarmac Pro Disc – SRAM ETAP

I am interested in purchasing specialized "Tarmac Pro Disc – SRAM ETAP" bicycle that comes with "SRAM Force AXS, 48/35T" crankset. I want a crank power meter and want to know if the "SRAM RED AXS ...
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1answer
194 views

Most effective > 200 mile ride training

On the 17th of August I'm doing a 250 mile ride in the UK in one day. I'm no stranger to longer rides often completing 100 mile rides and my longest ever was 175 miles (it was fairly unpleasant ...
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1answer
173 views

Campanolo record power meter crank with veloce crankset

Can I use a Stages Campagnolo Record left crank with my Campagnolo veloce crankset, if the sizes are a match? Want a power meter of some sorts and it would be far cheaper than getting vectors.
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57 views

Deore XT Power Crank

I have an Ultegra Crank set. I also have a Deore XT 175mm left side power crank. Can I use this on a road bike?
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54 views

Zero Offsetting P1 pedals using just Rouvy android mobile app

I don't have a bike computer, rather I use my old cellphone for that matter. Does anybody know how to do a zero offset of P1S pedals using Rouvy app? Apparently, there should be an option when you ...
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1answer
221 views

Since seat tube angle has little effect on max power output, why not adjust the reach with saddle setback?

According to this article, a seat tube angle between 65 and 110° has little effect on max power output. At most, it varied 1%. https://www.me.utexas.edu/~neptune/Papers/jab26%284%29.pdf Adjusting the ...
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538 views

Mixing Ultegra or 105 left crankarm with Shimano Sora support

I'm interested in buying this power meter: https://pl.aliexpress.com/item/XCADEY-Bicycle-power-meter-Crank-power-meter-Bicycle-GPS-Computer-Garmin-Edge-Bryton-IGPSPORT-Support-ANT/32798182129.html. I ...
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What method or algorithm is used for computing Power Curve on Strava?

Many cycling analytics apps like Strava, TrainingPeaks or GoldenCheetah are offering the Critical Power curve chart, computed from the power meter data. I'm familiar with the curve meaning and usage,...
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Understanding e-bike power/torque

In the UK e-bikes are currently limited to a maximum of 250W assistance if you wish to use them on public roads. However, it seems that the motors do vary in terms of the available torque - from ...
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1answer
178 views

Crank power meter incompatible with my bottom bracket

I have received a 4iiii crank power meter 170mm length that I can't install on my Merida trainer bike because it has square taper bottom bracket. What would be the cheapest way to have it installed? ...
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1k views

What is the drag / power lost to a safety flag?

I have a recumbent bike that has a safety flag on the top of a thin pole, so it flutters around higher than and after my head. How much power am I losing to this flag that could be used to power my ...
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2answers
390 views

Quarq Dfour Fit Problem

I recently buy my first Quarq Dfour power meter to replace my crank Shimano Ultegra 6800. but I have the problem that the quarq spindle its too short ( 106 mm quarq vs 109 mm shimano ultra ). I don't ...
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1answer
289 views

Can a BB30 Crank Arm (Left) power meter can be used with a BB386EVO Crankset

I have read many websites and articles about the interchangeability of BB30 and BB386EVOsuch as this and this YouTube video. Many say yes and many say no. Yet, I am not sure which Stages FSA power ...
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Rear wheel power spoke pattern

This is my first time posting here. I have been biking for a few years now and learning little by little how to repair my ride myself. My latest problem is 4 spokes of my rear wheel (36 spokes) ...
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3answers
550 views

Changing from Ultegra 6800 crank to r8000 dual power meter

I currently have a shimano ultegra 6800 crank set on my 2014 trek speed concept 7.0. I want to install a dual side power meter and can only find the r8000 dual side power meter setup. Will the r8000 ...
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112 views

Seeking powermeter data [closed]

I am developing a small tool that allows to pick a day for a long cycle trip. The idea is to use weather forecasts to compute how bad/good the wind along the route in the following days is. You can ...
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XTR M960 Crank to Stages power meter compatibility

I want to buy a Stages power meter but my MTB has an old XTR M960 crankset. I wonder if a Stages XTR M980, M985, M9000 or M9020 left arm meter can be installed replacing the left crankarm of my old ...
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2answers
259 views

Laws against electric assist bicycle with energy recovery? [closed]

Is an electric bike like this required any special license. The power applied comes from the collected kinetic inertia from going down hill or stored from the rider then the stored power can then be ...
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2answers
601 views

How much faster can my commute be if I use a power meter?

When biking to work, my routes have have stop signs, stop lights, and other interruptions every few blocks or so. My understanding is that if I reach my power at target heart rate soon after stopping ...
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2answers
904 views

QUARQ DFour installation on Shimano bike

I'd like to replace my Ultegra 6800 crankset with QUARQ DFour powermeter. But I don't know how to choose between BB30 and GXP versions. I have Shimano Pressfit SM-BB92-41B bottom bracket. Do I need to ...
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1answer
181 views

What target heart rate or power do people use when commuting by bike [closed]

Biking to work is good exercise. It can make it easier to meet our exercise needs. When commuting by bike, what heart rate or power zones do people usually use? What's a recommended target? Should we ...
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95 views

I'm looking for a chainring compatible with bb86

I'm trying to invest in a new powermeter (never had one) but my current cranks are FSA Gossamer which are no longer in stock by most. I looked at power2max and they don't have a compact chainring. Is ...
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1answer
393 views

Does Strava display live watts while biking?

Does Strava display watts from a bluetooth power meter along with a bluetooth heart rate in real time while I'm riding?
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4answers
245 views

What is the difference between a speedometer and a power meter in terms of performance measurement? [duplicate]

If I cycle the same route every day, what would be the benefit of having a power meter over a speedometer? Can't I just measure my speed and compare it against my last run and see if I've done better?...
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1k views

Does changing gear relation produce different speed at same applied power?

When you are starting the ride, I potentially believe ("know?") that with a smaller plate(cog with fewer teeth in the rear cassette), you obtain more velocity than with a bigger plate(cog with more ...
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1answer
529 views

What's the difference between power meter and bike computer?

I am currently using a IpBike computer app (on Android) with DuoTrap Speed and Cadence sensors on my bike. I was reading about power meters and how they would help in training by assessing the power ...
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Reverse FTP measurement

Often it is argued that an 8 or a 20 minute effort can be sufficient to estimate Functional Threshhold Power (FTP), an indicator of how many watts a rider can put out over the course of an hour (or 40 ...
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3answers
4k views

Estimating FTP from Strava analysis

I bought a power meter. I understand that you should do an FTP test to work out your threshold. But until I have time to do this, could I take a reasonable guess from a recent 35 mile road race? ...
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758 views

Stages FSA BB30 Power Meter on Cannondale SI BB30A Crankset

I have a Cannondale CAAD12. It has a Cannondale SI crankset. The frame's bottom bracket is BB30A. My question is, can I fit a Stages FSA BB30 Power Meter on the non drive side? My concerns: BB30A ...
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1answer
5k views

How to calibrate Garmin Vector 2 power meter pedals with a Wahoo Elemnt computer?

I just installed Garmin Vector 2 power meter pedals on my bike along and am using it alongside a Wahoo Elemnt bike computer. I've done a few rides now and my average wattage is reading very high (i.e. ...
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980 views

Big tires are rubbing in certain conditions so how can I fix my rear wheel play issues?

I have a 2007 Tarmac Expert Double with a Mavic Kysrium Equipe rim spoked to a Mavic Kysrium Equipe, 24 hole, Mavic QR rear hub. I recently upgraded to 28mm tires from 25mm and I had the rear wheel ...
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1answer
258 views

New chain, pedal power seems weaker

I'm a commuter cyclist who didn't for the last 18 months really do anything to take care of his bike - though it was stored inside between rides. Took it to the shop 12 months in for a service, but ...
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503 views

Low power while maintaining high cadence

I just started using a Tacx Smart Flow in combination with TrainerRoad to try maintaining and getting up my fitness level over the winter. My problem now is that TrainerRoad tells me to keep a power ...
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2answers
261 views

Can single-sided Power meters cause unnatural Bilateral asymmetric pedaling?

In case it is not clear for everyone, let me briefly explain the graph. The pink line represents the Power output along the y axis while the grey dots represent Left/Right balance in Power. The x axis ...
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5answers
1k views

What use does a Heart Rate Monitor have if you have a Powermeter?

When should you be riding by HR instead of Power and what can you learn from a HRM when you're riding by Power?
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1answer
628 views

Does a crank arm Power Meter measure power in both directions?

The leg on the upstroke weighs down on the pedal and creates additional work for the leg on the downstroke. A crank/hub power meter ignores that and gives you the effective power combined by both legs....
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3answers
1k views

Power Output at different Air Densities

Factors Influencing Air Density are: Altitude, Air Temperature, Air Humidity and Barometric Pressure. Calculator: http://barani.biz/apps/air-density/ How does riding at different air densities affect ...
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619 views

Speed to power calc on a 'basic' magnetic trainer

I'm a dedicated non-MAMIL, and I enjoy riding indoors on a cheap-and-cheerful 14-speed (max tooth ratio 48->14) attached to a $70 basic trainer while watching the footy or listening to music. No wind, ...
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3answers
312 views

Increasing stamina while in the office

I started to bike again after 3 or more months of hiatus. I'm currently using a XXS Merida Scultura 300 (I previously used a Trinx R300 needed to upgrade because of the wrong geometry). Thing is I ...
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2answers
570 views

Calorie Burn Meter Bicycle

Is there any bicycle with calorie burn meter in market? Its not the one on the gym. Normal bicycle for outdoors. Is there any bicycle like that in market? I have a project for my school work. Really ...
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2answers
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Is the real world experience of riding a light bike understated by physics-based calculators?

Take the case where you have two identical riders, Joe Slo and Billy Whizz. They both weigh 75kg and have identical aerobic threshold power output. Joe has a 11kg steel audax bike, but Billy likes ...