Which crank power meter?

majster

I’m thinking of getting a power meter for my road bike

It seems the crank based systems are probably more reliable in the long run although the convenience of pedal system seems quite tempting

I have a hybrid bike also and ideally it would be great if I could use the same system on both but not sure whether this compromises anything. Given the investment cost want something reliable rather than something flaky that will start to go wrong

Any suggestions - am I correct in assuming crack based system more reliable in long run

Currently looking at
stages left arm meter
4iii left arm meter
PowerTap p1/Garmin Vector pedals
Assioma pedals
Quark crank system but not sure if bottom bracket press fit BB86 type

Many thanks

imposter2.0

Depending on how serious you are about training with power, (as opposed to just looking at some numbers?), it's difficult to see past the stages..

cougie

Check out DCRainmaker for all things tecchy.
Also look up powertap wheels - they may work for you ?

majster

If I go for a crank based system, is it difficult to DIY change the bottom bracket.

Any idea which would be the best crank power meter to go for if fitting to a 105 5800 bike?

imposter2.0

'best' is going to be a very subjective recommendation, as a lot will depend on your intended purpose (as I inidicated earlier) together with things like budget and whatever your objectives or training goals are. Without further info, it's going to be difficult for anyone to offer anything meaningful, apart from Cougie's suggestion of checking out the DCR site..

cookeeemonster

Imposter wrote:

Depending on how serious you are about training with power, (as opposed to just looking at some numbers?), it's difficult to see past the stages..

From the reviews I've seen the stages are the least accurate? Know a few people who have problems and have had to send them back for a replacement, unless they've fixed that now?

StillGoing

Majster wrote:

If I go for a crank based system, is it difficult to DIY change the bottom bracket.

Any idea which would be the best crank power meter to go for if fitting to a 105 5800 bike?

I have a P2M Type S on a Rotor 3D24. I can switch it between 2 bikes easily enough. One bike is english thread and the other BB386. A Rotor BB reducing the BB diameter to 24mm allows me to fit the cranks to the BB386 without adapters and a standard Rotor 24mm BB means it fits the english thread BB.

cycleclinic

Garmon vectors are reliable so don't discount them. The other pm I like is Easton new effort. You need Easton or race face cranks though. The Garmon is double sided and I would get another set.

jrich

The only one of those power meters that I would describe as reliable is the Quarq.

With a BB86 bottom bracket you will need a GXP chainset, which is good because a GPX chainset can be fitted to most bikes. You will also need the correct press fit bearings, so you may well have to change your current bearings, but that's a very quick job for a bike shop to do (assuming you dont have the correct tools).

cougie

What are you going to do with it though ?
Unless your going to take training seriously - it's an expensive toy.

cycleclinic

that the problem. Even if you train seriously it is still a toy as effective training is possible without one.

StillGoing

jrich wrote:

The only one of those power meters that I would describe as reliable is the Quarq.

With a BB86 bottom bracket you will need a GXP chainset, which is good because a GPX chainset can be fitted to most bikes. You will also need the correct press fit bearings, so you may well have to change your current bearings, but that's a very quick job for a bike shop to do (assuming you dont have the correct tools).

I assume that you're referring to the list given by the OP, in which case, I agree.

secretsqizz

Power meters bring the worst out of forumites' mine's bigger than yours and I'm hard, arguments
Dude, if you want to flatter yourself, just get a s o called smart trainer and go on Zwift , you'll kill World Tour class.

It's all sh it really.

cougie

I think you missed out the bit about taking 20kgs off your weight to kick ass on Zwift.

bristolpete

Have run Rotor 3D24 with power2max for over a year now and cannot fault it. As as training to power tool great not missed a beat.

What I do enjoy about riding with power on the bike and post ride analysis is looking at how the road can affect power. Some days hammering along with low watts with big speed other days lots of power going nowhere. It is a great retrospective thing to look at. But sometimes when burying oneself, it can get overlooked but comes in handy on long measure efforts. Not about willy waving, simply a better understanding of our chosen sport.

mr_mojo

I’ve got a Pioneer crank powermeter on the best bike and have the Powertap P1 pedals I swap between the others. Like both and both have been reliable. Easy to swap the pedals with no torque requirements.

schlepcycling

I have a Rotor 3D24 with power2max which I swap between bikes one with a threaded BSA bottom bracket and the other has a BB86.

slowbike

I'm in my 3rd year of Stages PM - reliable? Yes - for me it has been - no replacements needed.

Grill

I currently have 3 P2M (and have sold another 2) and they've been super solid. My Stages is a steaming pile and can't wait to offload it. My PowerTap G3 is also great. So I vote for Power2Max or Quarq when it comes to reliable crank based PMs.

joey54321

I'd avoid any left only power meters, it's basically just a guess at that point. Better to use HR/PE.

Other than that probably not much in it.

sloppyschleckonds

PowerTap G3, Power2Max & Quarq are all time proven reliable and accurate.

Htclee

I have a 4iii left only power meter. Works excellently, also have the latest Wahoo Kickr and when calibrated they are consistently within a couple of watts of each other. If you feel you want to you can easily upgrade to the dual sided version. The other power meter I would consider is Garmin’s Vector 3 pedals because of the ease of switching between bikes in the future..

Juraj1711

What crank you have on bike now?

joe2008

I've used BePro's almost daily for 2 years without any trouble.

I would get the Assioma pedals without hesitation.

Bumo_b

+1 for 4iii Precision

ben@31

cougie wrote:

What are you going to do with it though ?
Unless your going to take training seriously - it's an expensive toy.

I actually own and use a powermeter.

From experience, I completely disagree with you.

My powermeter is one of the best things I've bought for my bike. Its the best way to determine the effort of your cycling (by the percentage of your FTP).

I soon realised that looking at speed is totally irrelevant when you have wind, gradients and so many other factors influencing it.

A powermeter will take all of these influences into account.... 200W is 200W no matter if it's doing 14 mph into headwind, or 25 mph with a stonking tailwind, or slogging uphill or on a long gentle decline that I never really noticed before.

I thought I was cycling fast, but it wasn't me that was cycling hard but just the decline and tailwind!

imposter2.0

ben@31 wrote:

cougie wrote:

What are you going to do with it though ?
Unless your going to take training seriously - it's an expensive toy.

I actually own and use a powermeter.

From experience, I completely disagree with you.

My powermeter is one of the best things I've bought for my bike. Its the best way to determine the effort of your cycling (by the percentage of your FTP).

I soon realised that looking at speed is totally irrelevant when you have wind, gradients and so many other factors influencing it.

A powermeter will take all of these influences into account.... 200W is 200W no matter if it's into wind, with a stonking tailwind, slogging uphill or on a long gentle decline that I never really noticed before.

You basically just confirmed what Cougie said...

FatTed

what's wrong with an expensive toy? A lot of peoples bikes are also expensive toys.

glynrs2

FatTed wrote:

what's wrong with an expensive toy? A lot of peoples bikes are also expensive toys.

Quite right! Otherwise we would make do some cheap thing from Halfords.

I have a Quarq crank powermeter. It seems to work very well and without any calibration or reliability issues. The only issue that I coul dsee is if you want to move your power meter regularly between bikes, then maybe a pedal based system would be better suited. But if you want a one bike solution this is great.

StillGoing

An expensive toy? A toy is surely something that you use for a few days, tire of and then consign to a cupboard never to be seen again. The analogy of a power meter as a toy must come from those that don't have one and fail to see the use. RPE is fine if you can be sure that you're on the same wavelength as the coach ie are they working by 5, 6, 8 or 10 levels. A power meter is never off or affected by outside influences such as illness, weather, terrain, what you've eaten etc. 200 watts is 200 watts on a good or bad day and whether you're averaging 20mph or 10mph. Its useful for knowing your 5 or 20 minute power etc too.

stueys

Check out dcrainmaker, he does a great power meter round up.

For me left only PMs had their place when full PMs had a big price uplift. Now that’s gone I wouldn’t go left only, it introduces another variable into the mix that you really don’t need.

Pedal based power meters are the most portable, I’ve had vector since ver 1 and initially had a lot of problems with it that garmin over time slowly resolved. I’ve also got a power2max type s which has been absolutely rock solid and just works, but is slightly harder to swap between bikes if that’s a consideration for you. If I was buying a new PM now I’d either get the power2max NG eco or, if I needed seomthing more portable, Vector 3.