Power meter and crankset

lochindaal

I am tempted to buy a Stages power meter based on cost and ability to move easily between bikes.

I currently have 3 bikes; good road, winter road and a TT.

My good road and TT are both new and have FSA BB30 crankset. The winter has SRAM GXP.

If I buy the stages fsa option I can cover both bikes but lots of people seem to not rate the fsa crank. Should I change the cranks on both bikes before investing in the stages or is the crank really not so bad?

Grill

Garmin Vector or Powertap are better suited to what you want to do. Were it me I'd just buy a Power2Max and change the bottom brackets accordingly.

napoleond

Grill wrote:

Garmin Vector or Powertap are better suited to what you want to do. Were it me I'd just buy a Power2Max and change the bottom brackets accordingly.

I'd go the P2M route too.

lochindaal

I spoke with another coach who uses multiple power meters with various athletes. He has found Garmin to be totally unreliable switching between bikes as it depends on the torque used putting the pedal on. Data was the worst on all solutions.

Grill

Worried about data quality and yet Stages is the top prospect... interesting...

Dodger747

Aren't all PMs subject to the correct amount of torque being used upon installation?

No point spending money on a SRM unless it's torqued correctly. DCRainmaker got accurate data from the Vectors once he torqued them up correctly.

iron_duke

Sorry to thread hi jack but rather than start afresh.

Interested in P2M and quarq elsa rs. Have two bikes one with 10 speed ultegra mix and one with 11speed di2. Am I right in thinking that the difference in 10 or 11 speed crankset a is minimal or is this a potential issue for me as would want to transfer the PM between the two? Assuming for the BB I will just need an appropriate adaptor?

Thanks for your help.

napoleond

Praxis chainrings run fine with 10 and 11 speed. Not an issue.

iron_duke

Thanks NapD

lochindaal

looked at the Power2max website and got very confused.

It seems you can buy the "unit" to add onto certain cranks yet for others (mine) I would need to buy the full crankset and I would need a separate one for FSA BB30 and GXP? What defines on the unit the fit?

napoleond

lochindaal wrote:

looked at the Power2max website and got very confused.

It seems you can buy the "unit" to add onto certain cranks yet for others (mine) I would need to buy the full crankset and I would need a separate one for FSA BB30 and GXP? What defines on the unit the fit?

Go for the Rotor 3D24, you can get the right converter BB for each bike then and use it between them (BB30 and BSA)

If you are confused, email them, they get back very quickly.

stueys

lochindaal wrote:

I spoke with another coach who uses multiple power meters with various athletes. He has found Garmin to be totally unreliable switching between bikes as it depends on the torque used putting the pedal on. Data was the worst on all solutions.

Tell him he's a plonker who can't use a torque wrench consistently

StillGoing

lochindaal wrote:

looked at the Power2max website and got very confused.

It seems you can buy the "unit" to add onto certain cranks yet for others (mine) I would need to buy the full crankset and I would need a separate one for FSA BB30 and GXP? What defines on the unit the fit?

As Nap D says, if you can't buy the P2M spider to fit your cranks and then use the available adapters to fit to a different BB, go for the Rotor 3D P2M. After reading what Grill reports in another thread, I've just switched from a Rotor Power Lt-R crankset to a P2M Type S spider to fit an existing Rotor 3D crankset. The crankset is intended for a BB386 EVO frame and with adapters will fit fine. It can also be switched to my other bike with a gxp BB should I wish to. Any problems just email P2M, they are quick to respond to whatever you ask.

lochindaal

Tell him he's a plonker who can't use a torque wrench consistently

Got to love assumptions made on the Internet!

I am getting the info from a coach working with lots of athletes using different power meter options. His observation has been he has seen least consistency moving vectors across bikes from those athletes data.

stueys

lochindaal wrote:

Tell him he's a plonker who can't use a torque wrench consistently

Got to love assumptions made on the Internet!

I am getting the info from a coach working with lots of athletes using different power meter options. His observation has been he has seen least consistency moving vectors across bikes from those athletes data.

My assumptions are based on being Vector owner for almost a year now, swap it from bikes 2 or 3 times a week. It works fine if you follow the instructions garmin have given, i.e use a torque wrench and tighten to a prescribed value. It takes 2 minutes to move between bikes and is easy if you can use a spanner and a gauge.

cycleclinic

I have also gone with Garmin pedals should get them tomorrow. I can't see how moving them between bikes will cause an issue unless the installation goes wrong. Not sure how easy it is to get it wrong but I am going to find out tomorrow. Hopefully the above posters experience means it is easy to fit without cocking up.

stueys

thecycleclinic wrote:

I have also gone with Garmin pedals should get them tomorrow. I can't see how moving them between bikes will cause an issue unless the installation goes wrong. Not sure how easy it is to get it wrong but I am going to find out tomorrow. Hopefully the above posters experience means it is easy to fit without cocking up.

Its very easy and pretty quick.

1. Use a washer on the pedal side only
2. Tighten to 30lb using a torque wrench. Use the same tightness setting every time.
3. Spin smoothly up to 90 rpm until the power meter registers
4. Stop, un-clip and calibrate the meter

That's it. When Vector was first released there were issues with dynamic calibration that introduced some quirks, Garmin deactivated that about a year ago.

There's a more detailed top 10 list on the support web site, I only follow the steps I've outlined above and get consistently good results on all of my bikes that I use it on (turbo/winter/nice).

https://forums.garmin.com/showthread.ph ... ith-Vector

steel191964

thecycleclinic wrote:

I have also gone with Garmin pedals should get them tomorrow. I can't see how moving them between bikes will cause an issue unless the installation goes wrong. Not sure how easy it is to get it wrong but I am going to find out tomorrow. Hopefully the above posters experience means it is easy to fit without cocking up.

Do those have a problem with the pods breaking?

jgsi

Most torque wrenches do not measure both ways.... I'm talking decent ones that cost a fair bit mid range 8 to 50Nms
You cannot convince me that those beam wrenches are accurate.
One eye on the scale ,ensuring the crowfoot doesnt slip, holding pedal... making sure the pod doesnt over rotate... an octopus would have difficulty.
So for the nds pedal.. its by feel and good expensive pedal spanner (one that has a beer bottle opener facility).
I like my Vectors, but hot swappability USP is probably overplayed a bit.
Once on, good data... thats it , thank you... yes I have managed to mangle 1 pod already!
RMA system works very well from Garmin.
I'm happy, otherwise my Vectors would have been Ebayed ages ago.

rudivoller22

Sorry to hijack but in toying between p2m and vector s. I have rotor 3d+ cranks on one bike and Ultegra 6700 on the other so p2m is more difficult of the options.

Any good deals on vector Anyone has spotted? Seen a few for around £530 from various German sites.

Dodger747

Got to be the German webshops with the echange rate currently.

For those who have Vectors [having just got a set myself] what torque do you recommend? I see DCRainmaker suggests 25lb, but other users suggest higher at around 30lb...

jgsi

Dodger747 wrote:

Got to be the German webshops with the echange rate currently.

For those who have Vectors [having just got a set myself] what torque do you recommend? I see DCRainmaker suggests 25lb, but other users suggest higher at around 30lb...

You can only damage by going higher... power data is unaffected... low torque is the one where power is undershown.
40Nms is more than adequate for a pedal... its the same as nipping up the cassette lock ring - and thats a hefty piece of iron work compared to alloy threaded cranks!
Over tightening and you can deform the pod - hence the breakages so be careful
It is just a knack for the technique of getting mechanical advantage with the pedal spanner so you can concentrate on tightening and the pod coming into the correct 90 degree angle to the crank when finished.
Using the supplied washers and a little bit of grease/copperslip. Dont rush it...

curium

Stueys wrote:

Its very easy and pretty quick.

1. Use a washer on the pedal side only
2. Tighten to 30lb using a torque wrench. Use the same tightness setting every time.
3. Spin smoothly up to 90 rpm until the power meter registers
4. Stop, un-clip and calibrate the meter

Garmin are quite clear that the washer goes between the pedal-pod and the crank.

See their instructive video - https://youtu.be/C77DbG8AjGU?t=1m28s

In the same video Garmin recommend 34 nM for the tightening torque.

sopworth

Thought i'd bump this thread….

Just bought some Vector S from Rose. Fitted them this morning using a Part Took Torque Wench and it was very simple. Quick turn on the turbo and the pedals reading fine and pretty similar to what I was getting on my previous Powertap, using the same resistance setting.

I'll post on here once i've given them a few rides/turbo sessions and let you know how I get on.
S

brettjmcc

rudivoller22 wrote:

Sorry to hijack but in toying between p2m and vector s. I have rotor 3d+ cranks on one bike and Ultegra 6700 on the other so p2m is more difficult of the options.

Any good deals on vector Anyone has spotted? Seen a few for around £530 from various German sites.

Why not get the P2M and then buy the Rotor BSA30 BB so you can swap between bikes?

fleshtuxedo

brettjmcc wrote:

rudivoller22 wrote:

Sorry to hijack but in toying between p2m and vector s. I have rotor 3d+ cranks on one bike and Ultegra 6700 on the other so p2m is more difficult of the options.

Any good deals on vector Anyone has spotted? Seen a few for around £530 from various German sites.

Why not get the P2M and then buy the Rotor BSA30 BB so you can swap between bikes?

^^^this

I'm in a big club with a large number of pm users and the consensus is strongly for P2M over Garmin. More reliable mechanically and more dependable readings too.

The Rotor adapters are very good. Fit a P2M to your 3d+ cranks, put a BSA30 adaptor in your BSA frame and you can swap your cranks between bikes in 5 minutes with just a 5mm Allen key and shimano dust cap tool, without interfering with the power meter and messing up readings. Swapping the garmins is far more finicky.

cycleclinic

Vectpr pedal insatltion is a doddle. If you damage anything it is because you have not read instructions or been hamfisted none lf which is the fault of the pedals.

I have been using the pedals for the last month and i cannot find fault with them. Mving the pedals between bike should not affect power readings unless yiu manage to damage something. Time will tell but how could tell if the readkngs are off anyway. Powertaps new crank based solution looks very useful. Verve pm chainsets k thjnk are the best chainset option.

sopworth

A week into using the Vectors and i'm suitably impressed. The power readings are almost identical to my old Powertap. I've switched between my TT and road bike the once and it's really a couple of minute job. Given the ease at changing the pedals between bikes I'd say early indications is that i've made the right decision in selling the Powertap.

curium

I often hear people rate a power meter based on how close it reads to their previous one.

How do they know that their previous power meter gave an accurate reading? How do you know if any power meter is reading accurately unless you place it in a lab with fixed environmental conditions and apply a known force to the pedals?

In summary, I just think it's a silly way to judge them. Far better to judge on durability, portability, ease of installation, compatibility with head units, battery life, customer service, software, etc.

Dodger747

Consistency is what I look for - I don't particularly care if one power meter reads 10,20,30 w different to another, as long as it is consistent.

As above, there's no way of knowing [really] which PM will be 'accurate'.

sopworth

curium wrote:

I often hear people rate a power meter based on how close it reads to their previous one.

How do they know that their previous power meter gave an accurate reading? How do you know if any power meter is reading accurately unless you place it in a lab with fixed environmental conditions and apply a known force to the pedals?

In summary, I just think it's a silly way to judge them. Far better to judge on durability, portability, ease of installation, compatibility with head units, battery life, customer service, software, etc.

Maybe we are just complimenting both systems for providing consistent readings. Yes, unless you go to a lab you are never going to if they are exact but as long as your power meter reads consistently it doesn't matter if it over or under wattage. I was making a comment on how it compared to my old PT in case others were interested in my switch or comparing them. There is plenty in this tread about durability, portability etc of some of the PM's mentioned.