16 replies to this topic Post Order

[ManicCycles]

Hi all.

Been looking around at options for power measurement on the mtb.

 

Would like to get some comments/ feedback / suggestions.

[29thumbs]

An iBike.
no wires, no fittings, no strange hubs, no special cranks
it will tell you exactly wot you need to know.

[Ab 1]

look threw these !!

http://www.bikeinn.c...0monitor/4025/s

[Minion]

MyTcr1, on 27 November 2010 - 10:11 , said:

An iBike.
no wires, no fittings, no strange hubs, no special cranks
it will tell you exactly wot you need to know.

The iBike estimates power based on gradient and relative airspeed. It then includes a correction factor for things like rolling resistance. Given the varying trail conditions and surfaces experienced while MTBing, I don't think the iBike will be all that accurate.

The gold standard for power measurement accuracy are direct force measurement power meters. These directly measure the amount of force applied (currently at the hub or the crank) and then calculate power from that. There are currently three options for DFM meters: Quarq and SRM (crank-based) and Powertap (hub-based). SRM and Quarq both have double chainring options, while only SRM currently has a triple option. Powertap make a disc brake power meter hub for MTBs.

Currently, the only Quarqs easily available in SA are for road bikes. SRM and Powertap prices through the local distributors were not much more expensive than CRC prices last time I looked, so it's worthwhile looking at getting them locally (though CRC does have good specials every now and again). The SRM will probably be around R30k for the crank only while the Powertap will be around R15k for the hub only. To that you'd need to add the price of a computer (e.g. R3k for a Garmin Edge 500).

Used properly, a power meter is probably the most valuable upgrade you can make to a bike as far as performance gains are concerned. If you're seriously considering getting one, you'd do well to spend R250 or so to buy and read this book first: Training and racing with a power meter. It has a useful comparison of the various meters currently available and will give a good start to understanding how to use the device to get the most benefit from it.

[SwissVan]

Wot about the new look Keo pedal (with Polar) with power measuring thingys?

Maybe they also got a MTB version in the pipe line?

[The_Break]

Powertap will be the cheapest and easiest to use.
Other Powermeters whilst good are expensive.
I would not recommend power meters that estimate power using calculations and estimations such as polar, I would only recommend using a power meter that calculates actual power from a strain gauge be it in the hub, pedal or crank. The reason you use PM is for accuracy as compared to heart rate. Using a poor calculated power is going back to that poor accuracy of actual effort. I don't think the Speedplay pedal PM would be good for MTB in any case.

[Willehond]

SwissVan, on 22 December 2010 - 11:56 , said:

Wot about the new look Keo pedal (with Polar) with power measuring thingys?

Maybe they also got a MTB version in the pipe line?

I'm actually more excited about the Garmin/Speedplay option. Hopefully it will be fully ANT+ so you can use your Garmin with mtb and roadbike. Well, that's my dream! For mtb's I hope they bring out a Shimano or eggbeater option

[The_Break]

Willehond, on 22 December 2010 - 12:08 , said:

I'm actually more excited about the Garmin/Speedplay option. Hopefully it will be fully ANT+ so you can use your Garmin with mtb and roadbike. Well, that's my dream! For mtb's I hope they bring out a Shimano or eggbeater option

Isn't speedplay a problem when you get into mud much more-so than most other MTB pedals? And then won't they wear out so much quicker so that you will have to replace your PM more often than is affordable?

How do you find walking/running in speedplay during portages?

[Willehond]

The_Break, on 22 December 2010 - 12:17 , said:

Isn't speedplay a problem when you get into mud much more-so than most other MTB pedals? And then won't they wear out so much quicker so that you will have to replace your PM more often than is affordable?

How do you find walking/running in speedplay during portages?

Nope, not suggesting using Speedplay at all for mtb, hence my mention of Shimano/eggbeaters...

[Sharkie 2]

Power meters are great but how can you constantly keep your watts where it needs to be a road bike with a power meter is a much better option, this is only my opinion though

[The_Break]

Sharkie 2, on 22 December 2010 - 01:13 , said:

Power meters are great but how can you constantly keep your watts where it needs to be a road bike with a power meter is a much better option, this is only my opinion though

I think there are long enough climbs and flat road stretches where it can be used effectively, but personally I would only use it during training. On an MTB I would rather be watching the terrain than looking down at my console the whole time. Either way, I guess it has its uses for all situations in Road and MTB.

[Willehond]

Sharkie 2, on 22 December 2010 - 01:13 , said:

Power meters are great but how can you constantly keep your watts where it needs to be a road bike with a power meter is a much better option, this is only my opinion though

Power meters are not just about timetrialling, they also tell you your progress and what your training stress is. Like Edam says, read Training and racing with a power meter to get more details. I would just like to have all the data from my roadbike and mtb for training purposes and racing stats. Keeps me motivated more than anything else

[kosmonooit]

I was thinking of another option to measure power: strain gauges on the cranks and processor and comms unit in the bb hollow? would need to be calibrated depending on cranks and setup but hmmmm ......

[SwissVan]

Power meters Pfft...

I still prefer my built in rev counter

[The_Break]

kosmonooit, on 22 December 2010 - 01:51 , said:

I was thinking of another option to measure power: strain gauges on the cranks and processor and comms unit in the bb hollow? would need to be calibrated depending on cranks and setup but hmmmm ......

Think SRM beat you to that idea over a decade ago.