il professore

I want a crank based powermeter. I just built my new bike up with SR11 so I'm hesitant to get rid of the crank but...

So Quarq looks cool but there isn't a compact yet- when will that happen?
Srm looks like the other option=more money?

I already have a 705 so that part is done. I do wonder if the interface, etc is better with the srm headunit than with the 705?

I guess I also wonder because I'm at a loss when I read threads on training with power. FTP, LT, LGBS, etc - I'm not sure if I'm even smart enough to get it..

ljrichar

Paging Dr. umd...

Buy this now. It will tell you whether you really want a PM.

https://www.amazon.com/Training-Racin.../dp/1931382794

Also,

https://67.201.16.77/showthread.php?t=488667

merlinextraligh

I don't have an SRM, so my answer is somewhat speculative. But I can tell you that the interface between the 705 and the Quarq is great. The 705 links to the Quarq with no issues. And you can custom tailer the display in about every conceivable way. It is much preferable to a Powertap display in that regard.

Just having looked at SRM displays, I would be the 705 is at least as good, if not better than the SRM head unit with regard to displaying the data you want, and customizing the display, and you get GPS to boot.

azdroptop

Racing and training with a power meter my Hunter Allen. <-------Everything you need to know. Why do you want to go crank based when the powertap is just as, or more acurate? Sure it measures actual power to the road and not at the crank, but so what? Just wondering.

umd

I don't know when compacts will be out... sorry can't help you there. As far as the Garmin as a head unit vs. the SRM's, there are a few things that Garmin doesn't "get" because it is still thinking of the Edge as a bike computer/navigation device more than a training tool, so some concepts are lost on them, such as not being able to separate the option for cadence and power averaging, and not having the ability to smooth the power display so that it is not as jumpy. A few people have had issues with file corruption but I do not believe that it is as widespread as it seems (internet forums can be an echo chamber in that regard).

Quarq is certainly cheaper than a SRM and more than a PT. That's just the way it is. A crank PM is nice for standard reasons of not having to be wheel dependent, which is especially nice if you switch between a training and racing wheel. So if that is more important that the price difference, then a crank PM is the way to go. If getting power as cheaply as possible is the priority, then a PT is probably the way to go. A PT is not more accurate because it measures power to the road (actually just to the hub, there are still rolling resitance losses to the road), it is just measuring slightly differently. For training purposes, knowing what you are actually putting out is more useful than knowing what is being applies to the road, but in practice I don't think it really matters at all.

wfrogge

Because you are stuck with whatever wheel you build up. Between my training rear wheel (32h Mavic), race wheel (Easton EC90 Aero), and my rear disk (Renn) Im not getting the full power picture everytime I ride.

merlinextraligh

Mostly it's wheel choice. With a Quarq I can train on training wheels and race on race wheels. And with a 5 minute crank swap, I can use the Quarq on my TT bike, and race with a disc.

When I used a powertap, I could only use one rear wheel, and you had the problem of compromising on what wheel you used, or not racing with the power meter.


Also, I believe there is a bit of a weight advantage with a Quarq, or SRM compared to a PT hub, but the newer PT's may have narrowed that.

jrobe

I use to want a crank based powermeter until I bought a timetrial bike. Now I can use my Powertap wheel on both bikes. I would never change now.

merlinextraligh

Do you run a disc wheel with your TT bike?

As long as you have a compatible BB installed on your TT bike, it is a less than 5 minute operation to move a crank based power meter from your road bike to your TT bike.