SBR "U" (Page 57)

Glad to hear everything is okay!

I think I need to send my Quarq back, but I'm not particularly mechanically-inclined....how difficult is it to pull off and put my old crank back on?  I could go to the bike shop if I need to, but would rather not deal with the hassle of doing so.

I'm pretty sure SRAM BB30 and GXP are the same installation method for Quarq.  I have a GXP quarq which replaced a SRAM Force BB30 crank than they install the same.

I'm pretty sure the only tools you need are a 8 mm allen key and maybe something like a rubber mallet to give a few gentle taps.  You don't actually need a rubber mallet...sometimes just tapping with my hand is good enough, but I remove my crank quite often to swap between bikes.  Sometimes cranks that haven't been removed in a while may not have good grease in there.  They key is getting a 8 mm allen key that will give you enough torque.  You're typical multi tool or 3 inch L wrenches likely won't cut it.  I use a 7 inch ratchet with socket keys.  The ratchet is nice because it takes a lot of turns to actually get the crank on and off.

There are youtube videos out there.  Just know that it's a self extracting bolt.  You'll see a 10 mm hole that is the end cap on the non drive side.  You don't remove that.  You work the 8 mm hole just beneath the cap to remove the crank arm.  The cap is what the bolt will push against to self extract.  I can give you more details if you want, but my guess is a youtube video would explain it better.

What exactly is making you think you need to send your quarq back in?

Glad to hear you're OK

Nicole - swapping cranks on a GPX bottom bracket is about the easiest thing you can do. I use a long torque wrench to break the bolt loose (easy to do even without a bike stand as you turn the wrench against the drivetrain direction). Then use an Allen wrench to take the bolt the rest of the way out. I also use the torque wrench to put it back on so I get it to spec. To send my Quarq in I had to take a crank off my old TT bike, and then take the Quarq crank off my road bike, and then put the first crank back on my road bike. It took a lot less than 5 minutes to do all that.

Also interested to hear what kind of problems you are having?

Nicole, one more thing.  You'll also need to remove the chainrings before sending it back to Quark.  It is as simple as using two allen keys, I think 5 and 6 mm.  When you put them back on though, you probably want a torque wrench.  I believe it is 8 nm for aluminum bolts and 10 nm for steel botls.  You likely have steel, but Quarq can confirm what they came with.

Thanks for the feedback on how to remove the Quarq!

The problem I'm having is that the power jumps around +/- 15-20 watts while holding steady cadence on the trainer (even with 10s power smoothing on).  It never used to do it until I upgraded to the latest firmware -- used to be that I could hold steady to within a couple watts.  It's not quite, but almost like a sine wave -- it'll be low for a few moments and then go high.  The average is probably where it should be, but it gets frustrating while on the trainer and trying to hold a steady power....watching it go between 155W and 185W while trying to hold 170W with a steady cadence.  

I've been dealing with it since last year (really should have sent it back while I took time off the bike over the winter, but I just didn't think about it), so I've gotten somewhat used to it, but when I first started dealing with it, I would try to correct for it and then my power would really be all over the place.  Now I just settle in and watch the cadence, but it's still irritating that it jumps around so much when it used to not.  

It does the same thing on the road, but I'm much more forgiving of that because I don't stare at it and watch it constantly!

Nicole,

I believe you can take the raw garmin file and import it into excel.  That should give you (and Quarq) a better idea of what's actually being reported on a second by second basis.  If you're seeing those type of jumps with 10s smoothing, you must be getting some really erratic data.  

If you haven't taken off your crank in a long time, it might be a good time to take it into the shop and have your bottom bracket checked out.  It's one of those things that most cyclists neglect...especially if you ride a lot...and ride a lot on the trainer where sweat tends to drip towards the bottom bracket.

Golden Cheetah will also show a table with that info, on the "Edit" tab.

Good advice -- thanks, Jason!  I'll shoot some info over to Quarq.  We had talked when this first started happening (it was fine until the day I did the firmware update, but they hadn't had anyone else with issues), so I'll follow up again and see if they still recommend me sending it in or if there are any diagnostics they can do remotely.

I haven't taken the crank off in a long time (since I got the PM...) and spend a lot of time on the trainer with my corrosive sweat!   Getting the bottom bracket checked out is probably something I should do!

TrainerRoad is where I notice it most....it's watching that where I see the almost sine wave power output most.  If I look at my Garmin at the same time, it'll do the same thing, so I don't think it's TR acting buggy.

It's hard to say for sure, but I think so.  I'd settle into it and watch it fluctuate (usually goes low), hold my power output steady, and then see it come back up to where I expected it to be.  I don't stare at my power out on the road the way I do on the trainer....and also understand that so many things affect power outside (wind, false flats, big trucks coming by, draft-legal slingshot benefit, etc.), whereas the trainer is a very controlled environment where I can hold the cadence steady and watch the power jump 15W in either direction...

Did you notice your HR dip with power drops?  Come back when the PM was reading what you'd expect?  Most of the things you list on the road will affect your speed for a power output, but your HR should be more closely linked with a real change in power (or not, if it's a bad reading). 

The trainer jumpiness sounds like it's broken, so being off in the race would make sense, but you might be able to use HR:W where you notice any sustained dips in power (that you didn't feel from an exertion standpoint) as a cross-check for the race data.

Matt

Glad the pain is abating.  That is a scary feeling, even if you're thinking it's not a heart attack.  Anything that feels close, well... feels like a heart attack!

Any idea how long before you're mended?

Matt

Do you live in a condo or apartment?  Could be interference in the 2.4ghz wireless spectrum, which ANT+ uses.  Of course so do phones, microwaves, routers, etc...

Awesome news on the power Marc!  Not so awesome on the brakepad.

I've got a 19k TT tomorrow morning, gonna be cold!

Just waiting for the Race Report before commenting.