Racer Tech Thread
#2826
#2827
¯\_(ツ)_/¯
Joined: Jun 2008
Posts: 10,978
Likes: 4
From: Redwood City, CA
Bikes: aggressive agreement is what I ride.
I'm in the process of buying a new house, and it has a level covered concrete back porch. Normal winter temps in the morning here are 30-50 degrees F. I'm thinking of doing trainer rides outside on the porch when it's rainy/wet/slick etc. The positive part would be fresh air while I'm on the trainer, negative would be having to stare at the backyard rather than the flat screen. Has anyone tried this, and if so, what are your thoughts?
#2828
Senior Member

Joined: Oct 2013
Posts: 1,766
Likes: 89
From: East Bay Area ,CA
Bikes: not enough
I have a tripod and a 24 inch Lcd screen I don't use much. I need to get a holder / bracket to fit the tv and tripod. Together with a laptop atleast I could zwift on a larger screen
#2829
Thread Starter
Senior Member
Joined: Aug 2007
Posts: 4,449
Likes: 0
the mtb shoes are very nice (as are the road shoes). not sure if you have the asymm tongue version on the road, but i find it is a nice perk.
#2830
#2831
I'm in the process of buying a new house, and it has a level covered concrete back porch. Normal winter temps in the morning here are 30-50 degrees F. I'm thinking of doing trainer rides outside on the porch when it's rainy/wet/slick etc. The positive part would be fresh air while I'm on the trainer, negative would be having to stare at the backyard rather than the flat screen. Has anyone tried this, and if so, what are your thoughts?
#2833
Has a magic bike
Joined: Aug 2013
Posts: 12,590
Likes: 425
From: Los Angeles
Bikes: 2018 Scott Spark, 2015 Fuji Norcom Straight, 2014 BMC GF01, 2013 Trek Madone
I'm in the process of buying a new house, and it has a level covered concrete back porch. Normal winter temps in the morning here are 30-50 degrees F. I'm thinking of doing trainer rides outside on the porch when it's rainy/wet/slick etc. The positive part would be fresh air while I'm on the trainer, negative would be having to stare at the backyard rather than the flat screen. Has anyone tried this, and if so, what are your thoughts?
Plus two box fans. I like airflow.
#2834
I bought a TV and hung it on the wall of my garage. I also had the garage wired for cable, and I have a DVD player sitting next to the TV. I also bring my laptop out and hook it up to the TV to watch Netflix or something whenever I'm on the trainer or rollers.
I'd venture that 75 percent of the television shows and movies I now watche are seen while riding in the garage.
I'd venture that 75 percent of the television shows and movies I now watche are seen while riding in the garage.
#2835
tl;dr: 'did science' and learned way too much about the garmin vector. my coworkers also now have proof postive i'm insane
Spent several hours over the last two days 'calibrating' my Garmin Vector power meter after physics suggested it was reading low (312W for something that should be 330-340W, as one example). Using the recommended procedure, I brought my bike to the office and set it up on a trainer between two standing desks (which were conveniently adjustable allowing for me to get everything completely level) and weighed my weight/string/hook on a calibrated scale to figure out what value I was looking for (27.84Nm). The pedals were reading low 27's, which wasn't quite the ~10% I was looking for and were at the low end of the +- 2% that the power meter was supposed to be accurate to. I then tried everything I possibly could to get the pedals to read the 'correct' value (though if I'm being honest, if I got them to instead report at the high end of the 2% range I would still have been happy with that...).
Doing this experiment in a building full of engineers meant I had lots of curious onlookers throughout the process with a number of suggested variables to try. I tried altering:
- torque on the pedals (25-30 ft-lbs is what is recommended by Garmin - I tried at pretty much every ft-lb increment)
- the number of spacers between the pod and the crank
- amount of grease on the pedals
- static calibration angle
- pod angle (not supposed to matter)
and several other things I'm now forgetting. Each setup required dragging the bike outside and putting on my bike shoes to do a few hard sprints to settle the pedals and then allow the garmin to figure out the installation angles, followed by numerous weighings on each pedal with numerous static calibrations in between. At one point I had the right pedal pretty much perfect (27.65-27.95 Nm no matter the static calibration) but nothing I did managed to bring up the left pedal from 27.2 (27.0-27.4). After spending way too much time on it I gave up and decided to do a clean install of both pedals and to just accept whatever values I got from it. Somehow, the ultimatum worked and I ended up getting it pretty much on the nose which was rather amusing... I'm looking forward to 2-3 rides at the correct calibration before something 'slips' and its back to crap values again.
The frustrating part of this 'calibration' process is that its not so much 'calibration' as 'continually testing and modifying until the test reports the right values'. It seems like I should be able to enter what the expected torque value should be to calibrate the meter (like you can with known GPS elevation, for example) which would have made the whole process take like 15 minutes. Either way, I'm going to continue to not recommend the vectors to anyone interested in power meters - the powertap hub on my other bike is much less stressful.
Spent several hours over the last two days 'calibrating' my Garmin Vector power meter after physics suggested it was reading low (312W for something that should be 330-340W, as one example). Using the recommended procedure, I brought my bike to the office and set it up on a trainer between two standing desks (which were conveniently adjustable allowing for me to get everything completely level) and weighed my weight/string/hook on a calibrated scale to figure out what value I was looking for (27.84Nm). The pedals were reading low 27's, which wasn't quite the ~10% I was looking for and were at the low end of the +- 2% that the power meter was supposed to be accurate to. I then tried everything I possibly could to get the pedals to read the 'correct' value (though if I'm being honest, if I got them to instead report at the high end of the 2% range I would still have been happy with that...).
Doing this experiment in a building full of engineers meant I had lots of curious onlookers throughout the process with a number of suggested variables to try. I tried altering:
- torque on the pedals (25-30 ft-lbs is what is recommended by Garmin - I tried at pretty much every ft-lb increment)
- the number of spacers between the pod and the crank
- amount of grease on the pedals
- static calibration angle
- pod angle (not supposed to matter)
and several other things I'm now forgetting. Each setup required dragging the bike outside and putting on my bike shoes to do a few hard sprints to settle the pedals and then allow the garmin to figure out the installation angles, followed by numerous weighings on each pedal with numerous static calibrations in between. At one point I had the right pedal pretty much perfect (27.65-27.95 Nm no matter the static calibration) but nothing I did managed to bring up the left pedal from 27.2 (27.0-27.4). After spending way too much time on it I gave up and decided to do a clean install of both pedals and to just accept whatever values I got from it. Somehow, the ultimatum worked and I ended up getting it pretty much on the nose which was rather amusing... I'm looking forward to 2-3 rides at the correct calibration before something 'slips' and its back to crap values again.
The frustrating part of this 'calibration' process is that its not so much 'calibration' as 'continually testing and modifying until the test reports the right values'. It seems like I should be able to enter what the expected torque value should be to calibrate the meter (like you can with known GPS elevation, for example) which would have made the whole process take like 15 minutes. Either way, I'm going to continue to not recommend the vectors to anyone interested in power meters - the powertap hub on my other bike is much less stressful.
#2837
Senior Member
Joined: Jul 2005
Posts: 4,850
Likes: 1
From: Blacksburg, VA
Bikes: Yeti ASRc, Focus Raven 29er, Flyxii FR316
#2838
Killing Rabbits
Joined: Apr 2005
Posts: 5,696
Likes: 217
tl;dr: 'did science' and learned way too much about the garmin vector. my coworkers also now have proof postive i'm insane
Spent several hours over the last two days 'calibrating' my Garmin Vector power meter after physics suggested it was reading low (312W for something that should be 330-340W, as one example). Using the recommended procedure, I brought my bike to the office and set it up on a trainer between two standing desks (which were conveniently adjustable allowing for me to get everything completely level) and weighed my weight/string/hook on a calibrated scale to figure out what value I was looking for (27.84Nm). The pedals were reading low 27's, which wasn't quite the ~10% I was looking for and were at the low end of the +- 2% that the power meter was supposed to be accurate to. I then tried everything I possibly could to get the pedals to read the 'correct' value (though if I'm being honest, if I got them to instead report at the high end of the 2% range I would still have been happy with that...).
Doing this experiment in a building full of engineers meant I had lots of curious onlookers throughout the process with a number of suggested variables to try. I tried altering:
- torque on the pedals (25-30 ft-lbs is what is recommended by Garmin - I tried at pretty much every ft-lb increment)
- the number of spacers between the pod and the crank
- amount of grease on the pedals
- static calibration angle
- pod angle (not supposed to matter)
and several other things I'm now forgetting. Each setup required dragging the bike outside and putting on my bike shoes to do a few hard sprints to settle the pedals and then allow the garmin to figure out the installation angles, followed by numerous weighings on each pedal with numerous static calibrations in between. At one point I had the right pedal pretty much perfect (27.65-27.95 Nm no matter the static calibration) but nothing I did managed to bring up the left pedal from 27.2 (27.0-27.4). After spending way too much time on it I gave up and decided to do a clean install of both pedals and to just accept whatever values I got from it. Somehow, the ultimatum worked and I ended up getting it pretty much on the nose which was rather amusing... I'm looking forward to 2-3 rides at the correct calibration before something 'slips' and its back to crap values again.
The frustrating part of this 'calibration' process is that its not so much 'calibration' as 'continually testing and modifying until the test reports the right values'. It seems like I should be able to enter what the expected torque value should be to calibrate the meter (like you can with known GPS elevation, for example) which would have made the whole process take like 15 minutes. Either way, I'm going to continue to not recommend the vectors to anyone interested in power meters - the powertap hub on my other bike is much less stressful.
Spent several hours over the last two days 'calibrating' my Garmin Vector power meter after physics suggested it was reading low (312W for something that should be 330-340W, as one example). Using the recommended procedure, I brought my bike to the office and set it up on a trainer between two standing desks (which were conveniently adjustable allowing for me to get everything completely level) and weighed my weight/string/hook on a calibrated scale to figure out what value I was looking for (27.84Nm). The pedals were reading low 27's, which wasn't quite the ~10% I was looking for and were at the low end of the +- 2% that the power meter was supposed to be accurate to. I then tried everything I possibly could to get the pedals to read the 'correct' value (though if I'm being honest, if I got them to instead report at the high end of the 2% range I would still have been happy with that...).
Doing this experiment in a building full of engineers meant I had lots of curious onlookers throughout the process with a number of suggested variables to try. I tried altering:
- torque on the pedals (25-30 ft-lbs is what is recommended by Garmin - I tried at pretty much every ft-lb increment)
- the number of spacers between the pod and the crank
- amount of grease on the pedals
- static calibration angle
- pod angle (not supposed to matter)
and several other things I'm now forgetting. Each setup required dragging the bike outside and putting on my bike shoes to do a few hard sprints to settle the pedals and then allow the garmin to figure out the installation angles, followed by numerous weighings on each pedal with numerous static calibrations in between. At one point I had the right pedal pretty much perfect (27.65-27.95 Nm no matter the static calibration) but nothing I did managed to bring up the left pedal from 27.2 (27.0-27.4). After spending way too much time on it I gave up and decided to do a clean install of both pedals and to just accept whatever values I got from it. Somehow, the ultimatum worked and I ended up getting it pretty much on the nose which was rather amusing... I'm looking forward to 2-3 rides at the correct calibration before something 'slips' and its back to crap values again.
The frustrating part of this 'calibration' process is that its not so much 'calibration' as 'continually testing and modifying until the test reports the right values'. It seems like I should be able to enter what the expected torque value should be to calibrate the meter (like you can with known GPS elevation, for example) which would have made the whole process take like 15 minutes. Either way, I'm going to continue to not recommend the vectors to anyone interested in power meters - the powertap hub on my other bike is much less stressful.
2% bias is so far from "crap values" it's funny. We pay for "certified" products where the 95% confidence interval is huge.
#2839
it was just outside the 2% originally. even when its 'within 2%' i also don't want the L and R to be at different ends of the spectrum (2% high on right and 2% low on left = ~right value for total but then the LR-balance is inaccurate which would bug me). i am admittedly insane.
really what I'm looking for is it to report the same values as when i had it installed on my old bike, even if it was wrong on the other bike.
i just bought a new bike and when i was picking out a crankset i 100% should have just gotten the SRM at that point. next time... 
i have more confidence in the scale's accuracy than any of the other variables involved. but you're right, theres tons of variables involved and plenty of room for measurement error all over the place.
as for my unhappiness with 2% - i agree, 2% would be great, and thats all the error I saw when doing the torque test, but its hard to square with the meter reporting on the order of 10% lower (than both my previous bike and any equation would indicate) in my field tests which is what sparked this whole endeavor. i think my main frustration is that i really trusted the values i was previously getting but now that i've switch bikes i'll constantly be doubting it.
really what I'm looking for is it to report the same values as when i had it installed on my old bike, even if it was wrong on the other bike.

Even calibrated scales have error, especially when working near the limits of their calibration ranges. If you did one measurement on one scale you have no idea of what the true value is. You need the mean and std dev of both values to compare properly.
2% bias is so far from "crap values" it's funny. We pay for "certified" products where the 95% confidence interval is huge.
2% bias is so far from "crap values" it's funny. We pay for "certified" products where the 95% confidence interval is huge.
as for my unhappiness with 2% - i agree, 2% would be great, and thats all the error I saw when doing the torque test, but its hard to square with the meter reporting on the order of 10% lower (than both my previous bike and any equation would indicate) in my field tests which is what sparked this whole endeavor. i think my main frustration is that i really trusted the values i was previously getting but now that i've switch bikes i'll constantly be doubting it.
#2841
OMC


Joined: Oct 2010
Posts: 6,973
Likes: 142
From: South Louisiana
Bikes: Specialized Allez Sprint, Look 585, Specialized Crux E5 Sport, Trek Domane SL6
This is how I got my SRM. Since it's on a non-racing bike, is there a downside to waiting until the battery dies to send it in? My race bike also has a power meter, so I can live without the SRM for a while if necessary.
__________________
Regards,
Chuck
Demain, on roule!
Regards,
Chuck
Demain, on roule!
#2842
Senior Member
Joined: Jul 2005
Posts: 4,850
Likes: 1
From: Blacksburg, VA
Bikes: Yeti ASRc, Focus Raven 29er, Flyxii FR316
#2843
That's what my plan is. My SRM started giving me warnings of a low battery after just one year - it should last more than that. I called SRM, and they told me to send it in once the batter was dead.
#2844
Nope. Battery life depends a lot on age and the model. Newer models are a lot more efficient. I expect to get three years out of a battery set with mine.
#2848
For UCI and (presumably) Nats only. Already legal under USAC.





