How does PC8 battery life w/GPS compare to the PC7?

Obviously I can't provide long-term info here, but from what I have observed battery life seems to be about 15-20h of ride time per charge. As you know, the PC7 had incredible battery life, so that is a very high bar.

I'm not a huge GPS guy (I love having GPS, but I tend to ride in the same spots and am an infrequent user of Strava), so this area was a worry for me: would we be sacrificing quite a bit of battery life for a feature that was not critical for me? Time will tell, but 15-20h per charge would be acceptable to me. One also has the option of disabling GPS for better battery life.

When I travel to new areas I do like to see where I've ridden, and occasionally I like to measure myself on a local Strava segment. It's nice in those instances not to have to carry a second GPS device, and having it on-board might make me use those services a bit more frequently.

Quite a bit of customization to be had on the PC8's screens.

There are 4 available screens. Each can be renamed as the user prefers, and the screen style can be chosen from one of 6 (on the right). Then, each data field can be selected from a variety of Power, HR, Cadence, Speed, etc. available fields.

Ok, here's a question...when am I going to actually be able to get this thing... :P

I've gotten these in customers' hands already. SRM continue to work through the preorder list.

Orders placed now are likely to be fulfilled in August, but there is the possibility that someone who is waiting for a unit in the next (mid-July for me) shipment may bail and move someone up. That happened already in the first shipment.

I cannot speak for all dealers but I seem to be pretty high up the chain.

Hope that helps.

A feature I've always appreciated about the PC7 is that it is always recording data. If the wheels are moving -- if there are numbers on th screen -- data is stored. Garmin users may know that one might see speed, power, cadence...and yet not have any data due to forgetting to hit start.

I've made that mistake and have seen it at least once with every Garmin user I work with. It sure is a bummer and makes one feel stupide. Garmin's teminder is nice but I perfect.

The PC8 retains this trait of always recording.....at least IF one has a speed sensor on the bike. I need to play with this more but if one is ONLY using GPS, then I believe one must manually start recording.

I also suspect but have not yet tested that if one has a speed sensor then speed/distance will be drawn from that and not GPS (though the GPS track is certainly also recorded). Need more time to test.

Thanks Tetonrider

I don't know what questions to ask, but want to know EVERYTHING! Been waiting for this a while and am thinking of placing an order here in NZ which I understand may be filled later this year.

Only specific question relates to the GPS. Is it accurate? I thought I read some initial reports that gave rise to question... I do use a speed sensor and don't look at speed that much while riding. But I do like to review my routes after the fact and look at the profile v power, etc.

My two biggest questions are, what colour?!?! They all look awesome. And, second, do I really want to be an early adopter of this or wait six months and let any mass production issues get worked out...

I never had a speed sensor on my mtb, and 1st thing is did was cut the sensor off of my S5.
Road distances, average speed, etc. seems pretty much the same.
Same for elevation.

I have been thinking a lot about that lately as well, but any issues will most like be updated via firmware. My thought is to get it now and just enjoy it - it might not have all of the promised features up and running, but everything that it does have makes it a big jump ahead of the PC7 (aside from battery life).

Has anyone ridden with it at night? How is the illuminated display?

It's this seriously that big an issue for you and others?

I've been using Garmin watches and bike computers just about daily since 2006 and have never forgotten to hit start at the beginning of a ride.

When I meet up with a group for a ride I usually get caught up talking to the other guys and when the ride starts I forget to hit start. Almost every darn time. I've been using a Garmin for about 6 months now because back then I had hopes that the PC8 was actually going to come out so I sold my PC7.

IMO, once is too many. you are the rarity; i just got back from a ride with my friend (he has a rotor SRM with a garmin head unit) and was asking me about the PC8. we talked about this very issue. he said he occasionally stops his garmin during a ride (e.g. coffee shop) and forgets to restart it. i have had athletes forget to turn on their garmin before a race. their minds were on other things and they saw power, HR, etc displayed.

you may have a different opinion OR simply place a lower value, but for me this is a design element that makes a person feel REALLY stupid when it happens.

similarly, having to press and hold lap/reset at the end of a ride AND shut the Garmin down in order to minimize the chance of file corruption was another unfortunate source of occasional error in a Garmin. it is by no means frequent, but one lost race, one lost threshold test can matter a great deal to some people.

You are not alone.

The tough part, I found, is that the Garmin is DISPLAYING data, and unless you have a time counter on that particular screen one may not notice. It would be better if no data was displayed, IMO.

When otherwise intelligent people can get something basic (like recording data) wrong, it is a sign that maybe the design has a flaw. Users are not stupid (I'm a guy who appreciates intuitive design).

Presence of power, speed, HR, cadence should be a signal to record. Storage is cheap. These devices no longer have that constraint so why not throw out selective recording? Let the user decide whether to save the data to his/her computer after the ride.

GPS has some known limitations for all devices. I've been running it side-by-side with a Garmin and a PC7 and comparing data. Consumer GPS is pretty good. Forgive me if I get a detail here wrong, but years ago when I first started using Garmins (late 90s) the more precise GPS system was only available in very high end devices and/or restricted use. When more satellites were opened up for civilian use, precision was improved. I think these devices, even handheld consumers ones, are accurate to within 3m. Like any Garmin, the PC8 can display the accuracy of the current reading.

The readings on my Garmin and PC8 match whenever I glanced at them (casually).

Over my 16+ years of using GPS to record on-the-bike data, I've found that the toughest test for these devices is on sides of mountains (possibly restricting the view to a sub-optimal # of satellites) and/or cases were there is HEAVY tree cover as well as many tight switchbacks in steep terrain (some MTB). Narrow canyons can be bad, too.

That said, in recent times I have found that if a device gets an initial good lock then it can hold onto it for far longer. If you try to get an initial lock in that slot canyon, all bets are off.

IMO GPS speed is accurate for almost all uses. One case where is it NOT good enough is if someone is doing aero field testing with a power meter; we need a speed sensor for that. Of course, GPS speed does not work if one is on a trainer and, say, wants to measure mileage for wear on a chain.

As to your other questions, I will see if I can take some good photos that show off the colors. If you've seen the anodized PC7s before, this is the same finish, which is to say a very polished-looking final product. Of course this is subjective, but they have a sturdy, sleek look about them. They may not be to everyone's taste.

Early adopter? Part of the reason things have taken so long is that SRM is not about to release a product that is not ready for prime-time. Unfortunately, any Garmin user knows that we were beta or even alpha testers when we buy a new product; things are more stable when they have released several firmware revisions. Lots of examples there.

SRM's entire reputation for their power meters and head units has been on data quality. While anything is possible, it is rather unlikely they would risk their reputation with a product that is not ready for consumers. I cannot comment on the long-term of course, but what I'm seeing is pretty good so far, and I'll be doing more testing. If SRM wanted to rush this product they would have released it for LAST TdF. This is not a rushed release.

You can decide where your comfort level is.

Thanks!

I am coming from a Garmin 910XT and am ready for a dedicated bike computer.

I think I will pull the trigger. There is no question SRM found it harder to produce these things than they originally anticipated, but as you suggest they did seem to put quality first, hence the delays.

I was set on red prior to the photo you added to the start of this thread! I have to admit that this is partly a training tool and partly bling for my bike, so want to get one that looks good with the bikes I have! I think red.

Cheers

Sam

Below are some features that I've found quite useful vs the PC7 and other Garmin units I've used.

1. Zones: User-defined
During a ride, a can bring up a zones screen. In the software one can define from 1-7 training zones where the user chooses the name and upper/lower limits based on power or HR. This screen seems mostly useful for time-in-zone, although it does have a total of 8 fields. (Seems to not be user-customizable at this point.) Zone boundaries are displayed; perhaps this is useful if you are an athlete who cannot remember where tempo ends and threshold begins.

2. Data Screens
Up to 4 data screens can be named by the user and each can take on one of 6 different formats (# and type of data fields). Fields include:

• Current power, AP, best 30" power (?!) in W or W/kg, max power, NP, power balance and kJ
• Current HR, avg HR and max HR
• Current cadence, average and max
• Current speed, average and max; total distance
• Time: Ride time, time of day, date
• Current altitude, ascent, descent and an altitude graph/widget
• TSS, IF and training zone (e.g. "1", "2", etc.)
• Temp, direction, current GPS accuracy

3. Ride Summary
There are some interesting ride summary screens containing stuff you'd expect (AP, NP, TSS, IF, max elevation, total ascent, etc.). Not incredibly useful for my own usage, but perhaps interesting for someone who wants to look at their ride data at the coffee shop before uploading.


4. Bike profiles
For me this is really nice. Garmin has had this feature for a while (though IME not without bugs--would often have to restart the device after switching bikes). This saves a PC7 user the trouble of pairing power meter and speed sensor before each ride. That didn't take a long time to do, but it is one more step before your ride. Nice details:

• Auto-zero can be turned on or off for each bike; I happen to never use auto-zero (I like to know exactly when it changes; I've seen many devices get a bad zero now and again--with the .FIT file spec included current zero with EVERY data point), but it is a nice level of control
• Last ZO for EACH meter/bike is recorded. Super nice as checking ZO at the start of each ride is good for the data but also serves as an early-warning indicator. I.e., if you generally see values of ~500 but suddenly you see 800, it could be a sign something is wrong. Not so tough to remember with one meter but gets more complex when you have multiples. Also....if for some reason you switch bikes and happen to forget to check ZO, it will start from the last known ZO with THAT meter, not the last ZO taken for ANY meter.
• Slope can be modified / user-defined slopes can be programmed for EACH bike.

Downside? Only 4 bikes. I wish there were more. Guess they have to draw the line somewhere; personally I wish it were >=5.


More to come tomorrow...

A couple things that I have noticed in the past few days.

1: I dragged and dropped a few .FIT files from the PC8 to TrainingPeaks Device Agent (for import into WKO3). I got a bit of a scare as the import interface said ride time for the most important one read "0:00." I have come to appreciate the bomber reliability of the PC7 and immediately thought "Oh no....is the .FIT format the source of errors" as I had experienced a number of corrupt files from Garmin devices over the years. Fortunately when actually imported into WKO3, the ride file was just fine (ride time, interval data, etc as expected). False alarm, but something I will be watching.

2: An old/minor frustration with the PC7 was the inability to display more than 20 intervals. This is pretty rare, but on rare occasion I have a bike session with more than 20 intervals that I want to mark. The PC7 always recorded all the intervals, but when you got to #20 and beyond you could only review intervals 1-19 on the device. If you forgot whether you were on 22 or 23, you couldn't be sure until arriving home. I hoped this restriction was eliminated and did a quick test. I was able to mark 20 intervals and review data from 1-20, but when I did the 21st it recorded but could not be seen in the interval review screen. Bummer. At the surface, this seems to be an arbitrary limit. Again, this is a rarity for me (1, 2x a year) and the fact that the data is recorded is most important, but it is still a minor nuisance.

3: I'm not certain why this happened, but I drove about an hour from home with my bike and hopped on it. It was just a casual ride with family, so I hopped on and didn't think much about the normal pre-ride stuff. I noticed the screen was not responding and it took several minutes before the display was back to normal. My suspicion is that I had traveled to a new place and -- perhaps -- the system was trying to acquire a new GPS signal. I've had this happen with Garmins before, so this is just a guess. However, I had a speed sensor attached so I would assume that would default to a speed sensor for recording data, but, no, nothing was on the screen related to the ride. GPS locks in a new locale can be slow if the device is moving, and I was riding.

Reminded me a bit of the Garmin Edge "Working...." message that will sometimes appear (I've had it take >15' before).

No idea why this happened, but again it is something I'll monitor. There was a message on the screen (can't recall what it said; it was simple/generic), but it was unrelated to "acquiring satellites" so that is pure conjecture on my part.

4: I wish there were unlimited bike profiles, or at least more than 4. I have 2 road bikes, TT bike, CX, MTB, etc. Probably rare for a user to have >4, but it is possible and the limit appears arbitrary to me.

On the very positive side, the display is VERY crisp and clear, even under the most intense sunlight. I was riding at high elevation in mid-day sun. I appreciate the clarity of the display. It is measures better than even the PC7, and much better than the 5x0/8x0s that I own.

That doesn't sound good to me. At what point did it start working normally?

can you update the SRM unit slope like the gamins do with the pc8 or still need a garmin to do that?

Couple of questions:
-What is the dimension from the right-outer edge of the bar mount to the center of the PC8? Just want to make sure I have enough room on my bar to center the unit properly to the stem.
-Is the intervals screen customisable?
-How does a 5sec/10sec GPS recording affect battery life? How does 5/10sec GPS recording effect the ride file (mapping, strava upload?)
-Will the PC8 remember and remain paired with my quarq PM on wakeup? A very annoying scenario is being in the gate at a mass start race... garmin turns off automatically... on wakeup there are multiple PMs broadcasting and the garmin doesn't remember to pair only with my Quarq.
-How does it handle zero cadence events on the powermeter. If I am going along at 200w, stop pedaling will it repeat the 200w for 2-3 seconds as the garmin headunits do?
-Can you see, in your FIT file, the zero offset value for all of the data records?
-Can you program 3s and 30s power on the same screen? I use those for most of my intervals.

You can update slope.
1 of my 4 bikes has a different slope.
I was able to program in that slope.

Hey iSam, I'm giving serious though to an SRM when I change my road bike in 2016 having seen a lot of people have continual hassles with Stages. Can I ask who you were looking at getting it from? Looking at a Domane/S-Works Roubaix build with the PM put in from the get-go.

---

----------------------------------------------------------------

Interval screen looks the same as main screen.
But you can disable the "return to main screen" so that it stays on whatever screen you are on.
I did is and then set up my alt screen as my interval screen- I have actual power and average power side by side on that screen.

I just wanted to mark that as it's the first time I'm aware that we'll have an audit trail and be able to examine the behaviour of torque zero offset settings.
This should be a standard requirement for all power meter recording devices IMO.

---

http://www.cyclecoach.com
http://www.aerocoach.com.au