djconnel

[QUOTE=merlinextraligh;15875327]For you, and maybe for DC Rainmaker, perhaps L-R balance is close to 50%. But for a given rider, it may or may not be. Without testing, how would you know? Granted, the screen shot I showed was at relatively low power (88 W). At higher power, L-R balance tends to be closer to 50-50. But data I've seen (from another pedal-based power meter) is it depends on fatigue and cadence. So if I change cadence and power increases, should I stick with that new cadence, or does it simply mean I'm pedaling more with my left leg at that cadence? This is a fundamental limitation. The limitation still results in a useful power meter. It's just not nearly as useful as a good 2-legged power meter, however.

merlinextraligh

^ No doubt it's a limitation. Personally, it's a big enough a limitation, I wouldn't put it on a single bike ( I'd either go with a powertap wheel for similar money, or pay more for a Quarq or SRM).

But given the extremely limited options for a tandem, the fact that it apparently will work with an Ultegra tandem crank is the appeal.

Another problem would be unthreading the pedal from the crank running it backward. I suppose you could use locktite, or maybe helicoil reverse threading.

Also, I'm going to talk to Stages, and see if they'd consider retrofitting a unit into the Ultegra tandem crank, getting rid of the pedal threading issue.

Ritterview

Looks like the Vector may be available this fall:

Garmin Vector power meter release date set for September
By BikeRadar | Tuesday, Jul 23, 2013

merlinextraligh

^ hope it actually happens this time. Close enough I'll probably hold off on the Stages.

waynesulak

Brim Brothers uses the Speedplay pedal as a platform and might will be out this year as well. No update from them for a while but DC Rainmaker has ridden a prototype.

https://www.brimbrothers.com/

p2templin

Although Quarq isn't as inexpensive as the Stages, Ric at House of Tandems has been doing captain Quarqs for nearly two years. Ever since they did our Quarq pair for our daVinci, he put a few pictures on his website, and he's had plenty of happy captains so far.

rahill

Apparently the Vector has finally been released:

https://www.cyclingnews.com/news/garm...-available-now

rahill

OK, it's all over all the cycling sites this morning, and Garmin's own home page. Specific details here: https://sites.garmin.com/vector/

waynesulak

Tentatively looks like Garmin has a nice product. I would love power measurement but neither I nor my stoker want to switch pedal systems so we are still in wait mode for now. I hesitate to buy ver 1.0 of anything so that is for the best.

I eagerly await comments from early adopters.

Chris_W

That is the one good thing about all the delays with this product, no consumer is getting anything like version 1.0. Garmin has been testing these things extensively over the last few years, and each time they got close to the release date they postponed because they wanted to release a more reliable version than what they were currently testing. It appears that they must have gone through more rounds of prototypes on this product than what is done on most other products. They're certainly trying hard to get it right first time for the consumer.

Unfortunately, I have no interest in wearing clumsy roadie shoes so I'll not be buying a pair until they release something that is compatible with MTB / walkable shoes.

waynesulak

I know that that Garmin has tried to get it right and hopefully they have however by definition the first product release is the first release. There is no getting around it. Internal product testing is just not the same as real volume production shipped to the public.

Chris_W

In all the news stories that are out there right now about this, there were a few mentions of different pedal types. Apparently almost every pedal company has been in touch with Garmin wanting to work on a system with them for their pedals, and it sounds like it's probably only be the initial release that is limited to one pedal type, but for now Garmin wants to focus on getting this first one right before they release any other versions. They even said that the next thing to be released will probably be something with a MTB pedal.

Ritterview

This note on the DC Rainmaker blog caught my attention.


The S-Works is based on the Lightning Crank, so I thought the Lightning at risk. FSA is the default OEM tandem crank.

Here's the video from Garmin that explains this.



I asked Tim Brummer at Lightning for the measurements.

This appeared to be outside of the Garmin specs, so I did some measurements.

The clearance between crank arm and chain appears to be 6 mm.



The width of the crank arm appears to be 15 mm. With the crank arm height 2 mm below spec, and the rounded profile, I think it will work.



It is a pretty close thing, however, and i think that Lightning crank users should do measurements. So too for the FSA tandem crank.

Edit:

I just ordered two Garmin Vectors from the LBS. The LBS's team discount of 15% is a great thing for something like this!

Ritterview

Mike's Bikes is working on getting the pedals installed, the 16.9 mm depth of the Lightning crank arm created some problems that are being handled with some filing and washers. Last I heard, one set was working, and they were about to get the other to go.

I do have a photo of a pedal at least:



This will be 90 grams more than the Candy 1 stoker pedals it replaces.

Dean V

Why are you putting on power meters?

Hermes

Ritterview, Thanks for the info and looking forward to your review and how they work on the tandem. Do you have power on your road bikes?

Ritterview

• Because the value of power for cycling is not in question.
• I have always wanted to have cycling for my half-bike cycling anyway, which I've not had, and the Vector allows me to have power for both half bike and tandem.
• With both stoker and captain having power, there will be clarity as to our relative contribution, which is otherwise opaque.
• We'll get a calorie count, which the stoker understands!
• A definitive answer to "She's not pedaling."

waynesulak

How do you plan to move the Vector power meter back and forth between your tandem and single? Moving pedals back and forth?

Some question why I care about measurement when I am slow and I don't race. I do however compete with myself. For me trying to improve makes any activity more fun. Other methods can be good approximations but power is a measure of the actual work done. While I could estimate the work done when lifting weights I would never do it. Does anyone not look at the real accurate measure of work done when they lift?

Unlike looking at the weights lifted, cycling power meters have big cost and complexity issues. Except for those issues it is the best way to go to get feedback on your workout.

Ritterview

Yeah, that's how its done. Not on a daily basis, but when I when I am going to be using one or the other for a significant stretch.

Dean V

Will you be able to manage the consequences when you do get a definitive answer to "she's not pedaling"?

waynesulak

I hope so.......

Ritterview

Just got a a couple of pics.

Hermes

Ritterview, I like it. I have an idea for you. Give the stoker both displays so she knows her power and your power.

colotandem

Ha! Good idea!

I'll stick with not knowing... We know that all the power comes from the back of the bike, right?

PMK

Curious if the loadcell transmitter, assuming that's what it is must be positioned at the right angle to the crank arm for function or just looks.

I ask, and wonder if the cornering lean angle will be reduced before a pedal strike, or in this case, a loadcell transmitter strike.

Guessing the photos do not give all the facts about ground clearance when railing a corner.

PK