WTB: Power Meter 172.5 / BB30 / 53/39

Classifieds
1

Looking to buy a crank based power meter. Shimano / Sram, preferably 11 speed. 172.5. BB30. 53/39. No more than 2 years old.

Thanks!

2

ME TOO! any luck on finding one?

3

Hey guys/gals. I have a 53/39 FSA SLK-Light -175’s though - that I am thinking of selling. It’s for sale on classifieds. Don’t know if that would work off you?

4

I have a Quarq S975 BB30 172.5mm with new black 53/39 Sram Red chainrings. It’s just under a year old, and has had a very stable zero offset 200 +/- 20, which is probably more important than anything with powermeters.

$900 Shipped USA

5

not to sound like a noob but what does this very stable offset indicate?

I know you said has had a very stable zero offset 200 +/- 20, which is probably more important than anything with powermeters but …I have never heard of looking into the offset to indicate power meter quality.

I would suspect a constant weather or temperature environment to provide a very stable offset “score” given that the materials do not expand and contract very much if at all.

Do tell me more as I am very interested? and… will this crank work with Sram22 ?

6

It’s basically a tare value in the calibration mode of whatever head unit you use.

So in a simplistic way of looking at it, it’s the value the unit displays in “calibration” with no torque applied to the crank/hub. The value rises as torque is applied (used for end user calibration, ex Qualvin etc), and sometimes rises over time as the power meter ages. If that’s the case, it may indicate the integrity of the strain gauges, or internals is degrading.

Powertaps are supposed to be 512 or something like that, SRM’s 500 +/- lets say 50htz, and the lower the better with a quarq. To the point that quarq used to claim units displaying over 500 or more, or any zero offset swing greater than 40pts over any given ride was “defective”.

I’m no engineer, so anyone please elaborate if you are, but basically you want a unit with a stable zero offset as it indicates the components of the powermeter are stable, and reliable.

I don’t own a 22 speed system, but I think the chainline is the same. I’d be surprised if it didn’t work.

7

I have a 172.5 BB30 Quarq S975 with 52/36 rotor rings and 50/34 red rings!!

8

Got one. Under $900.

http://forum.slowtwitch.com/gforum.cgi?post=4931375;search_string=quarq;#4931375

9

I’ve got a 175mm BB30 50/34. But, its a riken, so you can change out the rings all day long without re calibrating it!

10

Dont mean to hijack the thread but I am interested in a quarq BB30 172.5 130bcd crank. Can be riken or s975. Let me know…

11

Also interested in a Quarq 50 34 BB30 172.5 if anyone has one available?

12

I’ve got one.

http://forum.slowtwitch.com/gforum.cgi?post=4943263;search_string=%25ftp;#4943263

13

storric5, see the link above.

14

http://forum.slowtwitch.com/forum/Slowtwitch_Forums_C1/Classifieds_F2/FS_or_FT%3A_QUARQ_SRAM_RED_BB30_172.5%2C_53/39_RED_Rings_2012_Model_with_new_BB_incl_P4946463/
.

15

check out the two listed in this thread: http://forum.slowtwitch.com/gforum.cgi?post=4835294;

let me know if you have a difficult time finding them. thanks.

16

If anybody is willing to use and adapter I’ll make a sweet deal on the one I’ve got for sale. 172.5 53/39, but it’s GXP.

http://forum.slowtwitch.com/gforum.cgi?post=4945997;sb=post_latest_reply;so=ASC;forum_view=forum_view_collapsed;;page=unread#unread