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Tech & Wearables

Technical FAQ: finish line cameras used in other sports, SRAM Shifter Battery Drain, and more

VeloNews technical expert Lennard Zinn takes a deeper dive into finish line cameras, offers suggestions about SRAM drivetrain batteries, cardiac health and prevention, and oversized derailleur pulleys.

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Have a question for Lennard? Please email him at to be included in Technical FAQ.

Dear Lennard,
I’ve been following your column for decades, and I really find it fascinating the depth of knowledge you have on various subjects. Thanks for sharing it with us.

Especially interesting for me are the subjects about and for tall riders. I’m 2m tall (about 6’7″) and currently at 105.5kg (about 230lbs). I competed at three Olympics in rowing, and have been riding road bikes for over 40 years now.

During my rowing career, I was riding 20,000-25,000km per year on average, and I’m absolutely sure biking made me a better rower.

Before I started “serious” biking in junior categories I was pretty much average. Once I got my biking to a higher level (10,000 or more km/year), I got much better in rowing as well.

The scan of the actual photo finish from a newspaper I’ve kept after our semifinal race at the Seoul Olympics in 1988. Maybe the readers will better understand the concept of photo finish camera vs. time when they see this photo.

Semifinal 2 of the mens 4+ at the 1988 Olympic Games in Seoul, South Korea Photo: Courtesy Sead Marusic

From today’s perspective, it is really funny how it was handwritten the race number (No. 65), date, lane assignments (nearest to the camera is lane one) and three crews that made it to the final (two semifinal heats, three fastest from each heat advanced to the final).

Interesting to note is the fact that the slowest boat is the longest in the photo. What happened in our race is our two-seat (second from the front of boat) some 60-70m before the finish line (just about where this color photo was taken) shouted: “last five” strokes.

Semifinal 2 of the mens 4+ at the 1988 Olympics. Photo: Courtesy Sead Marusic

After five strokes, we actually stopped rowing, then I (in bow, at the front of the boat behind the coxswain) realized we had another 20 or so — maybe even less — meters to go and started to scream “ROW, ROW, ROW!”

We managed another confused stroke or maybe two, and at that point, there was the finish line siren with 6 beeps one after another, almost as one sound.

Needless to say, all this was happening at the verge of collapsing from exhaustion (we’d got salmonella some three weeks before the Olympics at the training camp, and didn’t fully recover before Games began).
— Sead

Dear Lennard,
I enjoyed your response to Linda’s question regarding photo finishes. However, you place a lot of faith in the people setting up the photo finish. What do you make of my analysis I posted where I found the photo finish and the finish line were more than 25cm apart?

In a follow-up post, I suggest the UCI may need to change their regulations to ensure the photo finish line and the actual finish line are more closely aligned. Do you think this is a good idea?
— Tom

Dear Tom,
I wish I’d seen your blog before writing my column last week! That’s a fantastic analysis. Yes, I think your idea for changing the specs of the finish line in your follow-up blog is a very good one. A white line in the center of the center black line with alignment squares on it would ensure that the finish line camera(s) is (are) lined up more closely with what the riders and the spectators see as the finish.
― Lennard

Dear Lennard,
I’m Miro from Slovenia, 72, triathlete. I ride a BMC TMR01 with, SRAM Red eTap 2×11, Miche SWR T 50/50 wheels.
I have a serious problem with my the right shifter battery.

I can make only one ride of about 120 km, and the right shifter’s battery is out of power. I made some contacts to Sram in Slovenia, Sram USA and Sram Headquarters in Europe, without success. The warranty period is over, and I should buy a new right shifter. They even don’t answer what’s the problem!

But the other problem is that these shifters are no longer in production, and the used ones offered online are rear only. I manage a ride or two with one battery.

I found in VeloNews some words about cleaning shifters. Should I try to clean my right shifter with a specific cleaner to overcome the battery drain? Please advise me about such a cleaner or whatever it is. Or, maybe you know another way hot to solve my problem.
Best regards from Slovenia,
— Miro

Dear Miro,
Last June, I answered a very similar question from a reader named Miro. Was that perhaps you? If so, did you try the software update I suggested? It totally fixed the same problem I was having with a 12-speed eTap shifter.

As for cleaning the shifter, I doubt that would change anything.

I’m clear that you’re talking about the non-rechargeable watch battery in the shifter, not the rechargeable battery on the rear derailleur. But just in case it’s the latter that’s draining rapidly, improper storage can cause the rear derailleur battery to discharge overnight, as this rider discovered.
― Lennard

Dear Lennard,
I am five years out from suffering a pulmonary embolism caused by a botched ablation for A-Fib. The article on VeloNews brought back memories of piss-poor medical care and gratitude to still be here afterwards. I have a thumb-width stent in my femoral vein and will be on blood thinners for the rest of my life.

For all of us that have hammered ourselves into submission and the various V-Tach or A-Fib that results, anyone considering an ablation needs to do their homework. By no means a simple, non-invasive procedure.
— Steve

Dear Lennard,
Regarding John’s unexplained HR spikes, it could have been caused by an erroneous reading from his HR monitor. I have an older MIO wrist strap HR monitor with optical technology, and every once in a while, it will suddenly report a very high heart rate—usually double my actual HR. Turning it off and back on fixes the problem.
— Bob

Dear Lennard,
I wanted to try oversized pulley wheels without paying too much and ended up buying these oversized pulley wheels.

I set them up on my well-used Ultegra derailleur expecting poor shifting due to added weight on a worn shifting spring.

However, the shifting turned out to be as smooth as butter, and I noticed much better traction on my chain and therefore a more responsive drive train. I did not need to lengthen my chain; however, I had to shift the whole derailleur block down by adjusting the screw on the derailleur hanger (the b-screw) — otherwise the top pulley ran into the big sprocket.

Overall, I am extremely pleased with the modification!
— Jim

Lennard Zinn, our longtime technical writer, joined VeloNews in 1987. He is also a custom frame builder ( and purveyor of non-custom huge bikes (, a former U.S. national team rider, co-author of The Haywire Heart,” and author of many bicycle books including Zinn and the Art of Road Bike Maintenance,”DVD, as well as Zinn and the Art of Triathlon Bikesand Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists.” He holds a bachelor’s in physics from Colorado College.

Follow @lennardzinn on Twitter.