Penises, Vaginas, and Bike Fit

I spent Friday evening in a lecture hall on a local college campus, listening to two leaders in bicycle fit science talk about what is known about bike fit. Dr. Andy Pruitt and Dr. Roger Minkow of the Boulder Center for Sports Medicine were the presenters, and you knew it was going to be an interesting evening when Minkow said he was here to “change the world one penis at a time.”

Drs. Pruitt (left) and Minkow address the crowd.
Drs. Pruitt (left) and Minkow address the crowd.

Minkow is the man behind the Specialized Body Geometry Romin saddle (Romin is a contraction of the first syllables of his names). He regaled the crowd with tales of measuring cyclists’ private parts to get the best handle on saddle design.

We’ve all heard that you sit on your sit bones. That they’re supposed to hit the wide part of the saddle, and that will make for a comfortable ride. But Minkow said that’s not really the case. He said we sit on the bottom of the pelvic bones, and it’s really more like a rocking chair. So the Romin saddle has a center channel and flares out toward the back. The “rockers” of the pelvic bone sit on the flares just outside the channel.

The process they went through to develop the saddle was the most interesting part of the evening, and drew the most crowd response in the form of giggles and guffaws. Back when they started testing blood flow (down there), Minkow said 50 percent flow was considered a good number. He developed a ring that fastens to the penis and can measure blood flow. Testers put on the contraption, and rode bikes in a lab. Minkow said as they modified their saddle design, they were able to get blood flow up to 75-80 percent in most testers.

“Austin is cool,” he said. “Austin was the first city where we got people to volunteer to do the blood flow test.”

It was one matter to design a saddle that would fit men’s anatomies, but when it came to women, Minkow ran into a problem.

“Where is the vagina?” he asked. The crowd gasped, then giggled.

“Well, yeah, we men know where it is in order to use it,” he added. But in terms of measurement, women aren’t as easy to decipher as men. And they can’t be tested for blood flow. Luckily, there’s a big difference in women and men.

“Ladies can draw a diagram and show every point of pain,” Minkow said. “Men don’t have a clue. They could be at zero blood flow and not be aware of it.”

So a pressure map was created to show where pressure on women — and men — is greatest.

“There is no mid-line pressure on Body Geometry saddles,” Minkow said.

That’s important, because erectile dysfunction can be a reality if you ride improperly or if the bike isn’t set up correctly.

“Bike fit,” said Pruitt, “is about making the bike look like you.”

He compared fitting a bike to buying a suit of clothes. You can go to a store and pick a suit off the rack, and eventually find one your size. But if you were to take that same suit to a tailor, he could make the suit fit you perfectly, rather than acceptably.

Specialized has developed a bike fitting regimen for Specialized based on x,y, and z axes — x and y are the two dimensions visible from the side, but Pruitt says the z axis — viewing the bike from the front — is the difference between the Specialized system and others. Pro cyclists who have been fitted according to that system show notable improvements in power output and time trial times.

The crowd for this event, which was sponsored by Bicycle Sports Shop — one of the biggest bike shops in Austin — was overwhelmingly made up of experienced cyclists. People who appeared to be racers and triathletes sat near me. Some of the questions thrown at Minkow and Pruitt were highly technical, and they did their best to field them in terms everyone could understand.

Both Minkow and Pruitt are on retainer from Specialized, so the evening had the feeling of a commercial for that brand, but overall, the discussion of bike fit and saddle design was worth attending. If the two make an appearance in your area, it’s worth a couple hours of your time.

Seat Adjustment

I had been bothered after a ride of any length lately. I’ve always had trouble being comfortable in the saddle after an hour or so, but now I was getting low back pain. It cleared up quickly once I stopped riding, but if I was going to continue to enjoy being on the bike, I would have to take some action.

The obvious culprit was the saddle. I had been fitted to the bike way back in 2009, and the most unexpected finding there was that my seat had been too far back. The fitter moved it forward, and I enjoyed the feeling of riding in a slightly upright position, with the bars a tad closer to me than they had been.

But in the intervening years, I’ve been experimenting — making tiny adjustments in the saddle position. Over time, those tiny adjustments became substantial changes. I guessed the problem must be that the saddle needed to move forward again, because at this time, it was as far back as possible. I had even considered getting one of those seat posts with the additional back offset. But I decided first that I would try to get the bike back to the original settings the fitter had come up with.

I didn’t have a sheet with my measurements, but I did have my garage window. On the window sash, I had written in pencil that the distance from the nose of the saddle to the headset was exactly 16 inches. Now, it was about 16 1/2 inches.

I made the adjustment. We’re told not to change things drastically — more than, say an eighth of an inch — so this was a drastic change. I rationalized it by reminding myself that I’d ridden in this position before.

On my first ride with the new position, I noticed the effect of the forward saddle right away. My arms bent naturally at the elbows. There was less pressure on my hands. I did a club ride of about 30 miles, and felt fine after it was all over.

Last week, I did a few short rides in the neighborhood before work, a longer ride with hills on Saturday, and a 37-mile club ride Sunday. No lower back pain.

It’s not perfect, but it’s pretty close. And I have a hunch that any further adjustment I make will be on the saddle height rather than fore and aft — remembering that raising the saddle has the effect of moving it back, and lowering it has the effect of moving it forward.

By all means, tweak your riding position for the most comfort — but be sure you have a record of your original settings. You might need them.

Some Basic Tips For Noobs

I decided not to ride Sunday morning, because it was pouring rain when I woke up. Dumb move. Things were pretty well dried out by 9 a.m., and if I’d been a little more patient, I could have gone. As it was, I did a short ride with my wife, as I mentioned in the last post.

But I wanted to make up for the lost B ride, so I posted that I would go Monday morning, since it was a holiday. We would do the Same Fitzhugh route that the A’s did on Sunday. Three others came out to join me, including Yasmin and Frank, two new B riders who rode with us for the first time last week.

Both of them have recently bought new bikes, and they’re both strong riders who will only get stronger and faster as they keep riding. As we negotiated the rolling hills along Fitzhugh Road, Frank stayed with Buddy, who moved well out in front. Yasmin got ahead of me, and while I had some trouble sticking with her, we were closer together than Buddy and Frank were to us.

At the turnaround, about 16 miles out from the start, Yasmin complained that her saddle was bothering her. She’s a tall woman, and the bike frame she had appeared to be sized for a man. But the saddle was a narrow racing style. I could relate to her distress. I rode a narrow racing saddle for about a year, when I finally ditched it some something wider and more comfortable.

“When you take it back to the shop, ask them to fit you with a wider saddle,” I suggested. Because of women’s wider pelvises, they need wider saddles than men, anyway.

At another rest stop farther on, both Yasmin and Frank expressed concern about their hands. They were getting numb, and they were shaking them out periodically.

In Frank’s case, he was riding with his elbows locked. “One of the guys told me to ride with my elbows bent,” he said. “I’m trying to get used to that.” Bending the elbows takes weight off the hands. The saddle should have been positioned in such a way that the elbows naturally bend when the rider is in his standard riding position. When I had my bike fitting some years ago, the fitter said it’s more common that people have their saddle too far back rather than too far forward. For most people, he said, moving the saddle forward will provide that elbow bend and make for a more comfortable riding position.

Fitters often use KOPS, or Knee Over Pedal Spindle, as a way to determine saddle fore-aft position. But the other day I was re-reading Peter White’s excellent contrarian article about bike fitting, where he pooh-poohs that notion. It’s all about balance, he says, the kind of balance between power and comfort. The article inspired me to do some tweaking on my saddle position.

It turned out that Yasmin was pushing her hands against the brake hoods. While that seems like a normal position for a new rider, it can cause the hands to go numb quickly. I showed them how to position the hands so the pressure is on the outside heels of the hands, not the webbing between the thumb and forefinger. “It usually doesn’t take much of a shift in position to relieve the pressure,” I said.

We wrapped up the ride and went our separate ways. I hope the tips about saddle width, bending the elbows, and hand position will help Frank and Yasmin enjoy their riding. I fully expect it will have negative consequences for me — it’ll just make them stronger riders, and I’ll be left behind again.