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.

Saddle Feels Funny – But In A Good Way!

I’ve been bugged lately by soreness in my butt during rides. This is a problem I’ve wrestled with pretty much since I started biking. A pro bike fit a couple of years ago helped, but not entirely. And in recent months, I find myself standing on the pedals at regular and more frequent intervals to take the pressure off from down under.

I finally decided to do something about it, and last weekend I dug out the Allen wrench and went to work on the seat. Well, nothing drastic. I just thought it made sense to scooch it back about an eighth of an inch. Using the time-honored method of gauging seat fore-and-aft, I realized that when riding normally on the hoods, the front hub stuck out from under my handlebars — just a little bit.

My first ride after the adjustment Friday afternoon was inconclusive. I thought maybe it felt better, but the ride was only for 20 miles — about an hour and 20 minutes. It wasn’t enough time to get a good feel for the new placement.

On Sunday’s ride though, I did spend enough time in the saddle. My ride was almost three full hours, and we traveled 43 miles. Sure, I stood on the pedals. But on a ride of that length, who doesn’t? What I did notice was that the seat felt more comfortable. I was sitting a slight bit back, and it seemed to make a difference.

When we got to the convenience store we use for a turnaround, I propped the bike up against a wall and went in to refill my bottles. When I came out, I took a look at the bike — then looked again. That saddle seemed to have a marked tilt down! I have no idea how it got that way, except that when I loosened the bolts to move the saddle back, I must have knocked it off level.

Even a quick snapshot in my cluttered garage shows the forward tilt to the saddle.
Even a quick snapshot in my cluttered garage shows the forward tilt to the saddle.

I’ve always set my saddles so they’re level. Well, maybe I fudge a little bit, and tilt it half a bubble down, according to my carpenters level. But this was lots different. The tilt forward was noticeable just by eyeballing it. My initial reaction was to reach for my multi-tool and set things right, but then I remembered — on the ride out here, my butt wasn’t bothering me. The soreness and pressure I usually experience just wasn’t there. I decided to leave well enough alone, and ride back.

I’ve already talked about that ride in the previous post. It was an easy ride for my companions, and a challenge for me. But even during the final mile, when I was pedaling hard to keep up with one of the club’s faster women, the saddle wasn’t bothering me. In fact, I seemed to be able to apply more power to the pedals in the new position.

Last summer, I rode with an older gentleman who tilts his saddle forward at a drastic angle. I told him I was surprised that he didn’t slide off during his rides — the tilt was that severe. He pointed out that he spends most of his riding time on his aero bars, and he needs a tilted saddle to fit the bars well with a well bent-over riding position. It must work — he’s a faster rider than I am.

So even though I’m riding with a greater forward tilt than I think I should, I’m coming to the conclusion that maybe I should have been doing it this way all along. My saddle tilt isn’t as great as that fellow’s, but as I said, it’s obvious even to the casual cyclist. I’ll let you know if I decide to keep it this way.

Sitting on the Sit Bones? Maybe Not

Long-time readers of this blog are aware that I have had an ongoing battle with various saddles. It seems that after about an hour’s riding, my butt starts to hurt. I’ve tried several different saddles, and thought I had finally hit upon one that was acceptable — not perfect by any means, but one that seemed to work better for me than most others I’ve tried.

Even with this one though, I have to resort to some tricks to stay comfortable. I stand and pedal every so often. Whenever I coast, I take the weight off my butt. I vary my hand positions on the bars constantly. But when riding Friday, I accidentally scooched into a position that was mahvelous.

The admonition when riding is to sit on the sit bones — the “ischial tuberosities” — that protrude from the pelvis. I’ve always been aware of this saying, and I thought I had always been abiding by it. But this shift of position moved me to the real sit bones. I could tell the difference. Suddenly, my bottom felt at ease — as though it should have been in this spot all along, and should continue there from now on.

Funny thing is, I’m not really on my sit bones. At least, not the sit bones we all think of. It was all cleared up for me when I stumbled onto Steve Hogg’s Bike Fitting Website. Hogg writes extensively about the arcana of a proper bike fit (Reading his articles is a great way to spend a rainy afternoon when you can’t get out for your ride) and you’ll learn a lot by visiting his site.

According to Steve Hogg, we really sit on the pelvic bones just forward of the ischial tuberosities.

He points out that the pelvis is not constructed for us to sit on the ischial tuberosities. Instead, the bones on each side of the base of pelvis curve a little bit lower than the tuberosities protrude. They angle from wide at the rear to narrow at the front, and if the saddle is the right design, they’ll rest right on top of it.

I must have rocked back just enough that these bones rested on the saddle, instead of my perineum. I’ve been crushing my taint all along, and apparently thought that was what we had to put up with when riding a bike.

It seems a lot of cyclists have trouble with finding the right spot. As our frequent guest poster Jeff Hemmel pointed out in a review of the Bontrager Affinity saddle, Bontrager designed its perch to facilitate finding the right spot on the pubic arch.

I spent the rest of Friday’s ride, and Saturday’s, changing my position on the saddle so I could practice getting back to the exact spot I needed to get to. I think I have it down. At any rate, my rides seemed more comfortable to me than they usually are after I’ve put in 15 miles or so.

Now, you might think that if I’m putting my weight a bit forward of where we have always thought it should be that I’d be crushing my softy bits. In my case, the Forte Classic saddle I ride has a cutout, so there’s no pressure there anyway. I’d be interested in trying one of my other saddles that don’t have a cutout to see just what the results would be — but I’m in no hurry to do so. For the time being, I’ll just enjoy my rides.