Tire Stuff: A Follow-Up

My post about the humble Michelin Dynamic actually garnered an off-blog reader e-mail from (I presume) a real person who just stumbled into this dark corner of the interweb. I was more than a little humbled (though not as humble as the Dynamic) to find out that my audience is bigger than just the visible core that comments on my prattle. So, in Aden's honor (hi, Aden!), I'll try to address some of those off-blog tire questions here for the (questionable) benefit of all.

Aden writes:

I live in a relatively rural area in central Virginia, and my riding will be about 80 percent pavement (and to a lesser extent, hardpack bike trails)--lots of group rides, limited commuting, etc--and about 20 percent unimproved roads (dirt/gravel), fire roads, and the like--just casual outings, nothing that would really qualify as "mountain biking". So should I go with the 700x28s or the 700x32s (my rims are 15mm wide, inside measurement, BTW, and I'm a light rider at 145 lbs). I'm sure the larger tires would be smoother riding and perhaps better on the trails, but I'm also concerned about weight and shooting for minimal rolling resistance since the larger percent of riding I will be doing will be on pavement. What to do?

First, I need to disqualify myself on two counts. One, I've never been to any areas of any part of Virginia, so I can't say what's suitable for a rural area in central Virginia. Two, I haven't been 145 pounds since about the fourth grade (yup, I was a husky lad), so the world of the sub-150-pounder is about as foreign to me as the Klingon home world.

But, with those caveats in mind, here's my nutshell response: Read Volume 5, Number 1 of Bicycle Quarterly. Seriously. I'm just a subscriber, not a shill (and I have my issues with some of BQ's other research/hypotheses), but V5#1 (commonly known as the tire test issue) is a winner. It's the only research I'm aware of that attempts to put tires to a real world test (where most of us ride) rather than spinning them on a steel drum in a lab and calling it good.

In that real world, I've found BQ's somewhat controversial assertion that wider tires at lower pressures actually roll faster to be true. How can that be, when everyone else seems to say that the skinner and harder you can run your tires, the faster you'll be? Think about the roads you ride on. Are they perfectly hardwood-floor smooth? I'm guessing not. Mine are pretty bumpy. And when I hit those bumps, a narrow tire with a lot of pressure tries to bounce. Maybe a tire bouncing Aden's 145 pounds is no biggie, but to bounce my girth takes some energy -- energy that's no longer available to move said girth forward.

Now, hit those same bumps with a tire that's maybe 10mm wider than race rubber (at least 32mm) and running down around 70-80 psi. The tire deforms rather than bouncing, and the bike/rider keeps plowing ahead with a lot less wasted energy. This is all a grotesque oversimplification of the fine work in BQ, but it at least gives you the drift.

Aden also asked about weight, which can often be the bugaboo of this "wider is better" argument. After all, tire manufacturers have chased that "skinnier is faster" fallacy for a while now, so they assume their 700x32/35/38 offerings are only being snapped up by tourists and commuters -- folks who aren't trying to get anywhere in a hurry, but want a tire that won't flat easily. That leaves the fat-tire buying public with a lot of similar choices: thick rubber, chunky sidewalls, belts to deflect poky objects, and a lot of weight -- which can take work to spin up to speed. The Dynamic isn't bad in a 700x32 (at a claimed 360 grams, though I kinda don't buy that), but it still starts with a thick cap of rubber in the tread area that could be lighter/more supple.

What I'd like to see is an unbelted, folding semi-slick for 700c wheels in about a 40mm width. No extraordinary measures to prevent flats, just a reasonable rubber cap and nice flexible sidewalls. Proponents of the kooky 650B tire size (tee hee, how I love poking the 650B bear) claim that the 650Bx42 Gran Bois Hetre (imported by Bicycle Quarterly, so I guess I am a shill after all) is the tire I seek, but I'd like it in a normal diameter, please. And while you're at it, how about black sidewalls and tread? That's not a baguette in my pannier (I'm just happy to see you), so I don't need to look like a 1950s Frenchman headed out for a picnic.

Um, Aden, what was that question again?

Product Review: The Humble Michelin Dynamic

I've been a skidge negative lately, so I figure it's time for a "happy human" product review.

Today, I give you the Michelin Dynamic. Let's not kid ourselves here. This is not a fancy tire. It doesn't claim to have any magical qualities in its rubber, no fancy dual-compound stripes, no flat-shielding belts, and not even much of a label. It has a basic steel bead. It's been around a while under different names -- back in the '90s, I think it was the Tracer. You can see that the poor Michelin website doesn't really know what to do with it. Sure, they made up RB and SW techno-jargon-acronyms (for "Rigid Bead" and "Skin Walls") just so there would be something to put on the "technical" tab, but I can hear the copywriter saying, "jeez, I dunno, it's just a tire."

So what's to like about the Dynamic? Well, in this age of hyperspecialization (and resulting hyperpricing), "just a tire" can be a pretty good thing. The Dynamic is an almost-slick tire in the tradition of the quietly legendary (and long gone, rumor has it) Avocet FasGrip series. It's nice and round, corners predictably, rides smoother than its price and utility would suggest, resists flats (around here) pretty well considering its lack of fancy belts, doesn't weigh a ton, and has pretty impressive durability. My set of 700x32s just got retired to the trash bin after three years and probably 8,000 miles of all-surface riding. They could have gone through the end of this season, but the tread was finally thin enough that they were flatting on things that newer ones would have shrugged off.

Did I mention cheap? I think the highest price I've ever seen for a Dynamic was $20 per tire. A savvy web shopper can probably scare them up for as little as $12. They're available in a full range of honest 700c sizes (23, 25, 28, and 32) that all measure true if not a bit wider. Retro-fashionistas will decry their black sidewalls, but I find that blackwalls hold up better to UV exposure (no science there, just personal experience.)

So there you have it: A good, cheap tire. Your mileage may vary, but I like 'em a lot.