Time Trial Tuesday

Not sure why, but I decided to run a little test today.

I’ve been struggling with a feeling that my Long Haul Trucker is more sluggish than it should be.

I know that it’s a touring bike, and I shouldn’t expect it to be “fast”. But when I came home in December, after riding the Dahon folding bike for a month, and rode the LHT for the first time, it felt like I was pedaling through mud. I actually took some things apart to see if there was something binding, rubbing, or not turning smoothly, but I found nothing wrong.

Eventually, I got used to it again, and it felt mostly “normal”.

But in addition, I’ve been riding the Puch bike a lot this year, and it always feels more lively than the LHT. My speeds are not always significantly higher, but it feels faster. And given that the two bikes share very similar, almost identical, geometries (see this photo), other than 26″ vs 27″ wheels … it’s had me feeling confused, and conflicted.

So I ran a little test. A short time trial, 4.2 miles (around the “block” in my neighborhood), two miles gravel road, and two miles paved. All right hand turns, so no physical need to stop unless traffic threatens. It makes a reasonable test course. Since it’s a square, any wind pretty much evens out between headwind, tailwind, and crosswinds. All runs at similar perceived effort.

My question was: How much of a difference do tires make?

Here are the tires I tested with:

1. CST Ciudad, 26″ x 1.50″ (40-559), rated 45-65 PSI, inflated to 55 PSI, weight 510 grams.
2. Specialized Fatboy, 26″ x 1.25″ (32-559), rated 100 PSI, inflated to 80 PSI, weight 363 grams.
3. Continental Double Fighter II, 26″ x 1.90″ (50-559), rated 65 PSI, inflated to 55 PSI, weight 705 grams.
4. Serfas Vermin, 26″ x 1.95″ (53-559), rated 40-65 PSI, inflated to 55 PSI, weight 733 grams.

Left-to-right: CST Ciudad, Specialized Fatboy, Continental Double Fighter II, Serfas Vermin.

Here are the results:

1. CST Ciudad: 16:32 = 15.24 MPH
2. Specialized Fatboy: 15:44 = 16.02 MPH
3. Continental Double Fighter II: 15:41 = 16.07 MPH
4. Serfas Vermin: 15:57 = 15.80 MPH

I each case, I changed only the front tire. The rear tire was a CST Ciudad, 26″ x 1.50″ at about 60 PSI.

Here’s the LHT setup:

The LHT was set up as I normally ride it: fenders, rear rack, panniers, handlebar bag, bento bag. The weight was about 35 pounds.

And, just for comparison’s sake, I also rode the loop with the Puch, on CST “Super HP” tires, 27″ x 1-1/4″ (32-660), specified for 80 PSI, inflated to 55 PSI. Setup comparably to the LHT, with rear rack, small panniers. Weight about 36 pounds. Result: 14:35 = 17.28 MPH.

For sure, I probably need to run this test several more times to get a better average, perhaps on different courses. But, can any conclusions be drawn from this first run?

I expected the Fatboy to be fastest (it’s the lightest, skinniest, smoothest, and highest pressure). I expected the fatter tires to be slower, but more comfortable.

Yet the Specialized and Continental tires turned out to be basically the same, speed-wise, followed closely by the Serfas. The CST Ciudad was much slower. Is that due to tire quality (the CST is pretty cheap, about $13, as I recall)?

The fatter tires were definitely more comfortable, but the Fatboy wasn’t bad (though it felt less stable in loose gravel). On an all-paved course, I expect the Fatboy would have come out ahead. On an all-gravel course, the Continental or Serfas would have been tops.

I bought the CST Ciudad because I thought it struck a good balance between smooth and fat, with just enough tread to be safer than the completely-bald Fatboy on gravel. I’ve found it comfortably enough in mixed-surface riding, and I love the reflective sidewall, but it’s a bit of a slug, speed-wise, apparently.

And yet, a cheap ($7!) CST Super HP tire on the Puch whipped ‘em all by a significant margin.

Whether that’s due to the tire, to the bike, or to the wheel size, I don’t know. Maybe a better-quality tire would make even more of a difference?

So I guess this does verify my impression of the Puch feeling faster (and being faster). But I’m still not sure why that is…

About DirtBum

I enjoy riding bicycles all over -- city streets, suburbia, rural roads, gravel roads, dirt roads, rail-trails, and singletrack. I love exploring the countryside and finding the interesting and historical treasures hidden in plain site.