This year we built a 650c Project bike , with the intent of reviewing as many 650c products as possible – wheels, tires, chainrings, and whatever else is out there. In our second Project Bike article, some folks commented that we should look at reviewing the Serfas Urbana 650c x 28mm tire, so that’s what we’ll do today.

A 28mm 650c tire, you say? Indeed:

The story behind the tire is actually very unique. If you go to the Serfas website, this tire is nowhere to be found, yet it is a current-selling 2013 product. There are no specs, no prices, and it is not in their print catalog.

That is because this tire is actually custom-made for a single bike shop in the world, R+E Cycles, or Rodriguez Bicycle Company, in Seattle, WA (www.rodcycle.com).

R+E was founded in 1973 by Angel Rodriguez and Glenn Erickson. Their business has evolved significantly over the years, and they aren’t your ordinary bike shop. They manufacture and sell their own Rodriguez brand bikes, along with unique accessories such as a tandem-specific brake.

One of the areas in which R+E specializes is 650c equipment. According to R+E owner, Dan Towle, Serfas manufactured and sold a 650x28 version of their Urbana tire for one year, and then discontinued it. Towle contacted Serfas directly and convinced them to make the tire for them as an exclusive distributor, provided they buy a certain minimum quantity. This deal continues to this day, and R+E is the only place on earth that you can buy the tire.

I cold-called Towle in search of this mystery tire. He and the R+E staff were very polite and prompt; only a few days later, I had my very own pair of Urbanas.

I logged quite a few miles on the 700c Serfas Seca RS tire, and this smaller 650c cousin looked very familiar to me. There are no frills – and none are needed. Steel beads, a puncture-resistant layer, and a simple-but-reliable construction. 340 grams of awesome.

When I rode the 700c Seca years ago, they always impressed me with their roundness and quality – especially given the price. These Urbanas look the same, and even have the old tread pattern that I remember:

Before receiving the tires, I asked Towle what the real-world width of the tire was. As we all know, the width that you read on the tire label doesn’t always match up to the measured width on a rim. Towle responded that the tires measure 26mm on a narrow Velocity rim and 27mm on a wider Sun rim. That’s not a true 28, but is much wider than your run-of-the-mill 23mm tire. In fact, this left me with hope that the tire would fit more aerodynamic tri bike frames that might not handle a real 28mm tire.

I built up a pair of low-cost training 650c training wheels a few years ago, consisting of Velocity Fusion rims, Joytech hubs, and DT spokes. Those rims are 19mm wide at the brake track, definitely putting them at the narrow end of the spectrum. With the tires mounted on the wheels and inflated to 90psi, they measure exactly 26.0mm.

When I originally wrote the spec list for the Serotta project bike, I asked for tire clearance for ‘at least a 25mm tire’. I didn’t know of any 650c tires over 25mm at the time, so it seemed like a safe bet.

With these 26mm tires installed, there is plenty of room to spare.

Up front, there is also sufficient space. Even with a wide rim such as the 650c Hed Ardennes, I imagine that the Urbanas would still fit.

Just for kicks, I wanted to test-fit the same wheels and tires on a more ‘normal’ modern triathlon bike – a 48cm Cervelo P2. I started by backing out the adjustable dropout screws…

…and was pleasantly surprised that the tires fit just fine.

Note – with the wheel that far back, there is not much thread engagement for the dropout screws. Damon Rinard, Cervelo Senior Advanced Research and Design Engineer, told me that they have a standard metric M3 thread, so it is possible to buy longer screws for your bike from a hardware store or McMaster-Carr. I would personally take this route if I wanted to use the tires on a 48cm Cervelo long-term.

The Cervelo front fork also manages to clear the large tire:

How do they ride? Don’t let the $29.99 price fool you – these are fantastic tires. They don’t feel like $100 tubular tires with latex inner tubes, but – to me – they feel just like most other normal clincher tires. I have no clue what the rolling resistance is, but for a training tire like this, I don’t really care.

I started with the tires at about 90psi, and ended up settling on about 80 - 85 as my ‘happy place’ (and I’m 170 lbs). If you weigh less, don’t be shy about dropping the pressure a little bit. At low pressures, the extra comfort is noticeable, especially when riding in your aerobars on rough surfaces.

Overall, these tires are a great buy. I’ve been riding around on them over debris and poor roads with zero punctures or problems. In a perfect world, we’d have a 25mm AND a true 28mm version of this tire, but the middle ground 26-27mm choice we have today makes a lot of sense given the low sales quantity. If they fit your frame, I can’t think of a better 650c training tire choice.