If you missed the memo, 2013 is the Year of 650 here at Slowtwitch. We built up a 650c project bike - Part One and Part Two. We also reported on new 650c wheels from both Zipp and Hed, linked at the bottom of this page.

Our initial release about the new 650c Hed Jet 6 came out a few months ago, and since then we’ve put considerable miles on our test pair of wheels. How do they roll? What about our accompanying Schwalbe Ultremo ZX 650x23mm tires? Let’s talk details.

Your Wheels… They’re Small

What’s the first thing I noticed about these wheels? Well, they’re exactly like the700c version, only smaller.

As we reported earlier, the 650c Jet 6 made a big change for 2013 – it got fat. More specifically, it went from a 19mm wide aluminum extrusion to a 23mm wide version (this happened several years ago for the larger 700c wheels). At the time we conjured up our idea about the 650c project bike, the rim change had just happened for the Jet 60, but the Jet 90 still used the old 19mm extrusion. It didn’t make sense to have one skinny rim and one fat rim, so we went with dual 60’s.

Overall, the ride quality impressed me. When I like a wheel, I can struggle with things to say about it. They work. They ride like wheels. They don’t rub the brakes, make noise, or go out of true. The aluminum braking surfaces stop predictably in a wide variety of conditions and temperatures. While I would have preferred the deeper rear wheel, I have no complaints about the 60’s. As we noted in our Project Bike articles, one of the things about 650c that benefits ALL riders (regardless of height) is their stability. No two ways about it – there is less wheel for the wind to see compared to 700c.

My unscientific calculation for exactly how much stability you gain goes like this: To have equal stability between a 650c and 700c wheel, you must subtract approximately 20-30mm from the rim depth on the bigger wheel (or you can add 20-30mm of rim depth to the smaller wheel). Assuming all else is equal, that means that this 650c Jet 6 is about as easy to handle as a 700c Jet 4. If you haven’t ridden many wheels (or wheels of both diameters), you’ll have to take my word on this one. I hate to point out the obvious, but all of you Kona-qualifying ladies and gentlemen of short stature – this is your front wheel!

I think the only thing that I dislike about the wheels is the fact that they don’t let me hang my bike up by one wheel on a hook. Perhaps I could try, but I’d be too afraid of causing damage. The aerodynamic fairing is rather thin (making it light weight), and it is flexible to the touch. I would probably feel better about hanging the bike completely upside down via two hooks, but that’s not how my garage is set up. So – the bike gets parked wheels-down.

What about aero data? For now, Hed simply told me that the performance of the 650c wheel is in-line with the 700c, plus the obvious crosswind benefit. The rim shape is identical on the smaller wheel, which tells me that these are among the fastest choices in the industry, provided an equal playing field of tire choice. Unfortunately, Hed did not have a plethora of charts and graphs to provide – due to low sales volume, they spend the bulk of their expensive wind tunnel time on 700c product.

Accessories and Details

My wheels came with everything I needed to get rolling – special wide rim tape, valve extenders, and quick release skewers.

Hed also gets a gold star for being the first company (that I’m aware of) that makes a proper 11-speed cassette spacer:

The latest Hed hubs are 11-speed compatible, which means that the freehub is 1.85mm longer than the old version. That older freehub standard already required a 1mm spacer to use a 10-speed cassette, so the 11-speed requires a total of 2.85mm. I’ve not seen a single brand aside from Hed that provides an ‘aggregate spacer’ like the one above (others require that you stack spacers up). Some other 11-speed wheels I’ve ridden actually come with completely incorrect parts – like an additional 1mm spacer to stack with your existing 1mm spacer… leaving you .85mm short. When you’re spending this much money on wheels, the details matter.

I must admit that I was not hot to trot on the valve extenders that came with the wheels. They work well enough, but I’ve been spoiled by the latest crop of removable-core valve extenders. Lucky for us, Hed just debuted their own version, available in two lengths ($25/pr):

Especially when using a preventative tire sealant, the removeable-core extenders are wonderful.

Schwalbe Ultremo ZX 650c tires

Our friends at Schwalbe sent along a pair of their high-end Ultremo ZX tires to use with these wheels ($80/ea). I’m a fan of the Ultremo, and put quite a few miles on the previous Ultremo ‘R’ tire in 700c size. In my experience, they have a very supple ride and good puncture resistance.

The tires did not disappoint. Installation on the Hed rims was what I’d call ‘average’ – not too tight, not too loose. I don't say this with any sentiment of discrimination, but tire installation is a big deal for the ladies. Put simply, they don't have the clumsy club-thumbs of us men, which can make it tough to install a difficult tire. I've had more than one female friend express to me that this is one of their most important considerations when looking at wheels and tires. I can confidently say that these wheels with these tires pass the test.

I was also pleased to see that the tires measured 24.0mm on the wide Hed rim at 100psi. I’d suspect that on a narrower rim (13 or 15mm internal width), the measurement would be closer to a true 650x23mm width.

I don’t have much rolling resistance information on the tire beyond Schwalbe telling me that the Ultremo ZX is their second-fastest rolling tire; they report that the tubeless version actually rolls a little bit better (but it is not available in 650c). Schwalbe also provided me with a rolling resistance test done by the German Tour magazine, in which the tubeless ZX won overall. Second place was the Continental Grand Prix TT, third was the Continental 4000 S, and fourth was the standard tube-type Ultremo ZX. Unfortunately, I do not have a detailed protocol for their test (i.e. inner tube material/thickness, tire roller size/speed, etc), so I can only pass along what I know.

The short version is this: I like these tires, and would have no qualms about racing on them.

Stop the Presses – New Jet 9’s

Let’s close out this review with a bang:

As of this writing, Hed has officially updated the 650c Jet 9 to the wider rim (23mm external width, 17mm internal width). The old ones have been discontinued, so anything you buy from here forward has the new rim.

If you ask me, that news is huge. I think it’s also fair to say that this cements Hed as the #1 wheel company in 650c. They have the Jet 6 and 9 in wide rims. They still offer the Hed 3 in both clincher and tubular - and in the special ‘deep’ version. That’s a total of six unique 650c wheel models. Even without a disc, I think we can agree that it's an exciting time for small wheel riders.