Measuring the SP PD-8 hub

UPDATE January 2015: You can now find a technical drawing with measurements here.
CORRECTION: Please note that an earlier version of the post claimed that the center-to-flange distance is 32mm. I've corrected that to 22mm. Sorry for the confusion.

I'm getting read to build up new wheels with my recently acquired dynamo hubs. In my previous post, I had posted the manufacturer's stated dimensions, but I realized that they only provided the pitch circle diameter and the flange diameter--the latter being irrelevant for determining spoke length--but not the center-to-flange distance and also not the spoke hole diameter.

The best instructions for measuring a hub come from Roger Musson, author of a popular book on wheelbuilding. Fortunately, he has made this part of the book freely available. All you need to take the relevant measurements are calipers and a ruler. Musson suggests to drill a piece of wood, so that you when you insert the hub's axle the wood will be flush with the locknuts. If you're building a lot of wheels this probably makes sense. As an alternative, you can just measure from the end of the axle and then subtract the easily measurable distance between axle end and locknut. Then use the ruler to measure the distance between the wood/axle end and the inner side of the lower flange (what Musson denotes as x). Then turn around the hub and repeat the measurement on the other side, giving you the y value. With the SP disc hub that's a bit tricky, as the diameters of the two flanges are different. Musson's suggestion is to use a small piece of cardboard, mark it, and then measure on the cardboard. I was in a bit of hurry and thus just eyeballed it with the ruler after seeing that x and y would likely be the same for this hub. X and y are not the actual values needed for calculating spoke length, but they allow you to calculate the desired value by subtraction from half of the over-the-locknut dimension of the hub, z in Musson's system. On modern front hubs for regular bikes you don't really have to measure this, as it is a standardized dimension at 100mm. For the PD-8, x and y equal 28mm (32mm-4mm for the distance from axle end to locknut), yielding a center-to-flange dimension of 22mm on each side.

The flange diameters can directly be measured with calipers. Just make sure to measure from the centers of the spoke holes. The PD-8 comes out to 52mm and 58mm. The spoke hole diameter is a bit tricky to measure: The inside jaws of regular calipers tend to be too big for such small holes. I measured 2.7mm, but as most hubs use 2.5mm holes I'm assuming this is a measurement problem.

Now you can plug your values into the spoke length calculator of your choice and voilá! I recommend Karl Stoerzinger's Freespoke or the DT Swiss calculator.

First impressions: SP Hub Generators PD-8 and PV-8 (updated)

Wouter Scholten's website is a great resource for all hub generator lighting issues. He extensively tests almost all models of hubs and lights on the market in real world settings, and he is also unusually well-informed with regard to the introduction of new products. A while ago, he wrote about a new player on the hub generator market, Shutter Precision Ltd. from Taiwan. As the name implies, they started as a supplier for digital cameras and then later moved into bike component manufacturing. While the company itself has little name recognition, they are (presumably) the suppliers for two better known companies, Velo Orange[1] and Supernova.

After having introduced their switchable dynamo (in my opinion a solution in search of a problem), at the 2011 Taipei Cycle Show SP announced what would be the lightest generator hub, the SD-8 (disc brake)/SV-8 (rim brake). These two hubs, however, only are rated to a power output of 2.4W in a 622mm wheel, making them not street-legal according to the German StVZO requirements. However, they also announced a slightly more heavy model rated at 3W, the PD-8 and the PV-8. The technical specs and the prototype tests by Wouter sounded promising, and when Wouter's shop, Gambiet Fietsen, offered them for pre-order in September I went in for two generators, one disc, one rim. The disc one will replace my Shimano DH3-N80 on the Cross-Check which I unfortunately messed up while trying to re-grease the bearings, and the PV-8 will be part of a second front wheel for Gunnar, finally allowing me to turn him into a real brevet bike.

The hubs arrived yesterday, at a total price of 180 Euro shipped. The actual wheelbuilding will have to wait for a little while longer, but I wanted to share some pictures and impressions.

PV-8 in its original packaging. I'm not sure if all the color and spoke count variants are or will be actually available.

The hub looks quite similar to the current SON 28...

...but it does have the same terminal as Shimano hubs

Here you can see the German K-certification wave, making the generator street legal in Germany

The weight pretty much exactly matches the claimed weight.

Both the disc and non-disc version of the hub match their claimed weight of 390 g and 410 g, compared to 440/460 for the new SON 28, 490 g for the Shimano DH3N80, and 399 g for the Supernova Infinity S (center lock disc mounts). Only the SONdelux at 390 g (rim) and 395 g (disc) can match this, but at a significantly higher price point.

SP claims that the new generators do not only excel in weight, but are also "the most efficient" generators (this refers to the 2.4W ones) and their product sheets has a couple of graphs that show the generators to be more efficient than the SONdelux. I'm somewhat skeptical about those claims and am very much looking forward to some independent testing.

Measuring the dimensions of the hubs is a bit tricky with the tools I have and I've only been able to find the manufacturer's numbers for the 2.4W version. Probably they're going to be the same for the 3W, but I'll confirm this with Wouter or measure myself. The bearings are sealed cartridges and I'm not sure if they are user-replaceable.

I think that's all I can say for now. Once I have the wheels built up and ridden them a bit, I will post an update.

Update 2011-12-16:
In the meantime I've found the website of SP's distributor, and their catalog lists the relevant dimensions as follows:

	PV-8	PD-8 (non-disc/disc side)
Spoke P.C.D.	52mm	52mm/58mm
Flange diameter	60mm	60mm/66mm

They also have "replacement instructions" on their site that might contain instructions on how to replace the bearings. Unfortunately, the document is corrupted, though, and can't be opened. I've sent them an e-mail and we'll see if I hear back.

[1] If I remember correctly, the Velo Orange switchable dynohub got some bad reviews. At any rate, they no longer seem to sell it.
[2] There is also a 2.4W version, called SD-8/SV-8, suitable for those on small-wheeled bikes or those who don't care about the extra power/street legality in Germany.

First impressions: Innova 700x35C Studded Tires

Update 2012-26-02: I now have posted an extensive review of the tire.

The first snow of this winter has arrived in Montreal, and it was quite a lot. As an avid follower of various kinds of weather forecast (yesyes, I'm soo boring) I was, however, well prepared. The night before I put on my new studded winter tires. I bought them sometime in spring, knowing that in winter it can often be tricky to still find studded tires in stock. The only tires in a suitable size -- my fenders only allow a max of 38 mm wide tires -- that my bike shop had available were Innova Snow Tires in 37-622. The tires have a pretty aggressive tread and a total of 110 steel studs, positioned in two rows near the tire's center.

The Innova website is pretty uninformative, and I also couldn't find much information elsewhere on the interwebs. I'm curious how the steel studs are going to hold up. More expensive snow tires from Schwalbe, Nokian/Suomi, or Continental use carbide studs which are harder than steel and should therefore last longer and will also not rust -- even though that is primarily a matter of aesthetics. In principle, the studs should be replaceable and I'm assuming that I could use carbide replacements if necessary. Measured width was about 33 mm on an Alex DA-16 (internal rim width 19mm).

Price

I paid 40 USD per tire at my LBS, which is a pretty good price for studded tires in North America. Last week I saw them at a bike shop in Montreal for 75 CAD each and on Amazon they sell for 64 USD (if you can fit 45mm, you can currently get them for 36 USD there). So they're not cheap when compared to normal tires, but in the world of studded tires they're probably the cheapest you can get. And if they prevent only one crash they're probably already worth it.

Ride quality

 I took the tires on a first 80 minute test ride on the night before the snow actually arrived. It is advisable to break in studded tires, i.e. riding them without hard cornering or braking, for a couple of kilometers in order to allow the studs to set themselves in the tire and avoid losing them prematurely. So I rode along the Lachine Canal bike path, which was mostly dry with some icy puddles. On dry pavement, you can clearly feel the increased rolling resistance of the tires. Up to now I have been on Vittoria Randonneur Pros in 35-622, which roll very nicely, and thus the difference was very noticeable. The best way to describe the feeling of the tires is "riding into a slight headwind." What is even more noticeable than the rolling resistance is the noise of the tires: people often joke that you can take off your bell when you're riding studded tires, and I have to agree: the sound is very similar to riding on fine gravel, even though I think the tires have gotten a bit quieter on the third day. There were some frozen puddles on the Lachine Canal path, and I somewhat cautiously tested riding over them. All went well and so I got a bit bolder: Braking on the ice also worked pretty well.

The next morning I rode into work once the snowfall had mostly stopped. I tried going my usual route on the Lachine Canal, but they don't clear the snow there at all and riding through deep snow wasn't too awesome, even with the new tires. At the next intersection I therefore turned onto the streets which were more or less snow-free. On the more snowy parts, the tires performed reasonably well -- I would say better than the Ritchey Cross-Pros I had been riding during the past winter, but it's hard to tell. On the way back, the roads were mostly snow free, but I did go across an icy pedestrian bridge near Atwater Market. Here the studded tires were great, and I think not having to worry about icy patches that can often be hard to spot is the main advantage of studded tires.

Since then it had gotten warm again and I have taken the tires off. The next snow and ice will come soon, though, and I will probably post an update at some point.

Product details:

Innova TR5263 Snow tire
110 steel studs
700x35C (37-622), also available in 700x45C
Price 40-75 USD

Ride report: 150 cold kilometers

It's time for the annual winter trophy again, and this year I'm member of a pretty hardcore team. My last two weekends were spent with conference and work travel and I had fallen behind quite a bit. The weather forecast for Saturday looked okay -- about 5 degrees and dry -- and so I decided to do what could be the last really long ride of the season. I combined a bit of a previous route with some new bits, resulting in a 150km course that would be almost exclusively on bike paths and lanes.

I made up my mind of where to go last minute, as per usual, and only got on the road around 11:30. The only crossing of the St. Lawrence that hasn't been closed for the winter yet is the Jacques-Cartier Bridge. The offramp of the bridge is only a few blocks away from the Route Verte 1, which led me out of Longueil first on bike lanes/cycle tracks and then on bike paths more or less away from traffic. There was a steady headwind coming from the south which kept my speed at around 20 km. Once I reached Chambly I made my first stop of the day on the beautiful shore of Lake Chambly. One of the things that suck when biking in the winter is that you can't really have any longer outside stops, and thus only ate a Clif Bar (as an aside: their new coconut-something flavor is great!). I had done this part of the ride before on the 100k-ride with the Biketopus, but now I crossed the Richelieu river instead of continuing along the Chambly Canal.

On the OpenCycleMap I had found the Route des Champs which leads east toward Granby. The description on their website promised a mostly paved, partly gravel route and so I was quite shocked when I got to what I thought was the trailhead outside of Chambly: the trail was basically an old railway bed with the tracks removed. I tried riding on it for maybe 50m, but it was almost impossible to ride on the loose rocks. At the next intersection I stopped and considered my alternatives. Only then did I spot the actual trail only 30 meters to the north, parallel to the busy highway. Phew.

The Route de Champs was very nice to ride on: very long straight stretches, few intersections, and a nice hardpacked gravel surface. The Route des Champs meets the Route Verte 1 in Granby, but that would've been too far and thus I turned south in Saint-Cesaire, now following the Yamaska River on a very quiet country road with surprisingly good pavement.

In Farnham I then turned west again on the Route Verte/Monteregiade and took another Clif Bar stop, which was highly overdue -- I could already feel some bonking symptoms. The Monteregiade, built on the right-of-way of a former CN railroad, is lovely to bike on and for the first time on the ride I had a bit of a tailwind. After less than an hour I arrived in St. Jean-sur-Richelieu and took another rest stop at the gas station (note to self: never again buy grape-flavored Gatorade). I was a bit disheartened to see a Route Verte sign saying "Montreal 60 km," but once I got going I felt pretty good again.

It was pitch black at this point, but with my trusty B&M Cyo lights riding the gravel trail along the Chambly Canal was very pleasant. The ride back to Montreal was not very eventful and after almost exactly 150 km and 7 h 25 minutes I arrived back home. The 29 Winterpokal points (at least temporarily) catapulted me on the third place in our team.

A Converge Show, a Night Ride and a Skunk

Mephitis mephitis by Dan Dzurisin, CC-By 2.0

A couple weeks ago I heard that Converge were going to play at the Lost Horizon in Syracuse and, Converge being one my absolute favorite bands, I wanted to go!

Only how to get there? Bus service to Syracuse is basically non-existent and taking the carshare car would have been too expensive. That left me with either getting a rental car or taking the bike. It's about 90 km to Syracuse, i.e. easily manageable for a one-way ride, but pretty far for a return trip. Initially I planned on riding there, staying overnight in a cheap motel and then riding back the next morning, but riding back the same night seemed like an interesting and challenging option.

I left Ithaca around 2 p.m. on Wolfgang, loaded with only a Frontroller. A large part of the route I had done previously on my Winter Adventures ride. Between Freeville and Munsons Corners I had a flat due to a not properly vulcanized tube patch. Because I only had brought one spare tire and didn't like the idea of potentially having to patch a tube on the night portion of my ride, I decided to stop at a bike shop in Cortland. Thanks to my smartphone and an open wifi access point I found my way to Action Sports on N Main St -- only to realize they were closed on Tuesdays! Oh well.

After that little detour I continued north on NY-281, with traffic gradually getting lighter. After a short break in Tully, I turned east on NY-80 and then turned left again onto Apulia Rd, leading me north towards Syracuse. Apulia Road is lovely: following a river and the railway, it is slightly downhill most of the time, pavement is great and traffic is very low. At Jamesville Beach County Park I made a stop to refill my water bottles (their restrooms were locked, unfortunately) and continued towards the huge quarries just outside of Syracuse. After going through an underpass across I-481 I then rode through nice residential neighborhoods on low-traffic streets and finally arrived at the Lost Horizon a bit past 7 p.m.

Unfortunately, there was no proper bike parking anywhere near the club and thus I hid Wolfgang behind hedge. The Converge show was really awesome and made me forget my slightly sore body. Therefore I decided to indeed skip the motel and ride back right after the show ended.

Converge by Francis Bijl, CC-By 2.0

I left around 10:30 p.m. and returned on the same way. Riding at night can be really nice: almost no cars, no noise except for the sounds of wildlife, and also no wind. The sky was mostly cloudy and the moon did not rise before 2 a.m. To prevent tiredness and boredom I listened to podcasts on my phone for quite some time but eventually ran out of them. Then somewhere between Tully and Cortland it happened. I wasn't properly paying attention to the road and suddenly I hit something. I didn't crash but it was quite a bump and a gross, cracking sound. I must have run over an animal, presumably an already dead one. I had little desire to go back and take a closer look and just continued on my way home. Only when I arrived in Ithaca at 4 a.m. and carried the bike up the stairs to our apartment I realized something was wrong: during the ride I had smelled skunk every once in a while but didn't think much about it -- it's a fairly common thing in rural Upstate NY. But not in our building! So it dawned on me that the run-over animal must have been a skunk. A smell test on Wolfgang's tire confirmed by suspicion and I decided to park outside...

Stats: 190 km, about 1400 m of climbing, average speed of 21 km/h

What keeps a bike upright?

It's rare that bicycles feature in the Cornell Chronicle, but today there is an article about interesting research by Cornell prof Andy Ruina on what prevents bikes from falling over. The main finding is that conventional theories of self-stability -- the gyroscopic effect of the spinning wheels and trail of the front wheel -- are not the main factors in keeping a bike stable. Ruina and his collaborators have constructed a bike (well, it doesn't look exactly like a bike) that has no gyroscopic effect and no trail -- but still stays upright on its own. Fascinating stuff with potential practical implications for bicycle design.

There's also a video explaining the research, and here's a the pre-print of the article which will be published in Science.

January to March Summary

Due to my injury there is not much to summarize here. I've just started to get back on the bike and in March I logged 170 km, all on Wolfgang. I lost some kilometers in January, before I broke my wrist and lost the bike computer, but that probably wasn't that many. I'll be back with happier news at the end of April!

Winter(pokal) is over

The Winter Trophy is over. Due to my broken wrist I ended up with only 182 points, putting me on place 1826 out of 2414 participants. I think the Winterpokal is a great motivational tool for getting you on the bike and I'll join again next year -- then hopefully without any further injuries.

Review: SKS Longboard Fenders

SKS Chromoplastic fenders are great. They're stylish, lightweight, and durable. The only problem was that they are too short and they don't come with mudflaps. If you're riding your bike year round, in any kind of weather, the longer your fenders are the better. A couple of weeks ago, ecovelo pointed out that Rivendell was selling a new model of SKS fenders, the Longboards. The main distinguishing feature is that they are longer and they do have mudflaps in the front and in the back -- perfect! Thus I ordered a pair from Swan Cycles and picked them up today.Of course, I couldn't wait to put them on and I wanted to share some pictures and give an initial review.

Before: front wheel with DIY Fructis mudflap

Before: rear wheel

The fenders come with minimal, functional packaging

Step one was to remove the old fenders. This was largely unproblematic, but requires taking off the rear wheel in order to get to the screw next to the bottom bracket. To give you a direct comparison between old and new fender, I've put them on top of each other. Clearly, they provide much more coverage, especially the front fender. (I bought the old fenders in 2008; I've heard that in the meantime the regular Chromoplastics have become a bit longer, but I'm not sure about this.)

Difference in length is not that significant

Much better coverage

Installing the new fenders took an unexpectedly long time. The main issue was cutting the struts to length. Now the older fenders, in addition to the coverage issue, had the problem that the end caps provided for covering the potentially sharp ends of the struts tended to get lost quite easily. I think I lost three of them within the first week of mounting the fenders. SKS has solved this issue by making the end caps longer and wedging them between the mounting hardware of the struts and the fender. While this may sound like a neat solution it comes at a cost: the struts have to be at exactly the right length for the system to work. Therefore, you first have to mount the fenders without the end caps, mark the struts, unmount the struts, cut the fenders to length, and then reinstall everything with the end caps in place. Cutting the fenders took me a bit, since I don't have the proper tools (read: bolt cutter); and fiddling the struts into the caps also was quite tricky. Well, fortunately you only have to do this once and now the fenders look really nice:

 

The end result

The coverage looks really good, even though I would have like then to extend a bit further to the front on the front wheel. The mud flap is made of a flexible material and is close enough to the tire that it shouldn't be an issue when riding down a curb. Now I'll just need a good downpour to confirm the Longboards' function.

SKS Longboard Fenders
45mm wide
available in black, silver, and creme
around USD 40.-

Edit 2011-04-02: After using the fenders for a few days, I noticed that the front fender does reach down very far -- maybe a bit too far. Therefore I have moved the fenders from being mounted at the rear of the fork crown to the front. This slightly increases the ground clearance of the fender and also extends them further by maybe 3 cm. I've ridden in light to medium rain a few times by now and the fenders work very well!

The toll of winter

I've said it before and I'll say it again: salt is bad for your bike's health. Don't believe me? Well, then check out the following pictures of Wolfgang.

These brakes no longer move by themselves.

Hopeless...

Okay, not directly salt-related, but anyway

Due to my wrist injury, Wolfgang was sitting outside for several weeks and when I tried reactivating him, it was pretty hopeless. The chain was stiff, the front derailleur only moved when being kicked with the foot; and the rear canti brakes didn't reset themselves anymore.

So I switched the chain, which also required me to put on a new Shimano XT 11-34 cassette, replaced the Tektro Oryx cantis with an Avid SD7, and replaced some of the brake and shifter cables. Quite annoying, but that's the price you have to pay for riding all year on well-cleared roads in Upstate NY.

Back on the bike

Okay, my wrist is no longer fractured, the cast came off 3.5 weeks ago, and thus I'm finally back on the bike. Of course, being in a cast and off the bike for over 2 months took its toll, and the wrist isn't fully healed yet. So I started slowly, with a 38 km ride into familiar territory: to Taughannock State Park and back. Spring hasn't arrived in Ithaca yet, and so I had to deal with temperatures of -5°C, cold winds, and at the end of the ride some snow. It felt very good to be back riding, even though my wrist hurt quite a bit when riding in the hoods -- riding on the tops seems to work better. I hope this is going to get better soon, as I need to do some serious riding to get back into shape for the season.

Great Sigma Customer Service

In the previous post I mentioned that I lost my Sigma BC1606L bike computer. I had always been very satisfied with the computer and replacing it with another model would have been rather costly when adding the price of an extra mount and cadence sensor for my second bike. Getting a replacement, however, appeared to be difficult: The 06-series has been out of production for quite some time now and thus I sent the (German) Sigma customer service an e-mail, asking if they could tell me where to get a replacement. Within a few days, the US distributor Sigma sent me an e-mail and offered to send me a replacement -- free of charge! This was a very pleasant surprise. The computer wasn't terribly expensive in the first place, but this is nonetheless great customer service. If I ever do replace my computer it will most likely be another Sigma.

Don't break your wrist!

Dear reader,
may I offer some good advice? Don't break your wrist.

A month without any blog posts is not due to the fact that I've been riding all the time, or to the awful winter weather. No, three-and-a-half weeks ago I broke my left wrist while---not cycling, but snowshoeing. Somewhat ironically, on just that day I had ordered my own pair of snowshoes, as I no longer wanted to rely on Glenn Swan's generosity in lending me a pair of his. To add loss to injury, I also managed to lose my bike computer while awkwardly trying to bike back home with my broken wrist.

While I'm on the way to recovery, biking will still have to wait for at least two more weeks. I tried getting some exercise today on the trainer, but my wrist still can't support my weight, and riding one-handedly gets old pretty quick. In order to get at least some exercise (and to get to places!) I've done a lot of walking, both with and without snowshoes. Once my cast will be removed (March 1), I'll hopefully be back on the bike, if not for longer rides then at least for running errands and buying groceries.

Be safe,

Hobbes vs. Boyle

Snow!

Ride report: Dip into Pennsylvania

"Visit PA" is what is written on Pennsylvania license plates, and last Wednesday I was ready to heed that call and do a bike ride into the Northern Tier of the Quaker State.
As per usual, I had a late start due to complete lack of preparation on the previous evening. The planned route was about 130 km and I didn't mind the fact that I would have to do parts of the ride in the dark. The weather forecast predicted temperatures around and slightly above freezing and possibly even some sunshine in the afternoon.

The plan for the ride was to get out to Spencer, head towards Waverly and then turn around, taking a different route. Since NY-34 between Ithaca and Spencer is somewhat annoying to ride on when you go towards Spencer (traffic, narrow shoulders, constant uphill), I decided to take a longer, more strenous, but also much more scenic way to Spencer and then take 34 on the way back. On my newly installed Vittoria tires, I headed out of town towards Buttermilk Falls State Park and then up Sandbank Road. From there I took the very quiet country roads towards Danby, from where I followed NY-96B for a few kilometers. Had it been summer I probably would've taken Michigan Hollow Road but I knew that it was a dirt road and I was worried that it might be too snowy. Instead I turned right onto S Danby and the continued on Fisher Settlement Rd. It turned out that most of Fisher Settlement Road is also a dirt road, and a pretty hilly one at that. The road surface was mix of snow and wet dirt but aside from slowing me down it was okay. Just outside of Spencer, Fisher Settlement Road merges with NY-34 and in Spencer Downtown I turned left onto NY-96 towards Candor.

On an FLCC Sunday ride earlier this year, I had ridden on Halsey Valley Road, but going the opposite direction. Today I followed Halsey Valley Rd South and then continued on Oak Hill Rd. Oak Hill Road leads all the way into the Susquehanna Valley. On small roads running parallel to the river and NY-17C I finally got into Waverly and after crossing the Southern Tier Expressway I was in Pennsylvania. The part of Pennsylvania I ended up in turned out to be a rather unexciting mix of warehouses, strip malls and lots of scary sounding warning sign about dangerous drivers. I took a longer rest stop at the Sayre McDonalds and refueled with a large coke and fries. I knew that the way back would be shorter, but I still had about 50 km to go. I followed NY-34 out of Waverly, heading north, until after 10 km I turned right unto Dean Creek Road. This turned out to be a very quiet country road, gradually climbing and then descending towards Spencer. In the meantime the sun had set and because the moon wasn't visible, I rode in almost complete darkness. I've really come to enjoy riding in the dark a lot -- at least as long as it is on quiet roads.

Once in Spencer I quickly contemplated stopping for a cup of coffee at the gas station but the prospect of the rest of the ride being almost all downhill made me continue. Traffic on NY-34 was light but still too much to make the ride in a starry night as pleasant as it could've been. After a quick stop at Taste of Thai Express in Ithaca to pick up dinner, I finally arrived back home after seven hours of riding time. A strenous but very enjoyable seven hours.

First Impressions: Vittoria Randonneur Pro 700x35c

I picked up my new tires last Tuesday and already put almost 200 km on them. Tueoo early for a comprehensive review, but not too early for some first impressions.

Sizing and weight

Dishonesty in tire sizing is a well-known phenomenon in the bike world. In order to be able their tires as especially light-weight manufacturers make them narrower than their designation implies, so your 700x28 c tire might be only 26 mm wide.¹ This is definitely true for the Randonneurs. Their measured width on a 19.6 mm Mavic Open Pro rim  is only about 32 mm.

The tires' weight as measured on my kitchen scale is fortunately closer to the manufacturer's claim: 472 g vs. 460 g advertised.

Rubber and Tread

The rubber is definitely softer than my Michelin Krylions and also a bit softer than my Continental Gatorskins. Tread is rather minimal, as you can see in the picture.

Mounting the tires

The Randonneur Pro is a folding tire and was reasonable easy to mount. Folding tires tend to be a bit more difficult to mount than wire bead tires because they don't stay in place by themselves. The trick thus is to fix them on the rim in one spot with a zip tie. From there I could easily mount them with two tire levers.

Ride quality

I took the tires on a 130 km ride, mostly on the typical wintry salt-water-grime pavement, but also several miles of partly snowy, partly muddy gravel roads. For pressure I followed the Bicycling Quarterly guidelines, i.e. 60 psi in the front and 70 psi in the back. The tires had a surprising amount of traction and the ride quality was nice. The rolling resistance is hard to assess: The moving average on this ride was only 19 km/h, which is fairly slow for me. But if that's due to the tires is unclear. The dirt roads, the hills and my general lack of energy on that day probably contributed more than the tires. But I will keep an eye olin that.

Conclusion

So far I'm happy with the tires. I'm annoyed that they are narrower than advertised but since I'm riding mostly on snow-free asphalt roads it probably doesn't matter too much. The main question is how puncture proof the tires will be. Updated will follow.

1 The whole issue gets complicated because of the various tire sizing systems. I have a rough understanding of how they work, but I, for example, still don't understand why 622-35 is the same size as 700x37C, and I have no idea if said tires are 35 or 37 mm wide.

December Summary and 2010 Recap

The final numbers for a successful 2010 are in and it time for both the regular monthly and the first annual summary
The larger goal of getting to 6000 km by the end of 2010 motivated me to keep my riding up in December, despite increasingly adverse weather. 6000 was still 491 km away at the beginning of the month, and only by December 30th had I reached the magical 6000 km. Most of December's riding was done on Wolfgang (494 km vs. only 15 km on Gunnar) and the average 16.4 km/day totaled at 509 km -- exactly the same value as last month.
For the whole year, I rode a total of 6018 km, at an average of 501 km/month or 16.5 km/day. I'm pretty impressed! The only months during which I rode less than 500 km were the wintry ones and July, during which I was traveling. I don't want to make any predictions for next year, as there are too many life changes ahead. But it's safe to say that 2010 was an awesome cycling year. I did my first 200 km ride, I rode more than ever, I did my first real road race (and probably my last one, too), I built up and rode the lovely Gunnar, I went on a nice bike weekend in the Adirondacks, and, most importantly, I had loads of fun and no crashes at all!
Happy 2011!