In-House Beta Testing Silk


For the last several months I’ve had the privilege of beta-testing a Silk, our new 20-inch Gates Carbon Belt Drive bicycle.

I’ve been impressed with the sturdiness and durability of the new design. I take the bike off curbs (sometimes up them). I drop the bike regularly. I never clean it. And I haven’t oiled it once.

Despite the repeated, and intentional, abuse it still runs smoothly.

My favorite moment, what really sold me on the Silk, came during a heavy downpour in the dark of night.

I was leaving the Bike Friday factory and traveling home via a bike path that runs alongside a canal.

I noticed that the water level of the canal was high but didn’t think much of it. When I came to the first underpass, however, I was abruptly soaked from the knees down by a long stretch of water 7 inches deep.

My rain gear didn’t hold up so well and my boots filled with water, but the Silk didn’t skip a beat.

A half a mile later, still cursing myself for getting drenched, I encountered a second underpass.

This time I knew the water was coming and I thought, “Well, I can’t get any wetter … let’s see what this thing can do.”

I sped down the underpass as fast as I could, hitting the water with an even greater splash.

This time it was up to my knees and pedaling through it felt like I had the brakes on.

Downshifting with the Shimano Alfine 11 hub and the Gates CenterTrack Carbon Drive Belt entirely submerged? Not a problem.

In fact, the drive system responded just as well as it does when it’s not under 22 inches of Oregon winter runoff.

I pedaled out of the flooded underpass feeling victorious.

Being very familiar with this particular bike path I knew that there was a third underpass still waiting for me.
I approached this final deluge with a great deal of enthusiasm and speed.
However, 20 feet in and I was up to my waist. This wasn’t just a little spillover, no, at this point I was very much in the canal.
I was heading upstream with the full weight of the flooding waters pressing against me.
By no fault of the bike, I couldn’t go any farther — the water kept pushing me over. It was clearly time to turn around, and going with the water this time made for a, relatively, quick exit.
I continued my journey home, water pouring out of my pants, alive with excitement and deeply impressed with the Silk.
The rest of that night, and from then on, the Silk has held up great.
No real problems, no real maintenance, and plenty more abuse.
It just keeps taking it like a tank, like a nimble, quiet tank.
[Editor’s note: Matthew is a member of our Production team that hand builds Bike Fridays when he isn’t splashing his way home.]

15 Responses

  1. Hope my Silk is not Beta tested; oh well then, okay for everyone to try it. Although the Alfine hub is not a submersible, and therefore not really totally water proof, I understand that you can just drain and replace the gear oil bath (basically a transmission oil change). Wonder if the hub wheel bearings are easily accessible for repack. The Silk fame seems quite adaptable to be configured either as mountain bike or road bike. From my mountain biking experience, the problem with submersion riding (like riding down the Coyote Canyon Creek) is that of cartage bearings, especially on the bottom bracket which, cannot be repacked, and are not easily replaced. One really nice mountain bike had grease injection plugs for its bottom bracket (hint hint). I understand based on a post over a year ago, that Rob English has been racing on a frame similar to the Silk: with a rear fork, rather than seat/chain stay triangle. So this rather radical new frame design is fairly tried and true. It makes me want to ask if that dampens the ride a bit: does the rear fork give a bit of a suspension without detracting from pedal power transfer? Seems as though it might. Also looks as if there is frame room on the Silk for me to put on the fattest 451 tires for to taking it off pavement, and the frame and wheels can hold up fine. If there is some slight loss of efficiency with the belt/gear hub drive train, it could be made up for, I should argue, by always being in the right gear at the right time. Derailleur gears may offer greater efficiency with less weight, but demand a great deal of maintenance and replacement to keep it that way – especially when used in the wet. So now you have essentially a foldable commuter bike with 20-inch wheel performance. As soon as everyone there is finished riding my purple Silk with drop bars and Alfine 11 hub, please send it to me.

  2. To think of it now, the Alfine 11 hub should be fairly water-tight. If in deed it is an oil-bath lubrication, then it must be oil-sealed, and therefore, rather impregnable. It is the Nexus that, being grease lubricated, is not sealed against submersion, and would need repacking. No matter how heavily greased is a chain, it is a mess when getting wet. Or else it starts wearing quickly, stretching, and will cause all the sprockets to be in need of replacement. Chains are high-maintenance, especially with derailleur gearing. That is just one thing I like about the belt. Have thought the Carbon Belt system might be vulnerable to mud or snow build-up causing it to jump and be damaged; whereas sprockets can push through the chain spaces. However in a race under heavy mud/snow conditions had even one-speed chain-cog drive trains clog and fail, where the Gates Carbon Belt drives were unaffected.

  3. Hey Matthew, great to hear your working with Bike Friday and great to read your bike testing story. The Silk sounds like a dream of a bike. I still ride my old Miyata on the Saint John River Road here in New Brunswick. I wish I could justify buying a Bike Friday Silk, but old age is catching up with me. I recommend Bike Friday every chance I get.
    Keith Helmuth

  4. Matthew, thanks for sharing your impressions with the Silk. I’m new to folding bikes, but I’m really pondering to get one (also, since I need to new bike).

    I am still a bit concerned about the durability of the bike, especially when I stand up from the saddle and lean onto the handlebar with my weight (I’m 6.1 ft and 165 lbs). Can do this with the Silk like to do with my normal bike (trouring/cross bike)?

    1. Matthew is busy building Bike Fridays, but I can tell you that our frames are guaranteed for life. We’ve built Bike Fridays for individuals 7-feet tall, weighing up to 280 pounds. They are built for the long haul.

  5. It should be noted that the Silk appears to come standard with the heaver rider frame. I still have a body weight in the lower 140 lb and I would of course not worry about my Silk frame. I recently marveled at how good my Silk took to a stretch of gravel road – until taking a pinch-puncture. With no rear triangle, the Silk looks rather fragile, but I recall an article by the Silk designer: Rob English, a Cat 1 class racer, discussing racing with a Silk configuration prototype bike. He was winning top-level hill climbs. Thus I do not think the frames have an inherent weakness. I have detected no instability in my Silk. Although the Silk is intended as a utility, touring bike, it also feels good to get out and hammer with it. I would not hesitate taking it on rough terrain, or getting out of the saddle to really push a climb. I think one can safely not hold back riding it. Go ahead and try to break that frame. The Silk I would venture is as sturdy as any bike. It seems well suited to standing out of the saddle to give it everything you have. Before long, you will consider the Silk a normal bike: I think – correct me if I am just hooting.

    1. Stuart, thanks for your feedback. Good to hear more impressions from a Silk owner. I was not really concerned about a frame, but more about the stem, when I get off the saddle. I am now in contact with a retailer here in Germany, so I can get some hands on experience.

  6. Having trained in competitive cycling, I retain the skill of pushing out of the saddle, as it is called. I have found that the Silk for some reason, invites me to do that. Without much thought, I have found myself pushing it out of the saddle (no not getting off and pushing the bike), and am surprised at how natural it feels. And even with a custom fit stem. I would notice if there were a lot of flexing, for the response would be noticeably soft, but, it is not soft. Although the frame is heavier and more durable, the bike seems to want to take the slams; there seems almost a shock absorbing character. That may be why it does not feel abusive to jump the bike off curbs. Wonder if that is related to the unique design.

  7. I would like to know if anyone else has put the bike friday folding full size rack on their bike friday. I have one on, and regularly put 20lbs or so on it, however both with and without weight on rack there is a certain amount of tweaking or torque with the back fork visibly wobbling. I was wondering if this is occuring on other silks or if mine might have a problem. I am 6’1″ and weigh around 195 so I put a decent amount of pressre on pedals howevrr after reading other comments they seem to have no issue like this.


  8. I rode my tikit through knee deep water and was concerned the Alfine 11 would be affected. From this experience, it seems it is watertight, which is a relief.

    Does the hub need servicing? How does one look after it though one of the reasons for getting this hub is so that it will not need looking after.

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