Bicycle Tire Chains!

A company called Slipnot has started manufacturing tire chains for bike tires!  They have a 29 x 2.5-3.5 size, it’s not clear if those will fit fatbike tires.

They’re currently taking pre-orders.  A great idea but they are rather pricey (about $95/set).

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Dark Side of the Floyd

A few weeks ago I got my hands on the new 120tpi Surly Black Floyd tire, a ribbed semi-slick fatty.  Everybody on the forums was raving about how fast they were, so I was pretty excited about it.

Let me digress to say that my original Pugsley setup was Larry on the front, Endomorph on the back.  My primary use for the Pugs (until winter gets here) is commuting on paved bike paths, so these tires are huge overkill.  They’re noisy and have a lot of rolling resistance.  The only reason I haven’t gone with a smaller-profile tire like a Maxxis Hookworm or a Vredestein Black Panther is because I was worried about pedal strike in corners.  I really wanted to get rid of the Endo until the snow flies because its flat profile has a lot of rolling resistance, it doesn’t stop worth s**t on pavement, the side knobs make it noisy, and I’ve had FIVE punctures in about 3 weeks!  So my plan was to put Floyd on the front, and then move Larry to the rear.

However, I was very disappointed in Floyd as a front tire.  In contrast to the very predictable cornering of Larry, with Floyd I felt like the bike was fighting me.  I’d lean the bike over, and the bike would suddenly try to jerk back upright.  I suspect the problem is the ribbed design, and that what I was feeling was the sensation of the tire alternately gripping and slipping as the ribs came into contact with the road surface one-by-one.  It might also have something to do with the very sharply sloping shoulders of the Floyd (in contrast to Larry’s more circular cross-section).  Whatever it was, I really didn’t like it.

Anyway, after two commutes I took off the Floyd and put Larry back on.  To soothe the pain of the additional weight, I set up Larry to run tubeless.

Finally, I’ve gotten around to trying Floyd on the rear wheel.  My initial reaction is that it fixes the problems I had with the Endo without any obvious downsides.  Of course, I don’t expect the same kind of traction, but for commuting it should be fine.  The bike still corners nicely and it definitely feels lighter to accelerate.  After a few rides this way, if I still like it I’ll probably run it tubeless as well.

So does this mean you won’t like Floyd?  I think that depends on your intended use.  Floyd is great for cruising along in a straight line on a paved road.  However if you like to turn aggressively (and I love throwing the Pugs around in the corners because of the tremendous grip those fat tires have), you won’t like it as a front tire.  And I fully expect that it has zero traction in loose stuff, although I haven’t tried it yet except at the local playground.

Nuts!

This morning I was fiddling around with my seat angle for the umpteenth time.  And I thought (why did I tempt fate!), “I wonder how long the bolts on this 20 year old seatpost are going to hold ou– CRAP!” Something snapped.  LOUDLY.  Turns out that I ripped the threads right out of the aluminum dowel nut that the bolt threads into. They came out in one continuous coil. Now what do I do?  The Pugsley uses a 27.2mm post,  and I don’t have another one.

Luckily, I’m a huge fan of the Performance brand seat clamp.  I have them on all my bikes because they use a stainless steel barrel nut so you can really crank them down tight. And I happened to have a spare one. Lo and behold, the dowel nut fit into the seat post and I was able to make my morning commute on the Pugs as I have grown accustomed to of late.

I can’t say enough good things about these seat post clamps. The collar is alloy, whereas the bolt and nut are stainless steel. In addition to having threads that are almost impossible to strip, the dowel nut design allows the bolt to pivot as it is tightened, preventing it from binding. IMHO this clamp is superior to much more expensive clamps.  It’s just icing on the cake that it happens to be about the cheapest clamp you can buy! I highly recommend it if you have seat post slippage problems.

Internally Geared Hubs

I was hoping to change my Pugsley over to an IGH (probably an Alfine 8 or 11) next spring, but this thread on forums.mtbr.com may have changed my mind!  The info presented there is bad news for IGH fans.

According to Aaron Goss of Aaron’s Bicycle Repair, and I’m paraphrasing here, IGH’s are best used sitting down, on relatively flat roads.  If you exceed a certain torque, whether by standing on the pedals, riding up steep hills, using an innapropriately low front chainwheel – back sprocket ratio, or a combination of the preceding, you risk stripping the pawls inside the hub.

According to Shimano, none of their hubs are suitable for off road use. Short steep grades increase the torque, as does standing on the pedals. Shimano IGH hubs fatal flaw is that they use a single (or in some gears just 2) pawls to transfer all the load. Modern Sturmey-Archer hubs have the same problem. SRAM hubs have 2 points on a sliding key which are designed to fail. Hubs we have found very durable are the SRAM P5. It uses 6 fixing points on the axle for the sun gear.

Now this is obviously bad news for someone who wants to use an IGH for off-road touring.  My current low gear on my Pugsley is a 20/34, which works out to 17.4 gear inches.  You read that right!  I hate getting off to push!

If I follow the recommendations in the spreadsheet of IGH gear ratios provided by Aaron, these are the lowest gear ratios I can achieve on various IGH’s (assuming a 29.5″ diameter for a Pugsley wheel and choosing the sprocket ratio for horizontal dropouts when that option is available):

IGH Min gear ratio Min sprocket ratio Min gear inches
 Alfine 8 0.527 1.43 22.2
 SRAM i-Motion 9 0.54 1.73 27.6
 Shimano Alfine 11 0.527 1.7 26.4
 Rohloff Speedhub 14 0.28 2.35 19.4

(Interesting to note that the internal minimum gear ratio of the two Alfines is identical, but the recommended minimum sprocket ratio is so different.)

Even with a Rohloff, the lowest gear recommended is 19.4.  That’s not too bad.  Moving to more affordable choices, the lowest recommended gear for the Alfine 8 is 22.2.  That’s a 28% jump over my current 17.4 gear inches.  That’s a BIG difference.

Aaron specifically singled out the SRAM P5 as being very durable, which means perhaps it could be run at higher torque than is recommended. Unfortunately, this hub has only a 250% gear ratio spread, which would not provide a high enough gear.  Also, the SRAM does not take a disc brake.

So, I’m kind of bummed about this.

Update: Here’s a nice comparison of many IGH’s.