Single Speed Mode

Mark built up the Modal in Single Speed Mode this week. There are lots of bike geek details to share and I’ll cover what I can and add a travel report from Texas this weekend.

One of Davidson’s specialities is S&S Coupling travel bikes and Mark has traveled with them more than 30 times, all over the world, in various configurations. From Mark’s experience, Davidson’s direction, and creative input from me, we began working the Modal Concept in May of this year. The Modal is a travel bike that folds and toggles between single, fixed, and geared modes.

modal_single.jpg

The concept isn’t presenting anything particularly new, but gathers various parts and ideas into a unique bike that I can travel with and ride in a city or a long tour. The bike switches modes with Paragon dropouts, a second set of bars, and cable split-stops.

Hinge v. Couplings

As our readers know, we’re into folding bikes and Dahons. The Modal is a different bike for a different purpose. I’m using it for longer rides and trips when I want a full road bike. For business trips and urban mobility, the Dahons are outstanding.

There are tradeoffs. Where the Dahon is heavier than the Modal, the Modal case is heavier and travel weight is about the same at around 45 pounds. I’ve also traveled with Sci-Con cases and the drawback to those is TSA and airline reliability. It’s very liberating (both in time and money) to check a bike as luggage and not have to wait for oversize to come out, hope that it wasn’t crushed, and that TSA didn’t unpack and repack it for you.

Single Mode Details

For the Modal to work, it’s built as a road bike with two sets of bars: one has shifters and other just brakes. I’m simply removing the derailleur, releasing the chain master link, swapping out the Paragon, changing the bar, and connecting the cable stops. After a few adjustments, the bike is ready to ride. The beauty of a single speed when traveling is fast rear wheel in and out. There’s also very little to break in transit.

  • 39 x 16 gearing with a chain-ring protector replacing the 53 chain ring
  • Ksyrium wheels with adaptor spacers
  • One position derailleur hanger
  • Carbon fork starnut adaptor thingy – don’t know the actual name, but this part replaces the expanding bolt method on some carbon forks with a star-nut style. If I need to drop the fork and for swapping bars, it’s way easier.

Due Props

The modal was designed by Mark V with help and advice from Bill Davidson. Building the bike was a group effort from the crew at Elliott Bay Bicycles.



17 Comments

Am I really seeing a disc-tab mount on there?!

Byron,

Just out of curiosity, why are you using a 39 x 16?  That seems pretty low…especially for mostly flat Texas.  I was running 42 x 15 for flat rides in ABQ…which was still pretty low but enough to climb out of the valley.

Tai

Actually, it’s a Salsa “Crossing Guard” cyclocross chainring guard.  Rather than use the Reynolds expanding headset plug, I epoxied in a machine aluminium sleeve with M5 threads so that the standard Aheadset cap could be used.  The plugs can slip over time, especially if you end up disassembling the headset/stem often.  As it is now, the steerer is also reinforced better than the plug would have done. 

The spacer kit that I got allows Byron to use a Shimano BMX cassette cog onto the normal 8/9/10-speed cassette body. It also allowed me to fine tune the chainline.

Andrew: that is a disc tab, but I recommend against disc brakes for travel bikes.  Disc rotors don’t pack well, require additional tools, get bent in shipping or all of the above. Besides, it’s 130mm spaceing and most disc hubs are 135mm.

And where does one purchase such a frame? It’s something I’ve been looking for for a while

Andrew,

Yes indeed those are disc tabs That’s a whole other mode for another time. I also want to build this up with Nexus.

Justin,

That’s a [custom Davidson frame](http://www.davidsonbicycles.com/html/home.shtml) and they’re available at [Elliott Bay Bicycles](http://www.elliottbaybicycles.com/) in Seattle. Call or email, ask for Bill and he’ll be happy to tell you all about the bike.

I just got back from the first Modal test ride. I’ll gather my thoughts and post a bit later.  Quick summary is an very impressive bike, with an outstanding ride. We rode from downtown San Antonio to a lake and back - 3 hours round trip. The ride was very relaxed.

Tai,

The gearing was perfect actually for the terrain. And it’s part of the Modal method to have one less step between modes. When I run geared, we’re just switching the front chain ring and thus the 39.

The single-speed was very liberating to ride. More on that in follow-on posts.

we did go with the 39 ring for simplicity, but for my travel bike i actually have two cranks: 1) 170mm 53/39 for geared road riding and 2) 165mm 42t with cross guard for fixie road riding.  If necessary, I could steal a real DA track crank off my primary track bike if i actually wanted to race on the velodrome with my travel bike.

one thing that byron and i decided on was that there was no need for his bike to be velodrome legal.  as such, i didn’t design the bike with a high bottom bracket, and anyways the paragon dropouts are track legal.  my own bike has track drop outs with a derailleur hanger and i use a 130mm width track hub.

byron’s bike would be fine for fixie riding on the road, but there’s a greater chance of grinding a pedal. 

also, i used to ride 39x16 single speed all the time in florida. for fixed anywhere between 42x14 down to 42x21.

39x16 is probably about right for a Nov 2nd ride.  I don’t think I was in much bigger a gear on my recovery ride home yesterday.  Yeah for the off-season!

Looks great - can’t wait to ride it.

oops, slight typo in my previous comment.  The Paragon Slider drop outs are NOT track legal.  Not track legal because they have to be rear facing horizontal, as specified in the rulebook.

What I found was that a single speed is a lot like not kitting up when riding the Bettie. I’m just relaxed and riding, focusing on my cadence, adding power here, backing off there.

I also felt different road sensations. That’s mostly the frame, but I think the single speed must change the vibrations from the tire to the wheel and into your legs. It was like I aws more connected to the bike and road.

Another part we’re going to try is [the Melvin](http://www.paulcomp.com/melvin.html) with two front chain rings. As you read in many of my reviews, I live on a very steep hill, probably 20%, and I personally think it’s stupid to walk that hill on a bike. If I can grunt up it in the 39 x 16, great. If not, the Melvin with two gears, may do it.

I’d love to see a freewheel version of Surly’s Dingle cog for the sake of having more variety in gearing.  It kind of defeats the purpose of single speed to some extent, but would be cool for a travel bike like yours.

Tai

The design direction is less about single speed and more about convenience, simplicity, and minimalism. But minimalism loses it functionality when you can’t climb hills. We talked at length about internally-geared but didn’t want the weight and finickiness. Makes ya think, well geez that old campy had a kick plate to shift gears. Two speeds would be nice, if the Melvin works. Cruising and climbing.

Since you have it setup with a freehub, you could just set it up with two cogs on there setup in the middle and swap it as needed.  You’re running a quick release, so it shouldn’t be any work to make that change.

andrew:

actually no, since the slider dropouts make for slow retensioning of the chain.  also, you really want to make the dropout fixing bolts tight, so roadside re-adjustments are kinda discouraged.  for this reason, multiple cogs or double-sided single-speed hubs are impractical.

we could have gone with paragon’s track dropouts with derailleur hanger rather than the “slider” type (similar to my steel Sycip “Modal” with Surly dropouts), but that would have made removing/inserting the rear wheel painfully awkward in the geared configuration because of the rear exit angle with the derailleur in the way.  byron and i talked it out and we chose to sacrifice the versatility of the single-speed mode for greater ease of use in the geared mode.

me personally, i wanted a bike that was track-legal and i knew i would be using double-sided hubs.

Oh right - I forgot about the Paragon setup.  So in order to go for the two-gear option, he’d need to setup a derailleur or something.  The same goes for the Surly Dingle Cog then too I imagine.

That’s what the Melvin was mentioned above and I don’t know if that’s a good idea or would even work. It seems sketch at best. I did climb up the hill, a hard grunt, but the 39 x 16 worked. What would be nice here, in the design, is a gear spread for cruising and climbing if I wanted to ride a longer time in a hillier locale. There’s a sweet spot, btw, for a lightweight internally-geared hub, with 3 gears tops, belt driven even . . .

And I’ve asked the shop to slice off the disc tabs because that gets everyone’s attention and I’d rather talk the concept than explain that yes it has tabs, but I’m not using them and that whole spacing issue exhausts me.

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