Sunday, September 16, 2012

Q&A: Are folding bikes twitchy; individual cassette cogs

Dahon's Mu Undo
Q: Hi Jim, I'm thinking of getting a foldable bike, a one-speed model with a coaster brake to keep it simple. I'm considering Dahon's Mu Uno (photo). Have you test ridden it? I'm wondering if there will be a big difference in handling from my full size-wheeled bikes. I've heard people say that folders feel twitchy. I'm also concerned about the durability and serviceability of coaster-brake hubs.


 A: I’ve got a few folding bikes, Arnold and like them a lot. I have a Dahon from about 1980 and even back then they had a solid reputation for making nice-riding, convenient to use portable bicycles.

I've ridden some recent Dahons at bike shows but not the Mu Uno. On their website it looks like a quality one-speed model featuring a butted 7005-aluminum frame, nice aluminum wheels and solid components stem to stern including a Kinetix forged-aluminum crankset, Suntour folding pedals, Schwalbe Marathon tires and a Shimano coaster-brake hub.

I think you’ll love the Mu Uno if you get it. You’ll want to ride it on mostly flat rides probably, since it has only one 62-inch gear and a foot brake, but it should be wonderful for that. The little wheels feel quick to most people and that’s great, but they can feel a little too easy to accelerate and steer - because they're smaller and lighter - at first and that’s why some feel that folding bikes are twitchy.

Good folding bikes aren’t really twitchy or hard to handle. They just feel that way because you’re used to steering a big, heavier larger wheel. When you get on your little-wheel folding bike you need to relax and let the bike steer itself. It doesn’t need much input from you. Once you relax and stop trying to steer the bike like you do your other bikes it gets natural and feels quicker and nimbler.

Folding a Dahon takes seconds
I take my Bike Friday whenever I fly somewhere, and I find it takes about five miles or so to remember which bike I'm on and get into the groove of riding it, whether it’s going from the full size-wheel bike to the mini-wheel one - or the other way around when I return from the trip and get back on my regular rides.

Regarding coaster-brake hubs, they are usually very durable. I would estimate that in most cases you wouldn’t need to service a hub like that for as much as five years or even longer if you stay out of the rain. In many cases they just keep going and going with no maintenance. Typically you don’t use a folding bike as much as a regular bike or ride it as far, either, and that helps keep the wear and tear down too - as will riding it on flatter terrain where you won't have to brake all that hard or often. Hope this helps and let us know how you like your Mu Uno if you get it.

When talking about folding bikes, I have to point out one more cutting-edge bicycle, the Brompton, which is my preferred city bike because it folds in a blink, sports lights, fenders, rack, prop stand and a ingenious front bag. Here's Brompton's current line-up.

Q:  Hi Jim, I recently purchased a Lapierre Audacio with a Shimano Tiagra C4600 12/28 10-speed compact cassette (with 50/34 chainrings) and I’m finding the top gear is too low.  I’ve inquired with the shop that sold me the bike as to whether I could change the small cog from a 12 tooth to an 11 tooth but they advise that I’d have to change the entire cassette.  I had expected that it would be possible to source a single 11 cog for this cassette given that there’s an 11/25 cassette in the Tiagra C4600 range. 

Would you be able to advise if a single cog could be sourced for this?

Kind Regards,

A: I haven’t tried their cogs, David, but I’ve heard that Miche makes individual cogs for Shimano cassettes. Here’s a link to an online company called Universal Cycles that carries these so that you can learn more.

You’ll probably want at least two cogs, since if you remove the 12 and install the 11, you’ll have an 11 to 13 jump as your first shift, which will probably drive you crazy and feel like you’re missing a gear. Having a new 11 and a 12 should let you end up with 11/12/13/14 etc. which will feel right (you’ll want to disassemble your cassette and compare it to the Miche cogs to make sure they will fit correctly and let you build the cassette you want).

Another issue will be the Shimano cassette lockring (the last piece you install and tighten with the splined lockring tool - video shows lockring and removal with the lockring tool and chainwhip tool). The one you have is correct for a 12-tooth bottom cog. If you go to an 11-tooth cog, you will need a lockring made for an 11-tooth cog too, since the 12-tooth compatible lockring will be slightly too-large diameter and can prevent the chain seating on the smaller 11-tooth cog. (Tip: you have to look closely, but, so that you can tell the difference, the Shimano 11-tooth lockrings have a little "11" stamped on them.)

I'd compare the cost of the 2 new cogs and lockring plus shipping versus the cost of a new cassette, keeping in mind that your original cassette has resale value and that might make up the difference.

If I were you, I’d be strongly tempted to return to the bike shop and tell them you want to trade the original cassette for the right cassette for you. Even if they only give you wholesale pricing for it in trade, you might end up spending less than ordering the two cogs. Just clean your cassette up nicely so it looks like new.

I hope something here helps and enjoy that beautiful new bike!

In case you can't see it, here's a link to the video:


djconnel said...


Years ago I got a used Friday because I thought it would be good for travel and Caltrain commuting. But the last time I did the Noon Ride on my Bike Friday I observed a few things. One was I couldn't keep up on the gradual descent of Sand Hill: the development of the largest gear had me spinning out. Then the bike was heavy (27 lb) so climbing was slowed. Finally, descending Hwy 84 was extremely slow: the handling in the corners was clearly inferior. I agree it's great for quick trips where packing regular bike (like my Ritchey Breakaway) doesn't make sense. But since I took up running my Bike Friday has been strongly neglected: either it's worth bringing the Breakaway or I decide I can do without a bike and run instead.

For Caltrain commuting, the combination of relatively poor performance in group rides and not-so-quick folding and unfolding (including chain exposure) means I take my full-size bike on the train, despite the risk of being bumped.

Jim Langley said...

Thanks for the great feedback. You said your Bike Friday weighs 27 pounds and doesn't handle well on descents and corners, so my best guess is that you might have a different model than my Pocket Rocket Pro. My Friday weighs 20 pounds and it's a fine road bike. I have tested it hard time and again including on serious group rides and speedy descents such as the awesome one down the Haleakala volcano in Maui - going so fast I passed all the cars. I wouldn't have bought a Bike Friday unless it could perform like my regular road bikes and it has been my go-to travel bike since 1994 and never let me down. If you ever get a chance to try one of their new road bikes, you should. I agree that it doesn't fold as quickly or as small as the Bromptons I mentioned or Dahons. But, for real riding I wouldn't want to be without it on trips - and it folds quickly and easily enough to fit in a tiny rental car's backseat or trunk. I agree that running is the easiest exercise in terms of getting ready and not needing equipment, but unfortunately my knee and back problems prevent me from doing it anymore (I used to be a pretty serious running road racer and ran a 2:56 marathon). I miss running, but still love riding my Pocket Rocket when I'm traveling. Thanks again for sharing your insights, Jim

djconnel said...

Interesting: it's a Pocket Rocket, but an old one. The wheels are very heavy, for example, with an internal geared rear hub (I got to reduce risk of getting pants legs dirty). I fear I don't have much of a chance of matching your 2:56 marathon on my 1st road marathon coming up in Dec (CIM). 3:05 is my reach target, 3:15 my conservative target.

Jim Langley said...

I was 28 when I ran that marathon, so it was a few years ago. The one thing I got right was not going out too fast. I remember we ran the first mile in 10 minutes. It felt like walking. We were probably near last place. Then we very gradually increased our pace. The plan was to go through 13 miles feeling like we had done no real work and then start really racing. I managed to break 3 hours but the guy I raced with came in close to 2:40, so the slow half start worked even better for him than it did for me. On your Bike Friday, I'm not sure why it performs the way it does. My first one was from around 1994 and it worked great from day one. Maybe if I saw your bike I could notice something holding it back. If you ever get a chance to try a new one you should give it a chance. Those guys are nice up there. They might consider helping you purchase a new one since you aren't happy with the one you have. Just an idea. Good luck in the marathon. I bet you have a great race. JIM

Anonymous said...

you ever ridden a Montague Folding Bike? I have read about them and they seem to have a good reputation and high quality. I am considering getting a Boston 8 model, but I would like to know your opinion first. Thanks!

Jim Langley said...

Yes, I have ridden Montague folding bikes, but not a recent model like the Boston. Montague makes full-size folding bikes so you get full size wheels and a frame that folds. That means the ride is the same as a regular bicycle and that the bike folds but not into a tiny package, but still a smaller, easier to pack one. The Montagues I've seen and ridden were nice bikes so I believe you'll like yours a lot. In cycling,
Jim Langley