Stoke your bak?

Richard and Jonathan have been heralding the rare but growing presence of a certain kind of Dutch workbike (Bakfiets) on the streets of Portland. Want a bike that seats five kids, with weather protection? No problemo (it’s the one in back, sans weather cover): 4oclock
Many commenters are quick to point out that these bikes are quite heavy, and dismiss them as unsuitable outside of the flat, dense, flat Netherlands. Enter Stokemonkey:

9oclock
7oclock

Apologies to Bianchi on the celeste/red thing, but the electrobrombakfiets moves. Here we are returning on a trip from NE to Milwaukie; I’m pretty sure the bullet-profile weather cover is an aerodynamic help:

33 thoughts on “Stoke your bak?”

  • Kevin

    <p>What IS that seat on the back of the Bak?! Way cool!</p>

  • Todd

    <p>The seat is a <span class="caps">GMG </span>brand … seat. I bought it several years ago in Amsterdam in a highly foggy moment of prophetic insight that it would prove useful someday, so when Dean rolled up on his new bakfiets I dusted it off and snapped it on. See, there’s a Dutch rack standard that this thing (and many other accessories) depends on, so if won’t work with any old rack. I’m half planning to make some things that will harmonize the Xtracycle carrier stuff with the Dutch rack standards, so Dutch items like seats and oilcloth panniers and so on can be used with Xtracycle-standard longtails.</p>

  • Allan F

    <p><span class="caps">OK, </span>you are on a desert island with a nuclear-powered electric generator, stokemonkey kit, and the fam’ If could pick just one: long-tail or bakfeit? :-)</p>

  • Erik Sandblom

    <p>Allan, I don’t think you need a nuclear power plant. Just rig up some palm trees as windmills by converting the leaves to wings. Run the Stokemonkey in reverse to charge the batteries.</p>

    <p>I would bring the Bakfiets to a desert island though. You could use the box part as a boat when the sea level rises and floods your island. Can’t do that with a longtail.</p>

  • Martina Fahrner

    <p>Hmmm…</p>

    <p>If it rains a lot and you have more than 2 kids, bakfiets — it has a nifty rain cover and becomes very much like a trailer. It’s also quite amazing what you can fit into it when it comes to shopping and hauling.</p>

    <p>If you have adults whom you give a lift, want to go camping and in general go more in a touring direction, I would say longtail…</p>

  • Ryan Cousineau

    <p>Surely the ultimate evolution of cargo bikes is a Stoked longtail bakfiets? The supertanker wheelbase would be a bit of a downer at first, but it wouldn’t be that much worse than a tandem…</p>

  • Todd

    <p>Ryan, I think you might bottom out on the crests of hills with a wheelbase like that.</p>

  • Mauricio Babilonia

    <p>If not at the crest of a hill, certainly in driveway-sidewalk-street transitions. Look at how many automobile undercarriage gouges there are in driveways where the sidewalk is higher than its parallel street. A longtail bakfiets would have a wheelbase rivaling many small cars.</p>

    <p>All this before we even start a discussion about pedal strike.</p>

    <p>Sorry Ryan, but I think you’ll have to pick one or the other… 8-)</p>

  • Richard Wilson

    <p>Ryan, you already need most of a typical residential street to U-turn with the long Bakfiets… so maybe a tricycle bakfiets with rear wheel stearing like this would allow you to add the surfable SnapDeck of your dreams and carry Costco loads of diapers!</p>

    <p>http://www.bakfietswinkel.nl/pagina26.html</p>

    <p>An extra-long wheel base would doubtless ride like a limo on the straights, though ;-) My regular “long” Cargobike really floats down the road with a heavy load.</p>

    <p>http://www.bakfietswinkel.nl/pagina26.html</p>

  • Ryan Cousineau

    <p>Richard: rear-steering tricycle? Really? From what little I know of the stability of rear-steering vehicles, I’m guessing these trikes are geared to no faster than 20 km/h or so.</p>

    <p>However, the other comments have convinced me that I should not expect to get a longtail bakfiets anytime soon.</p>

    <p>Hm. Maybe a sociable tandem bakfiets…</p>

  • Riggo

    <p>how’s the rear hub gear (I think a Nexus 8)coping with the stokemonkey’s torque?</p>

  • Todd

    <p>it’s showing no signs of distress yet. yet. cargo, assist, and hills push the brakes pretty hard too.</p>

  • Bill Manewal

    <p>I had a Nexus hub on a <span class="caps">MUCH </span>lighter electric assist bike and didn’t find the braking very effective. I was very thankful I had a disc up front.</p>

    <p>The Bakfiets appears to have a drum brake in front also. </p>

    <p>I’d be very afraid to head down a very steep hill with a controlled intersection at the bottom with any serious cargo load, especially if the cargo included another human being. </p>

    <p>It would seem to me that adding Stokemonkey to this rig could seriously aggravate what may already be marginal braking capability, at least on anything other than level terrain. </p>

    <p>What’s been the real world braking experience of real riders (as opposed to my hypothetical speculation)?</p>

  • Richard Wilson

    <p>Bill – the brakes on my Bakfiets long cargobike are certainly not as good as current state-of-the-art disc brakes on my buddy’s downhill rig, but they <em>will</em> stop the bike even with a significant load. You have to ride a loaded cargo bike more like you would drive a loaded truck, allowing for the increased stopping distance of the brakes. On downhill runs this means a much more prudent riding style and braking as you go down a hill before you get going too fast, particularly if you are carrying children. This doesn’t mean that you have to crawl around town at 5mph, the brakes are by no means that bad, but it just requires a different mindset than riding an unloaded roadbike or mtb…</p>

    <p>In my view putting a stokemonkey on a Bakfiets primarily adds the capability for climbing hills that would be difficult or impossible without assist (brakes not an issue uphill) and help with acceleration to cruising speed on level ground (again, brakes not much of an issue here). I don’t know why one would ever need or want to use the stokemonkey’s assist on downhills, the extra weight of the bike and/or cargo quickly gets you going faster than you want already, so for me the addition of a stokemonkey wouldn’t present any real change to the way I ride my current, un-stoked cargobike with respect to braking.</p>

    <p>Ideally future bakfiets would come equipped with heavy-duty disc brakes to give better stopping power with loads, but the geometry and handling of the bike is such that I don’t think it’s ever going to be safe to pretend it’s a motorcycle and cruise around town at 30mph…</p>

    <p>All this said, I am toying with the idea of adding a sturdier Rohloff hub, disc brakes and a Schmidt dynohub regardless of whether I stoke my cargobike. An extra margin of braking power is never a bad thing and the Rohloff/bakfiets combo seem a match made in heaven…</p>

  • Bill Manewal

    <p>Richard – I’m riding a SM/Instigator/Xtracycle with a Rohloff hub and a Hope Ti6 disc in front and a Magura Gustav in rear. </p>

    <p>With a cargo and/or passenger load and on the steep hills of San Francsico, I’m <span class="caps">REALLY </span>glad I have disc brakes. On the very steepest of downhills, even with all the braking power, I don’t feel safe going much faster than 10 or 15 mph. with a heavy load. And I alternate between front and back brake to prevent overheating. </p>


    <p>I think the idea you are toying with is a good direction for the Bakfiets. </p>

    <p>As to your wondering why anyone (in their right mind) would want to use the SM assist on downhills… the answer for me is simple and primal: for the adrenalin rush! There are some long downhills with no side traffic and no intersections where I’ve hit 45 mph. I tell myself that I do this when I’m running late to my next appointment, but the truth is that, every once in a while, it’s a blast. I would guess this behavior and motivation is not consistent with the Bakfiets’ vision :) And I’m certain that, were I riding a Bakfiets, I would forgo this cheap thrill.</p>

    <p>Thanks for your reply.</p>

  • josh

    how much does the electric assist weigh? how do you charge it? seems interesting...be careful putting a generator hub on a 20 inch wheel without any weight on it...especially turning on slick ground. are there 20 inch forks with disk brake mounts? or would you fab one up yourself? I like some of these ideas, but ha...

  • Todd

    josh, tech specs, principles of operation on stokemonkey are described <a href="http://cleverchimp.com/products/stokemonkey/" rel="nofollow">elsewhere</a>. there is no motor/generator hub involved with either wheel. suitable replacement forks are not available. i'm testing a means of retrofitting a disc brake to the rear wheel, though, which may beef up the braking adequately to make assist a safer option. unlike typical bikes, it is far easier to skid the front wheel than the rear of a bakfiets (skidding=bad, so you don't want the most powerful brake on the wheel most likely to skid)

  • fred

    here's a man who could use a Stokemonkey!

    http://www.youtube.com/watch?v=DCPyBNOhMfA

  • Bruce Alan Wilson
    Bruce Alan Wilson May 16, 2007 at 6:14 am

    I worry that 8 gears might not be enough. My Xtracycle has 24 gears and my Trek has 21, and there are places here in Charleston that I find very difficult to get to; WV is not called 'the Mountain State' for nothing. For example, this is how to get from my house to the house of some good friends: <a href="http://www.mapquest.com/directions/main.adp?do=nw&long=%2d81647223&2n=KANAWHA%20COUNTY&height=414&1y=US&r=f&1z=25302%2d1905&2a=%5b700%2d981%5d%20Viewmont%20Dr&mo=ma&2s=WV&2c=Charleston&dtype=s&cl=EN&1n=KANAWHA%20COUNTY&width=779&2v=STREET&lat=38367537&did=1179346161&qq=1ADqpk24ofC4hkXmOUeAqGJIEGFYKaYlU9SREGom4T%252bexkyFxnAWSmEUFxsV7zCjIUpTMewkRGoE%252bGpO6DELbfMXh0tjF21Vk2VpNUxsmqSQroLTOfCtId%252fXLPXoIvdZM9QltiH31UX2Svvrhd8RH2BhLlfpENu58k4%252bmk%252bMfW3MZpphrr9j1s%252bfDQBykXMZavUdaSj2GySzfvIZQ4AFvXUd%252fEMaaz%252fckw8q6yUDmmQfPewfXwKSNnCFuo0O7PA7a5SWR2sWIRPxnIeAZPXar7IqBnb%252b8yOiZs8cEbezRrhvfmndoxLF8tptt9p48JObNms%252fR4n0zKR%252boozm4KTCrqo%252bbAfBr6JWBc5F7dwi5znFSTKn%252fuSkGXlslSXupA5e1FNf1lIeQXIf%252bhCCKUuEm9oWRGnGTeZbildQ%252fWkYz74abvIrPHxVx387SqZmljnMzejwdiHB3tMbAEmdU3%252fed2IxYbO3UNlp&1a=513%20Hall%20St&2y=US&un=m&2z=25302&1s=WV&1c=Charleston&zoom=10&go=1&rsres=1&1v=ADDRESS&ct=NA&1l=xYBddN9u00pPk/MFFm3oCg==&1g=NWY7TOWJgIhbkVx9at8MOw==&2l=8YK95kreickmJ6PNeBa33Q==&2g=j+UdPPmSdwIKCkywYNdYdg==" rel="nofollow">Driving Directions from 513 Hall St, Charleston, WV to [700-981] Viewmont Dr, Charleston, WV</a> There are parts of this that the [i]car[/i] labors on, much less a bike. Of course, coming home is a lot of fun; particularly in the dark! I can tell you, I wish for a Stokemonkey when I try going up! (I'm saving my pennies.)

  • Bruce Alan Wilson
    Bruce Alan Wilson May 26, 2007 at 6:46 am

    I just talked to my LBS about a Stokemonkey if/when I save up my pennies, and he told me that they do NOT do electrifications, period.

    What other options do I have? I do NOT have the technical skills to install it myself.

  • Erik Sandblom

    Bruce, an eight-speed bike has more gears than you think, because none of the gears overlap. Your 24- and 21-speed bikes have a lot of overlapping gears. Shimano's eight-speed hub has a range of 307%, meaning the top gear is three times faster than the bottom gear. Sram has a nine-speed hub which has 340% range. I'm not sure how much range a 24-speed bike might have, but I suspect the eight- and nine-gear hubs are competitive. Then there's the Rohloff hub with 526%, but that's very expensive. See Sheldon Brown's website for more on gears.

  • Matthew Cole

    Regarind the gearing of eight-speed Nexus hubs, I recently wrote a brief article about them comparing them to classic Sturmey-Archer 3-speed hubs, 1970s ten-speeds and my current 27-speed Atlantis. This article can be found at http://www.uscoles.com/threespeedgearing.pdf. The fourth page is a graph showing the relative gearing of these various systems. I think a lot of people don't realize how many duplicates there are in derailleur-geared bicycles.

    Also, the gearing on the Nexus and Sturmey-Archer hubs is for the chainring/cog combinations I use. You can move the whole range up and down by fiddling with these.

    Note that this was written in relation to the Lake Pepin Three-Speed Tour and thus has a number of referneces to that ride and to the Sturmey-Archer gearing.

    I have a couple of years on a Nexus hub with no problems but it's well under 2,000 miles and is just a single bike, not an Xtracycle or anything.

  • Bruce Alan Wilson
    Bruce Alan Wilson May 29, 2007 at 4:10 am

    I'm not a technical sort of person, so I'll take your word for it.

  • Bruce Alan Wilson
    Bruce Alan Wilson May 29, 2007 at 7:03 am

    Matt, are you aware that there seems to be a problem with the link you posted? I wanted to print it out to give to my cousin who is a Mechanical Engineer.

  • Erik Sandblom

    Bruce, Mathew's bike has 27 gears and 413% range. So the eight-speed Shimano and nine-speed Sram hubs with 307% and 340% respectively will not be far behind your 24-speed.

    To read Mathew's link, you need to cut off the period at the end of the link. Like this:

    http://www.uscoles.com/threespeedgearing.pdf

  • Bruce Alan Wilson
    Bruce Alan Wilson May 30, 2007 at 1:59 am

    Thanks. I'll send the article to my cousin; as his mother (my aunt) is a retired English teacher, he's used to explaining things so that dumb humanities majors can understand them.

  • Kathleen

    Looking at the pages on the stokemonkey, it specifies that it only works with an Xtracycle. So how did this bakfiets get stoked?

    I test-drove a bakfiets this weekend and am now in love! Just thinkin' about that hill between my house and the grocery store....

  • Todd (admin)

    Kathleen, we made special mounting hardware just to try it. We won't make more. It "works," but we will not support this application as a product. We don't think it is responsible to enable people to haul hundreds of pounds of precious cargo up extremely steep grades when they very well might not be able to descend said grades safely. Longtails have much better high-speed handling and braking characteristics than bakfietsen.

  • BAW

    I understand that a bak won't take a Rolhoff, but would it take a Schlumpf up front? (http://www.schlumpf.ch/antriebe_engl.htm) That might help Kathleen. It isn't cheap, but if she's willing to invest that much in a bak, she might as well 'be hanged for the cow as for the calf.'

  • DrMekon

    Henry Workcycles reckons that the Schlump isn't a good idea. See his answer to "Can I fit a Schlumpf Mountain Drive 2-speed crankset to a Bakfiets Cargobike?"

    http://www.bakfiets-en-meer.nl/bakfiets-cargobike-tips-tricks-faq/

  • Vicki

    I'm looking into a GMG seat for my Azor. Will it really just snap onto to the rack? :)

  • Todd (admin)

    Vicki, Azor makes many bikes with different rack specs. And GMG makes many seats. I don't know of a US source for GMG. But this particular seat did indeed just snap on to the rack of this particular Azor-manufactured bike.

  • Vicki

    Thanks for your reply, Todd. I hadn't considered that. My rack is 15 cm wide. The seat I had in mind is one like <a href="http://www.fietskinderzitje.nl/collection3.asp?cat_id=3&collection_id=3&dessin_id=22" rel="nofollow">this</a>. Since I don't read (or speak) Dutch, <a href="http://www.fietskinderzitje.nl/cms/files/pdf/Montagevoorschrift-T30-NL.pdf" rel="nofollow">these specs</a> were not very useful. :/

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