home built Bakfiets
11-17-11, 07:43 AM
#1
Member
Thread Starter
Join Date: Dec 2006
Location: Porto Alegre, Brazil
Posts: 33
Bikes: M5 recumbent, long tail converted specialized
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
home built Bakfiets
Hi folks.
I've already built 2 long tail Xtracycle-type bikes. Both were succesfull, the second one got a little nicer than the first, I'm using it for hauling my kids and occasionally for some cargo. It's been a marvelous experience, one of the most fulfilling cycling related ones I've ever had actually. I'd like to express my gratitude to everyone who contributed to the xtracyle home build thread - it would have been a lot more difficult without that big help and inspiration!
I've put a tutorial together BTW. It's in Portuguese, but I've included pictures for each and every step of the process, including more than one solution for for some of them, so it's self-explaining to a degree. I very much hope it will help more people get to know the fun and utility of long tail bikes. It's on my blog:
https://pespracima.blogspot.com/2011/...sso-passo.html
So.
I've recently come across the concept of the frontloader 2-wheeler: Bakfiets, Long John, box bike, whatever you call them. I can't stop thinking about building one! I'm not planing to get rid of my beloved xtra, but I feel compeled to try the other side of the force too...
The purpose of this thread is to get some data and inspiration for that project. Perhaps more people will join and we will end up with a long rich thread similar to the "home built xtracycle" one?
For now, I'm asking some help from owners of "proper" (professionally made) box bikes such as CETMA Cargo, Bakfiets CargoBike Long, Joe Bike's Box Bike, Bullit, or whatever you might have. I'd very much like to know some rough measurements, so that I can rest assure I'm on the right track. This is what I have in mind:
https://www.flickr.com/photos/2376346...ream/lightbox/
I'm curious about this 4 dimensions (as indicated in my drawing) to begin with:
a) wheel base
b) length of the actual cargo holding section of the front frame
c) ground clearance
d) length of the steering column (or just the length of the short section that protrudes below the horizontal main tube)
I've already seen several tutorials/reports from people who built box bikes. Tom Cargo Bikes' pages are most interesting and usefull. But I've found little data regarding dimensions so far.
Before someone asks: I'm only trying to make one sturdy, rideable and usefull box bike - this is not about stealing industry secrets!
Box bikes are not available in Brazil (nor are Xtras), importing one is out of the question, so the only way is making one myself. I'm not particularly knowledgeable or skilled but I want give it a try.
I've already bought some tubing - hauled it over 20 kms:
https://www.flickr.com/photos/2376346...ream/lightbox/
Main frame will most likely be an old, sturdy, US made steel MTB.
Thanks in advance for any positive input.
p.s. I wasn't able to insert the images, so I put links to them.
I've already built 2 long tail Xtracycle-type bikes. Both were succesfull, the second one got a little nicer than the first, I'm using it for hauling my kids and occasionally for some cargo. It's been a marvelous experience, one of the most fulfilling cycling related ones I've ever had actually. I'd like to express my gratitude to everyone who contributed to the xtracyle home build thread - it would have been a lot more difficult without that big help and inspiration!
I've put a tutorial together BTW. It's in Portuguese, but I've included pictures for each and every step of the process, including more than one solution for for some of them, so it's self-explaining to a degree. I very much hope it will help more people get to know the fun and utility of long tail bikes. It's on my blog:
https://pespracima.blogspot.com/2011/...sso-passo.html
So.
I've recently come across the concept of the frontloader 2-wheeler: Bakfiets, Long John, box bike, whatever you call them. I can't stop thinking about building one! I'm not planing to get rid of my beloved xtra, but I feel compeled to try the other side of the force too...
The purpose of this thread is to get some data and inspiration for that project. Perhaps more people will join and we will end up with a long rich thread similar to the "home built xtracycle" one?
For now, I'm asking some help from owners of "proper" (professionally made) box bikes such as CETMA Cargo, Bakfiets CargoBike Long, Joe Bike's Box Bike, Bullit, or whatever you might have. I'd very much like to know some rough measurements, so that I can rest assure I'm on the right track. This is what I have in mind:
https://www.flickr.com/photos/2376346...ream/lightbox/I'm curious about this 4 dimensions (as indicated in my drawing) to begin with:
a) wheel base
b) length of the actual cargo holding section of the front frame
c) ground clearance
d) length of the steering column (or just the length of the short section that protrudes below the horizontal main tube)
I've already seen several tutorials/reports from people who built box bikes. Tom Cargo Bikes' pages are most interesting and usefull. But I've found little data regarding dimensions so far.
Before someone asks: I'm only trying to make one sturdy, rideable and usefull box bike - this is not about stealing industry secrets!
Box bikes are not available in Brazil (nor are Xtras), importing one is out of the question, so the only way is making one myself. I'm not particularly knowledgeable or skilled but I want give it a try.
I've already bought some tubing - hauled it over 20 kms:
https://www.flickr.com/photos/2376346...ream/lightbox/Main frame will most likely be an old, sturdy, US made steel MTB.
Thanks in advance for any positive input.
p.s. I wasn't able to insert the images, so I put links to them.
Last edited by artur elias; 11-17-11 at 07:49 AM. Reason: images not inserting
11-18-11, 06:34 AM
#2
Senior Member
Join Date: Oct 2007
Posts: 330
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 3 Times
in
1 Post
Bakfietsen are cool. I have argued myself into and out if making one several times.How are the roads where you ride? Ask someone with experience, but I have seen several mentions that a bakfiets may have trouble with curbs and poor roads, especially when the box is empty. There is an instructable that is useful as well.
11-18-11, 12:59 PM
#3
Member
Thread Starter
Join Date: Dec 2006
Location: Porto Alegre, Brazil
Posts: 33
Bikes: M5 recumbent, long tail converted specialized
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
We have 2 types of pavement basically: regular asphalt (ranging from new and smooth to minefield-like, with various degrees of craked pavement in between and all sorts of potholes and other obstacles you'd probably not going to believe unless you see it with your own eyes); and cobble stones (wich used to be sort of smooth and regular, relatively speaking, many years ago; nowadays the craft of cobble placement is going lost, so most of those roads are bad for cycling - unpaved roads like many we have in rural areas can be much nicer actually).
I can't figure why a front loader would behave any worse in rough pavement than a long tail - perhaps you can enlighten me?
Specially considering that any bicycle with an extended wheel base, all things being equal, will allways perform better (confort-wise) in rough pavement. Recumbent riders know that all too well, since even so called short wheel base 'bents have allready a longer wheel base than DF bikes.
I can imagine riding up curbs may be difficult, but I'm not planing to spend a lot of time riding on the side walk anyway.
Could it be that the particular steering geometry parameters of typical box bikes can cause the trouble you're refering to? My next question (after the one about the simple mesurements above) would be about head tube angle, rake, trail, etc. Looks like there are not so many box bike owners on this board, though...
Perhaps you should give it a try, then we can begin to build a shared data base here.
Did you see Tom's tutorial? Very nice even if it's short on details.
https://tomscargobikes.com/BUILD_YOUR_OWN.php
I can't figure why a front loader would behave any worse in rough pavement than a long tail - perhaps you can enlighten me?
Specially considering that any bicycle with an extended wheel base, all things being equal, will allways perform better (confort-wise) in rough pavement. Recumbent riders know that all too well, since even so called short wheel base 'bents have allready a longer wheel base than DF bikes.
I can imagine riding up curbs may be difficult, but I'm not planing to spend a lot of time riding on the side walk anyway.
Could it be that the particular steering geometry parameters of typical box bikes can cause the trouble you're refering to? My next question (after the one about the simple mesurements above) would be about head tube angle, rake, trail, etc. Looks like there are not so many box bike owners on this board, though...
Perhaps you should give it a try, then we can begin to build a shared data base here.
Did you see Tom's tutorial? Very nice even if it's short on details.
https://tomscargobikes.com/BUILD_YOUR_OWN.php
11-18-11, 01:13 PM
#4
Senior Member
Join Date: Jul 2011
Location: S. E. Michigan
Posts: 513
Bikes: Mongoose Switchback
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Another DIY bakfeit, https://www.cheaphack.net/2010/07/diy-bakfiets.html
but I think his cargo platform is too high.
but I think his cargo platform is too high.
11-18-11, 06:06 PM
#5
Senior Member
Join Date: Oct 2007
Posts: 330
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 3 Times
in
1 Post
I suspected that there might be some "interesting" road surfaces in Brazil, but didn't want to assume.
I wish someone with riding experience will comment, but this is my understanding:
Curbs are a particular problem due to the low ground clearance at the "steering column" location. If that control horn drags the ground as you pass over the curb, you will certainly fall. So you need to go quite slow, just in case, and going slow makes it much harder to balance.
To balance any bike you have to keep steering the wheels back under the weight whenever the weight starts to tip. There are various effects that allow the bike to do a lot of this steering for you, but most don't help much at very low speeds...more trail being the exception.
An unloaded bakfiets has most of the weight (the rider) at the back. So when you start to tip, you turn the the front wheel to correct. But at first this doesn't help much, because there is not much weight for the front wheel to move under. Only when the whole bike is turning does the back wheel begin to move sideways and come back under the rider. Due to the long wheelbase, this delay is much longer than on a normal bike, and also due to the wheelbase you can't turn very sharp, so there is a real limit to low speed stability...if you get too far off balance at low speed, you can't turn quickly enough to avoid falling over. This is much less an issue on an empty long-tail, because the long wheelbase doesn't much change how fast the front wheel can move from side-to-side to restore balance. In fact you are, percentage of wheelbase wise, much closer to the front wheel on a longtail...you can easilly balance, and the bike as a whole never much changes direction as a result. "Like it is on rails" is how riders discribe this. If you put a load on the back much heavier than the rider, though, you run into the same issue...but you don't have a steering linkage hanging down in harms way, so most of the time you don't need to go so slow.
The steering geometry used on a bakfiets adds to this issue. So that the steering is not too heavy when loaded, the bakfiets typically has lower trail, and this makes it less self stabilizing especially at low speed which adds to the problem.
Bakfiets designers have a compromise to make: They can make a large stiff structure connecting to the front wheel, but this adds weight and takes away cargo space. As a result, the bike ends up maybe being stiff enough, but maybe not, and with not much extra margin for unusual loads.
I think another issue with classic bakfiets is that the rider can't see the front wheel, so is often suprised by the timing of when it contacts the curb or other hazard. This probably improves with experience...just as a good car driver will instinctively know where their front wheels will run when driving a familiar car.
When weight is added to the box, both of these issues are reduced. Now when you start to tip, you turn the front wheel, and since there is now significant weight for the front wheel to move under, balance is quickly restored.
Also, with normally only a 20" front wheel, curbs, potholes and suchlike are more of a factor for the smaller wheel...much as even a small stone can stop a skateboard wheel. If building for rough roads, I would consider taking an unconventional route, and using a 26" front wheel...it makes the bike only a few cm longer for a given box size. You could also design for trail more like a normal bike, and accept that the steering will become rather heavy with bigger loads. You might also want to add a bash guard around the steering linkage that will prevent it from catching on rough roads. It will be bad to drag the bash guard, but not so bad as to drag the control horn and crash when the front wheel suddenly turns full to one side.
I wish someone with riding experience will comment, but this is my understanding:
Curbs are a particular problem due to the low ground clearance at the "steering column" location. If that control horn drags the ground as you pass over the curb, you will certainly fall. So you need to go quite slow, just in case, and going slow makes it much harder to balance.
To balance any bike you have to keep steering the wheels back under the weight whenever the weight starts to tip. There are various effects that allow the bike to do a lot of this steering for you, but most don't help much at very low speeds...more trail being the exception.
An unloaded bakfiets has most of the weight (the rider) at the back. So when you start to tip, you turn the the front wheel to correct. But at first this doesn't help much, because there is not much weight for the front wheel to move under. Only when the whole bike is turning does the back wheel begin to move sideways and come back under the rider. Due to the long wheelbase, this delay is much longer than on a normal bike, and also due to the wheelbase you can't turn very sharp, so there is a real limit to low speed stability...if you get too far off balance at low speed, you can't turn quickly enough to avoid falling over. This is much less an issue on an empty long-tail, because the long wheelbase doesn't much change how fast the front wheel can move from side-to-side to restore balance. In fact you are, percentage of wheelbase wise, much closer to the front wheel on a longtail...you can easilly balance, and the bike as a whole never much changes direction as a result. "Like it is on rails" is how riders discribe this. If you put a load on the back much heavier than the rider, though, you run into the same issue...but you don't have a steering linkage hanging down in harms way, so most of the time you don't need to go so slow.
The steering geometry used on a bakfiets adds to this issue. So that the steering is not too heavy when loaded, the bakfiets typically has lower trail, and this makes it less self stabilizing especially at low speed which adds to the problem.
Bakfiets designers have a compromise to make: They can make a large stiff structure connecting to the front wheel, but this adds weight and takes away cargo space. As a result, the bike ends up maybe being stiff enough, but maybe not, and with not much extra margin for unusual loads.
I think another issue with classic bakfiets is that the rider can't see the front wheel, so is often suprised by the timing of when it contacts the curb or other hazard. This probably improves with experience...just as a good car driver will instinctively know where their front wheels will run when driving a familiar car.
When weight is added to the box, both of these issues are reduced. Now when you start to tip, you turn the front wheel, and since there is now significant weight for the front wheel to move under, balance is quickly restored.
Also, with normally only a 20" front wheel, curbs, potholes and suchlike are more of a factor for the smaller wheel...much as even a small stone can stop a skateboard wheel. If building for rough roads, I would consider taking an unconventional route, and using a 26" front wheel...it makes the bike only a few cm longer for a given box size. You could also design for trail more like a normal bike, and accept that the steering will become rather heavy with bigger loads. You might also want to add a bash guard around the steering linkage that will prevent it from catching on rough roads. It will be bad to drag the bash guard, but not so bad as to drag the control horn and crash when the front wheel suddenly turns full to one side.
11-20-11, 11:12 AM
#6
Senior Member
Join Date: Sep 2008
Posts: 5,200
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 137 Post(s)
Likes: 0
Liked 81 Times
in
64 Posts
Also, with normally only a 20" front wheel, curbs, potholes and suchlike are more of a factor for the smaller wheel...much as even a small stone can stop a skateboard wheel. If building for rough roads, I would consider taking an unconventional route, and using a 26" front wheel...it makes the bike only a few cm longer for a given box size. .
any thoughts on the reason for 20" front wheels? Is it for better sight to what the front wheel is about to hit?
11-23-11, 07:16 AM
#7
Senior Member
Join Date: Oct 2007
Posts: 330
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 3 Times
in
1 Post
Also, small wheels are much stronger, so if you are on smoothish pavement the can handle a lot more load.
01-16-12, 04:30 PM
#8
Member
Thread Starter
Join Date: Dec 2006
Location: Porto Alegre, Brazil
Posts: 33
Bikes: M5 recumbent, long tail converted specialized
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Thanks for the responses so far. I'm sticking to the classic design for this first time. I need to know how that one handles and how well it works in ny terrain; then I might consider an alternative design. Besides, many (most models actually) Brazilian recumbents have small (20 inch) wheels up front. It's not considered a problem per se, even in our less-than-perfect streets and roads.
I believe I've just found the right person to help me with the welding (to do the whole welding work actually). A skilled, experienced welder who happens to be a passionate cyclist and even lives car free! I think I got him really interested.
I'm also on vacations right now so I have plenty of time.
I'm lacking more data and general info from those who have actual experience with box bikes. Please chime in folks!
I believe I've just found the right person to help me with the welding (to do the whole welding work actually). A skilled, experienced welder who happens to be a passionate cyclist and even lives car free! I think I got him really interested.
I'm also on vacations right now so I have plenty of time.
I'm lacking more data and general info from those who have actual experience with box bikes. Please chime in folks!
01-17-12, 12:00 PM
#9
Senior Member
Join Date: Jan 2012
Location: Amsterdam, NL
Posts: 157
Bikes: Yuba Mundo (sold), Yuba Boda Boda (sold), now I ride a batavus Personal Delivery Bike
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
01-17-12, 12:01 PM
#10
Senior Member
Join Date: Jan 2012
Location: Amsterdam, NL
Posts: 157
Bikes: Yuba Mundo (sold), Yuba Boda Boda (sold), now I ride a batavus Personal Delivery Bike
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
01-17-12, 12:07 PM
#11
Member
Thread Starter
Join Date: Dec 2006
Location: Porto Alegre, Brazil
Posts: 33
Bikes: M5 recumbent, long tail converted specialized
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Didn't know that one, looks promising, thank you.
01-17-12, 12:11 PM
#12
Member
Thread Starter
Join Date: Dec 2006
Location: Porto Alegre, Brazil
Posts: 33
Bikes: M5 recumbent, long tail converted specialized
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Of course, Toms bikes are a major source of inspiration!
I fear I'm not quite from the "cut twice, measure once" school of design (as he put it)...
Hence my need for getting more objective infos about box bikes before starting to cut, bend and weld.
Also because I have to pay for welding, so I'm not going to make an awful lot of experimentation. i may start with a quick prototype and then go for the real thing, though.
It would be VERY nice if people who actually built their box bikes (like Tom) would chime in, share their experiences and findings, guide us newbies - just like that wonderful homebuilt xtracycle thread.
I stil have some hope for this thread!
I fear I'm not quite from the "cut twice, measure once" school of design (as he put it)...
Hence my need for getting more objective infos about box bikes before starting to cut, bend and weld.
Also because I have to pay for welding, so I'm not going to make an awful lot of experimentation. i may start with a quick prototype and then go for the real thing, though.
It would be VERY nice if people who actually built their box bikes (like Tom) would chime in, share their experiences and findings, guide us newbies - just like that wonderful homebuilt xtracycle thread.
I stil have some hope for this thread!
Last edited by artur elias; 01-17-12 at 12:14 PM.
01-17-12, 01:21 PM
#13
Senior Member
I firmly believe in front-loading bikes. My Daughter designed this one.
01-20-12, 08:02 PM
#14
Member
Thread Starter
Join Date: Dec 2006
Location: Porto Alegre, Brazil
Posts: 33
Bikes: M5 recumbent, long tail converted specialized
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Very interesting.
Quite off topic, though...
Quite off topic, though...
01-21-12, 10:38 AM
#15
Member
Thread Starter
Join Date: Dec 2006
Location: Porto Alegre, Brazil
Posts: 33
Bikes: M5 recumbent, long tail converted specialized
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Well, I've had very little (none, actually) support from box bike/long john owners so far.
But I'm not giving up - not on the build (of course!), and not on this thread. Someday people who can't afford a brand name long john will find this source of information that will help them, just as it happened to the homebuild xtracycle thread.
Good news:
I found out there is a German Cargo Bike Forum ( www.cargobikeforum.de ). There are several interesting threads on home building over there. One of them mentioned this VERY INTERESTING endeavour:
https://wiki.webinprogress.de/index.php/Hauptseite
wich includes pages on home building cargo bikes of various types:
https://wiki.webinprogress.de/index.php/Bauanleitungen
one of them WITH MEASUREMENTS! :-)
https://wiki.webinprogress.de/index.php/Long_Andr%C3%A9
and one project for building a cargo bike specific jig:
https://wiki.webinprogress.de/index.php/BikeBench
I happen to know German well, but I think it's worth a click even if you don't. Many pictures/schematics that speak for themselves.
all the best
a.
------
But I'm not giving up - not on the build (of course!), and not on this thread. Someday people who can't afford a brand name long john will find this source of information that will help them, just as it happened to the homebuild xtracycle thread.
Good news:
I found out there is a German Cargo Bike Forum ( www.cargobikeforum.de ). There are several interesting threads on home building over there. One of them mentioned this VERY INTERESTING endeavour:
https://wiki.webinprogress.de/index.php/Hauptseite
wich includes pages on home building cargo bikes of various types:
https://wiki.webinprogress.de/index.php/Bauanleitungen
one of them WITH MEASUREMENTS! :-)
https://wiki.webinprogress.de/index.php/Long_Andr%C3%A9
and one project for building a cargo bike specific jig:
https://wiki.webinprogress.de/index.php/BikeBench
I happen to know German well, but I think it's worth a click even if you don't. Many pictures/schematics that speak for themselves.
all the best
a.
------
01-21-12, 02:59 PM
#16
Senior Member
Join Date: Sep 2008
Location: Suceava - Romania
Posts: 57
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
What about this?
https://www.instructables.com/id/buil...el-cargo-bike/
https://www.instructables.com/id/how-...bike/?ALLSTEPS
https://www.instructables.com/id/A-Pr...rike/?ALLSTEPS
https://www.instructables.com/id/buil...el-cargo-bike/
https://www.instructables.com/id/how-...bike/?ALLSTEPS
https://www.instructables.com/id/A-Pr...rike/?ALLSTEPS
Last edited by LucianTheOne; 01-21-12 at 03:02 PM.
01-21-12, 08:53 PM
#17
Member
Thread Starter
Join Date: Dec 2006
Location: Porto Alegre, Brazil
Posts: 33
Bikes: M5 recumbent, long tail converted specialized
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
hi Lucian
I've seen your 2nd long tail bike on the other thread!
Yes, I know that tutorial. It's a nice build. I'm not sure about stifness. Front frame tubing does look a little thin.
I'd like to remove the top tube of the donnor frame (or rearrange both top and down tube completely) so that you can mount and dismount relaxed and easily. Not bad specially when you have kids on board.
I got one piece of information from the tutorial I didn't notice the first time:
steering angle is said to be 75º.
This is important I think.
I would love to know the steereing geometry parameters of renowned box bikes like CETMA, Worcycles Bakfiets, Joe Bike, Bullit, Metrofiets, and others.
Steering angle and trail would be nice.
I've seen your 2nd long tail bike on the other thread!
Yes, I know that tutorial. It's a nice build. I'm not sure about stifness. Front frame tubing does look a little thin.
I'd like to remove the top tube of the donnor frame (or rearrange both top and down tube completely) so that you can mount and dismount relaxed and easily. Not bad specially when you have kids on board.
I got one piece of information from the tutorial I didn't notice the first time:
steering angle is said to be 75º.
This is important I think.
I would love to know the steereing geometry parameters of renowned box bikes like CETMA, Worcycles Bakfiets, Joe Bike, Bullit, Metrofiets, and others.
Steering angle and trail would be nice.
01-23-12, 12:49 PM
#18
Member
Join Date: Feb 2009
Posts: 37
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
As a CETMA owner, I have a few thoughts for how I'd build my own rig if I was starting from the ground up. If you are mostly using it to haul kids, I would put the box upfront. The most important reasons for this is the it's just way easier to communicate with them when they are in front and they can see more of the road when they are up there. Front-loaders really aren't a problem with regards to steering on normal or slightly uneven roads. It's a weird sensation at first, but really easy to get used to. Also there is enough weight on the front wheel that I never have had issues with the front washing out, even when riding on snow or ice.
For the most part, I think Kevbo's concerns are significantly overblown with regards to the front loader, with two exceptions. First, clearance could be an issue if you have REALLY uneven roads. I've never bottomed out, and I know another forum member, Coldbike, did a pretty epic trip with his CETMA that included some dirt. Second, it's probably easier to climb with long tail. Mostly because it's hard to stand on a front loading bike and really get leverage. I know and xtra is easier in this regard, and I'd assume a Madsen style bike would be as well.
A couple of things to think about on design:
1. I'd go with a 20" wheel upfront. I think this makes both the wheel and the frame stronger.
2. If carrying kids, I'd go with the schwalbe big apple tires (and build a frame in such a way as to provide enough clearance for these tire), as it'll give them a more cushy ride over the bumpy stuff.
3. I'd build a platform close to the CETMA. Make it a flat load floor that you can build a box on top. This allows you to take off the box when the kids get older so that you have a lighter and more capable cargo hauler.
4. I'd also build the "perimeter" frame for the platform. Run your tubes around the edge of the box rather than through the middle. It'll make your bike and platform stronger and save some weight.
5. The space for the rider on the Joe box bike is really small, even the CETMA space is a bit short (if you are running a small stem). Be sure that you have a reasonable cockpit.
6. Be mindful of your handlebar height as compared to your front passenger's head. Some bike provide way more space than others for this.
As far as actual dimensions, I'd contact Lane at CETMA directly through his website. He's a cool dude doing everything on his own and he was awesome in helping me along with my build.
For the most part, I think Kevbo's concerns are significantly overblown with regards to the front loader, with two exceptions. First, clearance could be an issue if you have REALLY uneven roads. I've never bottomed out, and I know another forum member, Coldbike, did a pretty epic trip with his CETMA that included some dirt. Second, it's probably easier to climb with long tail. Mostly because it's hard to stand on a front loading bike and really get leverage. I know and xtra is easier in this regard, and I'd assume a Madsen style bike would be as well.
A couple of things to think about on design:
1. I'd go with a 20" wheel upfront. I think this makes both the wheel and the frame stronger.
2. If carrying kids, I'd go with the schwalbe big apple tires (and build a frame in such a way as to provide enough clearance for these tire), as it'll give them a more cushy ride over the bumpy stuff.
3. I'd build a platform close to the CETMA. Make it a flat load floor that you can build a box on top. This allows you to take off the box when the kids get older so that you have a lighter and more capable cargo hauler.
4. I'd also build the "perimeter" frame for the platform. Run your tubes around the edge of the box rather than through the middle. It'll make your bike and platform stronger and save some weight.
5. The space for the rider on the Joe box bike is really small, even the CETMA space is a bit short (if you are running a small stem). Be sure that you have a reasonable cockpit.
6. Be mindful of your handlebar height as compared to your front passenger's head. Some bike provide way more space than others for this.
As far as actual dimensions, I'd contact Lane at CETMA directly through his website. He's a cool dude doing everything on his own and he was awesome in helping me along with my build.
01-24-12, 12:43 PM
#19
Member
Thread Starter
Join Date: Dec 2006
Location: Porto Alegre, Brazil
Posts: 33
Bikes: M5 recumbent, long tail converted specialized
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
dear HM
lots of good input in your post, thank you!
Since you mentioned you own a CETMA, I feel compelled to "confess" it's my favourite from all known box bikes. I like everything about it, it looks functional in every detail, sturdy, and pleasant to the eye.
I would purchase one if I could. I actually could afford the cost for a frame, but shipping/importing would make it cost over twice that value, wich makes no sense.
Back to your observations:
So do I. Vast majority of the recumbents sold in Brazil (probably all over the world too) have 20" front wheels.
I don't know about "real" xtracycles, but with my home built and 2 kids on board, standing and pedaling hard does not feel that good. But then, I'm a recumbent rider, so I'm used to just sitting and spinning, and that's what I do - hapilly - with my cargo bike too! This particular feature poses no problem as far as I'm concerned.
lots of good input in your post, thank you!
Since you mentioned you own a CETMA, I feel compelled to "confess" it's my favourite from all known box bikes. I like everything about it, it looks functional in every detail, sturdy, and pleasant to the eye.
I would purchase one if I could. I actually could afford the cost for a frame, but shipping/importing would make it cost over twice that value, wich makes no sense.
Back to your observations:
or the most part, I think Kevbo's concerns are significantly overblown with regards to the front loader
So do I. Vast majority of the recumbents sold in Brazil (probably all over the world too) have 20" front wheels.
it's probably easier to climb with long tail. Mostly because it's hard to stand on a front loading bike and really get leverage
I don't know about "real" xtracycles, but with my home built and 2 kids on board, standing and pedaling hard does not feel that good. But then, I'm a recumbent rider, so I'm used to just sitting and spinning, and that's what I do - hapilly - with my cargo bike too! This particular feature poses no problem as far as I'm concerned.
01-24-12, 01:02 PM
#20
Member
Thread Starter
Join Date: Dec 2006
Location: Porto Alegre, Brazil
Posts: 33
Bikes: M5 recumbent, long tail converted specialized
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
2. If carrying kids, I'd go with the schwalbe big apple tires (and build a frame in such a way as to provide enough clearance for these tire), as it'll give them a more cushy ride over the bumpy stuff.
3. I'd build a platform close to the CETMA. Make it a flat load floor that you can build a box on top. This allows you to take off the box when the kids get older so that you have a lighter and more capable cargo hauler.
a) the length - the CETMA and the other USA made box bikes seem to be shorter than the Euro made ones. I sense there is a (probably exagerated) concern with bike weight in the US (there is no similar concern about rider weight, it seems, but that's another subject alltogether). I think I could use a longer cargo bay but I stil need to make more drawings and tests with the kids.
b) is a platform really that useful/important? I imagine that being able to just throw things into the box and ride is a major advantage to any other arrangement that necessarily involves fastening of some sort.
4. I'd also build the "perimeter" frame for the platform. Run your tubes around the edge of the box rather than through the middle. It'll make your bike and platform stronger and save some weight.
5. The space for the rider on the Joe box bike is really small, even the CETMA space is a bit short (if you are running a small stem). Be sure that you have a reasonable cockpit.
Last edited by artur elias; 01-27-12 at 07:40 AM.
01-27-12, 07:31 AM
#21
Member
Thread Starter
Join Date: Dec 2006
Location: Porto Alegre, Brazil
Posts: 33
Bikes: M5 recumbent, long tail converted specialized
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Good news.
I don't need measurements anymore! I've (almost) made up my mind regarding dimensions. I guess I've started to think like a designer/builder instead of trying to emulate one.
There is the issue with the steering geometry.
One nice guy on the FB Cargo Bike group pointed me to the (rather obvious, dumb me) fact that it is not only possible but even easy to infer head tube angles from pictures. I've found angles ranging from about to 68º to 75º among several production (one prototype) box bikes: Metrofiets, Urban Arrow, Bakfiets.nl, the classic Monark long John, the German Long Harry.
Fork rake varies a lot too, and so does trail.
Any thoughts regarding steering geometry of box bikes are welcome.
I don't need measurements anymore! I've (almost) made up my mind regarding dimensions. I guess I've started to think like a designer/builder instead of trying to emulate one.
There is the issue with the steering geometry.
One nice guy on the FB Cargo Bike group pointed me to the (rather obvious, dumb me) fact that it is not only possible but even easy to infer head tube angles from pictures. I've found angles ranging from about to 68º to 75º among several production (one prototype) box bikes: Metrofiets, Urban Arrow, Bakfiets.nl, the classic Monark long John, the German Long Harry.
Fork rake varies a lot too, and so does trail.
Any thoughts regarding steering geometry of box bikes are welcome.
01-27-12, 07:39 AM
#22
Member
Thread Starter
Join Date: Dec 2006
Location: Porto Alegre, Brazil
Posts: 33
Bikes: M5 recumbent, long tail converted specialized
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I updated my flickr page with the 2 main designs I'm considering right now. Nº 1 is straight forward, simpler to build (less weld points), a lot like Tom's Cargo Bikes. But it is longer than a bakfiets "needs to be".
Nº 2 is more efficient lenghtwise, it has a slightly longer bay area for a shorter overall length.
One more thing. I've done something stupid and bought some stainless steel tubing I figured would be a great material. Than I got to know it's not safe to bond that to mild steel (wich the donnor frame is probably made of). So design 2 is an attempt to accomodate both materials; black being mild steel and the rest stainless steel. The two frame sections would be bolted instead of welded together. The idea was given to me by the welder. I'm open to critique and suggestions folks!
Nº 2 is more efficient lenghtwise, it has a slightly longer bay area for a shorter overall length.
One more thing. I've done something stupid and bought some stainless steel tubing I figured would be a great material. Than I got to know it's not safe to bond that to mild steel (wich the donnor frame is probably made of). So design 2 is an attempt to accomodate both materials; black being mild steel and the rest stainless steel. The two frame sections would be bolted instead of welded together. The idea was given to me by the welder. I'm open to critique and suggestions folks!
01-27-12, 09:15 AM
#23
Senior Member
Join Date: Oct 2007
Posts: 330
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 3 Times
in
1 Post
Both should work Artur. 60mm trail seems very high. Think about my idea of making a fork with long horizontal dropouts so you can easily experiment with trail changes. This is the thing that will change the handling the most.
MossHops: I wasn't trying to discourage Artur or be critical of Bakfietsen in general. Just trying to give him an idea of how the trade offs work, and why the typical designs are how they are.
MossHops: I wasn't trying to discourage Artur or be critical of Bakfietsen in general. Just trying to give him an idea of how the trade offs work, and why the typical designs are how they are.
01-28-12, 12:12 PM
#24
Member
Join Date: Feb 2009
Posts: 37
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Kevbo,
No problem. I understand your general point that every design has trade-offs and I agree that the long john style has some definite pluses and minuses.
Artur, the CETMA is 8 1/2 feet or so, so they didn't do much to cut down on size (or weight) compared to regular bakfiets. I agree that once you are on the bike, length doesn't matter. It only is an issue for me when I try and lock it up at a regular bike rack. I would say however that the longer your runs of steel tubing are, the more flex you'll have on your bike. I think flex is a bigger issue than weight or total length.
No problem. I understand your general point that every design has trade-offs and I agree that the long john style has some definite pluses and minuses.
Artur, the CETMA is 8 1/2 feet or so, so they didn't do much to cut down on size (or weight) compared to regular bakfiets. I agree that once you are on the bike, length doesn't matter. It only is an issue for me when I try and lock it up at a regular bike rack. I would say however that the longer your runs of steel tubing are, the more flex you'll have on your bike. I think flex is a bigger issue than weight or total length.
01-28-12, 12:15 PM
#25
Member
Join Date: Feb 2009
Posts: 37
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
As far as flat floor vs. box goes... box is easy to "throw it in and go" whereas the flat floor definitely allows you to take larger, awkwardly sized objects. The best solution depends on what you want to carry most often.