Posts Tagged ‘mundo yuba’


May 12, 2010

For the mundo rider who has everything, a colour matching Jellibell! Look good and sound friendly!

And get that tight rear end you have always wanted with these little beauties! 25mm furniture endcaps. Available from your local hardware store now! (warning end caps may cause rear end fluid retention leading to premature rustification).

…and for the nature lover why not go troppo with this great garden setting for your Yuba Mundo! (children not included)


Brake 3

March 20, 2010

The adapter for the rear bb7 185mm disc arrived from Yuba. It seems they have gone to a lot of trouble to have it CNCed and are likely not making any money selling it for $30. I had a lot of trouble working out how to use this adapter (no instructions included) but finally worked out that you need to use one 1/2 of the BB7 adjustment shims with the bolts and washers they send with the adapter. After a bit of  moving the caliper position with washers etc I got it to mount ok.

Correctly mounted adapter before I broke it

 Then I broke it.

The caliper mounting bolts only go into the adapter about 3 or 4 threads deep so of course when tensioning it up I was a bit over zealous and stripped the thread in the soft alloy adapter. I might work Ok for you but watch out you don’t tension it too much. I probably didn’t need to do it up that tight but I have used a similar tension on the original BB7 adapter with no problems. The Yuba adapter is certainly weaker than the original, so maybe it wouldn’t have coped with braking forces over time and I’ve saved myself future problems?

Yuba adapter compared to the original Avid BB7 adapter note same bolt used

OK so long story short I had a 160mm BB7 rotor and after stuffing about with the adapter I thought I would just put that on and be done with it. But it didn’t fit! Certainly not with the standard adapter and mounting bolts. It might fit if the caliper bolts are adjusted/shimmed etc. I may try again if I can be bothered changing the rotor yet again.

I wonder how many people have successfully mounted rear discs on the Mundo? I only know of one other on the web and he mentions having to “man handle” the mounting tab.

So I have the 3 rotor sizes for BB7s and adapters and none of them mount on the rear of my Yuba without significant change to the mounting bolts or using a fairly weak adapter, nice.

Never fear on we go on this glorious rear brake adventure! I would have given up long ago and gone rear V Brake but as I previously mentioned my rims don’t have a V Brake track.

So nothing to lose with the ruined Yuba 185mm adapter I drilled it right through, made a couple of  “shelves” with my Dremel tool and some cutoff discs (a free Dremel tool should really come with every Mundo frame!), and mounted using some longer bolts with nylock nuts. Mounts nice and secure and so far so good with a 185mm rear brake!

Modified adapter

Mounted on the Mundo

My front brake mounting (original Mundo fork) was never all that good (203mm rotor) and needed alignment but I couldn’t get it to line up without bending the brake mount tab slightly and grinding all the paint and some metal off the inside of it. But it seems Ok now, but it does still shudder a bit if I really pull on the brake, not sure if this is the fork or something else.

Victory? Well it feels a hollow victory really. Are you building a Mundo with disc brakes? Ask youself do you really need them? Anyway maybe I’ve made all the mistakes for you. My pleasure that’s what I’m here for!


February 19, 2010

yes my workshop/corner of the garage is a mess...

My grand father was a carpenter but unfortunately he wasn’t the mentoring type and I didn’t pick up much from him. He mainly made formwork anyhow. but I’ve got a couple of his tools. These are pretty easy to make with or without power tools, I used a cheap jigsaw and a belt sander and powerdrill which made the whole thing pretty quick, maybe 3 or 4 hours start to finish.

It has been hot lately (up to 41deg C the other day) with lots of evening storms and rain perfect weather for disappearing into my cool basement garage to do some woodwork.

I bought some 6mm hoop pine plywood but I wished I had time to look harder for some 2nd hand stuff, you don’t need much. The 6mm stuff is very light (the top deck and the side loaders combine to just over a kilo). The 6mm is fine for the top deck as its well supported along its length but its a bit flexy for the side loaders. It would be quicker just to use thicker ply, but I just screwed and glued an extra “stringer” of ply underneath to increase the strength. However standing towards the inside edge is still pretty flexible.

Just trace around the side loaders and cut with a jigsaw

It’s tricky to figure out exactly where to drill the holes for the mounting screws (which are already on the V3 Mundo). I just clamped the boards into position and it left an impression in the wood showing where I needed to drill. I also greased all the mounting bolts so they don’t rust into position. The heads on these hex bolts are notoriously easy to strip.

These are the dimensions I got for the top deck but measure for yourself!

I used some leftover Tung based flooring oil to seal the boards; 3 coats. It created a beautiful yellow-gold matt finish which I think suits the bike well.

boards getting oiled - stringers on sideloaders

As well as the top and lower boards I put some side boards to keep my boys feet out of the spokes and allow me to easier mount some kind of foot rest for my younger shorter fella. I drilled some holes in these to allow strapping points for cargo and to keep the weight down (shaved a whole 200gms off, yes I am embarrassed to say I did weigh them…), plus it looks funkier!

I’m kind of glad I’m still waiting on the rear brake as it has made me focus on the boards this weekend. Test ride was great all tight and good. There was a weird reverberation off the lower boards from the drive drain, just sounded a bit weird.

I’ve now got some Yuba soft spot seat which seem pretty good and sturdy. With these you don’t need a topdeck, they have a thick flexible plastic base. I was going to drill some cutouts in the topdeck to allow the pannier bag to fit but I’m just going to go with the soft spots without a deck. A pity it looked great with the deck!

Elated 2

February 13, 2010

I finished fitting the Elation Kit. It was pretty quick (quicker than fitting mudguards anyway!) of course there were a couple of small hiccups.

The main strap mounts are great and seem very secure. There is also an adjustable “torque” bolt on the left side designed to run from the plate up to the seatpost to aid in keeping the motor from slipping. It is one of those adjustable double threaded rods you find holding the mast of a sailing boat up or on wire ballistrading.

I could not get it to fit right (without bending the torque bolt) to attach to the clamp on the seatpost so I ran it further back to a bar behind the seatpost and attached it with the smaller clamp (needed to shim the smaller clamp with a bit of old inner tube). Seems secure.

Elation Torque Bolt not fitting

Elation Torque Bolt fitting!

My problem with the battery mounts was that the plastic plate didn’t have holes drilled. I drilled some as Allan at Elation suggested I could, but the bolts were too loose so I just used some other nuts and bolts I had hanging around (you guessed it, more skateboard stuff!) and it fits fine.

So I fitted everything up, hand grips, accelerator, zip tied everything securely and went for a ride….a short ride.  I broke the main bike chain (not the motor drive chain) about 1k from home. Bugger…my fault I guess, Im not too experienced at breaking and rejoining chains and I guess one of my links was poor and a side plate had slipped loose.

While it went, it went great. I can’t give you any speed data as it was the middle of the night and I couldn’t see my speedo!  I have a lot of steep short hills near my place and it climbed well, I did need to pedal to do it at any speed of course, but for 200 Watts it went great.

My first impression, having come from a bike with a hub motor, was that it did lack the simple elegance and smoothness of a hub system.

The most difficult thing was changing gears, or should I say sensing when a gear change was needed. The motor takes away that sensitivity you get through the pedals to sense when to change up and down. I was more like driving a car listening to the note of the motor or just noticing how fast you were pedaling to pick the changing point, rather than feeling that change in effort through your legs.

It was also a lot noisier than the hub motor. With the hub lots of people would look curiously then ask if I had a motor. I’ll get no questions about the motor with this one, you can see and hear, it clearly has a motor! I’m not talking about a 2 stroke offensive kind of sound, just an obvious whirring noise.

All up an Ok first experience, but I’m keen to get out again when the chain is mended.

Not much let to do now I need to tension the threaded headset (any hints on how I could do this without buying another tool would be most welcome). Finish making the wooden boards, and sort the rear brake out (still waiting on this from Yuba, they say it was sent 11 days ago). Then I need to fit some stoker bars for my passengers.


February 9, 2010

Ok fenders if you insist.You know I found this one of the slowest and most fiddly jobs on the build so far. I work pretty slow but it took me a whole afternoon.

I have some Planet Bike 60mm full length plastic fenders and they look good but I guess I should have googled fenders and disc brakes before I started to fit them.

I suppose generally fenders and disc brakes don’t go together, fenders being a commuter thing and disc brakes being a down hill mountain bike thing.

The front has the common problem with the disc rotor getting in the way of the lower “stay”. I thought about bending the stay in a visually attractive manner around the disc (an old coat hanger works great to create template for this) but my stay wasn’t long enough to allow for all the bends. Check this for a nice how to guide.

In the end I used a 185mm BB7 disc brake post mount adapter for which I had no other use to extend the mounting point below the disc brake. So far this is working and looks Ok but I might need a bit of lock tight to keep the whole thing in place.

The rear was another matter. The rear should have two stays each side running up from the Mundo mounting points near the drop outs up to the mudguards.  When both stays and the mounting bolt are installed the whole thing protrudes in towards the wheel a fair bit. No prob on the right side but on the left it fouls the disc brake rotor ( this is likely no matter what size rotor you have by the way!).

The solution was to only run with one of the stays and attach the mudguard at other points, thankfully not a big issue on the Mundo with a couple of zip ties attaching to the rear carrier. However with the standard Planet Bike mounting bolts it still fouled the disc rotor. I dug out a low profile bolt and it now clears the rotor by 3 or 4 mm (actually I used a standard 1 inch skateboard truck mounting bolt, skateboard stuff comes in so handy!).

Drive side with standard bolt , no problem

Disc side with low profile skateboard bolt (blurry sorry!)

A small point but these 60mm guards look a bit  narrow for the Fat Frank tyres when viewed from the top, but it’s only an aesthetic thing, I’m sure they’ll function fine.  In general however I love the look of the black guards, wheels and tyres and think they highlight the orange frame nicely.

Lastly you need to mount rear guard as high as you can or the top of the chain line may catch the guard in very low gears. They have a cutout to suit in that position you just have to watch out how high you mount it . In fact my chain pretty much touches the side of my rear tyre in low gears, A factor of having a long frame I guess.  It’s not too bad especially as my tyres have no knobbly tread to catch the chain; the only solution I can see would be narrower tyres or a slightly wider bottom bracket.


February 7, 2010

As you may know the Mundo has those big 14mm dropouts on the rear.

I have had word form others that a well tightened quick release using the 14mm adapters will hold it just fine and mine did hold Ok eventually on a recent test run. However I thought I would try to devise some better means preventing the rear wheel slipping in the dropout.

Firstly, I looked on the net for some burly splined washers as I don’t have alot of time to get to bike shops except Saturday morning, which is not a good time at bike shops! But I think I will still try to source some of these at a local BMX place at some point.

The first issue with adding extra washers to a wheel with quick release (QR) skewers is that the skewer needs to be long enough to accept the extra width. The Mundo frame is already extra thick at the dropouts and this can limit the depth of bite a skewer bolt gets into the “nylock” bit of the  skewer nut.

I ordered some extra long skewers made by Halo called “porkies” made to fit bikes with thick dropouts (by thick I mean the thickness of the steel, not the extra big 14mm dropout slot). These are Ok about 5mm longer than standard but are all alloy for lightness, so I’ll keep looking for a steel alternative a well.

Also, a washer designed for a 14mm dropout has a huge hold in the middle compared to the thin QR skewer, so it might tend to float around a bit. I tried making my own washer from “Mudguard Washers”  which are big and have a smaller hole in the middle. I tried to punch divets into them, and drove holes into them in an effort to make a grippy surface, but really the metal was too weak and offered little extra grip when in position.

Finally I dug out a couple of large “cup washers” from my longboard skateboard gear ( It is alloy but the cup shape gives it rigidity. I drilled 2 holes to size and screwed in a couple of  “sprigs” from my new platform pedals. The sprigs bite into the frame offering grip (which can be adjusted with a small allen key), I might even drill a couple of shallow holes in the frame to give these some more grip. These are really like “tugnuts” without the tug!

Drawbacks could be the the light alloy washers tearing or the cup shape working “sled like” to negate the extra grip, however it test rode fine in a high gear standing up on the pedals applying lots of pulling force. We’ll see how it hold ups.

Mundo Yuba Cargo Bike?

January 20, 2010

I’m right in the middle of building up a cargo bike using a Mundo Yuba frameset. I intend to blog some details and pics…but the road to hell is paved with such intentions too.

Mainly I want to pick the brains of the world to help me with problems and maybe allow others to learn from my mistakes. Of which there are a few at the moment.

So if you have helpful comments or questions comment away. Anti bike diatribes, negative input? Use the back button!