Mundo
100 W
My V4 Mundo is a treadless fork/headset....My V2 is treaded.
Warning to Yuba Owners - don't use large rotors
- Thread starter Philistine
- Start date
boostjuice
10 kW
Mundo said:
My V4 is...or rather was, threaded. Go figure....
Hmm .. I'm late to this too. I have 203mm Avid BB7 brakes on the front of my Yuba but mine is an early v3 with the round profile forks. I have not ever been happy with the flexing in the forks and seemed to get lots of vibration but better brake pads and better setup seemed to have improved things.
I agree about the rear on a Yuba being essential, i think the way the weight is all in the back and the long wheelbase makes the back brake much more effective than a standard bike.
I'm really not sure how the size of the rotor has much to do with it. If you can brake to lockup with a 160mm disc then this is really the maximum force going through the fork right there. I assummed the larger disc was just more efficient at getting rid of heat on downhill bikes and the like.
I'll keep my forks for now but I will be checking them and listening for any tell tale noises!
I agree about the rear on a Yuba being essential, i think the way the weight is all in the back and the long wheelbase makes the back brake much more effective than a standard bike.
I'm really not sure how the size of the rotor has much to do with it. If you can brake to lockup with a 160mm disc then this is really the maximum force going through the fork right there. I assummed the larger disc was just more efficient at getting rid of heat on downhill bikes and the like.
I'll keep my forks for now but I will be checking them and listening for any tell tale noises!
GMUseless
100 W
Yeah, to be honest..this thread has me feathering the front brake on my Mundo. I too have 203mm BB7's on there. I've got 5 bikes, and pretty much standardized on the BB7 203's a while back. You're correct that the force for a 160 is the same once you lock it up...this was covered a little earlier in the thread.
My problem is, I only ride the Mundo if I need to a) haul a huge load, or more often, b) have two kids on the back. Anytime I get up to 20mph with kids on there, I cringe thinking about what happened to Phil. I inspect that front fork before every ride. Once I can find a good deal on a dirt jumper fork, I'll think I'll change it out; mostly for the added suspension...but the piece of mind as well.
My problem is, I only ride the Mundo if I need to a) haul a huge load, or more often, b) have two kids on the back. Anytime I get up to 20mph with kids on there, I cringe thinking about what happened to Phil. I inspect that front fork before every ride. Once I can find a good deal on a dirt jumper fork, I'll think I'll change it out; mostly for the added suspension...but the piece of mind as well.
Philistine
100 kW
- Joined
- Aug 15, 2010
- Messages
- 1,736
So I spoke with Ben from Yuba, and he offered to send me replacement forks. I was nothing but reasonable and fair in my correspondence (I will post it up in a few weeks when I have time and have finished my deadline). He directed me to the local dealer here, but then basically things broke down, and Ben demanded that if I wanted the forks replaced (these being the forks that nearly killed me), I would have to pay the postage (which being in Australia, would be nearly the cost of the forks).
I can't wait to post up the emails to show what a total reasonable and fair gentleman I was in all the correspondence. To say I am let down about how Yuba Mundo choose to run their business is an understatement. The last thing I like doing is going around demanding crap of people. I was totally reasonable, I said it didn't matter how long it took, I was happy to wait for it to be posted out to me, but apparantly having forks collapse and nearly kill me (covering me in cuts and bruises), means that what you should do as a businessman, is when that customer calmly and reasonably just asks for a set of replacement forks, you should make him pay the postage.
Clearly a business going places.
I can't wait to post up the emails to show what a total reasonable and fair gentleman I was in all the correspondence. To say I am let down about how Yuba Mundo choose to run their business is an understatement. The last thing I like doing is going around demanding crap of people. I was totally reasonable, I said it didn't matter how long it took, I was happy to wait for it to be posted out to me, but apparantly having forks collapse and nearly kill me (covering me in cuts and bruises), means that what you should do as a businessman, is when that customer calmly and reasonably just asks for a set of replacement forks, you should make him pay the postage.
Clearly a business going places.
Chalo
100 TW
Philistine said:
I recommend chopper-style triple clamp forks. They are cheap, not ridiculously heavy, and very strong.
Chalo
Philistine said:
When my month-old 2005 Columbia road bike (now DayGlo Avenger, but unmodified at the time) had the weld on the handlebar stem break while riding at normal low pedal speeds on a street(transitioning to sidewalk via driveway ramp), without hitting anything first, causing me to be holding handlebars no longer connected to the bike except by cables, and then hitting a now-unavoidable curb edge which stopped the bike but not me, landing on the point of my shoulder and *almost* breaking it...Columbia very quickly replaced the stem and paid postage for the new one to me and the old one back to them so they coudl find out why it broke so it couldn't happen again.
That's how things should have happened for you. I'm surprised that they did not.
Philistine said:
Perhaps he would have preferred to simply receive a court summons for a civil suit instead?
We complain about our overly-litigious societies, but if some people refuse to face their responsibilities such things will happen.
hoppydawg
1 mW
Can somebody chime in here about their yuba v3 brakes? I have the stock tectro option shipped from Yuba and have never been too thrilled with them. Is there any special modification necessary to upgrade to the BB7? Also would you go with the 185 on both front and rear? Thanks!
Kiwi
1 kW
..no words needed.
Chalo
100 TW
Kiwi said:
..no words needed.
Are those Surly 1x1 forks? I once bent a pair of those doing stoppies on my mountain bike. No crash, no running into anything, just braking-- and a bent steer tube.
The sideways width of the fork legs has almost nothing to do with the forces that actually bend forks, which are fore-to-aft. And once the two legs together are much stronger than the steer tube, then they cease to be relevant too.
Chalo
Farfle
100 kW
Chalo said:
WOW! What a difference!
You know, i really wonder about why they made the front fork so weak. Could it be that the front of the frame itself isn't very strong - so they'd rather have the fork collapse than the head tube get ripped off?
Just a thought.
On that note, are there folks here with upgraded forks who have been running 203mm brakes with no issue?
I'm really thinking about getting one of these, so i figured i'd ask.
You know, i really wonder about why they made the front fork so weak. Could it be that the front of the frame itself isn't very strong - so they'd rather have the fork collapse than the head tube get ripped off?
Just a thought.
On that note, are there folks here with upgraded forks who have been running 203mm brakes with no issue?
I'm really thinking about getting one of these, so i figured i'd ask.
http://yubaride.com/yubashop/mundo-utility-bike-parts/90-fork.html
I was looking at the yuba site today and noticed this fork. Looks a bit like a surly fork.
Also, they seem to have a 'version 4.2' now.
I wonder if they have silently fixed the problem.
I was looking at the yuba site today and noticed this fork. Looks a bit like a surly fork.
Also, they seem to have a 'version 4.2' now.
I wonder if they have silently fixed the problem.
Philistine
100 kW
- Joined
- Aug 15, 2010
- Messages
- 1,736
I thought you had a Da Bomb or a different cargo bike Neptronix? Or is this for the missus?
After much work on my part and getting my replacement fork, I am still using it with a 203mm rotor. I don't use the bike much due to a variety of factors, one being that it has been off the road for a while until I can find time to fix a few issues, I must say I am still not comfortable with the flex that I can see in the replacement fork (which is a replacement stock) when I brake hard. I am sure the fact I have the X5304 and the ammo cans and my 95kg on board (plus two kids sometimes) doesn't help, but there is no question in my mind the stock fork I have is insufficient (the one you post a picture of looks different to my stock fork, so perhaps they have improved the strength). When I get a moment I will post up better photos of my busted fork with the insides of the collapsed part showing, so you can see how thin the wall is.
But I do think these cargo bikes when electrified put a lot of strain on forks in general. My mate has a Surly Big Dummy he electrified which he has put very solid suspension forks on, and he says he worries about his flex too.
The Yuba is for the missus. She's been thinking about one for about a year solid now.
Yeah i've thought about that a lot too. These forks weren't meant to deal with that kind of weight. I don't think any bike fork was meant to deal with it either. We're in motorcycle fork territory here.
I've tested quite a few suspension forks for flex, and found that the FOX shocks are pretty good compared to rock shox, etc. The crazier the angle, the better, because when you brake, the response is to bend less and compress more. There are some very good solid forks out there - liveforphysics likes the DMR trailblade. But here's what i worry about - how strong is the head tube? anyone want to find out the hard way?
Biasing rear brake via regen and getting some really thick custom torque plates might be the answer for you.
Philistine said:
Yeah i've thought about that a lot too. These forks weren't meant to deal with that kind of weight. I don't think any bike fork was meant to deal with it either. We're in motorcycle fork territory here.
I've tested quite a few suspension forks for flex, and found that the FOX shocks are pretty good compared to rock shox, etc. The crazier the angle, the better, because when you brake, the response is to bend less and compress more. There are some very good solid forks out there - liveforphysics likes the DMR trailblade. But here's what i worry about - how strong is the head tube? anyone want to find out the hard way?
Biasing rear brake via regen and getting some really thick custom torque plates might be the answer for you.
Chalo
100 TW
neptronix said:These forks weren't meant to deal with that kind of weight. I don't think any bike fork was meant to deal with it either. We're in motorcycle fork territory here.
I've tested quite a few suspension forks for flex, and found that the FOX shocks are pretty good compared to rock shox, etc. The crazier the angle, the better, because when you brake, the response is to bend less and compress more. There are some very good solid forks out there - liveforphysics likes the DMR trailblade. But here's what i worry about - how strong is the head tube? anyone want to find out the hard way?
You're actually in tandem bike territory, in terms of fork stresses. Tandem forks have thicker, stronger steer tubes than normal forks.
No single crown fork is ideal for the job, but some are better than others. The Surly Instigator (which is tandem rated) is another commonly available one to go with the DMR Trailblade.
The problem with many suspension forks is that they have aluminum steer tubes. Aluminum is only a third as stiff as steel, such you could make a steer tube out of a solid aluminum bar and it would not be as stiff as a thin-walled steel steerer. So if you take a suspension fork that is physically longer than a rigid fork, and then make the steerer and stanchions from aluminum instead of steel, what you have is a recipe for extreme flex. it would be quite bothersome or even alarming to most people if it were not masked by the squish of the suspension itself.
Lately, the industry has addressed this shortcoming of single-crown forks by making frames with tapered head tubes, so that the fork steer tube can be 1.5" in diameter at the lower end even if it's only 1.125" at the top. It's a neat idea in principle, but it practice it's an expensive game to play at this time.
The best solution from a technical standpoint is to use a dual crown fork. That takes the bending stress off the steer tube, braces the fork legs, and stiffens things up out of proportion to the increase in weight. I'm not crazy about interference between the upper fork stanchions and the down tube, but that's the tradeoff you make.
Here's a picture of Mike Augspurger's custom titanium fork from around 1990. It was stiffer and lighter than a conventional rigid fork. This one appears to be set up for a U-brake:
boostjuice
10 kW
Once you go dual crown you'll never look back 
.
.Mundo
100 W
Hey Boostjuice,
What fork is this?
I am thinking of re-building my V2 Mundo.
What fork is this?
I am thinking of re-building my V2 Mundo.
boostjuice
10 kW
Destickered 2011 Rockshox Domain Dual-Crown (chromoly stanchions)
Mundo
100 W
WOW! Pricey, my wife would kill me....
Kai
10 W
- Joined
- Aug 4, 2008
- Messages
- 86
Looks like Yuba (or factory) shaved off too much weight and vent too far.
I had a really heavy V1 Yuba Mundo (non electric), but I sold it because I wanted to commute with lighter bike. That first version was really heavy. I welded disc brake tabs myself to it I never got those disk brakes working well, a lot of screeking sounds.
Now I have a short longtail Kona Minute with motor and large battery, and with this load I really start missing that Yuba :/
Perhaps I try to buy it back.
I had a really heavy V1 Yuba Mundo (non electric), but I sold it because I wanted to commute with lighter bike. That first version was really heavy. I welded disc brake tabs myself to it I never got those disk brakes working well, a lot of screeking sounds.
Now I have a short longtail Kona Minute with motor and large battery, and with this load I really start missing that Yuba :/
Perhaps I try to buy it back.
ohzee
100 kW
boostjuice said:
Boost you have a build log somewhere for that yuba ? I really like how that front fork looks.
I run a 5404 on my yuba and I could really use some shocks on that front wheel.
Also what kind of motor you running on that ? Hard for me to tell on the pic.
Anyway bike looks sharp. I need to lower my battery as well to help with center of gravity.
Goathead
100 W
Second.
Apparently, you have done what I have been contemplating . . .
boostjuice
10 kW
No build log. I didn't collect photo's along the way, and I can't be bothered documenting everything as it has evolved through trial and error.
Presently it's in pieces undergoing drivetrain/battery pack overhaul. It will return with a battery enclosure in/around the frame and a HPM5000B single ratio LHD, 2-stage drive system with 13.5:1 reduction. With 72V @130A it will be speed limited to about 30Mph (50kph), but get there in a flash due to up to 250Nm of torque being available at the wheel.
Presently it's in pieces undergoing drivetrain/battery pack overhaul. It will return with a battery enclosure in/around the frame and a HPM5000B single ratio LHD, 2-stage drive system with 13.5:1 reduction. With 72V @130A it will be speed limited to about 30Mph (50kph), but get there in a flash due to up to 250Nm of torque being available at the wheel.
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