Warning to Yuba Owners - don't use large rotors

[Russell]

The problem is that although Kiwi's torque arms offer resistance both ways (so theoretically support regen), I found that the force of the regen would eventually force the rear axle down and out of the drop out (you need to appreciate that the dropouts on the Yuba are massive BMX drops, so the axle doesn't slot in, it is like the proverbial case of throwing a sausage down a hallway, if the Yuba's rear drops were a vagina, it would "hang open and loose like a tired dog's mouth" as it were). This was happening to me with (the name eludes me, the ratcheting washers, whatever they are called). I personally think if you want to run rear regen on the Yuba with a heavy wheel like the X5, you need to modify the frame with a bolt on torque plate. The photo below hopefully illustrates the problem I am talking about.

[

Note that Yuba does offer axle adapters for the rear dropouts. I get a "malware warning" when I try to visit the yuba bike site so I can't show a picture but they are offered by retailers for around 20 bucks.

-R

 

[deVries]

Right where your's bent it looks like the metal does a type of indentation like the inside of the U rather then the opposite.

Thought that was a bit weird. Seems to me just going straight would give it more strength.

I don't know jack about these types of things tho just something I thought weird.. Will grab a pic in a bit.

Definitely might be a design flaw if it matches the same spot, though I wonder about proper heat treatment too.

Luckily I was not going fast when this happened, but whilst braking (not suddenly or heavily), the forks on my Yuba collapsed and I crashed. As I said, I wasn't going fast so was only bruised, but if I had been going downhill it could have been possibly fatal.

Personally I think it is not a failure specific to that very fork, I think it is too underbuilt for its purpose.

 

[mdd0127]

'We strongly recommend rim and/or disc brakes, though these carry their own risks:
under severe loads (as when carrying a passenger or cargo at high speed a very strong front brake can lead to
failure of the front fork. For this reason, don't use the front brake by itself; the rear or rear and front brake
should be used in all braking situations.' Basically, our forks are under engineered for our bikes and are a huge liability. Get a well made fork asap.

I fixed it.

Like someone pointed out, it doesn't matter where the brake is mounted because the stopping force is applied at the axle, by the axle, as the wheel is forced to stop. Anyone going downhill or riding with a load could potentially have this happen to them. The fact that Yuba put this warning in the manual proves that they have known about the fact that their forks are insufficient for the application that they've been used on. If the wrong person hurt themselves because of this, they could be sued out of existence.....and they'd lose without a doubt. I hope they get on fixing this asap. I've emailed a few people that I recommended these bikes to and warned them to replace their forks.

I hope the company fixes it for everyone that's bought one of these bikes. Scary stuff.

 

[neptronix]

Hm.. would a car manufacturer design a car that could potentially have it's front bend, snap, and fall out underneath the car if you hit the brakes too hard?

How fast do you think they'd be sued out of existence?
What would be the excuse? ( but we shaved 8lbs off the car! )

Bike safety/strength is too often neglected in the name of weight weenie-dom.. i hope Yuba takes notice, because this is serious..

 

[ohzee]

[/URL]

Hopefully you can see what I mean by this pic it was hard to capture with my subpar phone camera.

 

[Kiwi]

I see it. I see it on my bike too, there is a concave surface on the fork at the bend, a result from rolling the tube. Yes, basically a "start to collapse here" point.
I could design a fork strengthener, that clamps around the tube above the fork, and connects to the V brake lugs. This could stop catastrophic failure. I would need a couple of forks to do failure tests on, to see what difference a strengthening plate would make.

 

[chroot]

WoW unbelievable, Thanks for warning and I will check my Yuba bike.

 

[Kiwi]

Considering this is a Cargo bike, promoted for caring around your kiddies, with a 200kg load rating......and you can collapse the fork under the bikes own weight....this is not good. I will design a strengthening plate and sell it at cost to anyone who wants one. But really, Yuba need to send out new forks to everyone with a V3 bike before someone splatters their kids.
Kiwi.

 

[SamTexas]

This is getting more and more interesting. So hard to believe that Yuba actually designed a fork like this.

If I have to guess, I'd just say that you got unlucky. In my opinion, you got a defective fork.

Doesn't look like a defective fork anymore. It's now more a defective design.

But really, Yuba need to send out new forks to everyone with a V3 bike before someone splatters their kids.

Along with an apology and sufficient fund to pay a local bike mechanic to swap out the defective fork.

 

[ohzee]

Considering this is a Cargo bike, promoted for caring around your kiddies, with a 200kg load rating......and you can collapse the fork under the bikes own weight....this is not good. I will design a strengthening plate and sell it at cost to anyone who wants one. But really, Yuba need to send out new forks to everyone with a V3 bike before someone splatters their kids.
Kiwi.

I was told my bike is a v4 version. I bought it a little over 2 months ago.

 

[John in CR]

Philistine,
Glad you're okay. Come on strong with them and force a quick settlement of your issue, because they're as good as goners now. Too bad because they're a nice looking cargo bike. They deserve to be out of business though, since they knew the fork was weak. Tell them they almost got you killed and need to rectify this immediately, and not by a replacement having the same design. It's inexcusable.


Ohzee,
I wouldn't ride that bike another foot.


SpinningMags,
What's this "Normally I'm not a fan of regen, for me its just an unnecessary complexity."? Have you ever ridden an ebike with nicely tuned regen? Complexity? What complexity? More range from your batteries, less brake maintenance, and it adds safety, especially on hills, so your mechanical brakes are always fresh and ready for an emergency stop...well, unless you ride a Yuba. It's just a matter of connecting a 2 wire plug. What's complex about that?

 

[Gordo]

I wonder if that fork was originally designed for rim brakes only and that disk brake mounts were added later? Am I right in assuming that part of the braking forces of rim brakes are transmitted straight to the top of the forks through the caliper unlike disk brakes where all the force travels through the fork leg?

If that is correct it might help explain the failure or be a contributing factor.

Gary

Edit --- Wait, that force is pushing forward at the caliper, so would that have no effect. Sorry, I was never good at this kind of thing

It does not matter what design the brakes are, the lever arm is from the axle to the top of the fork. Whatever is stopping the wheel does not matter. Even if it was a stick through the spokes. This bike is cheap Chinese crap at it's finest. Standard Ornamental cargo bike marketed as a yuppy kiddy carrier to those with more money than brains.

 

[neptronix]

This bike is cheap Chinese crap at it's finest. Standard Ornamental cargo bike marketed as a yuppy kiddy carrier to those with more money than brains.

Are you making this statement based on the fork alone?

Me and my girlfriend are both about 250lbs and we are tall as well. With both of us on the bike, we felt that the bike was VERY solid. Side-side flex seemed to be mostly absent, definitely less flexy than my mountain bikes. Welds looked great. Tubing looked thick. And it was heavy with the triangulations being in all the right places to support really heavy loads.

I can't disagree with you more. I am very picky and very much critical of things that are under-built. I felt like the frame itself is both a great deal for the $ and also well constructed. This bike is not ornamental.

 

[amberwolf]

The front brake is the main brake on a bicycle - the rear doesn't have much stopping power in comparison and a lot of us have learned correctly to use the front brake only 90 per cent of the time.

There is a difference when riding a longtail cargo bike, especially when loaded, vs any regular type of bike. The rear can have so much weight on it vs the front that it's brakes can be just as effective as the front, especially if you have limited or no front suspension (as in the Yuba). Depends on the load, tires, bike design, etc.

It does look like Yuba's site has been hacked:
http://www.google.com/safebrowsing/diagnostic?site=http://yubaride.com/&hl=en

Safe Browsing Diagnostic page for yubaride.com

What is the current listing status for yubaride.com?

Site is listed as suspicious - visiting this web site may harm your computer.

Part of this site was listed for suspicious activity 1 time(s) over the past 90 days.

What happened when Google visited this site?

Of the 4 pages we tested on the site over the past 90 days, 2 page(s) resulted in malicious software being downloaded and installed without user consent. The last time Google visited this site was on 2012-06-18, and the last time suspicious content was found on this site was on 2012-06-18.

Malicious software is hosted on 1 domain(s), including vlagskiper.ru/.

This site was hosted on 1 network(s) including AS17139 (CORPCOLO).

Has this site acted as an intermediary resulting in further distribution of malware?

Over the past 90 days, yubaride.com did not appear to function as an intermediary for the infection of any sites.

Has this site hosted malware?

No, this site has not hosted malicious software over the past 90 days.

How did this happen?

In some cases, third parties can add malicious code to legitimate sites, which would cause us to show the warning message.

Next steps:

* Return to the previous page.
* If you are the owner of this web site, you can request a review of your site using Google Webmaster Tools. More information about the review process is available in Google's Webmaster Help Center.

Updated 5 hours ago

© Google - Google Home

 

[Chalo]

WOW! I would have never guessed that the front fork was made so weak for a bike like this!

Time for a surly fork! I've had 2 of their solid forks... and they were wonderful. 203mm stops from 42mph, no prob.

I bent a Surly 1x1 fork once doing nose wheelies on a normal pedal bike at walking speed. Surly forks are just Taiwanese made chromoly forks, with some subtle and thoughtful design features. They are only strong to the same degree that they are heavy. Get the Instigator model if you need extra strength.

The fork on the Yuba is not necessarily weak compared to other MTB-type rigid forks. The thing about the Yuba that is different is the long wheelbase. That makes the bike harder to tip up, thereby raising the amount of braking force that can be applied before tip-up imposes an absolute limit. Tandems have the same issue, and I think a longtail should probably have a tandem-spec fork, or one designed for dirt jumping.

During the early mainstreaming of mountain bikes in the late 1980s, I used to bend (but not collapse) a fork every few weeks with braking power alone. I used cantilever brakes to do it, because linear-pulls and discs were not even a speck on the horizon. Eventually I cured the problem by switching to a Bontrager fork with a mechanically clamped crown. Between having no heat affected weld zones, and the robust materials used in its construction, it could withstand the punishment without giving out.

Chalo

 

[boostjuice]

Me and my girlfriend are both about 250lbs and we are tall as well. With both of us on the bike, we felt that the bike was VERY solid. Side-side flex seemed to be mostly absent, definitely less flexy than my mountain bikes. Welds looked great. Tubing looked thick. And it was heavy with the triangulations being in all the right places to support really heavy loads.

I can't disagree with you more. I am very picky and very much critical of things that are under-built. I felt like the frame itself is both a great deal for the $ and also well constructed. This bike is not ornamental.

+1, I absolutely agree, the main frame is STRONG in my experience, even loaded up with 2x adult passengers on the rear it still feels rigid and confidence inspiring to me. However when i first laid eyes on my V4 my frameset i did think that the standard fork looks weak, primarily where the two fork prongs join at the stem. In my mind though any owner should just swap the standard rigid fork out for a decent short travel suspension fork as a matter of course, regardless of this new found risk issue. Rigid forks should be left in the 90's/the local garbage dump.

 

[Alan B]

Philistine, would you consider changing the title of this thread to something like "Warning to Yuba Owners - check your front fork".

One of these days I want to get a Yuba. Looks like a great ebike.

 

[ohzee]

I have been holding back in contacting Yuba. If someone does hear back from them please post here.

I rode my bike into work today. I use the brakes evenly and so far have not really loaded up my bike so
I am not to worried about collapsing the front fork. I know it's a possibility , but it's not going to keep me
from using it.

Still I like the idea of replacing the front work with a suspension one Just not sure what I could use.
Thought I heard others say a rigid fork is better ? On yuba's site replacement front forks are 65$ US.

 

[Chalo]

In my mind though any owner should just swap the standard rigid fork out for a decent short travel suspension fork as a matter of course, regardless of this new found risk issue. Rigid forks should be left in the 90's/the local garbage dump.

This is poppycock even for the purposes of regular single bikes, but it's especially misguided for longtails. Suspension is by nature designed to dissipate energy, which is contrary to every other design element of a bicycle. That's why bicycle suspension first showed up in the 1870s, and was continuously developed through the turn of the century, but was abandoned and didn't become common until the 1990s, after Western riders no longer regarded bicycles as regular transportation.

Normal bikes have a static weight distribution that places between 2/3 and 3/4 of the rider's weight on the rear. Longtails divide it almost equally front and rear. Thus the fork will see a static applied load of two or three times what it was designed for, and the spring constant will be all wrong. Most good forks don't even have replacement springs available that would make sense for a longtail loaded to capacity. You could use an air fork instead, but the stiction and risk of seal failure would be elevated in proportion to the pressure required.

And of course, just like on a single bike, a boingy fork squanders some variable percentage of the rider's muscle power just moving the bike and rider up and down. Because the pedals are proportionally closer to the fork on a longtail, this effect will be relatively exaggerated as a result.

Chalo

 

[flathill]

They spec: Cruiser Fork D Type
They spec a tandem rear wheel but a regular front...
they shoulda spec'd a tandem front fork if they advertise carrying 2-3 KIDS and cargo
generally, cruiser bikes only have rear brakes only....coaster brakes

they thing with QC in China is they will make it good for a while, only you are watching/checking, then they start taking shortcuts because their profit margin is so thin because you've negotiated to a tenth of a penny like walmart (they have marathon 12 hour negotiations over a tenth of a cent, for real, no joke)...mix with unstable commodity prices and soaring labor costs and you have a recipe for disaster, simply because of greed

no matter what happens to the bike owners yuba is shielded because they are a corporation who can simply go bankrupt which negates fear

 

[Chalo]

They spec: Cruiser Fork D Type
They spec a tandem rear wheel but a regular front...
they shoulda spec'd a tandem front fork if they advertise carrying 2-3 KIDS and cargo

I agree about the tandem fork. A normal front wheel should be OK because a normal front wheel is so much stronger than a normal rear wheel. A disc braked front wheel isn't, though-- it's dished (offset) just like a rear wheel, and is therefore a bad idea for heavy-duty use.

I bet that the fork as designed is large enough, heavy enough, and basically adequate for the job. The bends as illustrated in the photo earlier look pretty sloppy and possibly compromised. Or it could be that the OP's fork had a material flaw in a highly stressed location. There are a few ways it could be a manufacturer defect, but it doesn't look like a grievous lack of due diligence to me.

Chalo

 

[ohzee]

I got a response from Ben that they are looking at the fork issue... He also confirmed the site was hacked , but said it's good now.

 

[flathill]

There are a few ways it could be a manufacturer defect, but it doesn't look like a grievous lack of due diligence to me.

Chalo

Huh? Did you read the slimy lawyer speak manual saying using any type of brake is risky behavior
I mean what is someone thinking using a brake
don't they know that is risky

"We strongly recommend rim and/or disc brakes, though these carry their own risks:
under severe loads (as when carrying a passenger or cargo at high speed a very strong front brake can lead to
failure of the front fork. For this reason, don't use the front brake by itself; the rear or rear and front brake
should be used in all braking situations."

I'll be sure to use my rear brake in ALL situations like rain or down super steep hills where it is worthless
oh and I've never had a rear brake break (cable snap or hydro blowout) or overheat on a CARGO bike in an emergency braking situation
it is criminal to use a standard cruiser grade fork made for cruiser bikes with no front brake

 

[neptronix]

Well, no duh! It's much safer just to crash into the object you are heading towards with 600lb worth of stuff behind you, than use the wimpy bicycle grade brakes and hurt the poor wittle fork!. :lol:

 

[Farfle]

A failure of a fork like that is unacceptable. You should be tearing the headtube off the bike before the fork fails. Whether that is from braking forces or from being heavily loaded.