Bent rack - how big a deal is this?

Espresso_
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Bent rack - how big a deal is this?

Postby Espresso_ » Fri Jun 26, 2015 8:36 am

This morning at the playground I noticed that the aluminium rack beneath my child's seat is bent. See attached.

It's a Racktime, made by the same company as the people who made my Tubus (steel) racks so I was expecting better than this. Load rated to 35kgs, and the child + seat weighs around 20kgs.

Is this dangerous and likely to break?

Or should I not worry?

Image

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thecaptn
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Re: Bent rack - how big a deal is this?

Postby thecaptn » Fri Jun 26, 2015 9:10 am

By the time they're 18 your kids should probably have their own bike.

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bychosis
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Re: Bent rack - how big a deal is this?

Postby bychosis » Fri Jun 26, 2015 10:21 am

Looks likely to bend more. I'd be looking to replace or stiffen it up somehow before the little one turns into a bigger one.

The 35kg rating is probably for a load spread over the rack. The seat design appears to be point loading the rack where it has little support.
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pedalleur
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Re: Bent rack - how big a deal is this?

Postby pedalleur » Fri Jun 26, 2015 5:28 pm

ask for a refund if it doesnt live up to it's specs

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RonK
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Re: Bent rack - how big a deal is this?

Postby RonK » Fri Jun 26, 2015 5:31 pm

I doubt even a Tubus rack would survive that kind of weight distribution.
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Espresso_
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Re: Bent rack - how big a deal is this?

Postby Espresso_ » Fri Jun 26, 2015 5:33 pm

RonK wrote:I doubt even a Tubus rack would survive that kind of weight distribution.


It probably won't - Tubus don't recommend using their racks for attaching child seats:

Question: Is it allowed to fix a child-seat on a tubus carrier?
Answer: No! Please, don´t. Our carriers are made of thin-wall steel tubes, which are not suitable to clamp a child seat onto them. We assume no liability for any kind of harm or damage, caused by noncompliance to this rule.

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pedalleur
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Re: Bent rack - how big a deal is this?

Postby pedalleur » Fri Jun 26, 2015 5:34 pm

or maybe its not designed for a child seat

here it shows 3 support legs on the rack..
http://www.99bikes.com.au/accessories/b ... s-trailers

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Re: Bent rack - how big a deal is this?

Postby Espresso_ » Fri Jun 26, 2015 6:14 pm

pedalleur wrote:or maybe its not designed for a child seat

here it shows 3 support legs on the rack..
http://www.99bikes.com.au/accessories/b ... s-trailers


That's for a different child seat altogether but I get the point.

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human909
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Re: Bent rack - how big a deal is this?

Postby human909 » Mon Jun 29, 2015 12:03 pm

The clamping and the focused weigh distribution make for an issue. A stated weight limit is likely assuming an evenly distributed weight. Instead you have a situation where at least 50% if not more is focused on one point well away from the supports that is also slightly(or significantly) compromised by the clamps. All the bicycle racks intended for child seats that I have seen have 6 support posts not 4.

The bend has now reduced bending moment loads on the rack so there is a good chance that it will continue to survive. However should it bend further or break you could end up having it interfering with your rear wheel and possibly leading to a crash.

Personally if it was just MY personal safety being compromised I wouldn't worry about it. But with a bub as well on your bike I think caution is the best approach.

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Re: Bent rack - how big a deal is this?

Postby Espresso_ » Mon Jun 29, 2015 12:06 pm

human909 wrote:Personally if it was just MY personal safety being compromised I wouldn't worry about it. But with a bub as well on your bike I think caution is the best approach.


Yeah I'm just going to get a new rack. The Blackburn EX range have similar load carrying ratings but actively speak to their use in a child seat carrying capacity (unlike the Racktime range) so I'll probably go for one of those.

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il padrone
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Re: Bent rack - how big a deal is this?

Postby il padrone » Tue Jun 30, 2015 10:41 pm

Personally I'd recommend saving up for the kiddie-trailer. You could even get the two-child model so you're ready for the second :D

I've never been impressed with the kiddie-seat approach. Our two always travelled in the trailer, until we moved on to the tag-along and tandem with kiddie-cranks.
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Biffidus
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Re: Bent rack - how big a deal is this?

Postby Biffidus » Tue Jun 30, 2015 10:49 pm

You could always buy the bracket that allows you to attach your Yepp Maxi to the Seat Tube instead...

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Re: Bent rack - how big a deal is this?

Postby Espresso_ » Wed Jul 01, 2015 6:00 am

Biffidus wrote:You could always buy the bracket that allows you to attach your Yepp Maxi to the Seat Tube instead...


That wasn't an option on my bike - the front dérailleur is top-pull and the cable stop is right where the seat post clamp would go.

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outnabike
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Re: Bent rack - how big a deal is this?

Postby outnabike » Wed Jul 01, 2015 8:07 am

Hi Espresso_
It is called the point load. And as others have noted it is too concentrated and poorly placed.
I would straighten it up and put a support at rear of load. A simple ally bracket further back would do it , or sleeve the tubes once straightened.Cut some ally tube longitudinally, open it , fit it over then re close it. but go a bit thicker than that steel tube.
I reckon a replacement rack will simply collapses at the first bump again.
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Espresso_
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Re: Bent rack - how big a deal is this?

Postby Espresso_ » Wed Jul 01, 2015 8:10 am

Thanks Outnabike - I've already ordered another rack of a different design. I've gone with a triple strut version which means those load points will be much closer to a strut join than with the old version.

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human909
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Re: Bent rack - how big a deal is this?

Postby human909 » Wed Jul 01, 2015 11:18 am

il padrone wrote:Personally I'd recommend saving up for the kiddie-trailer. You could even get the two-child model so you're ready for the second :D


IMO, if we rated kiddie transport in terms of enjoyment of the child, parent and the general public then you can't beat front mounted seats. :wink: Of course it all depends on the sort of bike you have as they may not fit all bikes.

In my experience all road users can't help but smile when they see a smiling toddler on the front of a bike. :mrgreen:

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il padrone
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Re: Bent rack - how big a deal is this?

Postby il padrone » Wed Jul 01, 2015 1:00 pm

I found the big plus for towing a trailer was that every car approaching from the rear, always gave plenty of space, mostly a full lane change. It always stood out like the proverbial.

People sometimes made comment about the children's safety, even criticised us for "placing them in danger". But experience soon showed that we could ride with the trailer on a main road, and always were given a large margin of room.
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Re: Bent rack - how big a deal is this?

Postby find_bruce » Wed Jul 01, 2015 2:07 pm

il padrone wrote:I found the big plus for towing a trailer was that every car approaching from the rear, always gave plenty of space, mostly a full lane change. It always stood out like the proverbial.

People sometimes made comment about the children's safety, even criticised us for "placing them in danger". But experience soon showed that we could ride with the trailer on a main road, and always were given a large margin of room.

Exactly my experience too. In 12 months of towing my little boy in a trailer followed by 2 years of him riding the weehoo virtually every driver hangs back & only overtakes when there is heaps of room, whether full or empty like this
Image

I have had my share of close shaves, but never with my little boy on board.

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Biffidus
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Re: Bent rack - how big a deal is this?

Postby Biffidus » Wed Jul 01, 2015 10:35 pm

human909 wrote:In my experience all road users can't help but smile when they see a smiling toddler on the front of a bike. :mrgreen:

I'll second that, it was a pain to mount tho.

Espresso: does a rear-rack get in the way of the seat post mount as well?

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Re: Bent rack - how big a deal is this?

Postby Espresso_ » Wed Jul 01, 2015 10:38 pm

Biffidus wrote:Espresso: does a rear-rack get in the way of the seat post mount as well?


I dont think I understand the question, because in the Yepp system you need either a seat post mount or a rear rack mount specific child seat. But I think the answer is "no".

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human909
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Re: Bent rack - how big a deal is this?

Postby human909 » Thu Jul 02, 2015 10:03 am

il padrone wrote:People sometimes made comment about the children's safety, even criticised us for "placing them in danger". But experience soon showed that we could ride with the trailer on a main road, and always were given a large margin of room.

That makes sense. The rear visibility of a trailer has its advantages in areas where you might otherwise be passed in an unsafe manner.

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Re: Bent rack - how big a deal is this?

Postby Espresso_ » Fri Jul 10, 2015 7:50 pm

The Blackburn EX1 Disc rear rack that I ordered to replace the bent Racktime rack arrived today. Given my discs are mounted on the chainstay on this bike, I didn't specifically need the disc version of the rack (which mounts via the quick release axle rather than rear eyelets) but I thought I might as well get a version that can be swapped on to my 26" rigid off road "bikepacking" bike, in case I ever want to carry more on that bike than my alone bags will allow.

Image

I haven't fitted it to the bike yet, but one benefit is already clear - I can mount my Yepp Maxi child seat directly to the Blackburn rack, rather than using the adaptor plate I needed with the Racktime (see first post - its the silver bit). Given the adaptor plate was the source of the stress points, I hope this avoids any future problems.

Not using the adaptor also lowers the mounting height an inch or so, which is helpful for centre of gravity. As people on this thread have pointed out there are many alternatives to rack-mounted bike seats, and the high centre of gravity and resulting lower stability is definitely a downside of this approach. It was VERY difficult to find info which racks were direct-mount compatible with the Yepp Maxi when I bought it, so this is a lucky find.

Here's hoping direct-mounting the seat doesn't bring another problem of fouling against the top of the rear mudguard.

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Re: Bent rack - how big a deal is this?

Postby tubus-racktime » Wed Aug 10, 2016 1:46 am

Hi,
My name is Peter from Tubus-Racktime, the manufacturer of the bent carrier. I just found the thread, to explain my lat comment....

The YEPP childseats which are fixed by such a clamp-mechanism are extremely hazardious !!!
The bended carrier can crack easily, with the result that the child in the seat can fall backwards without
any protection. This can cause injury and dead !!!
We herewith warn to use them on any bicycle rack, despite of the brand.
A bicycle rack is a tubular structure, made out of tube in different sizes. I is made to take load which is
loaded and distributed onto the rack in a way that the vertical struts holding the horizontal loading platform
can handle the load.
A clamped weight between the vertical struts is highly dangerous !
The DIN-EN 14872 standard allowing a maximum load of 25kgs for a bicycle rack, does not automatically allow the use of a child-seat !
After reading the above case, we will warn all consumers by our websites http://www.tubus.com and http://www.racktime.com to
use the YEPP clamping adapter or similar solutions.
We will also write a warning in all of our mounting instructions of rear carriers.
Peter

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Biffidus
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Re: Bent rack - how big a deal is this?

Postby Biffidus » Sat Aug 13, 2016 10:11 pm

Yepp has a new adaptor now which doesn't clamp the tubes in the same way. That black burn rack sounds interesting it mounts the seat directly...

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Re: Bent rack - how big a deal is this?

Postby Espresso_ » Sun Aug 14, 2016 2:19 am

For anyone following this thread, the Blackburn rack has worked fine. The seat mounts directly without the adaptor and has taken months of use without issue. I recommend it for Yepp Maxi users.

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