Ikea recalls it bikes

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Vorpal
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Re: Ikea bike

Postby Vorpal » 27 Oct 2016, 4:19pm

Brucey wrote:- The most sensible way of setting the gears is so that you cruise on the flat in the high gear and then use the low gear for hills. I assume this is how the IKEA bike is arranged. This leaves you riding in the non-direct drive gear most of the time, which reduces the mean efficiency of the whole system. Arguably it would have been a better idea to make a hub with a direct drive high gear and a reduction low gear instead.

Unless of course they are designed for a hilly place such as might be found in much of Sweden and Norway :mrgreen:
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Brucey
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Re: Ikea bike

Postby Brucey » 27 Oct 2016, 6:25pm

Vorpal wrote:
Brucey wrote:- The most sensible way of setting the gears is so that you cruise on the flat in the high gear and then use the low gear for hills. I assume this is how the IKEA bike is arranged. This leaves you riding in the non-direct drive gear most of the time, which reduces the mean efficiency of the whole system. Arguably it would have been a better idea to make a hub with a direct drive high gear and a reduction low gear instead.

Unless of course they are designed for a hilly place such as might be found in much of Sweden and Norway :mrgreen:


eh? In which case you would have two low gears....?

cheers
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Vorpal
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Re: Ikea bike

Postby Vorpal » 27 Oct 2016, 11:14pm

Brucey wrote:
Vorpal wrote:
Brucey wrote:- The most sensible way of setting the gears is so that you cruise on the flat in the high gear and then use the low gear for hills. I assume this is how the IKEA bike is arranged. This leaves you riding in the non-direct drive gear most of the time, which reduces the mean efficiency of the whole system. Arguably it would have been a better idea to make a hub with a direct drive high gear and a reduction low gear instead.

Unless of course they are designed for a hilly place such as might be found in much of Sweden and Norway :mrgreen:


eh? In which case you would have two low gears....?

cheers

??
I just meant that it's better to have the low gear be the direct drive one, if you spend lots of time going up hills.
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Postboxer
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Re: Ikea bike

Postby Postboxer » 27 Oct 2016, 11:53pm

Maybe it's always better that way, being inefficient when it's easy, efficient when it's hard. Otherwise you may be struggling up a hill wishing it was the other way round.

rfryer
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Re: Ikea bike

Postby rfryer » 28 Oct 2016, 7:36am

Another thing worth noting about the SRAM Automatix (unless it's peculiar to my example) is that jolts to the hub can cause premature shifting. The hub has a hair-trigger for shifting from low to high, but shifting back down involves taking pressure off the drive. As you get closer to the shift point (in my case, tweaked to 16mph), the less of a jolt it takes to switch into high gear.

In practice, this means that it shifts reliably on smooth cycle tracks, especially when used in combination with high volume tyres, and with a low shift point so that minor deviations aren't too noticable. To fair, that's probably the main use case, allowing easy acceleration and hill climbing.

But when fitted with narrow rims, it's a nightmare on hills with a rutted road surface, where you can find yourself shunted into top gear at precisely the wrong moment. I'm in the process of converting the bike in question back to fixed, because I've lost patience with this behaviour.

If I were recommending how to set up a bike with this hub, I would suggest having top gear as the gear you would normally choose as a general SS gear, then set the shift point to a cadence of around 60. That way, you get the low speed benefits, but shifting will never put you in an unreasonable gear.

On my bike I set the gearing to "bracket" my preferred SS gear (shifting up at around 90rpm), with the intention of having generally lower gearing to make low speed riding (ie hills) easier, and a high gear to use only when up to speed on flats or descents. However, having a tall high gear means that unanticipated changes are more of an issue.

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Re: Ikea bike

Postby Brucey » 28 Oct 2016, 9:47am

Vorpal wrote:
I just meant that it's better to have the low gear be the direct drive one, if you spend lots of time going up hills.


ah, I see what you mean! I suspect this feature comes (as much as anything else) from a desire to make the hub more suitable for small-wheelers whilst retaining sensible chainring/sprocket sizes

rfryer wrote:Another thing worth noting about the SRAM Automatix (unless it's peculiar to my example) is that jolts to the hub can cause premature shifting. The hub has a hair-trigger for shifting from low to high, but shifting back down involves taking pressure off the drive....


you are quite right, all the examples I have ridden do exactly this, and as you say it is worse with skinny tyres and on bumpy roads. I've also had a Moulton with the same hub and (despite fat tyres) it was about as bad as a rigid machine with skinny tyres, presumably because the suspension allows the wheel to jiggle up and down more than it might otherwise.

The effect of this is that there is effectively a narrow range of speeds that ought to be avoided whilst in the low gear; to my mind it makes a fair bit of sense to set the shift point so that one is pedalling faster than is comfortable (for any length of time) in the low gear. This way it is less likely that the shift will come when you don't want it, and if you should want to ride at that road speed, you can still do it using the high gear. A snag with this is that the hub will downshift every time you freewheel, and this will force you to speed up again (briefly) in order to initiate the shift.

In point of fact the shift control mechanism inside the hub ought to be mass-balanced, and thus more or less immune to jolts; there are two opposed weights which are coupled via a shift control plate. However only one has a (shift control) spring on it, plus there are clearances that allow the weights to chatter, and the shift control plate will move more easily in one direction than the other, thus shifts are not as well controlled as one would like.

At some point I plan to install two (identical, but each weaker than normal) springs so that each weight has its own spring. I think this ought to make the shifting slightly less erratic. If that doesn't do enough good, I might try reworking the shift control plate so that there isn't so much clearance between this and the other parts, thus allowing less chatter.

cheers
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mercalia
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Ikea recalls it bikes

Postby mercalia » 1 Jun 2018, 12:06pm

didnt know they made bikes. it seems that

"Ikea has issued a worldwide product recall for its Sladda bikes due to a fault in the belt drive that can lead to it snapping, potentially causing the rider to fall off and sustain injury.

The aluminium unisex bikes, available in 26- and 28-inch versions, were launched two years ago amid much fanfare, and with Ikea claiming that the belt drive would be good for 15,000 kilometres of riding."


http://road.cc/content/news/242791-ikea-makes-global-product-recall-its-award-winning-bike

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Re: Ikea bike

Postby mjr » 1 Jun 2018, 12:14pm

Recalled! viewtopic.php?p=1239181
mercalia wrote:"Ikea has issued a worldwide product recall . . . . .
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
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Re: Ikea recalls it bikes

Postby Zanda » 12 Jun 2018, 10:25am

The Ikea Sladda doesn't have a chain, it is belt-driven. Ikea have received a few reports of the belt snapping. Two of these incidents caused minor injuries including scratches and bruising. Ikea were advised by a component manufacturer to recall all of the bikes. They are offering full refunds, without the need for receipts.

Here is the full story as reported by road.cc in May 2018

http://road.cc/content/news/242791-ikea ... nning-bike