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First time here!

My brand new bike arrived this evening and I’ve broken it with an hour.

It’s a Vitus Nucleus 27 VR Bike (Altus 2x9) 2020

I took it out and about 50 mins into the ride I noticed the right pedal was feeling a bit off.

I just had the default plastic pedals on so assumed I’d just pushed them too hard.

Turns out I must have cross threaded the pedal and now there’s no thread left in my drive side crank arm.

The crankset is the SR Suntour XCM 36/22T 175mm.

I can’t find a direct replacement - it’s out of stock everywhere.

My question: What are my options for replacing this? Is there another crankset that I could easily slot into place? Is there an obvious upgrade?

Thanks for your help!

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    You might have installed the left pedal to the right crank and vice versa rather than too far.
    – Vladimir F Героям слава
    Commented Jul 16, 2020 at 21:34

3 Answers 3

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You could replace the crank with any Shimano 2x9 crank for a square taper cartridge bottom bracket (with the same chainring sizes are crank arm length or course). If the bike is equipped with an Altus groupset then an Altus 2x9 crank would be a reasonable choice.

There is a bit of an annoying wrinkle to this, different square taper crank models require different specific axle lengths to achieve the correct chainline. The existing bottom bracket axle might not be the correct length for the crank you choose.

As an example The Vitus Nucleus 27 VR page helpfully tells us the the BB axle length is 113.5mm. The Altus FC-MT101-2 crank needs a 'LL123' code bottom bracket axle which I think is actually 122.5mm.

Often it's easier to buy and install a crank and the correct bottom bracket at the same time. This also opens up the possibility of a 2x9 crank with a Hollowtech II external cup bottom bracket, which I think are in the Acera line and would be an upgrade.

Special tools are required to remove and install bottom brackets, and a crank puller is needed to get crank arms off square taper axles. Bottom brackets and crank arms should also be installed with a torque wrench. It's especially critical to get square taper crank arms tightened properly.

If you had a an issue with pedal installation you'd probably want a bike repair shop to do the installation for you, and they will of course have the tools.

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It might be possible to make a new thread using helicoil. It is a job for a good bike-shop but should be cheaper than a good pair of cranks.

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    At $45 for a new M3000 crankset, I very much doubt helicoil will work out cheaper.
    – mattnz
    Commented Jul 17, 2020 at 1:32
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    @mattnz Could be, in my country the first random service quotes ~11EUR for work. Maybe that is for one side only, I do not know. But after looking at kdev's profile, it can be very different in England, I saw English bike shops quoting 25GBP for a spoke exchange. I would never pay that, I always bought tools when I lived there. With English prices Even bearing non-professional bearing pullers, presses, tappers and facers can easily come out cheaper than a single piece of work...
    – Vladimir F Героям слава
    Commented Jul 17, 2020 at 8:12
  • helicoil repairs are used for all sorts of things - you might find a local machinist or even engine / automotive service shop that would be capable of doing this. Its just a threaded hole, not really specific to bicycles.
    – StayOnTarget
    Commented Jul 17, 2020 at 13:46
  • You can buy a tap wrench pretty cheap, as long as you know the threads and diameter you need. However, that could also widen the diameter enough that the pedals would have to be modified to fit.
    – jpaugh
    Commented Jul 17, 2020 at 17:38
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    I’ve ordered some DIY kit to try to re-thread the crank arm. It’ll be a temporary fix and if I botch it I’ll replace the whole crankset.
    – kdev
    Commented Jul 20, 2020 at 8:34
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I know this is late and you’ve sorted this now, but the easiest thing to do is replace the arm and ditch the pedals. New arm would cost around £10 and get some half decent pedals. Can get Burtecs for around £40 half price from £80 from most places. This may help someone🙏🏻

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    Some cranksets cost hundreds of euros. And can be damaged in the same way, by improper pedal installation or tightening.
    – Vladimir F Героям слава
    Commented Oct 26, 2020 at 22:46

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