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I recently purchased a Boardman SLR 8.9 which features 105 shifters, 105 11/30 year cassette, 105 front and rear derailleur, FSA compact 50/34 gossamer 172.5 crankset and tektro front and rear rim brakes.

On my first ride, after 10 miles, my front right pedal detached whilst going uphill, stripping the threads completely.

I returned the bike to the retailer who was unable to tap the crank due to the damage.

They’ve replaced the FSA Gossamer crankset with a shimano sora r3000 50/34 175cm crankset.

My question is I see that the Sora is listed as a nine speed crankset and not 11.

I’ve been advised it’s all working fine and I’ve yet to pick the bike up.

Will this cause me any issues or am I over thinking this?

Many thanks.

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  • If they don't have a 105, Gossamer or comparable crankset I would ask for a little bit of discount for having the Sora crankset instead. Then I would take my time to source a good deal on (2nd hand) crankset in 172.5 as I would prefer the shorter crank arm if the bike was sized with it. I'd aim for 105 or Ultegra when sourcing the replacement crankset. With the discount and the sale of the Sora you'd probably come close to break even.
    – Superman.Lopez
    Commented Jun 15, 2022 at 8:38

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I personally think that it's a bit too much of a stretch. 1-speed difference (in the front) is acceptable, 2 starts to be problematic.

That being said, there is currently another reality: serious supply issues. Maybe your retailer couldn't have 105 (or Tiagra) crankset reasonably fast (small shops have more supply issues than big online brands). Personally I would inquire in that direction, and if it's the reason, see if they accept to install a 105 crankset if you can procure one.

Also, if it's your only/best bike and chain wear is the only consequence, it might be an acceptable compromise to ride it with a Sora for a few months and then replace the crankset when you can have one.

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It’s not the greatest component choice for two reasons. Firstly, the 11s chain has an increased risk of getting caught between the chainrings. A 9s crank will have wider spaced chainrings than an 11s crank, and so the chain could get stuck in this increased gap.

Additionally, the Sora crankset is a heavy bugger that has no place on a $2000 CAD carbon bike with 105. The shop is ripping you off in a sense.

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  • I don't believe the teeth are actually wider on 9 speed. I think both 9-10 and 10-11 increases were achieved by making the outer plates thinner.
    – Andy P
    Commented Jun 14, 2022 at 20:08
  • I think this answer explains it: bicycles.stackexchange.com/a/66494/14027
    – Andy P
    Commented Jun 14, 2022 at 20:09
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    @AndyP Thanks, will fix.
    – MaplePanda
    Commented Jun 14, 2022 at 20:14
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    I’m also going to forward that the fsa gossamer is crap too, so that’s replacing like for like in one sense.
    – Noise
    Commented Jun 14, 2022 at 21:48
  • Thanks for the input everyone. Greatly appreciated. This is my first “decent” road bike as far as my budget allows and was disappointed to have a mechanical issue on my maiden outing. I’ve picked the bike up but yet to ride it. It’s shifting well in the stand across the gears as well as off the small to large chainring and back. I’ve a day off work on Thursday so will take it out properly then. I asked the mechanic if the 105 r7000 crankset could be a direct replacement without changing the bottom bearing and he thought so.
    – John
    Commented Jun 14, 2022 at 22:45

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