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I just bought a 2020 Kona Lava Dome (the details of this bike/components are at the end of this question) and I can't use the low (small) front sprocket. Under any load (like a hill climb) the chain slips. This came up on my very first ride. It doesn't come off or change gears, it just slips. I've tried to find answers/suggestions online and other questions on here, but they all suggest the following:

  • Replace worn components - not applicable, everything is brand new
  • derailleur adjustments (front and back) - The bike was assembled by the shop, I independently re-set everything, and the bike shop inspected the drive train again when I brought this issue to them, no obvious misalignment/misadjustment
  • Wrong/stuck link/worn chain - It had a brand new chain, the bike shop tried replacing the stock chain with a Shimano chain to see if it would fit their components better, it did not fix the issue.
  • bent hanger - Again, the bike is brand new and the shop assembled it and later reinspected it when trying to repair this issue.

I tried looking around to see if this was a known issue on this particular bike or crank set and I couldn't find anything. The bike shop is going to contact Kona and Shimano to try and figure out a solution. For the time being, I'm stuck with only using the large front sprocket. With the bike/parts shortage going on right now, I'm worried I'm going to be stuck with this issue for a long time, especially if the solution is to throw parts at it and hope it works. (for those outside the USA, there is a nationwide bike shortage here in the states)

I'm hoping someone may have come across this before, maybe with this specific bike or components and might have a suggestion/idea what is wrong or something I can try to fix it.

The bike is totally stock; the full details are on the Kona website but the relevant components are:

  • Shimano HG200 11-36t 9spd freewheel
  • Shimano Altus shifters and front drive
  • Shimano Alivio rear drive
  • Shimano bottom bracket

Update: my bike shop's contact at Kona said he has never seen this problem on any of their bikes. When they contacted Shimano, they sent out a complete crank assembly (which hopefully includes the bottom bracket and bearings) to replace the one on the bike. I will report back once it arrives and the shop installs it to see if that resolves the issue.

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    Could be the freehub might be slipping - thats the bit that allows freewheeling. – mattnz Jun 6 at 21:21
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    Freehub slipping under the higher torques produced by the small ring is a very good thing to check. On a new bike that's something that can happen if the grease/lube in the freehub is too heavy, and it's easy to fix. Get someone to put eyes on the crank area if possible to see if the chain is actually slipping on the ring. Other things to check would be deformation of any kind to the ring, or indication from marking that it's always falling at the same place. – Nathan Knutson Jun 6 at 21:42
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    Very unusual for the chain to slip on the front ring like that. I'd suspect that the chain is too slack for some reason. – Daniel R Hicks Jun 6 at 22:39
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    Subbing in a different wheel, ideally something that's the same compatibility but higher end to eliminate more variables, is also a good test. – Nathan Knutson Jun 6 at 23:24
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    Don't discount the derailleur hanger because it's new. It could have been bent in box. If the shop hasn't checked it with a derailleur alignment tool, then they should. Are they sure the chain is the right length for the model and drivetrain? – shox Jun 6 at 23:59
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The problem turned out to be the crank assembly. Apparently the chain ring offset on the original crank was wrong. The replacement that Shimano sent (having been given the bike year/make/model/groupset info etc) was a totally different offset than the one Kona shipped with the bike. The new crank resolved the chain slipping problem.

I don't know who messed up here. The bike shop thinks Kona shipped the bike with the wrong hardware, possibly on just my bike or potentially some set of the 2020 Lava Domes. Kona certainly didn't take responsibility originally though. Regardless, the issue was resolved by putting the right parts on the bike, thanks to Shimano. Thank you everyone for your responses and suggestions.

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    Nice case study of how having bought a bike at a local bike shop can be a big help if there is an issue with it. – Armand Jun 20 at 16:58
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Check that the top idler gear on the derailleur isn't riding on the smallest sprocket somehow and preventing the chain from sitting down into the teeth properly.

There's an adjuster screw on the rear of the mech hanger (about 9 o'clock on the mounting screw where the mech attaches to the hanger) that you can use to control where the mech sits in relation to the axle that would allow some control of this.

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  • The chain is slipping on the small chain ring at the crank, not the small sprocket on the rear, am I misunderstanding your recommendation? – Alex Jun 11 at 21:11

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