Thought it might be an idea to share my experience here also.
I’ve got a M7100 SLX crankset and I’d just bought an XT chainring for it which has 8 very small bolts
So I got the AXO-SHIMANO-MTB-8-100 model to suit this, which I think looks brilliant on the bike
To fit this you have to remove 8 very small Torx screws & there’s no clear indication on the torque spec required when you want to put the ring back on - I’ll assume the requirement is rather low. I ended up slightly rounding one of the heads fitting it, which really isn’t ideal! My assumption is that I don’t think these bolts are generally intended to be taken off. Have since bought a decent quality Torx head for my torque wrench, but I’m going to have a very nervous time when it comes around to fitting a new chain ring.
In hindsight if I’d been planning this better. I think the traditional style with a 4 bolt 104bcd i.e. this model AXO-SHIMANO-MTB-4-104 would be a much safer option!
It wouldn’t look as good on the bike, but you can use any 104BCD round chain-ring that you like & you aren’t limited to the model specific shimano rings with unique torx screws not seen anywhere else.
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As for accuracy, not sure if it’s my model. I still get occasional spikes, most notably if you’re putting down sudden power to clear a log/step up type thing is when it will happen. Once a couple of times per ride, So if I look at the power curve for rides I’ll often have 1 to 5 seconds worth of 800 watt effort that are false.
Otherwise it works brilliantly. Very happy with the numbers. I think if this was on a road or gravel bike you’d probably not ever see a power spike.
I did also find that if you spin a very high cadence of say 110+ you can also get high power readings to happen. Both issues I guess are cadence related.