I have the cheapest 850 which came with steel wheels. A zillion years ago I picked up some 15" volvo alloys off ebay. I've been running those wheels for a long time but do switch back to the steels yearly as they have snow tires.

Any idea if i am making a mistake here? Galvanic reaction if alloys have a different design. Is there any 850 parts lookups online, that might have told me if there are different lugs available. I don't care if alloys got a prettier chrome plated bolts.

On my 83 audi there is a label in the trunk showing the allows take a longer bolt.

If you do decide to get new lugs, get some like I have in our '08 and '12 XC70s - they are two piece and you can torque them up and find that they loosen easily!

I think that this has to do with less friction between the taper on the bolt and the wheel - the friction is between the two pieces of the bolt.

All of the 11 Volvos that we have owned (we still have 4) had steel bolts or nuts.

A couple of videos on how the chrome fails and the underlying hex is no longer 19mm and folks round off the remains. Youtube video 'DIY Seized/Stopped Lug Nut Removal' by south main auto channel is probably not the best example but one i saw this month. So one piece ugly steel will remain my favorite if possible.

Soon i expect plastic lugs, even oil pans are plastic on ford trucks.

I have been using/abusing chrome lug bolts for 20 years without any problems. Like all DIY'ers, I tend to remove wheels more often than most car owners. Of course, some of the bolts are scratched and getting ugly with rust, but the 19mm socket still works fine.

I suspect some of these 'rounded' bolts are from men/boys wielding high pressure air guns pretending to be NASCAR pit crew, and not having the socket secured on the bolt properly.
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Keeping it running is better than buying new

I'll second that, there's no reason for concern. I think you'll notice too that there's a steel insert in the aluminum wheel where the taper of the lug-bolt contacts the wheel.

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XC60 / Odyssey

Not a problem. The chrome bolts do look a lot nicer! The chrome on the bolts where it touches the wheel wears off quickly anyway. There is a length difference, but just the head of the bolt, not the threaded part.

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Keeping it running is better than buying new