Mrs.Kennerley’s was stolen a few weeks ago so I bagged her a used Carrera as a replacement. It’s just for pootling about duties, no rough riding!

I’d like to spruce it up a bit, drop a bit of weight from it and simplify it for her as she says herself she never uses the other front rings!

Its currently Altus 3×7. Will any narrow/wide plus a chain guide be ok with the 7 spd chain?

Crankset is 104bcd I think, I know I need short bolts, but will these just plop the single ring in the right position to get good chain line?

You should be able to pick up a narrow/wide chainring from somewhere for not much money to get this working without any bother. When I did my 9 speed 1X conversion I just popped the narrow side ring into the position the middle ring had been in previously and never had any bother. I did have a minimal chain guide that I put on at the same time but I’m not sure if it was really needed.

This might be a sensible option as they seem to come with the bolts needed for fitting (my snail one mounted up using my existing bolts).

https://amzn.eu/1zaXgu0

Any half decent worth their weight lbs should have short cr bolts to run 1 ring.

Any 104bcd N/W will do for give take £20 oh and confirm that she is happy with current T cr.

I’m sure you’ve checked, but I think that some Altus chainsets have riveted, rather than bolted, rings.

They’re connected to the crank with normal looking bolts, but the chainrings themselves look like a load of steel dinner plates! Probably are riveted together. I’ll make sure I can get the whole lot off first!

Its currently Altus 3×7. Will any narrow/wide plus a chain guide be ok with the 7 spd chain?

IME a 10 or 11 speed chain seems to work better, holding on to the N/W ring and bending side to side to accommodate the full cassette without riding off the ring. Should still work fine with a 7speed cassette…

If it is square taper these single chainsets are good for the cash. Alloy cranks. Steel ring for longevity. No ramps on the chainring. I have no problems with the chain dropping. 38 and 44T options here. 33T options elsewhere.

https://www.bikester.co.uk/m-ighty-crankset-1-gang-38-teeth-aluminium-steel-M426342.html?vgid=G477664&cgid=36938

Widely sold. The 46T option at Hewitt Cycles for £19.99

As above. Just stick a cheap N/W chain ring on and off you go

7 and 8 speed use the same width chain so could look at old 8 speed stuff too.

Snail chainrings off eBay, I get 1700+km out of them for typically less than a tenner. Those £20 cranksets have got to be worth a punt, though – any idea what BB axle width they need?

I wouldn’t even bother with the narrow/wide chain ring, if you’re just pootling it’ll stay on just fine