Are they to cope with a big build rider on a lightish steel singlespeed for trail use at the hardest riding style of my build or are they strictly xc and that only?

they are an xc rim but it also depends on the number/type of spokes as to how strong/stiff the whole thing is.

I used 24 spoke on pro3 for ages with no problems until a dog side-swiped me.

Rebuilt with the modern equivalent which is a crest.

the main difference is that a crest has a bigger ERD so is more suited to normal tyres run tubeless, whereas on a 355 you can fit UST tyres a bit easier, such as Maxxis LUST, and therefore you will have a more robust sidewall than a crest and normal tyre.

I have just had a new 355 on pro2 eve built with 32 super-comp spokes for that reason.

Ok, thanks for the info, they re 32 holed rims which will be running tubed intense 2.0 system xc tyres with stainless silver spokes, cheapies which merlin promote to use so often.

The crest is not the lightest rim in the range and not the strongest
But most of my friends use them for general riding inc welsh trail centres

You can’t get 24 hole one other than in a wheel from hope

It also depends on how heavy you are and how you ride

I have used them for 4 years on a ht. I’m 14 st. Very few problems here. Crashed once and taco’d the front. Replaced it with a Flow. The rear is still going strong. If you are clumsy I would get something stronger. If you want to jump then get something stronger. If not then you should be OK.

If its light but a bit tougher you are looking for I’ve just buildt a pair of arch ex with stans own hubs.
1525g for the pair

I would run it tubeless with a Maxxis LUST tyre – robust and a lack of punctures.

Ignitor LUSTS for me.