Hi folks, I have built up my genesis longitude with a set of hope wheels laced with stans 29er 355 rims and would like to try some plus size tyres. I am currently using continental xkings with a 2.4 inch carcass. How wide can I go on these rims and what advice does everybody have for tyre choice or is the consensus of the tribe that I should invest in some wider rims?

Thanks, Chris.

Isn't the 355 quite a narrow rim (less than 25mm outside to outside)?

If I'm correct, then I think adding anything larger than the X-kings will just be lugging extra weight about with no gain. I really do believe that 3" tyres need 35mm or above rims before you start to see any benefit ... expensive / heavy / disappointment - pick 3

I've ran 29er+ Knards and Chronicles on 45mm and now 52mm rims and I wouldn't think about running them even on a 35mm rim which I have on another bike.

I ran a knard on a 35mm beadless rim for a while. It wasn't great. If you ran them low to get eh benefit of 29+ they felt like they might come off in fast corners etc. Pump them up, you lose the benefit.
I use 45mm rims now and they work ok. If I was building again it would be 52mm Hugo's or similar.

On a 355 rim I'd stick to around 2.3 max. but probably 2.2 They're a light rim, might as well have speedy tyres on?

I've been running a chronicle I front on a 35mm rim for a couple of weeks.

It seems ok to me. Sure it has a bit of a lightbulb profile but doesn't look too extreme. Have run it between 8-15 psi and not felt like it's going to come off.

Still early days but it's coming to the borders with me. Which should provide enough riding time to form a view!

I run a Knard on a Flow and have had no issues at all with it. A 355 is considerably narrower though so it might be completely different and I wouldn't risk it tbh.

My mate ran Knards and Crests on his Krampus for a good while. Wouldn't say it was ideal but he's still here to tell the tale.

You could try the Vee 29+ tyre as that comes up a bit smaller than a Knard? - just can't quite remember what it's called.

The Dirt Wizard is about 2.8. I think the Fat B Nimble is about the same if you want a less chunky tread.

One of the wheelbuilders on the MTBR forum reckons 35mm is ideal.

I'm running 50mm Mulefuts with Chupas (dirt wizards on the shelf for later in the year) - the do look nicely flat sided with 50mm rims.

I ran a Knard on a Crest for a short while. I didn't die but I didn't feel totally confident in it either and certainly wouldn't have dropped the pressure low enough to get full benefit.

V tyre trax fatty comes up at about 2.8 and works well as an all rounder. Mind you a 2.5 maxxis minion is only slightly narrower, a bit lighter and £25 cheaper....
Chronicles are pretty good and burly plus are the widest of the 29+ options currently available. Forthcoming 29+ buldozer looks good