Looking at the Grinduro (basically a Plug 1 Disc?) – not sure what size to get, but I believe I’m a medium based on this size chart from Evans. I ride a size M/L Giant TCX road bike, am usually a 17 on MTBs (brand depending) – 5′ 11″, 32″ inseam. Can anyone with an existing Charge CX bike confirm sizing?

I’m 5ft 8 and have ridden a small an medium plug, though medium felt a bit tall for me and required a 70-80mm stem, while I could use a 100 with the small. Don’t know if current geo is same. 17 MTB is small for 5ft 11 I think, but just at the limit with that inseam I suppose?

Find out the effective top tube length and compare it with the Giant, and also the seat tube angle if possible – steeper can make smaller sizes it feel much closer to handlebars than a simple 1cm difference in effective top tube length. Though slacker can feel less scary going downhill, if between sizes it can make the reach to bars seem a stretch.

The top tube on my older plug is short for the given size, so you’d probably be safe with large, but get the numbers.

I’m 5’10” and ride a medium plug. Some on here are of a similar height and ride a large. Seems bonkers to me that the UK Nat average height (5’9″) is right on the cusp of frame sizes between med and lrg.
I went with the med as it gives the option of running a shorter stem for off road / gravel use and a longer stem for road use (more stretched position) or a some where in-between stem for both. If you find your too stretched on a lrg frame, your stuffed. Again with headtube length, it’s easier (although not fashionable) to adjust with spacers, where as you could end up having a fixed position on the lrg.
I also found that my Cannondale save seatpost, which has a bulge in the upper part only just fits at the correct height for me, if I’d gone with the lrg frame I’d have needed a new seatpost. – A specific issue with using that seatpost.

On mtb’s everyone advises to go up a size if your between sizes for handling reasons (more stability, better DH handling etc). On road bikes it’s a different game, as getting the correct position is more important than handling (IMO)

5’10” here too and ride a medium plug.
Similar inseam to op. My road bike is a cannondale 54.

Doh! Double post. Blinkin’ phone.