At 5’10” I guess I’m kinda in between sizes. I’ve had an 18″ inbred for a while but always felt I should’ve got a 16″ instead as I’d prefer it to be more flickable/manoeuvrable in corners. I was having a look at the geometry pages on On-One’s website and the top-tube length difference is only 13mm! Would this really make that much of a difference or would I be better off looking elsewhere?

Has anyone tried both sizes and felt there was a noticeable difference?

5’9″ here & used to have a 16″. Always felt I was running too much seat post, & that it was a bit cramped (even with 90mm stem). Trying my mates 18″ confirmed that I should have gone for the bigger size. Now on an 18″, but the 29er version & it fits like a glove (with 70mm stem). Very happy with the fit.

I’d say stick with the 18″. 😕

You will get a more flickable bike by the back end being shorter.
The 456 is quite long wich makes it great at soeed but a bit less flicky than some hardtails. BB height plays a big part to.
The 456 is such a good alrounder because it is not too flicky . One mans flicky, is another mans twitchy , is another mans broken collar bone……

I’m 5’10” with a 16″ inbred – occasionally it feels a bit too small, but it’s my second bike for short play rides so it’s fine for what I use it for. I don’t know if I’d get on with it so well if I used it for much longer rides.

Food for thought – thanks for the feedback. It sounds as if the only way I’ll find out for sure is to try a 16″ out for myself.

Anyone want to go the other way and swap their 16″ for my 18″?

I’ve got a 16″ steel ss inbred, an 18″ tinbred and an 18″ whippet. TBH I don’t notice a lot of difference between the 16 and 18″. I think having a longer seatpost on the 16 actually helps with comfort. Wish I’d got a 16″ whippet for that reason as its very stiff! (quick though)

I’m 5’10” too.

If you are anywhere near the New Forest you are welcome to have a go.

Owned both sizes and the same height, I prefer the 16″
16″

18″

Even use my Mrs 14″

All good 😉

I’m 5’11” and have run both sizes. For longer rides the I found the 18 better but for chucking about on shorter rides the 16 is better. As you say, the difference is pretty small.

I’ve had both, 16 and 18, and Inbred and 853. All gone except the 16″ DN6. I am slightly shorter but found the 16″ perfect. Infact if anyone knows where I can lay my hands on an early 16″ non disc frame, I have a plan…