Frame stack and reach

Mr. Cats

I’m looking at changing a frame to something new. I’ve seen something available but the differences to current frame are:

• Reach - 3mm shorter
• Stack - 38mm lower

The existing bike is ‘all day comfortable’ if that makes sense. I do feel though that the current frame head tube is a bit too high. I’ve no spacers under the stem and am often in the drops as I find it comfortable.

At the same time I sometimes feel a bit too constricted in current set-up - ie it would be nicer to be a bit more stretched out. Current stem is 100m, 0 degree (I think).

So my question - is a drop in stack of that size likely to cause issues? Should the bike fit otherwise? Is it enough to just look at these or are other measurements critical?

Its a second hand frame and steerer is cut so no spacers possible I think to increase effective stack. Also, not built up so no possibility to test it out. It’s a 54 whereas existing is a 56 if that means anything.

Squidgy Black

Near 4cm drop in stack is a big enough difference, I wonder would a negative degree longer stem (like a 120mm -8 deg) be worth a shot on the existing bike to sort some of the issues on your existing frame?