In my MX180C with 29" tires using 48* flaps, I find that at stall the plane dives to the left. This does not happen at any other flap setting or with 8.5 tires. On any landing surface other than hardtop no problem, but on hardtop it really can get interesting. My approach speeds, depending ,are 60 to 65 mph. final.

A simple rule to protect flap stress is to limit flap deployment to ;
90mph max for 24
80mph max for 40
70mph max for 48
In the 48 position, the flaps are not fully down until the aircraft reaches 55mph. Watch the movement downward through the window, and when movement stops, look at the ASI.
If the spring cartridge protection is not strained, the ASI should be 55mph.

Jeremy, is full deployment of the other flap settings also delayed/limited byt the spring?

In other words, if I pull flaps 24 at 90 MPH will they be less deployed than when the plane slows to 65 on short final?

The spring cartridge is a safety device, not a limiting device.
To see what happens, pull flaps at any white arc speed, look out the window at the flap (right side easiest) and see if it moves up or down as you change speed.
I dont expect any movement at 24 but at 40 you may see movement.
Sometimes the spring gets tired from overspeed flap use.

Screech wrote:In my MX180C with 29" tires using 48* flaps, I find that at stall the plane dives to the left. This does not happen at any other flap setting or with 8.5 tires. On any landing surface other than hardtop no problem, but on hardtop it really can get interesting. My approach speeds, depending ,are 60 to 65 mph. final.

Either you don't have enough right rudder in, or something's out of rig? Suspect with the bigger taller tires, your nose is considerably higher and you are probably getting a little P-Factor effect and if correcting with aileron instead of rudder, that would explain it? I have no such problem with 31" tires on mine?