Twitchy steering in wet

Hi all, I've just finished building up my Colnago frame which in the dry has been an absolute dream to ride!!!

I've ridden in fairly heavy rain over the last few days though and it seems like as soon as something on the bike gets really wet the steering gets ludicrously heavy. Even when just pedaling normally, in a straight line, it feels like it wants to change direction. As you can imagine cornering is also an absolute nightmare, in fact, just pulling out to overtake other bikes is pretty sketchy.

I've had a carbon road bike and also have a 531 steel single speed and don't have this problem on either of them in the wet.

I thought it may be the tires but if it was surely it would handle like this as soon as i get out in the wet weather, but it doesn't. I also thought about the deeper section wheels being blown around a bit, but also feels fine in the dry.

Would really appreciate some help as this is a massive frustration as i use it for commuting.

The bike :

Cheers,

AJ

Maybe the tyres. It shouldn't handle like that. Unless something's collecting water - maybe the fork legs? What happens when you turn the bike upside down after riding in the rain?

Haven't tried that, but i will do next time. That would make sense though as it's absolutely fine for the first 15-20 mins of riding. I'll try and report back. Sods law states it'll be dry for the next few days now though.

I had one bike that would collect water in the frame when it was wet – if you stood it up on the rear wheel after a rainy ride, water would drain out of the stays.

Risers in the wet, bro.