Does anyone use 20 mm tires up front and if so, do you notice any significant advantage/disadvantage with this setup? This would be for my track bike on the street, but not in the city.

I do as the fork on my Tommaso will not accept anything over 21. I see no problem with it. (FWIW, I also run tuffys in that wheelset).

Thanks. I couldn't imagine it would make too much difference, but I thought I'd check.

I was running 19mm conti pro slicks for years - they were more durable than Michelin 21mms I have now on one of my bikes. Only recently my fixie wears 23mm ones and I think they wouldn't last as long.
Cheers,
v

i've ridden l o n g distances on 20mm tires, front and back, with no ill effects. just keep them way full of air; when they get down to 100 psi they feel spongy (to me, anyway).

Yeah, you'll need to keep them pumped higher because the smaller contact patch means that you need more pressure to avoid pinch flats. This will also make for a harsher ride. Also, the smaller tires may actually roll slower because surface features will have a more pronounced effect when you go over them. However if you're riding a lot of country miles on clean smooth pavement, it may be just fine.

"higher" and "harsher" are terms I can't quantify, being a 23c junkie myself.

Just out of curiosity, what do you run on the rear?

23s, Armadillos.

Sorry to drag this up again. I have the 20 mm tire and it's fine, but someone mentioned I should keep it at a higher pressure than the 23 mm. How much higher? On the side of the tire it says the maximum pressure is 125 psi which is the same as the maximum pressure for most of the 23 mm tires I have had (I think the Armadillos are 130 psi). Typically, I inflate my tires a little bit more than the maximum, but how much more is safe for the 20 mm tire or the 23 for that matter?

I've heard that tire manufacturers establish the max pressure by going up to blowoff and then halving that number, so you should have plenty of head room. But that's just what I've heard.

First of all, there is no advantage to running a smaller tire in front, other than the tiny difference in aero profile. I've never used 20s, but had a 19 once for a TT bike, and it cornered like crap. The higher pressure combined with the small contact patch promoted its hopping over surface deformities, rather than maintaining even contact with the pavement- which I consider to be a disadvantage. I like to keep my tires on the pavement. There is some research to suggest they actually have higher rolling resistance.

If, however, they are dirt cheap on sale- because they are 20s, that might be an advantage- but I would not go out of my way to pay full price for them.

If you have a 'dillo in the rear, I can assume you aren't looking for an exquisite ride? BTW- 'dillos definitely appear to be larger than advertised- their 23 is more like a 25.

It's a pretty cheap Performance tire; I got it because they didn't have 23s in stock and I didn't figure it would make much difference.

Yes, I prefer not getting flats to an exquisite ride.

I ride with an Armadillo in back, and it feels good; not rough at all.
However, I find an Armadillo on the front kinda harsh.
A Continental GP 4 Season in front and an Armadillo in back works for me.
I wonder how rider weight enters into all of this.
Would a lighter rider do better on a thinner tire than would a heavier rider?
I weigh 215 with messenger bag.

My Schwinn Le Tour has a Tufo Giro Twix (21) up front
and an Elite (23) on the rear. It works fine for me.