so i came into possession of two 700x23 armadillos, and have a 700x25 bontrageer tire that works well up front. i used it until my 700x25 armadillo in back ate ****. i wanted to run the same size, so i'm running armadillos front and back. the handling is, well, not what it was. manageable, but i have to slow down into turns way more, and be careful if it rains. i'm also thinking it'd be nice to save one of the armadillos some wear so i have a backup for when the next one eventually eats it as well.

i couldn't find any threads on this--any advantage/disadvantages/unique issues for mixing tire sizes like that?

Mr. Brownstone talks about it on this page. Towards the bottom.

https://sheldonbrown.com/tires.html

Sheldon weighs in here.

I'm running a 28 in the back and a 23 up front. The front will soon be a 25. I haven't had any problems with it. Seems like a good plan to me since i usually pull up my front wheel over bumps/driveways/potholes, but the rear takes the full force of it.

I recently put a set of Conti GP 4000's on my bike.
The rear tire started collecting cuts and dings almost immediately.
That little voice (you know the one I mean) told me to put one of my Armadillos on the back before I got a tire-ending flat.

So, yesterday morning as I prepared to ride to work I found the rear tire dead flat.
Bummer.

Last night I put an almost new Armadillo on back and this morning I rode to work with the Conti/Armadillo combo.
It felt great.
Super handling and excellent power transfer to the ground.

I have run a similar combo with a Conti 4 Season in front and an Armadillo in back, and I now prefer this type of mixed arrangement over matched tires.
I've never had a front flat, but I've had a front tire slide out from underneath me.
The Contis do the front tire thing beautifully.
In comparison, the rear tire of a bicycle takes the beating, and nothing beats an Armadillo.

As for mixing sizes, I don't know.

That said, putting a lightweight, good handling tire in front, and a tough, heavy-duty tire in back makes sense to me.

I've got a 20 in the front and a 23 in the rear and I've had no problems yet

great handling and good traction on turns

I run 25 rear and 23 front. Mainly because I didn't have a 25mm front.

is a 25 taller than a 23? or is it wider?

HereNT has some pretty mismatched tires on his Fuji, with the front being bigger. I think it's a 700x40 up front and a twenty-something in back. He hasn't complained about it that I'm aware of.

It's larger all around. A tire is really nothing more than a strip of rubber that when attached to a rim on both sides forms an air bladder. Inflate a tube inside of it and it forms a round cross section except for where the rim forces it to do otherwise. A 23mm tire will form roughly a 23mm circular cross section on the appropriate width rim.

ok, got it!

It was actually 42 up front, and 32 on the back. Until yesterday. Now it's 32 front and rear... Both Bontrager Race Lites...

Partswasher and I agreed on the larger front thing - you want the more cushy tire there. True, you have to lift higher to get over a curb, but you also have more give from the tire and tube. It's more comfortable. You don't want your larger contact patch on the back where it increases the drag. The front is pretty much just along for the ride.

I'm going back to the 42 next winter, possibly with some DIY studs. But the last 24 hours and a very few miles without the knobbies up front, I'm thinking my summer setup on the commuter is done...

what model armadillo are you using? why not a gatorskin?

okay, yeah, this is the sort of thing i was looking for. thanks a lot, that works great.

also, i'd looked at sheldon's page, but i thought he just talked about a bigger rear. guess i was wrong.

sounds like bigger in back is more common, though. huh.

and ken, that's weird about the dead armadillo (that would sound so much funnier out of context). those have always seemed totally bombproof to me. if the other one was new, i'd check the inside for the offending object and put it back on...seems like just a freak thing. it happens sometimes. and as far as cushy, better handling tire up front, i think that makes sense, also paired with hereNT's suggestions about rolling resistance and curb jumping (which i actually do find pretty helpful here and there).

On my commute home the other day there were 4 wheels at the side of the MUP with a "free" sign by them. I grabbed a front with some kinda Shimano hub and 700x20 Conti. Much to my surprise the wheel was pretty true and the tire held air so I slapped it on my fixed bike (running a 28s at the time) to test it. I was kind of shocked at how little difference I noticed. I guess when ya can't coast it's harder to tell.

right...but what if you'd had a 20 on the rear and put the 28 on front? that's the sort of setup i'm curious about.

i guess i'll try it, just in my mind it seems ****ed up somehow.

Those 20s sound like they'd wear out fast, especially on the rear.

Just because it's more common doesn't mean it's the best idea. Partswasher, the guy I was talking to about it, is probably my most trusted wrench. He was asking awhile ago when I was running a 23 up front and a 32 in the back, which is why I eventually went with the 42 up front. I was thinking that I wanted the knobbies in the back for traction on the snow and ice. That's when he pointed out the shock absorbtion and that you want the grip more when going around corners and stuff on the front rather than the rear...

I guess the only way to really know which you prefer is to try it out. I'm betting that you'll like the larger tire up front...

I've rode a variety of 23-25-28 combos with the front taking the bigger one. Its a good way to go cause the bigger front gives you a bit better handling and the thinner rear means less drag. Nothing major though, 25 front 23 back should barely be noticeably different than rocking a matching pair in either of those sizes.

it's not. might look a bit funny but it should be a fun set up.

i run a 25 up front and 23 in rear. both are gp4000s and i love the way it handles and rides.

banking it into corners is a non issue--it'll lean as much as i have guts to let it lean. i have wider tires up front to dampen the road vibration since i dont run bar tape.

yeah, hereNT, i was just making an observation. now, as soon as i feel like letting the air out of my tubes and putting it back in...i'll dooo it.