Beachgrad05

I recently had an issue with Continental tire. They sent me a replacement but in 23 not the 25 it replaced. Rather than deal with trying to send back for a 25 I wonder if I can use it on bike with other tire being 25.....if so...better to have 23 on front or back?

I rode motorcycles and front was skinnier than rear tire so am guessing ok to use 23 on front and 25 on back.

A friend just told me they run 23 on back wheel and 25 on front for “stability on descents as well as speed”. This person doesn’t like descending steep grades. Has vertigo.

So what would be best overall for handling and safety?

surak

I had a 23c in front when I wanted fender clearance. I swapped it for a 25c after deciding some fender rub was better than the sketchy handling I experienced with the 23c in urban environments.

DaveLeeNC

When the 23 that I have on the rear wears out, I plan to replace it with a 25. But 23 is the biggest that fits on the front, so I will be riding 25R and 23F.

dave

znomit

I'd put it on the front because the comfort and handling is more important there.

Beachgrad05

Put 23 on front?

znomit

Sorry for mixing that up, no put the 25 up front. There are benefits to going both ways though, so the correct answer is of course "it depends".

https://www.sheldonbrown.com/tires.html#mixing

ridingfool

when I use 2 sizes I always put the 23 on the front and never seems to be a problem. I'm also a heavier rider so prefer a 25 on the back

sdmc530

I run two different sizes on my two of my bikes.


I have 28R 25F on one bike and 25R and 23F on another. Never had an issues. I try to stuff the largest tires on my road bikes I can and this is what I can do on two particular bikes with good enough clearance. I would run what you got and don't worry about it. When it wears out buy what you like.

DrIsotope

TWENNY THREE ON FRONT BECOZ MOAR AERO!1!

But for reals, in my case it would be the 23 in the front because I wouldn't want to pump my rear tire to like 110psi.

For most folks, it probably makes no difference. If your wheels are wider than 18c, it's gonna mount to about 25 anyway.

Beachgrad05

Thanks everyone. Think I will go with my initial instinct of 23 on front. As an Athena I think I prefer the 25 on rear wheel. Doubt I would experience handling issues. Have experience with 23’s on bike before switching to 25’s. Plus motorcycle experience with front being not as wide on my sport bike.

canklecat

For awhile last year I ran 23 front/25 rear. No problems. Ditto on my hybrid, 32/35. No problems with handling.

I've since switched back to 700x25 front and rear on one bike, both 23 on the other, and 700x42 on the hybrid. But that's just because I settled on tires I liked better for comfort. Not an issue with handling on turns.

diphthong

you'll be just fine and i doubt you'll really notice much difference between the two. rocking a '28 up front and a '25 in back on
a mid-80's steel bike that doesn't have clearance for the '28 in back. thought it did. take it on the road and light dirt and it does just fine.
i do like to switch it up occasionally and swap the wheels with '23's from the other bike. the mid-80's bike feels like a new, racier bike at that point.

WhyFi

Yeah, unless we were talking about gravel/dirt, I'd put the larger on the rear so that I can run a little lower pressure (vs the smaller tire) without increasing the chances of a pinch flat. For gravel/dirt, some prefer the larger tire up front for handling on loose surfaces, iirc.

WhyFi

Oh wait - I forgot a classic BF answer:

Put the smaller tire up front so that you're always riding on a slight downhill, bruh!

RGMN

I run a 23mm on the front of my Ritchey Road Logic 2.0 simply because I can't fit a larger tire. A 25mm rubs the underside of the Campag Skeleton brake. A 25mm or 28mm fits in the rear no problem. I've had no issues with it setup this way.

Kimmo 

Here's a tip from @FBinNY from the mechanics forum: epoxy a couple of short lengths of spoke in each dropout, then you can run a 25.

BengalCat

My personal experience, (YMMV) IMO was black and white is to go wider on the front on mismatched sizes. It produced better handling and a more comfortable ride.

Point

According to Sheldon Brown, the newer tire should always be in the front. You want the tire with less chance of failure there.

Doge

The front tire is more important for grip. the rear tends to hit things you may dodge with the front. So for that - bigger on rear is better.
But...if you don't wack things, the smaller profile on the power wheel is more responsive.

You can do either. Pros and cons to both.

RGMN

Yeah, I've seen that hack. It's really entertaining when (not if) one side falls out. Bring wrenches to remove the brake.

Kimmo 

By that logic, anything bonded should eventually asplode.

Gotta glue to clean surfaces. I'd build up the epoxy to surround the bits of spoke, to form a new arch for the dropout.

IMO the biggest issue with it is what it'd do to the geometry by raising the front 4mm instead of 2.

RGMN

No, my logic is that most mechanics are not well versed in properly bonding metals with adhesives. They won't get an adequate surface prep (likely needs to be etched,) the joint will fail and the spokes will fall out somewhere down the road, usually at the most inconvenient time. Like my buddy who had the spoke fall out while fixing a flat on Mt Evans, just after 11 switchbacks. Shifted the tire enough that it hit the fork. He said he walked a LONG way carrying the front of his bike before someone offered him a ride.

Frame manufacturers typically know how to prep the joints properly. Cleaning only part of the surface preparation.

Jax Rhapsody

If anything; pure aestetics alone dictate skinnier tire up front.

Sportbike
Hotrod
Dragster
Sand Rail
Chopper

Wouldn't look right any other way.

SCTinkering

Yep, that's how I do it on my MTB. Oh the bygone days of the Panaracer Smoke 2.0 on the rear and Dart 2.3 on the front. The Dart just looked wrong. Handled awesome, but the optics were...strange.

DrIsotope

My "SoCal fire road" setup is Panaracer Gravelking SKs, 700x43 in the front and 700x38 in the back. Partly because the chainstays won't clear a 43, but also because for whatever reason the 43 has two more rows of knobs than the 38. When it gets loose, I'm very thankful for those two extra rows.