Mulberry20

Physics say yes, what say you?

fietsbob

What ever.. I don't think Isaac Newton wrote about bike tires .. do you have a Thesis to quote ... footnotes??

I bought 2 406 - 40 tires, I always put the new one on the front, the old front a 406 - 47 is on the back,
when its worn I'll put another 40-406.. on the front...

will 3mm matter? others ask can I put a fatter tire on the front to be more comfortable ?

you certainly can try it..





...

JohnDThompson 

No worries. BITD, it was pretty common to run 25 or 23mm tires on the rear and 18 or 20mm tires in front.

crankholio

I'm not really sure if there's any gain in having the narrower tire up front. Most of the weight is in the rear, so I'd use the narrower tire there since it'll run higher pressure and roll with less resistance. Then the larger tire up front can take up bumps better.

BillyJohnLee

I have done 23/25 tbh couldn't notice the difference in ride between that and 25/25.

trailangel

Puffier tire on the front

70sSanO

Typically a wider tire in front will provide more cushion than one on the rear. I really doubt that there is any speed difference regardless. Although 25 to 28 is not going to make much more of a smoother ride, you might as well take advantage of it.

John

burnthesheep

Backwards. The rear bears more weight so would benefit from more tire if you're going to run staggered tire sizes. Why would you over inflate a smaller tire on the rear just to wind up increasing the crr and lowering the ride quality?

Also, aero wise.......run the narrower up front since the front wheel sees undisturbed air and benefits from that. The rear sees the air already churning by the bike and rider, so the larger tire doesn't matter as much.

If there isn't a bicycle dimension restricting what I use and I'm not racing......I use the same. If I'm in a TT, smaller front optimized to the wheel larger rear optimized for crr. Cyclocross same size for both, the most I can run on the bike suitable for the conditions and allowed at the race.

But yes, you can do it. It is common. And the smaller one goes up front.

wipekitty

I recall a tire set sold like that - narrower tire for front, wider tire for rear. Go for it!

Geekage

Maybe the front would be softer, but then the rear would be much harsher. The gain isn't in having a narrow tire in front, it's having a wider tire in the rear.

And I believe it's been shown that higher pressure narrow tires don't necessarily have lower rolling resistance.

Mulberry20

The rear could be wider. It would improve power transfer, stability and braking. I am toying with the idea. It makes a whole lot of sense.

trailangel

Larger tire goes on the front.

fietsbob

Opinion-theories abound on many topics , this being one ..

Mulberry20

I cannot think of another application where the larger tire goes on front.

Physics would confirm the rear.

trailangel

Which is easier to control. A front tire washout or rear tire washout.
Put this in your physics slide ruler.

wolfchild

I never understood the logic behind putting a smaller tire up front and bigger in the rear and it doesn't make sense to me for a bike that is used on pavement. I prefer the same size tires on my bikes which I use for pavement or gravel riding...but if I was going to run different sized tires I would put bigger tire up front for better handling and comfort and smaller tire on the rear for better acceleration and rolling resistance....Right now I am running different sized tires on one of my mountain bikes: 2.35 inches in the rear and 2.5 inches up front. The bigger tire up front gives me better handling, traction and comfort and the slightly smaller tire in the rear gives me better acceleration and makes climbing hills easier.

wolfchild

I say it doesn't make any sense.

ofajen

I’d say people sometimes overestimate the difference in weight distribution because they don’t consider the weight distribution during braking nor while standing out of the saddle. I prefer to run the front pressure no more than 10% below the rear. So I just run similar tire sizes.

OTOH, it will totally work to run different sizes front and rear. It accomplishes different things depending on where you put the larger tire. Larger tire in back and you could run pressures the same, and probably is more efficient. Larger tire in front means lower pressure and maybe easier on your hands.

Otto

tkamd73 

That’s what’s on all my bikes, except for the Sports Tourer. Played around with the pressures, and settled on 85psi rear, and 75 psi front. But then again the roads around my house really suck!
Tim

aclinjury

For the front, one should use narrower tires that are supple and lighter weight overall, this will translate into faster reaction to turning. Supple casing means more shock absorption. Also, if you use aero wheels, most are optimized for a 23mm or 25mm tire. A good front tire would be something like Veloflex Corsa or Vittoria Corsa.

For the rear, one should wider tires with harder casing and a tad tougher rubber. This is mainly for wear and puncture resistance. A good example here would be Conti 5000GP, Vittoria Rubino series,

There is nothing more enjoyable then riding a front tire that allows the bike to carve naturally around curves. I have tried 28mm tire for the front once, then took it off after a few ride. It's akin to buying Ducati and then proceed to put Harley tires on them... very vague, floaty, and imprecise feel for the front. Oh sure, if you use a wider tire and lower the pressure, it'll give you more comfort... until you try to hard corner,.. then you curse wtf!

skidder

Bigger tires all around. I've got 700x32's on both front and rear on my roadie and single speed. Tour bike has 700 x 35's. No problems with either set up.

Atlas Shrugged

Power transfer? You have traction problems on acceleration, now that’s a first.
Stability? Your rear tire has stability issues, that’s also a first.
Braking? Considering weight transfer and all never considered the rear having a major influence on braking performance! A first for me.

justslow

While it's an interesting question, I'm not convinced anyone can tell the difference.

Ironfish653

Only if you make more than 0.33 Horsepower.
You’re not a dragster. Unless you routinely spin out on your 25s, tires won’t have any effect on power transfer.
Same for braking; skids under braking are more to do with weight shift, or lack there of, than tire contact patch.

In the rigid MTB days, it was not uncommon to run a bigger tire on the front, so you could run lower pressure for absorbing bumps, and for more float over the loose stuff.

No no real reason to stagger sizes on a road bike, unless those are the only two tires that you happen to have on hand. In that case, I’d run the 28 on the front, since your hands aren’t as good of a shock absorbers as your butt.

ofajen

For those of us who regularly ride gravel and crushed stone, 32 mm is just about the smallest useful width, so we have that to consider.

If that is not a factor and it’s only for road use, there is still a consideration of the effect of tire size on trail. As I expect you know, a properly designed frame will have the head tube angle and fork offset chosen to produce an optimal amount of trail (for that head tube angle) for an assumed wheel size, which includes an assumed tire size.

Smaller tires reduce trail, larger tires increase trail. For a given frame, excess trail makes the handling more stable but slower, while less trail makes it less stable but quicker. Changing front tire size can definitely make a noticeable effect. Whether you like it is a matter of preference.

Otto