FoxMulder

If both front and back tires are worn down and you were to replace just one, which is the best choice?

ahsposo 

Front.

10 Wheels

Back takes + 60% of the weight.

Wanderer

Put the new one on the front, and keep the best old one for the back......... A front tire going south can be catastrophic , the rear not as much.

fietsbob

If the front tire fails you are likely to crash. less likely if its the rear, flatting.

FoxMulder

3 votes for front, 1 for back. Sounds like front is winning. BTW, it's a mountain bike if that makes any difference.

chaadster

If you're trying to forestall the inevitable replacement of the second tire, put the new on the rear; wear is much slower on front. If you know your front tire is worn, just don't hit the turns so aggressively, brake more gently and progressively, pick smooth, clean lines, and you should be fine. While a front tire flat can be more catastrophic in terms of outcome, they rarely are, and as long as you're not shooting around like a world champion, and rather riding more conservatively, taking a flat up front can be easily handled safely.

chaadster

It is much harder to get propulsive traction on dirt/gravel/mud/sand (i.e. off road) without tread than it is to get propulsive traction, or grip of any kind, from a slick tire on smooth, high-grip pavement, so that's another scenario that recommends rear tire replacement.

knobster

I think it's a stupid question, no offense. Road bike a little different, but a mountain bike, you should replace both if they are worn to the point where you're losing traction. Mountain bike both are important in traction and will be much more evident than a road bike.

Looigi

Front. Always. I can't think of a realistic exception on mtbs, road, track, motorcycles, cars, trucks....

xenologer

Fix the front. Failure on front means loss of steering and likely crash. But really if both are worn you should replace both. Dont cheap out on safety.

FoxMulder

That's OK. I was expecting someone to bash the question eventually, like, "Dude, which leg is most important? Your right or your left? *yuk* *yuk* *yuk*"

Wilfred Laurier

new tire goes on the front
always
and best of the old tires goes on the back
this is the equivalent of rotating your tires

wphamilton

I'd rather have a flat on back than on front, rear tire wears faster and is more likely to flat. That said, it doesn't really matter that much which gets the new tire. Flats are not more likely on the more used tire unless it's so worn that you need to change both.

Other considerations: on one bike I like to have 32mm on front and 28 on back, which makes the decision right there. On another I prefer higher pressure on back, so I generally like the tire with higher pressure rating there. If you're concerned with being the most aero, the narrower tire goes on front IMO. The only time I rotate tires is when I'm seeing thread on the front, but that situation is only going to last as long as it takes to get a new tire.

chaadster

Anyone who would give a definitive answer to the question without knowing the condition of the worn tires, how the bike is to be ridden, and the objective in replacing only one tire, isn't considering the situation fully.

FoxMulder

Well, if I only replace one, I'll put it on the front. The tires still have some tread and they aren't worn horribly, but I'm noticing that in some instances I don't have the same traction on the trail that I used to.

Wilfred Laurier

please name one situation where you want a new tire on the rear and worn one on the front

chaadster

See post #8 .

As I suggested there, if you've got a bald rear tire on a trail that's loose or sandy and hilly, you may not even be able to get the bike moving under pedal power, rendering both tires meaningless, including any new front one. A new tire with tread on the rear that lets you pedal up that loose, sandy, gravelly hill gets you back to biking, which I presume is the whole point.

chaadster

See post #7 .

If they're not worn terribly, and I wanted to get as much mileage as possible out of my tires without having to pony up for two, I'd put the new tire on the rear because it sees more wear more quickly. A front tire will last much longer than a rear.

chaadster

See post #15 .

What do you mean by worn?

10 Wheels

I always put the New Tire on the Rear.

Wilfred Laurier

if a tire is so worn that bicycling is almost impossible
then you absolutely do not want that tire on the front
in such a scenario
the best solution is to put the good tire on the front
and walk up hills too loose and sandy to ride
because if you have a tire so bald on the front
riding down the other side will be dangerous

Wilfred Laurier

the owner of the bicycle decides the tire needs replacing

Wilfred Laurier

this is not proof that new tires should go on the rear
only an example of why i would not let you work on my bike

rdtompki

If you're riding in Florida it might not matter so much; front tire failure at 20 mph not so bad. If you're riding in the mountains the correct answer has to the "the front".