Does it make sense to replace just one tire with treadwear?

[Ailish]

Does it make sense to replace just one worn bicycle tire?  When fixing a rear flat, today, I noticed that the tread on that tire is very worn.  (I have fenders, so I almost never see the rear tread.)  Today's puncture was a sharp stone that had gone through the tread.  The front tire, by comparison, looks much better, and I imagine it has rather more life in it.  I can get a new matching tire for the rear, or I can change the front/rear both, which would give me more options, albeit at at least double the cost.

The current tires are Continental Contact 700Cx37 that came standard on my LHT.  I've ridden them for three years, and about 7000 km (~4500 mi), mostly locally (non-touring).  Today was the first flat I've had.  If I change both tires, I might drop to something in a x35, or maybe even a x32, in the hopes of getting something a bit faster, while not sacrificing too much in comfort or durability.  But if I'm likely to still get a few years on the good looking front tire, it's way more frugal to just replace the back with a new copy.

[JDFlood]

Typically the tread will wear around twice as fast on the back as on the front. So, you'd be throwing away a lot of tread on the front.

[Ailish]

Ah, thanks!  So, it sounds like the sensible plan is to replace the just rear tire with one of the same, this time, and in another few years, both will be worn enough to replace as a pair.

[JDFlood]

That is what I do. I would imagine most folks do. I think the weight on the front versus back is something like 40/60...hence the back wears much faster than the front.

[DaveB]

For all practical purposes, bike front tires don't wear at all.  Weigh a new front tire and weigh it again after say 5000 miles.  The weight loss bill be negligible while a rear tire under the same conditions will be worn down to the casing well before that.  Nevertheless, front tires do age and harden with years and miles and shouldn't be used forever.   

I start with two new tires and ride them until the rear is showing casing under the tread.   I replace the rear and keep the front.  When the second rear wears out, I then replace both.

[Ailish]

... I think the weight on the front versus back is something like 40/60...hence the back wears much faster than the front.

I've thought of that, and while I think weight distribution is a factor, I don't think it's the only one, and likely not the biggest one.  The main one, I think, is that the back wheel is used to drive the bike forward.  Friction between the tire and the road is what allows the bike to advance.  The front wheel, by contrast, just passively rolls along.   The other issue is braking.  While the front wheel gives more stopping power, I often use the rear wheel first or more strongly so as not to pitchpole the bike.

Thanks, DaveB and JDFlood!  You've confirmed what I suspected, but I didn't want to replace the rear wheel only to have the front suddenly prove in need of it, too.

[DanE]

My strategy for tire replacement is new tire installed on front wheel, tire on front wheel moved to rear, worn out rear tire goes to trash. Just my two cents.

[JDFlood]

I start with two new tires and ride them until the rear is showing casing under the tread.   I replace the rear and keep the front.  When the second rear wears out, I then replace both.

This is what I do also. I do as little tire changing as possible.

[DaveB]

This is what I do also. I do as little tire changing as possible.

Yeah, that's my feeling too.  Sort of a let sleeping dog lie approach.  I once tried rotating a used front to the rear and replacing the front.  To my surprise the former front wore out very fast as a rear tire, much sooner than a new rear would have.  I expect the time and miles had effected the rubber even though there was little to no apparent wear.

[John Nelson]

My algorithm is pretty dirt simple. When a tire is worn out, I replace it. I try not to overthink this.

[Pat Lamb]

My strategy for tire replacement is new tire installed on front wheel, tire on front wheel moved to rear, worn out rear tire goes to trash. Just my two cents.

That's my overall strategy, however, I'm sometimes in a rush and sometimes just not motivated to do the double swap.  I usually end up swapping the front to the back roughly every second back tire change.  I have seen a front tire start to disintegrate from age when I only swapped rear tires.

[Old Guy New Hobby]

The last couple of years, I found myself with 5,000 miles on the tires (more or less) and a tour coming up. The tires still looked OK, but I changed them both anyway. The piece of mind out in the middle of nowhere outweighed the cost. After all, how many more miles was I going to get? I kept the front tire around in case of a mid-year blowout, then I tossed it when I had the second used front tire. Of course, this strategy wouldn't work for the high mileage guys.

[johnsondasw]

My algorithm is pretty dirt simple. When a tire is worn out, I replace it. I try not to overthink this.

Ditto.  I watch the two little wear holes on my Continentals.  Also, sometimes a rear tire will keep getting frequent flats and then I change it.

[PeteJack]

According to Sheldon the tire that is least likely to fail should be on the front. Sheldon's words on tire rotation are as follows: "The idea is to equalize the wear on the two tires, but this is a serious mistake, don't do it!"

[Louis Le Tour]

My algorithm is pretty dirt simple. When a tire is worn out, I replace it. I try not to overthink this.

Prezactly.