My 2010 Fit Sport MT is close to 50,000 miles. Time to replace the stock Dun(s)lops. I deliberated about what to do. Really didn't have a huge problem with the stockers except that I felt that they are maybe too progressive for my driving style.

Looked at cost and outer diameter compatibility. Turns out that the Kuhmo Ecsta AST in 205/50 16 is within 1 revolution per mile of the stockers (863 stock vs 862 Kumho).

I never talk about grip comparing a worn out & heat cycled to death set of rubber with a brand new freshly scrubbed set. It's just plain dumb. I did notice more noice right off that bat and I can immedately see a mileage drop. I would regularly get between 38 and 42 mpgs. Now it's looking like I've lost a couple or three mpgs. It's only a few hundred miles in but....

Kinda hard to tell what's the extra 20mm width and what's the tire design. Just wanted to pass along a narrative. Perhaps I'll update as I pump a few more tanks...

-Saro

 

Last summer I added new tires/wheels to my old Fit. I stayed with 16's but went from 6" wide to 7' wide and went with 205/50's but went with Continental DWS' and lost nothing as far as mileage but gained handling, BIG TIME I never really did a before and after on the mileage but with mixed driving I would get 35-37 mpg and on the freeway I would get anywhere from 39-43 mpg, not to mention the wheels had more offset too fwiw. Now the weight of the tires you chose may have something to do with it, sorry to hear your tires are loud too, the DWS isn't loud at all, infact they're quiet compared to the stockers. Its good to see that you got the mileage out of the stockers without an issue with the sidewall, good for you. Double check your air pressure too, I always ran about 36 psi or so in mine, just a bit more than normal.

Maybe next time you can get some DWS'

 

^^everything he said^^

50K on the OEM tires is crazy, well done! I'll guess that once your new treads break in you'll see the mileage come back.

post back results - keep the thread alive.

 

What's crazier is that I live up a mountain road. And, truth be told, it was slightly under 49k. Like 48,8something. I have a tough time digesting the extreme negative commentary directed at the stock rubber. But that's another show.

I need to put my pyrometer (old school probe style!) to the tires after a trip down San Francisquito Canyon and gauge how the recommended 33 cold psi fares on these things. Hopefully they'll actually warrant a couple more psi and I'll see a couple more mpgs. I ain't holdin' my breath, but who knows.

-Saro

 

If your driving on twisties, then for sure bump them up a little (3-4 psi) and even though its not related, check out my mileage thread (don't worry about reading everything) but to cut through ALL the reading, using premium in the Fit netted me much, much better mileage, especially in the winter, no doubt about it and get this, if you switch to premium your only looking at about $2.00 more per tank and that's on an empty tank, noone does that Give it 2-4 tanks for the ECU to adjust and I think you'll be pretty surprised as to what happens next, I was

 

More than 3 tanks into these tires. Be it the 20mm, the compound, the tread pattern, or something wonkey in the carcass, I lost an easy 3 mpgs to these tires. At least they were cheap - $75 each. So, compared with $99, I saved $96 ($24 x 4) on this set of rubber. If they last 40 thousand miles (another 50 seems inlikely) at $3.5 / gal (SoCal) I pay about $300 more in gas over the life of the tires compared with $96 initial savings. Close to $375 if I do make another 50k.

Over inflating them made no noticeable difference in mileage and it markedly hurt grip. Made these tires feel like about 10k miles of my heat cycles. I've yet to observe mileage differences with octane with me driving on this car. My wife's Smart is a different story...

 

Maybe the DWS can be on your list down the road because myself and others who've went this route have had nothing but driving pleasure with them, I took NO mileage hit going 20mm wider and 5% less aspect ratio

 

New tires will take a bit to break in. Weight is the biggest factor overall. A slight compromise on MPG for good handling is worth it, however. I tended to agree with you on the OEM duns until I got the DWS's. They are an incredible tire in the Fit.

Not that you need to worry much about snow, but over the holidays I traveled 3hrs on a blowing snow swept/packed powder Maine Turnpike with little to no issues. As usual it was the other fools that were the problem.

 

If I don't get the bikes rolling again soon, I'll probably get a chance to try the DWS in a bit over a year - if they're still being made.

-Saro

 

This tire just came out last year, so you'll be ok. It replaced another Conti tire in their line up, can't remember which one but based on the reviews this tire gets, its not going anywhere anytime soon

I'll be getting myself a set in the spring for my CR-Z, can't wait for that because with its steering, it will only be that much better with wider tires, then factor in the Conti DWS construction and call it a day. I never thought a tire could be all things to all conditions, Continental has really done something here, just hope more and more people find out about these tires so they too can experience the safety and performance of this great tire

 

If you had replaced your tires with identical stock Dunlops your mileage would have still decreased ~1-2mpg. Half of that is phantom mpg you thought you were getting due to old worn out tires being smaller diameter and speedo/odo not as accurate. The other half is from lighter weight (less rubber) and less rolling resistance due to tires worn out and less tread grip. I imagine at 49K miles they were pretty slick. I replaced my stock Bridgestones at 45K and they were toasted.

With my old tires and the car parked in the garage on level smooth concrete I could put my foot outside the door and with a gentle push get my Fit rolling. Maybe rolling isn't the right word, more like an ever so slow snails crawl. After putting on new tires this was no longer possible. It takes a big push and then will only roll maybe a quarter revolutuion. Traction is your friend while driving, even if it costs you a mpg or two.

_

 

Except I was getting that sorta mileage from day 1 on my car (bought brand new) - and stock Dunlops.

A little bit of math and comparing a 10/32" (stock tread depth according to TireRack) vs 0/32" tread depth (I wasn't down that low, but...) on a 185 55 16 results in less than a 1% change in diameter, rollout, whatever. 1% of 40 mpgs is less than 1/2 an mpg - something that would not have jumped out like that. I'm easily seeing 3-4 mpgs less. My old rubber still had tread on it. Also, my driving is predominantly highway - and momentum focused mountain road driving (minimal accel / decel). This sorta thing minimizes the effects of weight - be it sprung or unsprung.

Are you new tires identical to your original tires?

-Saro

 

No, I replaced with 205/50's same as you. Tire width wouldn't have as much affect on this though as tread and stickiness of tire rubber.

Also better double check your math. Remember tread thickness will add twice (top and bottom) to circumference measurement. Still not a major difference though by itself but a cumulative affect. Diameter, weight, tread and width.

_

 

Math:

Original tire is 185 55 on a 16 inch wheel.

Tire sidewall is (theoretically) (185mm / 25.4) * .55 inches or 7.28" * .55 or just about 4".

So, we get an 8 inch wheel radius (16/2) + a 4 inch sidewall = which is 12" wheel + tire sidewall radius.

Now we're comparing 12 0/32" with 12 10/32" or roughly 12.31".

So, you're correct. I was wrong. There's a roughly 2.5% change in radius (and rollout, etc etc etc). 2.5% of my 40 mpgs is 1 mpg - but that's probably not how things work out.

I don't really feel like doing the math, but what would the difference in aerodynamic drag be at 65 mph vs, eh, 65.65 mph? etc, etc, etc... Hint: drag does not increase linearly.

The answer, I suspect, is "not much" - and probably not 3-4 mpgs.

And as far as stickier rubber goes - do you have durometer readings from these tires? I never took readings on the new tires (I do have a durometer) but the treadwear rating indicates that the stockers are LESS long wearing than my current Kumho Ecsta AST - 340 vs 400 - and that the stockers are presumably somewhat softer / grippier.

Tread depth matters. Compound matters. But seems that they shouldn't matter to the tune of 10%. ANd in this case, if treadwear roughly correlates to grip, I should have less grip, and therefore less rolling resistance (all other things being equal, which they ain't).

If you have some alternate numbers, please share.

But this is a pointless discussion with holey data. I'm passing along my observations. These accounts are all anecdotal - an inherently dangerous thing.

-Saro

 

My best hwy mileage was with my 205/50 Conti DWS (43 mpg) compared to 41 mpg with the stockers, but get this, the 205/50's had aftermarket wheels on them too which were 1" wider, this makes it even more impressive IMO

 

compare the weights of the old and new tires. heavier tire will cost mpg and if its a hipo tire the rolling resistance gets you too. and remember your old worn tires are a lot lighter than when they were new; at the tread where it counts the most.

 

Both weight and rolling resistance come to mind. I would air them up to at least 37psi to reduce resistance and see if that makes a difference.

 

I changed my tires 2 months ago, putting Toyo Proxies 4 195/50R16 (the only one available at local shop).
The mileage went down 5-7%. I have to say my stock tires were pretty bold...