I've had these on mine since 2012 and our typical mileage around Seattle metro area is 34mpg which is the same as we saw w/the OEM Dunlops. Initially, I noticed a ~2mpg drop but mileage went back up after a bit (better driving, break-in, dunno). I did a 3600 mile road trip from Seattle to San Diego along the coastline mostly and saw 35.1mpg for the full trip average. When I focus my driving habits and drive on mostly 50mph country roads, I get closer to 38mpg including some fairly spirited cornering, etc. I like the 4x's enough, I think I'm going to buy them again. My pressure is typically 40psi @ all 4 corners.

 

Reporting in after 1000 miles on the kumho ecsta 4x 205 50 16. I achieved 32.1 miles. The first 1000 I was getting a constant 30 MPGs.

 

I currently have Kumho ecowing 205/50-R16. They have been good (even in ice and snow), and didn't affect my mileage very much. I think the LRR countered the wider tire. I went to 205 trying to limit the amount my 2009 Fit sport is thrown around by grooved concrete. It helped some, but only about 30% improvement in steering on grooved concrete. I need new tires now (only got 2/3 of the warranty miles). I'm thinking of either going to a 215/50 16 (anyone done that?) to help with handling on the rapidly deteriorating roads, or going back to the original 185/55-16 for better mileage and just tough out the potholes, cracks, and grooved payment. I don't think I'll keep the 205's. They seemed to not handle the grooved pavement or get great mileage (I still get 35-40 mpg, depending upon the usual factors).

 

There was another thread about this somewhere else on the forum, someone else had done this with success I believe, however know that your speedo will be off a little bit

 

Wider tires are more affected by grooves. Going wider usually means more weight; more weight means harder work for engine and thus less mpg. Greater diameter means weight at greater radius and again hharder work for engine unless you aren't accelerating a lot as in interstate at constant speed on level ground then its a plus.
Use tirerack to check weights, diameter, and customer reveiews and performance laps.

 

Well guys, I have put on about 2 full tanks of fuel on the new tires. 205/50/15 versus the 205/60/15s

New tires are only 0.7 pounds lighter I believe, I cannot find official weights for my sizes, so had to rely on what other users of the interwebernetz provided

So far, if any mpg improvement is there, it is minor.

4th gear is MUCH more fun, and the car does pull in 5th sort of, so the smaller tire size is definitely noticable.

However, I dont think the engine much cares. Its strange how it feels so much better, yet I may only be getting 1-2mpgs better.


Time will tell. So far avg MPG gauge reads 34 after driving 80% city

 

If you're using now 205-50-15, your speedo will read 3.9% faster comparing with the stock tires, does means if your speedo mark 60mph you're actually running at 57.6mph

Verify here

Tire Size Calculator

Luis
Honda Fit Sport 2013 - Vortex Blue Pearl

 

Purchased 4 General Altimax RT43 all season tires . Should be little under $60 each before tax . Price includes the $50 rebate , that's if all goes well . These are 175/65-15 .

 

Should be an awesome tire. The obvious Michelin ride quality should be there as well as good tread life. I'm not completely sold on the "evolving sipes" yet as I haven't seen any worn down enough yet(way too expensive for most people in my area). I'm also curious to see if they perform better in the snow than its predecessor, the Primacy MXV4. Time will tell though. We should start seeing reviews on snow traction in the next few months, so keep an eye out for that

 

If you are comparing going from 205/60x15 to 205/50x15 the change is 24.68" to 23.07" diameter which is a 6.9% change in distance traveled per theoretical revolution. Since the OEM tire is 175/65x15 the difference is 24.07 vs 23.95" so the speedometer error is only 0.47% and that means the OEM 60 is now 59.7 mph. Worse, since any speedometer device is subject to a 2% error by spec your speedometer reading is close enough to ignore any difference.
I'm surprised you haven't seen a considerable change in mpg going from 205/60x15 to 205/50x15 but getting an accurate mpg calc with just 2 tank refills could be the reason. You already noticed the better acceleration in 4th and 5th so you can be sureyour mpg is just as much better.
BTW check tirerack for weight and diameter data and if you really want accuracy compare revs per mile between the two which is the accurate measure of tire diameter changes instead of calculated diameter due to tire deformation at the ground..

 

Where did you do your math?

its a 3.7% reduction, so at speedo 60mph, vehicle is moving at 57.8mph

What I just proved with going from oversized tires to undersized tires, is that while it made the motor much happier, it is ALWAYS at a higher rpm for the same VEHICLE speed.

Easy way to think about it is this

small tires rotate MORE at the same vehicle speed as big tires rotate SLOWER.

find that miata tire calc and look at tire revolutions. 842/mile for stock GE 15s, 874 for my new tires.

VROOOM!

 

The speedometer is caklibrated on 175/65x15 tires, not 205/60x15. While it may be a 3.7% reduction the speedometer error is 23.95/24.07, 0.995, or one half % of change so when the speedometer reads 60 mph you're actually doing 59.7 mph. Using 205/60x15 tires had the speedometer read 60 at a true 61.8 mph.
BTW the diameter of 205/60x15 is 24.68" and the 205/50x15 is 23.07: that ratio is 23.07/24.68, or 6.9% change. The 205/50x15 is the preferred tire size for performance because the diameter is slightly less than OEM and when the tire is heaier it pays to go a little smaller diameter to reduce the torque loss that handicaps mpg and acceleration.

 

My math is from stock tires to my smaller new ones, not from my old bigger tires.

I didnt get the smaller tire for performance, I got it for handling. the 205/60 sidewall on a 15 is too large for this car. the 205/50 sidewall is MUCH stiffer and better around the corners.

The fact it effects the gearing in a positive way is simply a bonus to me.

 

2 lb for 4 wheels is 8 lb; at a radius of 1 foot thats 8 lb-ft of torque. Considering you only have a maximum of about 90 lb of torque from your engine that 8 pound-feet will indeed soak up a bunch of mpg considering most of your driving is done around speeds where the torque from the engine is only 60 lb-ft.
The harder it is to turn 4 wheels, the more work the engine needs to do and the more work the more gas it takes. You can't fool mother nature. You can minimize extra weight by less tire diameter but it won't go away.

 

I also have Ecopias on my 09. I haven't studied them enough to know if they improved my mileage any, but they are good enough tires with good enough ratings that I will take their word for it.

 

I don't know that this is a fair comparison- because once the wheels are spinning the rotational inertia continues. As opposed to say, all the other factors that require constant torque because there are forces against it- mainly wind resistance and friction of the tires against the road. If there were no wind resistance once the car gets moving it wouldn't take much gas to keep it moving. But since there is air to be pushed against, you're constantly using energy to overcome that.

 

your math and theory is way off.

So If I buy some guady nasty 19s or 20s for my car that weight 35-40 pounds and put on stupid thin tires that still manage to way 25-30 pounds, my car will not move properly? By your math it will have less then 30TQ to use.
I bet the car would STILL manage to hit over 100mph

Seriously, you will not find numbers on the paper that have a big difference with just 2 pounds.


I certainly dont feel it, and I can feel the difference between my subs at the far back, or them sliding forward under hard braking. The car tends to slide the rear out more when the subs are sitting behind my driver seat (rear seats are gone)

 

You have to multiply by the gear ratios in the transmission. Even in 5th gear (.727), you have the final drive of 4.62, giving you a final ratio of 3.36. Your 100 lb-ft of torque then becomes 336 lb-ft in 5th gear. First gear is all the way up at 1528 lb-ft. Yes, you will lose some to the wheel and tire weight, but you're actually starting with much more than the published specification. Transmission gears are wonderful.

Even if you subtract 20% for drivetrain losses (gear friction), you're still at 1200 lb ft in first and 268 in fifth.

 

Cmon now. Fifth gear is where the action is and yes you are right; fifth multiplies the torque by 3.36 but the torque that is actually available at street speeds is more like 100 lb-ft at the rpm ranges there. Adding 24 lb-ft to the load means the engine works harder using more gas to produce more power unless you rev it up. At least until the hp curve is reached. Then you must dhift gears or slow down. Once you shift to lower gears gas consumption rises very quickly. A loss of 2 to 3 mpg is not at allunusual. going from 175/65x15 to 205/50x15 even when the radius for the torque arm is reduced. If it weren't the loss might be 3 to 4 mpg.

 

I am very interested in the General Altimax RT43, they sound like a great, very balanced tire. Would very much appreciate hearing your thoughts after a 1000-2000 miles.
Thanks