Turanza LS-H observation and fuel mileage

[Chris B]

I made an interesting observation last night while unloading my new Turanza LS-H tires on my Avus II wheels from the wife's CRD last night. They BARELY fit into the rear cargo compartment. The door had to be really squeezed shut. This is with the tires standing upright and facing front to back.

The old tires, the stock Michelin's, which were down to about 1/8" tread, fit easily with slop to spare. Both are 196/65-15 size.

Granted, they had a lot of tread worn off, and the Turanzas have some REALLY deep tread, but there seems to be a marked difference in rolling diameter. My Firestone Winterfire tires also seem larger in OD. Haven't measured those, tho.

I'm wondering if this diameter difference is really the source of the mpg hit most people see when switching from the Michelins? A larger OD tire will roll farther for the same indication on the odometer, giving 'measured' poorer fuel mileage.

Maybe the stock tires aren't so low in rolling resistance after all, but merely made to a smaller OD range than 'regular' tires of the same size to give the *impression* of better fuel mileage? Conspiracy?

Anyway, just stirring up some thoughts. I'll mount the Turanzas this week and bleed the brakes with my Mity-Vac at the same time, they are quite overdue for a fluid change.

Chris

 

[spoilsport]

According to The Tire Rack, the diameter of the Michelin Energys are 24.9 and the Turanza LSHs are 25.1.

If you take away 5/32 of tread around the whole tire, you then have a diameter of 24.6 inches, or 1/2 inch total difference.

Could that explain it?

 

[Davin]

Assuming a nominal mileage of 50 mpg, that difference in tire diameter by itself would result in a "phantom" 1 mpg mileage hit. In other words, all things being equal, your fuel mileage does not change at all, but if you compute it from your odometer readings, it would go down to 49 mpg.

 

[Chris B]

Well, I've had the new tires on for about 1-1/2 weeks now. Fuel mileage definitely isn't where it used to be with the Michelins, but I've not had to fill up yet to really tell.

Overall impressions of the tires are that they handle HUGELY better in the rain. The Michelins were downright dangerous. I could spin them in 3rd gear just by nailing the pedal if it was wet. And that's with a stock engine!

Handling in the dry is also much improved with better road feel. Noise is about the same, maybe a wee bit more. The Michelins were very quiet tires.

Rolling resistance is definitely higher. I used to have to hold the brakes on the slightest incline. Now it will stay put. It doesn't coast as well, either. So, I don't think it's a diameter/size issue alone, but also one of the increased rolling resistance. I also wonder if the 11/32 tread depth vs. the 9/32 of the Michelins when new affects that?

I hate to loose the fuel mileage, but the handling is so superior, especially in the wet, that it is worth it to me. It's a nice feeling knowing I can stop.

Chris

 

[landrumdh]

I noticed more than a 1mpg drop when I dropped my stock Continental tires to the LS-H's a year ago.

I've got to say thier dry and wet handling and wear have been subpurb. I will definatly look at them again for my next tire.

Food for though LS-H is a standard tires on the new civic.

 

[tjl]

Overall impressions of the tires are that they handle HUGELY better in the rain. The Michelins were downright dangerous. I could spin them in 3rd gear just by nailing the pedal if it was wet. And that's with a stock engine!

Was this when the old tires were new? I'd guess that any worn out tires will do poorly in wet conditions compared to new full tread tires.

 

[raybo]

I had LS-H's and had a 1 or 2 MPG hit. They were really great with wet cornering. I never thought that they were good with hydroplaning - the original Conti's were much better in standing water, even with half the tread. The LS-H's are a good alternative to MXV4 for rear-drive Mercedes.

 

[Chris B]

Was this when the old tires were new? I'd guess that any worn out tires will do poorly in wet conditions compared to new full tread tires.

---> Yes, indeed! Even when the tires were new, I had some scary moments in the wet on freeway off ramps, etc. It wasn't a hydroplaning problem due to standing water, but more of a low speed adhesion/traction issue. They were just simply slippery on wet pavement, and REALLY bad on wet concrete with some of the agregate showing. That was like driving on ice.

Chris

 

[tjl]

---> Yes, indeed! Even when the tires were new, I had some scary moments in the wet on freeway off ramps, etc. It wasn't a hydroplaning problem due to standing water, but more of a low speed adhesion/traction issue. They were just simply slippery on wet pavement, and REALLY bad on wet concrete with some of the agregate showing. That was like driving on ice.

I had the same Michelin Energy MXV4+ tires that came with the car; they seemed to be fine until they got about half worn, when they started to hydroplane too easily. At the beginning of this rainy season, I replaced them with Falken Ziex ZE-512 tires (the MXV4+ tires had only about 3/32" tread left).

So far, the ZE-512 tires are fine, though they seem to cost about 2-4% in fuel economy. However, even with the extra fuel cost, they will end up cheaper than another set of MXV4+ tires (the ZE-512 tires cost $60 each, versus $110 each for the MXV4+ tires; extra fuel usage over the 60,000 mile lifetime will amount to about $30 per tire).

 

[bjmarler]

Was this when the old tires were new? I'd guess that any worn out tires will do poorly in wet conditions compared to new full tread tires.

That's a yes for me also. I replaced the Micheline Energy's at 30,000 miles. I should have done it at 5 or 10,000 miles. From the beginning they were not good in the rain, but after about 10,000 miles they were deadly in the rain. I've seen hot butter stick better to a Teflon coated pan than these tires could stick to wet pavment.

I kept thinking that I needed to get my moneys worth our of them so I kept using them and just tired to remember to drive like a granny in the rain. Well, after a few narrow misses where they sent me sliding instead of stopping I realized my reasoning was all wrong. To bet a few hundred dollars -vs- $20,000 was not good reasoning. So, I got the Turanza LS-H's.

Now with over 10,000 miles on the Turanza's they still feel as safe, and grip as good as the day I got them. No sign of getting slippery as they age. On occasion I even try to make them slide in the rain just to see how they are aging. So far the are great still.

Yes, I lost a few mpg. But my reasoning now is that a few hunded dollars is much better spent buying the absolute best/safest tire possible to protect my $20,000 investment. Oh and also to protect me and my wife! lol

Long story short. I'll never skimp on tires again. There's too much riding on it. (pardon the pun.)

 

[ChiTDI]

The mileage drop doesn't go away as the tires age either. I'm looking at 45000 on my LS-H's and with 7/32nds tread the mileage has been consistent since day one. ( A drop of 8%).