Tire Upgrade

As I posted in a couple of other topics I changed to all season performance radials, sized 205/60R15 about 3000 miles back. I am very happy with the decision and would buy that size again. I chose tires that have 847 revolutions per mile compared to 855 for the stock tires. This corrected most of the speedometer error, it is now about 1 MPH fast at 70 MPH; before it was about 2 MPH fast at that speed.

I originally posted that highway and around town mileage seemed unchanged. I now think that I may have lost 1 or 2 MPG in around town driving. Highway mileage does seem unchanged which makes sense because aerodynamic factors would tend to override rolling resistance at highway speeds.

I think the only reason the North American version has drum brakes on the rear is because they are cheaper and The people who make such decisions at Toyota think most Americans are to dumb to tell the difference anyway. They may be right.

 

I have gotten an abundance of useful information from these posts and I think I have mass quantities of info to help me make my tire decision. However, how or where do I find the RR (rolling resistance) for all the tires mentioned here? Mileage is important to me and that is why I purchased a Prius. Since I’m in the south, all weather tires are of a lesser degree of importance. Enlighten me. :mellow: :huh: B)

 

Drum brakes in rear are just fine.

The thing you mention emergency stopping is not an issue. If the drum brakes couldn'd do the job with the little braking needed in the rear we'd all be better off putting much bigger disk brakes in the front first.

The only downside I see mentioned to drums is fading from overheating as when coming down a mountain.
The electrical braking and engine braking should prevent this being a problem like non-hybrid cars would have.

And disk brakes always drag a bit, so mpg should be better with drums. Disks in front still let us stop on a mountain even if the drums give out. So we get the best of both!

 

I would gladly pay for the most effective braking SYSTEM for the Prius. For me that's the current set-up, which differs significantly from non-hybrid/non-regen cars. Basically the regen, for me, more than makes up for the "poor" braking of the rear drums. I have no probs stopping when I need to. I get the best value for this particular car. YMMV.

Not sure what the rear disc in Europe means? Maybe standard requirement forced by gov't standards? Europe has faster speeds, requiring "better" rear discs? Cultural thing, meaning to sell a high-tech newly evolving car, you have to have rear discs to compete?

Lots of things are on across-the-pond Prii that we in the US don't get on our Prii. Different driving patterns/marketing/perceived need.

Cheers,

Curt.

 

<div class='quotetop'>QUOTE(grasshopper @ Jun 29 2006, 11:36 AM) [snapback]278598[/snapback]</div>

I know little, Grasshopper, but have shared a few sources and tips in a new thread: http://priuschat.com/index.php?showtopic=21415&hl=

Since you have little need to worry about snow or ice traction, you might consider the Sumitomo HTR 200 high-performance summer tire. The HTR200 is recommended by GreenSeal as low rolling resistance and is very highly rated at TireRack.com and here at PriusChat. It's also very competitively priced. Two possible downsides is that Sumitomos aren't widely distributed in the US (you'll probably have to order it through tirerack.com or your tire dealer) and it's only available in a 1 cm wider than OEM 195 section width tire.

 

<div class='quotetop'>QUOTE(nyprius @ Jun 29 2006, 06:23 AM) [snapback]278529[/snapback]</div>

As I understand it, modern drum brakes are as good as disk brakes, if not better, in stopping power. Better in that they are resistant to weather and environment so they can't "get wet" or get oil/mud all over them to affect braking.

The weakness of drum brakes is heat. They can't dump heat as fast as disk brakes which are fully exposed to the air and vented rotors for our disks. So drums are great in the back where they don't get used as much and are resistant to stuff getting kicked toward it.

You can bet on drums giving you one good hard brake pass for avoiding hitting that truck, but it's unusable if say you were on the Nürburgring where you have to constantly hard brake multiple times.

I understand it the good trucks out here in the US use drum braking for the rear, and god help the disk ones.

 

Re brakes-once the ABS kicks in does it matter what kind of brakes they are?

 

I've gone nearly 60K miles with my 2004 Prius and I'm on my 3rd set of tires.

Stock - These tires were just too slippery for me in most conditions and I was eager to swap them out.

TT - These solved my traction problem but they made for a harsh ride, cost me about 3-5MPG and they were not the original specification size. They also got a little noisy as they wore down. The MPG improved SLIGHTLY as they wore but they never got close to stock tires in this regard.

Ziex - These have been a good compromise. My MPG jumped back up and the handling was somewhere between the stock tires and the TTs. Noise is still an issue so they are not perfect and I'm not sure how long they will last but they seem like a good bargain.

I'm still waiting for the tire that combines LRR with some handling and a quiet ride...

 

<div class='quotetop'>QUOTE(vintagebob @ Jul 6 2006, 03:49 PM) [snapback]282173[/snapback]</div>

Thank you for sharing your experience. IMHYBRID who drives one Prius with HydroEdge tires and another with Falken Ziex ZE-512 tires also compares the Falken ZE512 favorably the Michelin. Here is his PM to me:

We got 50,000 miles of wear on the Falken Ziex ZE-512's on our Civic, before we replaced the Civic with the Prius. The Falken's still had maybe 10,000 miles of wear left.

If you want equal or better LRR, better handling, and less noise than the Integrity, you might consider the Continental ContiProContact.

 

<div class='quotetop'>QUOTE(nyprius @ Jun 29 2006, 08:23 AM) [snapback]278529[/snapback]</div>

Higher end cars have lots of features that aren't necessary for operation of the vehicle but the buyers expect them. Rear drum brakes work fine in the Prius. I haven't seen one person report an incident of brake fade because of the rear drums.

In 1978 if you had brake fade, you should have been using engine braking to go down a long winding mountain pass. If big tractor trailers can go down the mountain safely using engine braking, then I'm confident any car, even with drum brakes (proven reliable over time), can also safely transverse the road using engine braking as needed. The Prius has the same capability and those who've driven down steep mountain roads have reported here they had no problems braking.

 

I’ve read several threads about tires, and specifically concerning Goodyear Assurance with TripleTred and a concern about reduction in miles per gallon. As this quite well-written thread looks most generally at tire choice, as a Goodyear associate, I thought I’d share a few points that may be helpful.

Assurance TripleTred is a premium replacement tire. Its construction, tread pattern and multi-compound tread rubber deliver outstanding traction in any conditions. It also contributes to great treadwear; as those who bought them know, they come with an 80,000 mile treadlife limited warranty.

Construction of OEM tires is a little different from replacement tires. There is more silica in the compound, for example, to reduce rolling resistance and help the car manufacturers meet MPG goals. Generally speaking, an OE tire will have shorter tread life than a quality replacement tire, such as Assurance.

Lower rolling resistance (LRR) tires would likely increase gas mileage under comparable circumstances. But the gains made in MPG are traded for the loss of treadwear. Additionally, depending how the LRR tire is constructed, there could also be a trade-off in traction or performance.

As an aside, we developed Assurance (and other tires) after hearing what consumers wanted. “Better traction, confident handling, performance in all sorts of driving conditions†summarize the responses. At the time (2002/03) higher MPG wasn’t a priority. Keep in mind that the consumers drove – and Assurance was developed for – a wide variety of vehicles, some fuel-efficient, some not.

Many of the readers here probably know this information already (seems to be a smart group from the posts I’ve read), but I thought it could be helpful.

Also, you might be interested in knowing that performance tires are much more popular in Europe than in the US -- but Goodyear and our various brands have many excellent hi-perf tires for the US market that are quite well rated -- The Eagle F1 and Eagle ResponseEdge with Carbon Fiber Technology, and the Dunlop SportMaxx and SP Sport 9000 are big winners in many head-to-head tests.

 

GoodyearGuy

Which Goodyear Tires ARE LRR?

That's the question everyone wants answered. Not 'why the TT isn't' and not an explanation of what the trade-offs are for Rolling Resistance.

Publish the Rolling Resistance of your tires and then let people decide based on that and the other factors you mention.

 

I went maybe 1/3rd of the way through my Prius' first winter before ditching the (not much) Integritys. They would slide coming to a stop in MINIMAL snow, on plowed roads. The traction control would kick in even with a light foot starting in MINIMAL snow or gravel. I'm not sure what "all season" means to tire manufacturers but for the Integrities, it ISN'T "All Seasons" in Vermont. There is a VERY wide range of "all season".

If possible, I wanted to stop the twice a year tire swap and STORAGE required with snow tires. I settled on the high end 195/60 TTs and am very happy with them. I would say that they are a tad noiser than the Integrities. MUCH MUCH better in snow. MUCH MUCH better in rain, and there is a noticable improvement in stability on interstate exchanges. While the body lean doesn't change, the improved tire grip is noticable. I can hold a higher speed on the exchanges I use regularly without feeling like I'm at the edge.

I may have lost a little MPG but I can't say for sure. I thought I might have so I put the Integrities back on in May of 2005. The TTs went back on in November for winter and are still there. Nose to tail comparison suggests little if any difference. Two weeks ago my wife and I came back from dropping the kids at camp - 150 miles, all interstate. We came from different directions to drop them so we had both the 2004 with 21K miles and TTs and the 2006 with < 2K miles and Integrities. The final 30 "five minute bars" were pretty similar. Since neither of us reset our computer MPG (what and screw up the spreadsheet!?!?) I can't give an exact MPG comparison. Riding in her car, I would say she might get a bit better 'glide' distance but that is to be expected since her tires aren't as 'grippy'. I'll let her decide if she wants dedicated snow tires or high end all seasons come winter. One thingis certain, the Barcelona Red will NOT be spending the winter on the Integrities.

 

<div class='quotetop'>QUOTE(nyprius @ Jul 6 2006, 05:02 PM) [snapback]282231[/snapback]</div>

I replaced the OEMs and the TTs early. The OEMs scared me, especially in the rain, and the MPG hit with the TTs, along with the harsh ride, started to bug me after awhile. I have the same problem with golf clubs, I'm always seraching for the perfect set.

 

I have a question for everyone like me that lives where it hasn't snowed since the Great Depression and therefore don't need All-Season TIres...

Are you using "Summer Tires" and if so how is the treadwear, MPG, and wet traction?

It scares me that most of what I'm finding have no treadwear warranty and are only Ultra High Performance type (not that I mind that part).

 

<div class='quotetop'>QUOTE(bad monkey @ Jul 13 2006, 12:30 PM) [snapback]285678[/snapback]</div>

I always bought summer tires when I lived in Arizona and California, but I didn't have a Prius then. I still usually choose the tires for family members in Phoenix.

If I were out there now, I'd choose the Sumitomo HTR 200 for the Prius. It's well rated at TireRack, inexpensive, and has long treadwear for a summer high performance tire. The unusually Low Rolling Resistance is likely to increase your MPG by 1-3 mpg over other summer tires. This could save you another $60 to $200 in fuel costs over the life of the tires, not to mention reduced emissions, easier EV mode, and longer glides . The maximum pressure is 51 psi, giving you more freedom in choosing your tire pressure.

The Bridgeston Potenza RE-960 is a M+S tire that offers outstanding performance aside from lousy snow traction. We've used the RE-950, the Yokohama AVS ES100, the Kumho KH11, and the BFG G-force Sport with good performance, lousy mpg, on other vehicles. I miss driving on summer tires.