2.0 / 2.5 Roadster / Roadster Sport Tire Thread

[Doug_G]

Driving on A048's

I recently got a second set of rims with A048 sticky tires, for use in autocross. My first event of the season was a school in Toronto. No problem, I've done that trip before many times.

Got a nasty surprise - the temperature was unexpectedly low on the trip out - and back! Despite being quite warm at other times, I was driving long distances both ways at 4 - 5 degrees C. At those temperatures my power consumption was about 25% above "ideal". Wow - I've never seen anything like that before. The rolling resistance of those tires is horrible in the cold.

This made things a little tense in terms of "schedule anxiety". Because I kept an eye on things and slowed down appropriately, I was never in danger of running out of charge, so no "range anxiety". But I ended up driving slowly and the only charge stations available right now are only 30A. So the trip took much longer than planned. Despite leaving ample time, I ended up very nearly missing a flight (had to do a side-trip for business along the way).

All that said, the A048's are absolutely awesome for autocross. What grip! Huge difference in the cornering!

 

[strider]

Doug, were you running lower pressures for added grip? Could that have contributed to the loss of range?

 

[Doug_G]

Doug, were you running lower pressures for added grip? Could that have contributed to the loss of range?

No, I was running on the highway so I had the pressures set to Tesla's recommendation. The next day when the temperatures were at 16C the range was back to normal.

Interestingly skid pad testing indicated that those pressures were just fine for autocross, too.

 

[btown]

I replaced my first set of rear tires (7K miles) with AD08s hoping for a bit longer tread wear. I found them to be very comparable to the original AD07s in terms of grip, but after just 5K miles they are down to the wear bands. A bit earlier in the year they gave me a bit of a scare on the freeway in very heavy rain when I could feel the car start to float slightly back and forth. I backed down my speed immediately (but very cautiously as well). The tires had plenty of tread when this happened and I guess it makes sense for all these performance tires to not do so well in the rain, given all the flat surface areas on the tires. So I'm back looking at options and considering moving towards something with a bit better rain performance/safety. Longer wear would be welcome as well of course. A couple of folks (hcsharp and augkuo) mentioned putting on the Michelin Pilot Super Sports, but I don't think either of them have reported back after getting a bit more experience with those tires.

So this is a call to hcsharp, augkuo and anyone else running the Michelin Pilot Super Sports to chime in on how these tires are doing in terms of rain as well as dry performance.

 

[Doug_G]

btown - My Toyo T1R rears are now down to the wear bars, and I had a hydroplaning incident pretty much identical to yours. I already have a set of AD08's to swap in, and just hadn't got to it yet. (Will put original AD07's back on the front.)

 

[ggr]

So this is a call to hcsharp, augkuo and anyone else running the Michelin Pilot Super Sports to chime in on how these tires are doing in terms of rain as well as dry performance.

I'm happy with mine in the dry, but in the three months or so I've had them on the rears, I've been somewhere else every time it rained.

 

[btown]

I'm happy with mine in the dry, but in the three months or so I've had them on the rears, I've been somewhere else every time it rained.

How do you feel they compare to the original tires (AD07s) in terms of dry conditions grip? Do you notice less traction or anything like that?

 

[dsm363]

I replaced my first set of rear tires (7K miles) with AD08s hoping for a bit longer tread wear. I found them to be very comparable to the original AD07s in terms of grip, but after just 5K miles they are down to the wear bands.

The AD08s lasted 2,000 miles than the AD07s for you? I was thinking about going to the AD08s on the rears but still have another 4,000 miles to go on my new AD07s.

btown - My Toyo T1R rears are now down to the wear bars, and I had a hydroplaning incident pretty much identical to yours. I already have a set of AD08's to swap in, and just hadn't got to it yet. (Will put original AD07's back on the front.)

That's scary. Glad you're ok. I've never checked my tires as much in my life until I got the Roadster. I'm going to be very conservative from now on with my tire replacement schedule and replace them earlier than normal (probably 4/32 tread instead of the 2/32 inch I've read about).

 

[btown]

The AD08s lasted 2,000 miles than the AD07s for you? I was thinking about going to the AD08s on the rears but still have another 4,000 miles to go on my new AD07s.

That's scary. Glad you're ok. I've never checked my tires as much in my life until I got the Roadster. I'm going to be very conservative from now on with my tire replacement schedule and replace them earlier than normal (probably 4/32 tread instead of the 2/32 inch I've read about).

I think you read my comment wrong, or I was unclear in the way I stated it. For me, the original AD07s lasted 7K miles. The AD08's are already down to the wear bands and have only 5K miles on them. I was expecting/hoping the AD08s would last a bit longer than the AD07s, but instead they wore out even sooner. 8^(

In my case, the hydroplaning occurred when there was still a good amount of tread left. It was VERY heavy rain though and the freeway I was on had ruts which I think added to the issue. Definitely didn't give me a good feeling though, and I've learned to be very cautious at higher speeds in the rain.

 

[dsm363]

I think you read my comment wrong, or I was unclear in the way I stated it. For me, the original AD07s lasted 7K miles. The AD08's are already down to the wear bands and have only 5K miles on them. I was expecting/hoping the AD08s would last a bit longer than the AD07s, but instead they wore out even sooner. 8^(

In my case, the hydroplaning occurred when there was still a good amount of tread left. It was VERY heavy rain though and the freeway I was on had ruts which I think added to the issue. Definitely didn't give me a good feeling though, and I've learned to be very cautious at higher speeds in the rain.

Hi. I typed my response incorrectly and left out the word 'less'. I meant to write the AD08s lasted 2,000 miles less than the AD07s. I thought they were rated higher than the AD07s. If that's the case, I'll just stick with the AD07s then. They've driven fine for me in the rain (yes, we've had rain recently in Texas:smile. Good info, thanks.

 

[Doug_G]

That's scary. Glad you're ok. I've never checked my tires as much in my life until I got the Roadster. I'm going to be very conservative from now on with my tire replacement schedule and replace them earlier than normal (probably 4/32 tread instead of the 2/32 inch I've read about).

Funny how I wore the original AD07's down well past the wear bars (wasn't paying enough attention back then), and never had a hydroplaning incident. Must have never happened to drive in the wrong conditions.

As a driver I've become much more sensitive to grip thanks to the Roadster, and not just because of simply driving it. It inspired me to try motorsports. I've taken a couple of advanced driver training schools, and have been doing autocross and lapping*. I've come to the conclusion that you don't really know how to operate an automobile unless you've taken one of these courses. I think this helped me when the rears started hydroplaning, because (a) I felt it right away and (b) I knew better how to react to it. No harm done but it really alarmed me.

*Lapping in another car due to lack of charging at the track... and the fact that the Roadster is pretty much irreplaceable now. :scared:

 

[btown]

Funny how I wore the original AD07's down well past the wear bars (wasn't paying enough attention back then), and never had a hydroplaning incident. Must have never happened to drive in the wrong conditions.

As a driver I've become much more sensitive to grip thanks to the Roadster, and not just because of simply driving it. It inspired me to try motorsports. I've taken a couple of advanced driver training schools, and have been doing autocross and lapping*. I've come to the conclusion that you don't really know how to operate an automobile unless you've taken one of these courses. I think this helped me when the rears started hydroplaning, because (a) I felt it right away and (b) I knew better how to react to it. No harm done but it really alarmed me.

*Lapping in another car due to lack of charging at the track... and the fact that the Roadster is pretty much irreplaceable now. :scared:

It's possible the freeway ruts contributed to the problem by pooling the water. I felt the mushy hydroplaning feeling right away (as the rain really came on) and backed down immediately. The entire event probably lasted about 1-2 seconds before I backed off on my speed. Perhaps it was just the perfect storm...

 

[Doug_G]

It's possible the freeway ruts contributed to the problem by pooling the water. I felt the mushy hydroplaning feeling right away (as the rain really came on) and backed down immediately. The entire event probably lasted about 1-2 seconds before I backed off on my speed. Perhaps it was just the perfect storm...

Yeah, it was the same with the "ruts", but I think also amplified by the fact that we've had very little rain prior to that night. The road gets layered with rubber, oil, etc. over time if it doesn't get washed off.

 

[jerry33]

In my case, the hydroplaning occurred when there was still a good amount of tread left. It was VERY heavy rain though and the freeway I was on had ruts which I think added to the issue. Definitely didn't give me a good feeling though, and I've learned to be very cautious at higher speeds in the rain.

Hydroplaning occurs when the pressure in the wedge of water which is created in front o the tires is equal to the inflation pressure. The wider the tread width is, the faster pressure build up. So don't be stingy on pressure in your tires when it's raining.

 

[hcsharp]

...
So this is a call to hcsharp, augkuo and anyone else running the Michelin Pilot Super Sports to chime in on how these tires are doing in terms of rain as well as dry performance.

Good timing because it rained hard yesterday and I did a bit more testing. I have about 450 miles on them so not entirely broken in but close enough to have a discussion.

They have excellent grip and handling with what appears to be much longer life than the Yokos. The dry grip and traction is very slightly better with the AD07, but not much, and wet grip is much better with the MPSS. I have the adjustable suspension so I had already dialed out some of the understeer. With the MPSS on the rear and AD07's on the front the understeer was further reduced, but not a big difference. On dry pavement I have a hard time making them let go before the fronts, and when they do it's predictable and still quite strong. On wet pavement I could not make the rear tires let go first, and overall their wet performance is notably better than with AD07s on the rear.

For flat-out acceleration, I could not detect any difference between the AD07 and MPSS. That doesn't mean there isn't any. I just don't have a good way of measuring 0-60 times. I also switched to forged rims which might have helped. The MPSS are also lighter than AD07. Augie said he measured .1 to .2 sec slower 0-60 using his phone dyno app. That wouldn't surprise me. I could not make TC light come on during full acceleration on dry OR WET pavement. That last part is interesting to me. With AD07s on the rear, even w/ lots of tread, they would sometimes slip enough to trigger TC on full accel in heavy rain. Not so with the MPSS.

In summary, I think you give up a very small amount of dry grip/handling in exchange for a lot better wet performance, much longer tread life, less money and possibly more range. If only they made this for the front...

 

[dsm363]

Thanks for the review. I find it highly annoying that Lotus picked a tire size where only one manufacturer in the world made both front and rear tires sizes.

 

[hcsharp]

Continuing the discussion of the Mich Pilot Super Sports on the rear with AD07s on the front.
The other thing I noticed in the rain the last two days is I appear to get better range with these tires. I don't really have enough data to call this for sure, but I drove 50+ mile routes the last 2 days in the rain and yesterday I almost matched the ideal miles. 11 of those 50 miles were at 65mph and it rained the entire time, sometimes hard! I drive these routes a lot and rarely match ideal miles when dry, and it's normal to see an additional 10% usage with rain. More if you have to run the defrost like I did for part of yesterday.

This would be consistent with Consumer Reports, one of the few places that tests tires for their rolling resistance. They reported this tire to have both excellent gas mileage and outstanding performance, a rare combination.

 

[btown]

Continuing the discussion of the Mich Pilot Super Sports on the rear with AD07s on the front.
The other thing I noticed in the rain the last two days is I appear to get better range with these tires. I don't really have enough data to call this for sure, but I drove 50+ mile routes the last 2 days in the rain and yesterday I almost matched the ideal miles. 11 of those 50 miles were at 65mph and it rained the entire time, sometimes hard! I drive these routes a lot and rarely match ideal miles when dry, and it's normal to see an additional 10% usage with rain. More if you have to run the defrost like I did for part of yesterday.

This would be consistent with Consumer Reports, one of the few places that tests tires for their rolling resistance. They reported this tire to have both excellent gas mileage and outstanding performance, a rare combination.

I noticed these tires are about 3lbs lighter than the stock tires. I wonder how much of the range difference may be due to that. The lower the mass in the tire, the less energy required to spin it.

I think I'm going to give the MPSS tires a try for my next set unless I hear some compelling reason not to. So far it doesn't seem like there is only marginal down side if any. I also read in some of the reviews that they are quieter than the AD07/08 tires, so that would be a nice bonus as well. Too bad they don't have them for the fronts, as Michelin is running a sale with $70 off on a set of 4.

 

[strider]

Thanks for the review. I find it highly annoying that Lotus picked a tire size where only one manufacturer in the world made both front and rear tires sizes.

Toyo makes tires in Front (Sport) and Rear sizes.

 

[dsm363]

Toyo makes tires in Front (Sport) and Rear sizes.

Oh, didn't know that. I guess I only checked on Tirerack.com so that's good to know there is another option at least. Thanks.
I have a regular Roadster but with the sport wheels and suspension upgrade so it should work.