Now have some miles on new MPS tires-question....
10-17-2005, 10:26 PM
#1
Le Mans Master
Thread Starter
Now have some miles on new MPS tires-question....
I have 265/40/17 on the front & 315/30/18 on the rear of my 03Z06 w/ stock size chromies. These are NOT the PS2's!
I find that when I take curves at high speeds that these tires feel like they're letting go and are near their maximum grip.
I did get a new alignment after I installed them.
I went with these tires vs. the PS2's because I liked the tread pattern better & the #'s compared to the PS2's & stock F1's are negligible or so I thought.
When I tried the same maneuvers on the F1's, the tire feedback was as if I could have done it at another 20mph...I'd be scared to attempt the same thing at an additional 20mph on these tires. As it is, it's a little scary.
Any thoughts or similar experiences???
Ron
I find that when I take curves at high speeds that these tires feel like they're letting go and are near their maximum grip.
I did get a new alignment after I installed them.
I went with these tires vs. the PS2's because I liked the tread pattern better & the #'s compared to the PS2's & stock F1's are negligible or so I thought.
When I tried the same maneuvers on the F1's, the tire feedback was as if I could have done it at another 20mph...I'd be scared to attempt the same thing at an additional 20mph on these tires. As it is, it's a little scary.
Any thoughts or similar experiences???
Ron
Last edited by Dr.Ron; 10-20-2005 at 05:01 PM.
10-18-2005, 01:52 PM
#2
Former Vendor
that is not surprising at all since your tire size selection increased sidewall deflection rates and understeer tendencies
10-19-2005, 12:33 AM
#3
Le Mans Master
Thread Starter
Originally Posted by Luke@tirerack
that is not surprising at all since your tire size selection increased sidewall deflection rates and understeer tendencies
Thanks for the response Luke.
Ron
10-19-2005, 07:17 AM
#4
Race Director
Originally Posted by Dr.Ron
I have 265/45/17 on the front & 315/35/18 on the rear of my 03Z06 w/ stock size chromies. These are NOT the PS2's!
I find that when I take curves at high speeds that these tires feel like they're letting go and are near their maximum grip.
I did get a new alignment after I installed them.
I went with these tires vs. the PS2's because I liked the tread pattern better & the #'s compared to the PS2's & stock F1's are negligible or so I thought.
When I tried the same maneuvers on the F1's, the tire feedback was as if I could have done it at another 20mph...I'd be scared to attempt the same thing at an additional 20mph on these tires. As it is, it's a little scary.
Any thoughts or similar experiences???
Ron
I find that when I take curves at high speeds that these tires feel like they're letting go and are near their maximum grip.
I did get a new alignment after I installed them.
I went with these tires vs. the PS2's because I liked the tread pattern better & the #'s compared to the PS2's & stock F1's are negligible or so I thought.
When I tried the same maneuvers on the F1's, the tire feedback was as if I could have done it at another 20mph...I'd be scared to attempt the same thing at an additional 20mph on these tires. As it is, it's a little scary.
Any thoughts or similar experiences???
Ron
Each car/tire/driver WILL vary, play with your pressure first IMHE
10-19-2005, 09:23 PM
#5
Le Mans Master
Thread Starter
Originally Posted by ALLTHROTTLE&NOBOTTLE
Tire pressure will have a key effect on that as well............I find when doing that kind of fun..35 psi hot on all 4 has helped.
Each car/tire/driver WILL vary, play with your pressure first IMHE
Each car/tire/driver WILL vary, play with your pressure first IMHE
Ron
10-20-2005, 11:57 AM
#6
Melting Slicks
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Originally Posted by Dr.Ron
Why is that? I went wider on the rear & stayed stock in the front.
Thanks for the response Luke.
Ron
Thanks for the response Luke.
Ron
10-20-2005, 05:01 PM
#7
Le Mans Master
Thread Starter
Originally Posted by frank dupuy
I think the stock size tire is 265/40/17 not the 265/45/17 you listed as using.
OOps...Corrected typo. I did state stock sizes though...
Thanks!
Ron
10-21-2005, 01:02 AM
#8
Le Mans Master
Originally Posted by Dr.Ron
Why is that? I went wider on the rear & stayed stock in the front.
Thanks for the response Luke.
Ron
Thanks for the response Luke.
Ron
You have obviously changed the chassis dynamics insofar as altering the size of the rear tires, and their "working" relationship to the fronts. The 315 rear tires also have a higher sidewall than the 295s; yes I realize they're both 35 profile tires, but the sidewall has to be taller on the wider tire to maintain the ratio/proportion. With the bigger sidewall will come (all other things being equal) more deflection. You may also be on the fringe of tire size/rim width compatibility - I'm not sure what the Michelin's specs accomodate. Finally there is the question of construction, compounds, etc. - I would assume Luke should be more versed about this, given his job, then the rest of us, so I'll just say that this would play a role also (but how I don't know as this is relatively esoteric IMHO).
10-21-2005, 04:26 PM
#9
Le Mans Master
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Originally Posted by Dr.Ron
!
I find that when I take curves at high speeds that these tires feel like they're letting go and are near their maximum grip. As it is, it's a little scary. Any thoughts or similar experiences???
Ron
I find that when I take curves at high speeds that these tires feel like they're letting go and are near their maximum grip. As it is, it's a little scary. Any thoughts or similar experiences???
Ron
It was a very interesting experience to say the least.
My tires are 270/40/17 on all 4 corners and I was at 38lbs cold (perhaps I was over inflated)
Last edited by Mr. Peabody; 10-21-2005 at 04:31 PM.
10-21-2005, 10:30 PM
#10
Le Mans Master
Thread Starter
Originally Posted by wamara
Ron,
You have obviously changed the chassis dynamics insofar as altering the size of the rear tires, and their "working" relationship to the fronts. The 315 rear tires also have a higher sidewall than the 295s; yes I realize they're both 35 profile tires, but the sidewall has to be taller on the wider tire to maintain the ratio/proportion. With the bigger sidewall will come (all other things being equal) more deflection. You may also be on the fringe of tire size/rim width compatibility - I'm not sure what the Michelin's specs accomodate. Finally there is the question of construction, compounds, etc. - I would assume Luke should be more versed about this, given his job, then the rest of us, so I'll just say that this would play a role also (but how I don't know as this is relatively esoteric IMHO).
You have obviously changed the chassis dynamics insofar as altering the size of the rear tires, and their "working" relationship to the fronts. The 315 rear tires also have a higher sidewall than the 295s; yes I realize they're both 35 profile tires, but the sidewall has to be taller on the wider tire to maintain the ratio/proportion. With the bigger sidewall will come (all other things being equal) more deflection. You may also be on the fringe of tire size/rim width compatibility - I'm not sure what the Michelin's specs accomodate. Finally there is the question of construction, compounds, etc. - I would assume Luke should be more versed about this, given his job, then the rest of us, so I'll just say that this would play a role also (but how I don't know as this is relatively esoteric IMHO).
It's only evident on evasive steering wheel movements or taking turns/ramps at speeds your everyday driver wouldn't even attempt, so it's no REAL issue...I just know which tires I'll be buying next (returning to).
Thanks for the responses..Any & all comments are welcome.
Ron
10-26-2005, 05:10 PM
#11
Former Vendor
the problem iss not in the front ... it is in the rear ....
by running the wider rear tire you chose you have two things going on ...
#1.) by running a shorter tire out back than you should it has less sidewall deflection than the front which will cause a car to feel "twitchy" at the limit since the tires sidewalls will continually be loading and unloading at different rates with the road undulations
#2.) by having the rear tire that wide you are effectively forcing the front tire to work to hard which is basically the definition of "induced understeer"
by running the wider rear tire you chose you have two things going on ...
#1.) by running a shorter tire out back than you should it has less sidewall deflection than the front which will cause a car to feel "twitchy" at the limit since the tires sidewalls will continually be loading and unloading at different rates with the road undulations
#2.) by having the rear tire that wide you are effectively forcing the front tire to work to hard which is basically the definition of "induced understeer"
10-27-2005, 12:24 AM
#12
Le Mans Master
Thread Starter
Originally Posted by Luke@tirerack
the problem iss not in the front ... it is in the rear ....
by running the wider rear tire you chose you have two things going on ...
#1.) by running a shorter tire out back than you should it has less sidewall deflection than the front which will cause a car to feel "twitchy" at the limit since the tires sidewalls will continually be loading and unloading at different rates with the road undulations
#2.) by having the rear tire that wide you are effectively forcing the front tire to work to hard which is basically the definition of "induced understeer"
by running the wider rear tire you chose you have two things going on ...
#1.) by running a shorter tire out back than you should it has less sidewall deflection than the front which will cause a car to feel "twitchy" at the limit since the tires sidewalls will continually be loading and unloading at different rates with the road undulations
#2.) by having the rear tire that wide you are effectively forcing the front tire to work to hard which is basically the definition of "induced understeer"
Would the next size up on the fronts help (275/40/17)?
Thanks again!
Ron
10-28-2005, 09:09 AM
#13
Former Vendor
the wider tires would offer better traction but, since you only put them in the rear you will only see a benefit in a straight line .....
10-28-2005, 10:09 AM
#14
Le Mans Master
Thread Starter
Originally Posted by Luke@tirerack
the wider tires would offer better traction but, since you only put them in the rear you will only see a benefit in a straight line .....
Would the next size up on the fronts help (275/40/17)?
Ron
10-30-2005, 02:43 PM
#15
Le Mans Master
I had the exact same feeling when I was driving with my original GY run flats - like the car was always close to letting go. Maybe it was that those tires were stiff and would hop so much. Don't know.
Anyway, I changed over to GS-D3s and the hop and loose feeling went away. I feel a lot more confident driving. Plus now I can actually hear my radio.
Anyway, I changed over to GS-D3s and the hop and loose feeling went away. I feel a lot more confident driving. Plus now I can actually hear my radio.
