Basic mix'n match question from a newbie...
07-17-2001, 09:06 AM
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Basic mix'n match question from a newbie...
I have a 1990 carrera 4 for about 3 weeks and managed to get a flat rear offside tyre on the M25 in London, UK at the weekend.
Took it to a tyre shop and they put on a pair of 255x40x17 Conti Sport Contact N0s, and said there were no problems with keeping the Michelin Mxx3 NOs on the front for a few thousand miles until they need replacing.
Seems to drive OK - I'm not racing or anything, just street use, but wondered if this combination is OK or if I should get the fronts changed to the Conti as well?
Ta
Brad
Took it to a tyre shop and they put on a pair of 255x40x17 Conti Sport Contact N0s, and said there were no problems with keeping the Michelin Mxx3 NOs on the front for a few thousand miles until they need replacing.
Seems to drive OK - I'm not racing or anything, just street use, but wondered if this combination is OK or if I should get the fronts changed to the Conti as well?
Ta
Brad
07-19-2001, 04:45 AM
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Dear Brad,
Mixing tyres is not a good idea on a C4 for the following reasons.
You are only allowed a 6% differential in tyre dimensions FROM ORIGINAL. If you start getting PDAS/ABS warn lights coming on whilst driving, guess what, the mix does not work.
Mixing tyres can adversely affect handling on the C4. I have personally tested this and I found one mix that did work but not your mix because I have never used these tyres.
The difference in tread patterns can induce some strange vibrations, especially at the front.
The fact that they are of the same rating helps but drive on this combination for a while and when you go back to the all same brand mix, then you will say, boy what a difference.
Only a C4 owner really knows Brad, through trial and error. You will learn the same way. It is fun though and you can share your results.
Yes you should worry about it at first and work it out because of the 6% differential. This is in your owners manual by the way.
For low speed road use I think you will not have any problems but the grip differential will play a role in handling when you really need it and the understeer may be somewhat increased when the traction control kicks in. The different grip abilities of the different brands plays a significant role here. I know many people who have mixed and matched. In general it is not a good idea and should be avoided unless using a tested set up. Maybe you could REALLY test this set up and share your findings with the board.
When owning a C4 it is a good idea to follow these basic rules,
4 tyres same brand
4 tyres same N rating or 4 tyres without N rating if you so choose (not my choice but not to be discounted)
4 tyres with similar tread patterns
4 tyres each less than 4 years old.
I speak from some experience in this matter,
Ciao,
Adrian
911C4
PS: I know of people running the Contis and they like them, I also know people running these Michelins and they like them. Do not know anyone running a mixed combination. The mixed combo I tested and was brilliant was
Yoko A008P (N0 rated)up front and Yoko AVS Assymetrics (N0 rated) on the rear. Tread pattern was similar. This combo also works well on the 964 Turbo (3.3).
Adrian
Mixing tyres is not a good idea on a C4 for the following reasons.
You are only allowed a 6% differential in tyre dimensions FROM ORIGINAL. If you start getting PDAS/ABS warn lights coming on whilst driving, guess what, the mix does not work.
Mixing tyres can adversely affect handling on the C4. I have personally tested this and I found one mix that did work but not your mix because I have never used these tyres.
The difference in tread patterns can induce some strange vibrations, especially at the front.
The fact that they are of the same rating helps but drive on this combination for a while and when you go back to the all same brand mix, then you will say, boy what a difference.
Only a C4 owner really knows Brad, through trial and error. You will learn the same way. It is fun though and you can share your results.
Yes you should worry about it at first and work it out because of the 6% differential. This is in your owners manual by the way.
For low speed road use I think you will not have any problems but the grip differential will play a role in handling when you really need it and the understeer may be somewhat increased when the traction control kicks in. The different grip abilities of the different brands plays a significant role here. I know many people who have mixed and matched. In general it is not a good idea and should be avoided unless using a tested set up. Maybe you could REALLY test this set up and share your findings with the board.
When owning a C4 it is a good idea to follow these basic rules,
4 tyres same brand
4 tyres same N rating or 4 tyres without N rating if you so choose (not my choice but not to be discounted)
4 tyres with similar tread patterns
4 tyres each less than 4 years old.
I speak from some experience in this matter,
Ciao,
Adrian
911C4
PS: I know of people running the Contis and they like them, I also know people running these Michelins and they like them. Do not know anyone running a mixed combination. The mixed combo I tested and was brilliant was
Yoko A008P (N0 rated)up front and Yoko AVS Assymetrics (N0 rated) on the rear. Tread pattern was similar. This combo also works well on the 964 Turbo (3.3).
Adrian
07-19-2001, 04:54 AM
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I'll treat it as an experiment, then! Got a good run out to a Porsche rally in the UK at the weekend, and I'll see what happens on that.
The tyres are all N0, and have very similar tread patterns, so hopefully no major dramas.
PS - what's PDAS? I'm not yet up on the 911 lingo!!
The tyres are all N0, and have very similar tread patterns, so hopefully no major dramas.
PS - what's PDAS? I'm not yet up on the 911 lingo!!
07-19-2001, 10:20 PM
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Brad,
There are several posts by Adrian regarding PDAS/ABS on the tech.rennlist.com site that might help answer your question. You can also search on the www.rennlist.com email site for more of Adrian's informative posts.
There are several posts by Adrian regarding PDAS/ABS on the tech.rennlist.com site that might help answer your question. You can also search on the www.rennlist.com email site for more of Adrian's informative posts.
07-27-2001, 03:59 PM
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Adrian,
Im new to Porsche, having just bought a 1990 C4 i found the abs light coming on for no reason, also the light above the 4 wheel drive selector in the centre console would come on and stayed on for a while. I mention this as the car is imported from switzerland and still has a set of winter tyres on, could these be the cause of my problems? I have been meaning to change them but keep finding other things taking priority(such as suspension,brakes ect). Also the tyres have stacks of tread left.Am i going to notice the differance with a decent set of tyres on? i intend to change from 16" to 17" or 18",any ideas........which size is best?
Im new to Porsche, having just bought a 1990 C4 i found the abs light coming on for no reason, also the light above the 4 wheel drive selector in the centre console would come on and stayed on for a while. I mention this as the car is imported from switzerland and still has a set of winter tyres on, could these be the cause of my problems? I have been meaning to change them but keep finding other things taking priority(such as suspension,brakes ect). Also the tyres have stacks of tread left.Am i going to notice the differance with a decent set of tyres on? i intend to change from 16" to 17" or 18",any ideas........which size is best?
07-30-2001, 07:38 AM
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Dear Ian,
You are really going to have to split up this question for me.
Which lights are coming on. The ABS light cannot come on, on its own. The PDAS light has to come on with it.
There is no such thing as a 4WD selector. The AWD is mechanical and permanent. The **** on the centre console selects the traction control program. Locks all your wheels together. You will have to purchase my book when it is finished.
Winter tyres of the incorrect profile can cause some problems yes.
17 inch wheels are the best all round size wheels for the 964s in summer and 16 inch in winter. 18 inch wheels are not approved for installation on the 964 C4 and they will more than liekly take you over the 6% diferential limit. Again will be explained in my book,
Ciao,
Adrian
911C4
You are really going to have to split up this question for me.
Which lights are coming on. The ABS light cannot come on, on its own. The PDAS light has to come on with it.
There is no such thing as a 4WD selector. The AWD is mechanical and permanent. The **** on the centre console selects the traction control program. Locks all your wheels together. You will have to purchase my book when it is finished.
Winter tyres of the incorrect profile can cause some problems yes.
17 inch wheels are the best all round size wheels for the 964s in summer and 16 inch in winter. 18 inch wheels are not approved for installation on the 964 C4 and they will more than liekly take you over the 6% diferential limit. Again will be explained in my book,
Ciao,
Adrian
911C4
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07-30-2001, 02:56 PM
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I plan to get a set of 17" genuine porsche cup alloys in the next couple of weeks,I have been told i need N rated tyres and i cant put any make on ( this seems to restrict me to Bridgestone,Conti's and P7000's) is this true or can i choose some like Fulda or Goodyear?
Since i found this forum last week ive posted 3 Questions, and you have answered them all!! If i dont know everything that you do by the time your book comes out(due to me asking and you answering) i'll have a copy!
Regards and thanks again
Ian
Since i found this forum last week ive posted 3 Questions, and you have answered them all!! If i dont know everything that you do by the time your book comes out(due to me asking and you answering) i'll have a copy!
Regards and thanks again
Ian
08-01-2001, 04:10 AM
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Iant
You've got exactly the same problem with warning lights as I had - and yes, Adrian came to my rescue - I WANT THE BOOK!!!!
In my case, a change of brake fluid cured the warning lights once and for all.
Cheers
Brad
You've got exactly the same problem with warning lights as I had - and yes, Adrian came to my rescue - I WANT THE BOOK!!!!
In my case, a change of brake fluid cured the warning lights once and for all.
Cheers
Brad
08-01-2001, 05:18 AM
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Dear Ian,
I always recommend you use N rated or Porsche specification tyres. However you do not have to. It is your choice. Cheap tyres make for cheap handling as well. Hard and long wearing tyres make for let us say, less than adequate handling. Actually cheap tyres waste much of the fun you can have in a 964 but it is up to you of course.
There are a number of companies selling Porsche Spec or N rated tyres. Bridgestone, Pirelli, Yokohama, Continental, Dunlop, Goodyear. I am sure I forgotten a couple.
Kumho also make a good range of tyres.
What you want to do with this 964 Ian is really what is going to determine the tyres you get.
For 16 inch wheels I recommend Bridgestone SO2 Potenzas (N3).
For 17 inch wheels I recommend on the front Yokohama A008P (N0) and on the rear Yokohama AVS Assymetrics (N0). Technically this is a mix and match but these tyres are so similar in design it really does not count too much they are different model numbers. This combination has been tested on the 911C4 and 911 Turbo.
Ciao,
Adrian
911C4
I always recommend you use N rated or Porsche specification tyres. However you do not have to. It is your choice. Cheap tyres make for cheap handling as well. Hard and long wearing tyres make for let us say, less than adequate handling. Actually cheap tyres waste much of the fun you can have in a 964 but it is up to you of course.
There are a number of companies selling Porsche Spec or N rated tyres. Bridgestone, Pirelli, Yokohama, Continental, Dunlop, Goodyear. I am sure I forgotten a couple.
Kumho also make a good range of tyres.
What you want to do with this 964 Ian is really what is going to determine the tyres you get.
For 16 inch wheels I recommend Bridgestone SO2 Potenzas (N3).
For 17 inch wheels I recommend on the front Yokohama A008P (N0) and on the rear Yokohama AVS Assymetrics (N0). Technically this is a mix and match but these tyres are so similar in design it really does not count too much they are different model numbers. This combination has been tested on the 911C4 and 911 Turbo.
Ciao,
Adrian
911C4