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      12-29-2010, 06:02 AM   #1
SteveChester
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Mixing RFT with non RFTS

To cut a long story short - need to replace rear tyres, front ones ok.

Sick of RFTS so I am buying two Falken 452.

I understand that you aren't suppose to mix RFT/NON RFTS but whats the deal with it?

Also where is the best place to get a compressor/tyreweld kit to put in the boot?

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      12-29-2010, 06:12 AM   #2
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i bought my car with RFT's on front and non-RFT's on the back. Handling was a pile of poo. Tendency to be unstable at high speed. Changed to non-rft's all round, world of difference, that's my opinion.
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      12-29-2010, 07:59 AM   #3
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Running non-RFT on rear, RFT on front, handling better than when all RFT as much less tramlinng.
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      12-29-2010, 08:06 AM   #4
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Mixing is definitely not recommended in the tyre industry. For all the obvious reasons of mismatched characteristics.

Remember there could also be insurance implications, if involved in an accident, as the industry does clearly state the reasons why not to mix RFTs with non RFTs, even axle wise.

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      12-29-2010, 09:48 AM   #5
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Quote:
Originally Posted by SteveChester View Post
To cut a long story short - need to replace rear tyres, front ones ok.

Sick of RFTS so I am buying two Falken 452.

I understand that you aren't suppose to mix RFT/NON RFTS but whats the deal with it?

Also where is the best place to get a compressor/tyreweld kit to put in the boot?

Steve.
I would change all four and sell the RFT's on ebay. There seems to be a market for them; can't imagine why.

A guy on the site bought a Continental mobility kit for a reasonable price. I typed in "mobility kit" and this came up:

http://cgi.ebay.co.uk/NEW-RENAULT-Co...item4aa761ae0f

Looks OK to me, however, to buy a compresser and sealant does not cost a fortune.

Have a look at this as well:

http://www.sospuncturerepair.co.uk/i...?info_id=68042
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      12-29-2010, 01:52 PM   #6
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Quote:
Originally Posted by Jeff123 View Post
I would change all four and sell the RFT's on ebay. There seems to be a market for them; can't imagine why.

A guy on the site bought a Continental mobility kit for a reasonable price. I typed in "mobility kit" and this came up:

http://cgi.ebay.co.uk/NEW-RENAULT-Co...item4aa761ae0f

Looks OK to me, however, to buy a compresser and sealant does not cost a fortune.

Have a look at this as well:

http://www.sospuncturerepair.co.uk/i...?info_id=68042
I was one of them.

The Conti mobility equipment is standard on Alpinas (RFT? of course not lol!)
and also standard in Mercs and new Fords.
Try a breakers for an unused item, or eBay as suggested.
Mine is from a Galaxy - 20.
You can buy replacement sealer cartridges.
The pump part can be used any time to inflate stuff too.
S.
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      12-29-2010, 03:44 PM   #7
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Quote:
Originally Posted by SteveChester View Post
To cut a long story short - need to replace rear tyres, front ones ok.

Sick of RFTS so I am buying two Falken 452.

I understand that you aren't suppose to mix RFT/NON RFTS but whats the deal with it?
Steve.
As said, change all four for sure, mixing is forbidden by tyre manufacturers and just not worth it on any car, let alone a decent one.

Sell the rfts on ebay, i got 150 for 2 front 18" rfts with 6mm on them.

Nationwide there are more BMW owners after part worn rfts than are looking to change to non rfts.
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      12-29-2010, 03:54 PM   #8
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Sell them all would be my recommendation.

Sold my front RFTs to ^^^ m1bjr I seem to recall - sold on here so you can avoid eBay fees & hassle, even if you could get a bit more for them. I think I got 100 for mine with 5-6mm?
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      01-02-2011, 08:03 PM   #9
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Quote:
Originally Posted by rup View Post
Running non-RFT on rear, RFT on front, handling better than when all RFT as much less tramlinng.
I too ran with this combination for a while and didn't have any problems at all. I eventually did replace the fronts to non-RFT but only because they wore out.

My only concern would be the insurance implications.
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      01-03-2011, 05:20 AM   #10
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sell the front rft's on fleabay, you will get quite a good price for them if they are in 6mm+ nick.

If they are worn below this then you won't get as good a price but still something.

Even if you only get enough to pay for 1 falken tyre form the sale, paying for the other tyre yourself will mean you have 8mm on both fronts so you aren't losing any money in the long run......

running different sets like this is seen as dangerous by some.
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      01-03-2011, 09:27 AM   #11
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Quote:
Originally Posted by RichardM View Post
I too ran with this combination for a while and didn't have any problems at all. I eventually did replace the fronts to non-RFT but only because they wore out.

My only concern would be the insurance implications.
As has been said, the 'on limit' characteristics would change (i.e. wet driving or earlier and unpredictable) and this is where I would be concerned.
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      01-03-2011, 05:45 PM   #12
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BMWs can really, really hate having different tyres on different axles, to the point where they are dangerous.
Problem is you never know which combo really doesn't work until you get them.
Don't risk it, just get 4 all round and sell the run flats on ebay.
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      01-03-2011, 07:57 PM   #13
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I was in the same boat as you my rfts at the rear needed replacing. I replaced them with non rfts this was ok at normal speeds but on the motorway or a decent road the handling went at speeds over 60. The rear wobbled and it felt horrible. Get all 4 changed at the same time, it will completely change the car, you will have so much grip and no tramlining.
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      01-04-2011, 08:12 AM   #14
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Quote:
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I was in the same boat as you my rfts at the rear needed replacing. I replaced them with non rfts this was ok at normal speeds but on the motorway or a decent road the handling went at speeds over 60. The rear wobbled and it felt horrible. Get all 4 changed at the same time, it will completely change the car, you will have so much grip and no tramlining.
Good to see an honest assessment, we do see a few comments which are more towards the "I can get away with it". Too big a risk if we want high safety factors. We've only got 4 little contact patches with the road, we need the best we can get.

gIzzE's comment is so valid as well, BMW cars can be very sensitive to the tyre set. gIzzE's got a lot of experience, so he know's what he's talking about.



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      01-04-2011, 08:28 AM   #15
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As a point of interest has anyone got a link to something authoritative which says they must not be mixed?
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      01-04-2011, 08:30 AM   #16
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All the tyre manufacturers said you should not mix RFTs with normal tyres when they first started really pushing them, not sure if it is still on their websites or not?
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      01-04-2011, 08:32 AM   #17
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I thought that was to do with (inadvertently) mounting RFTs on a non-RFT rim.
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      01-04-2011, 08:44 AM   #18
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Main thing when you do mix tyres is 'never' mix an asymmetrical tyre with a symmetrical tyre, this is when BMWs throw a real wobbly, more so than mixing say a Michelin Pilot Sport ZP with a Michelin Pilot Sport 2, which have the same tread just different compounds.

The worse case I have experienced is with a Michelin Pilot Sport 2 on the rear and a Michelin Pilot Sport 1 on the front, I thought the car was knackered, 3 techs also through the car was knackered, they replaced front wishbones, rear trailing arm bushes, top mounts and rear suspension and still no better.
Then somone who races CSLs took it out, we pulled off the roundabout and took the first corner and he looked at me and said "You've got mixed tyres on this!!"
To which I replied "Nope, they're all Michelin Pilot Sports."
We got out and that was the first time I had clicked that the fronts were 1's and the rears 2's. Put 2s on the front and everything was perfect again.

I think as the car gets more powerful it starts to show how bad mixing tyres can be, I spent a week with run flats on the front of my 320d touring and Michelin Pilot Sport 2s on the rear and that was not bad unless I pushed it in the wet, but generally not enough grunt to make the back snap out, but still noticed that it was not 100% planted sat at motorway speeds. The CSL put the back end out overtaking on the motorway at 60mph, that is how much it affected that car.


I just don't see why anyone would buy a BMW and then put mixed tyres on it?? It turns a great car into something a bit shit.
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      01-04-2011, 08:45 AM   #19
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Quote:
Originally Posted by xenon View Post
I thought that was to do with (inadvertently) mounting RFTs on a non-RFT rim.

No, they explained that the run flat compound is a much harder compound and it changed the grip levels of each axle, which is never a good thing.
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      01-04-2011, 08:45 AM   #20
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I just don't see why anyone would buy a BMW and then put mixed tyres on it?? It turns a great car into something a bit shit.
I'm not advocating that you should - I just wondered if there was anything definite (i.e. from an insurance perspective) which says you must not.
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      01-04-2011, 09:08 AM   #21
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http://www.national.co.uk/informatio...lat-tyres.aspx

Mixing run flat tyres with standard tyres - The handling characteristics of run flat tyres are different to those of conventional tyres and therefore should not be intermixed on a vehicle.
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      01-04-2011, 09:09 AM   #22
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Quote:
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I'm not advocating that you should - I just wondered if there was anything definite (i.e. from an insurance perspective) which says you must not.
You need to call your insurer anyway if your came with run flats and you put normal tyres on. They will do whatever they can to get out of paying you.
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