Mixing normal and RFTs

[Big Bad Boris]

I am viewing potential purchases at present. One of them appears to have 3 run flats and a 1 normal tyre (car got a puncture and the shop had no RFTs in stock). How big an issue is mixing RFTs with non RFTs on the same axle?

Obviously the thing to do is ditch the other 3 ASAP. But it isn’t my car !

 

[brillomaster]

its preferable to have either runflats or non run flats all round, though at the very least the tyres on the same axle should be the same.

though again, i did trackdays for years with all different tyres, and didnt die. the only time i noticed a problem was when the rear left was a budget ditchfinder, and the rear right was a conti sport contact... that did get a bit twitchy when braking hard.

but i wouldnt let it put you off buying, just budget for at least 1 new tyre so that you're matching across the axle.

 

[Anonymous]

Its technically illegal to have any combination of runflats and normal tyres, either across axles or even front and rear pairs

 

[brillomaster]

Do you have a link to the legislation? I only thought mixing cross plys with radials was actually illegal, and everything else is just guidance...

 

[scootr]

Ask the seller to discount the cost of the correct tire. You seriously want all the tires the same on a a sports car. As a kid I mixed radials with non radials and spun out in the rain rather easily Mixed tires will have different traction and breaking limits etc.
When I purchased my Zed the tires were all run flats but mismatched pairs. The dealer discounted the car 400usd for replacement. I put the money towards a set of Michelin PS4 and couldn't be happier.

 

[buzyg]

As the other have said. Don't mix them. You might be able to sell them on in two's if they are in good condition.

 

[mmm-five]

As the other have said. Don't mix them. You might be able to sell them on in two's if they are in good condition.

Not when there's 3 x RFT, and 1 x non-RFT

 

[mmm-five]

Do you have a link to the legislation? I only thought mixing cross plys with radials was actually illegal, and everything else is just guidance...

This is all I can find...

http://www.legislation.gov.uk/uksi/1986/1078/regulation/26/made

I try to keep the same tyre all round - and if I can't, I will at least keep to the same performance level & manufacturer (so a Michelin Supersport and/or a PS4/PS4S if I must).

 

[brillomaster]

Do you have a link to the legislation? I only thought mixing cross plys with radials was actually illegal, and everything else is just guidance...

This is all I can find...

http://www.legislation.gov.uk/uksi/1986/1078/regulation/26/made

I try to keep the same tyre all round - and if I can't, I will at least keep to the same performance level & manufacturer (so a Michelin Supersport and/or a PS4/PS4S if I must).

Yes, and furthermore, the government website specifically states that 'Run flat and conventional tyres can be mixed on the same axle, although this is not recommended'

https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles/5-axles-wheels-tyres-and-suspension#section-5-2-3

So yes, while it is not recommended, and i don't recommend it myself, it is perfectly legal to mix run flats and non run flat tyres, even on the same axle.

 

[mr wilks]

Do you have a link to the legislation? I only thought mixing cross plys with radials was actually illegal, and everything else is just guidance...

This is all I can find...

http://www.legislation.gov.uk/uksi/1986/1078/regulation/26/made

I try to keep the same tyre all round - and if I can't, I will at least keep to the same performance level & manufacturer (so a Michelin Supersport and/or a PS4/PS4S if I must).

Yes, and furthermore, the government website specifically states that 'Run flat and conventional tyres can be mixed on the same axle, although this is not recommended'

https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles/5-axles-wheels-tyres-and-suspension#section-5-2-3

So yes, while it is not recommended, and i don't recommend it myself, it is perfectly legal to mix run flats and non run flat tyres, even on the same axle.

My thoughts too., it's frowned on & obviously not ideal but isn't a Mot fail to have a pair of runflats on same axle & a pair of non runflats the other axle.
If it was a fail then I suspect this forum would be riddled with tales of Mot woes & I can't recall one single member having been pulled up for it.

 

[Anonymous]

To be pedantic illegal is made of many factors..

If the manufacturer of the tyre says its not approved (which most do) then its a legal fail under this

"Tyres
Passenger vehicles and trailers must be fitted with pneumatic tyres. Recut tyres may be fitted only to passenger vehicles that are also “heavy motor cars”.

No vehicle or trailer may be used on the roads when fitted with a pneumatic tyre if:

the tyre is unsuitable for the use to which the vehicle or trailer is being put or to the types of tyres fitted to the other wheels"

The tyre manufacturer ergo has said its not suitable..

Now how enforcebale / how much effort the police would put into it is another matter..

The good news is that if you maimed someone in an accident and tyres MAY have had an impact you can bet your insurance compnay is going to say byeeee!

 

[mr wilks]

To be pedantic illegal is made of many factors..


The good news is that if you maimed someone in an accident and tyres MAY have had an impact you can bet your insurance compnay is going to say byeeee!

That old one :roll: how about a crash with dirty windscreen & empty washer bottle or faulty heater that won't de-mist etc etc.
You can conjure up endless scenarios like that Re insurance companies but the bottom line being if all 4 tyres are in good order, decent tread & the car has mot then it's highly improbable they would fail a claim on that basis providing the same sort of tyre is fitted to the same axle.

 

[Anonymous]

We come from different sides of the street, having spent many weeks with lawyers and insurance companies on litigation I'm not suprised how they try and get out of things..

However I do agree, statistically its more remote..but that was not what the question was..

The question should have been ' is it good practice?'

Or is there any legal basis?

I've moved from riding a Laverda 1200 in T shirt /running shorts / bare sandals through high speed concrete tunnels to a risk averse is there anything remotely incorrect approach..civil aviation operations and airworthiness management has strange side effects..

 

[buzyg]

As the other have said. Don't mix them. You might be able to sell them on in two's if they are in good condition.

Not when there's 3 x RFT, and 1 x non-RFT

Well if it's a question of expense then another run flat to match the 3 existing. Then ware them out. Then replace with normal tyres. Other wise ditch the run flats and replace with normal tyres now.

Personally whatever the rules say, there is no way I would run different tyres across an axle on a sports car. But if your just commuting to work and back I guess it makes bugger all difference. Your only ever going to find out if it works at the limit of grip on one of the tyres. :|

 

[Mister T]

Its technically illegal to have any combination of runflats and normal tyres, either across axles or even front and rear pairs

Where did you get that information from?

Even Michelin state that it is permitted (albeit temporarily):

Can I mix run flat tires with normal tires?
Never mix run flat tires with tires that do not have run flat technology (conventional tires) - unless in an emergency situation on a limited, temporary basis. The conventional tire should be replaced with a run flat tire as soon as possible.
It is also not recommended to mix different run flat technologies/products together.

 

[mmm-five]

The tyre manufacturer ergo has said its not suitable..

Does every manufacturer stipulate that mixing them is forbidden, or just not recommended?

Michelin also state you must not put different RFTs on different axles - so no mixing manufacturers, nor different models from the same manufacturer. I assume they want you to buy 4 when your front/rear size is NLA

 

[Big Bad Boris]

Thanks all, looks like I kicked off a decent debate.

However, the car in question sold this morning. It only came on the market yesterday, nice low mileage 30i at a good price, I immediately contacted the seller, we exchanged Emails last night and I thought for once I’d spotted a good one and got in quick enough.

I was planning to make the 4+ hour journey down to Bournemouth tomorrow to view and buy, he sent me copies of the service history etc this morning, everything good. He then sent me an Email about 10 minutes later saying he’d just sold it to a local dealer, Aaaargh, not again.

So no doubt I’ll be able to buy the same car in a few days with 3 new tyres a cheap as chips warranty and a £2-3k higher price tag. It’s really annoying, every low mileage 30i that comes seems immediately to be snapped up by a dealer who does little to the car other than lump up the price. OK as you were rant over.

 

[Anonymous]

Its technically illegal to have any combination of runflats and normal tyres, either across axles or even front and rear pairs

Where did you get that information from?

Even Michelin state that it is permitted (albeit temporarily):

Can I mix run flat tires with normal tires?
Never mix run flat tires with tires that do not have run flat technology (conventional tires) - unless in an emergency situation on a limited, temporary basis. The conventional tire should be replaced with a run flat tire as soon as possible.
It is also not recommended to mix different run flat technologies/products together.

Mister T, I clipped the piece off the Construction and Use regulations that gives dispensation for temp tyre placement..the OP wasn’t asking that question..temporary is normally regarded as max 80km..

Continental clearly state that it is not permissible..

The reverse question is probably more appropriate..show me a tyre manufacture that recommends or approves mixed axle or mixed construction across axles please?

 

[Anonymous]

The tyre manufacturer ergo has said its not suitable..

Does every manufacturer stipulate that mixing them is forbidden, or just not recommended?

Michelin also state you must not put different RFTs on different axles - so no mixing manufacturers, nor different models from the same manufacturer. I assume they want you to buy 4 when your front/rear size is NLA

I just used Continental..couldn’t be that interested to do a poll of every tyre manufacturer..an EU premium manufacturer is good enough for me..

 

[Anonymous]

Thanks all, looks like I kicked off a decent debate.

However, the car in question sold this morning. It only came on the market yesterday, nice low mileage 30i at a good price, I immediately contacted the seller, we exchanged Emails last night and I thought for once I’d spotted a good one and got in quick enough.

I was planning to make the 4+ hour journey down to Bournemouth tomorrow to view and buy, he sent me copies of the service history etc this morning, everything good. He then sent me an Email about 10 minutes later saying he’d just sold it to a local dealer, Aaaargh, not again.

So no doubt I’ll be able to buy the same car in a few days with 3 new tyres a cheap as chips warranty and a £2-3k higher price tag. It’s really annoying, every low mileage 30i that comes seems immediately to be snapped up by a dealer who does little to the car other than lump up the price. OK as you were rant over.

It is strange..I’ve seen recently a number of sensibly priced ‘toys’ fly off the shelves PDQ..good luck with the hunt..