Tyre pressure issue

[Dragonslock]

Hi all

so I have a Mk3 Leon FR but I can’t figure out my tyre pressures.

so I do have different tyres than it should have on it. I should have 225/40/R18 but when I got the car it had 225/45R18’s on it.

I have stuck with the 45’s rather than the 40’s but as it’s not a conventional tyre to hae on the car I can’t figure out what pressures I should be set to.

at the moment I have set 36 PSI (2.5 bar) front and 33 PSI (2.3 bar) rear

thanks

 

[RUM4MO]

I'd always worry about fitting an alternative tyre size to any car I have, these cars have been homologated with a only a few different sizes of tyres and your insurance company will be aware of that, have you informed that that your car has a non preferred size of tyres on it, I think that you should check up, better now than finding out that they get unreasonable after you need to make a claim.

In reality, there is probably nothing wrong with using that size of tyre, but it sounds like it is not a preferred size for this car and that is the bit that could cause you trouble.

Many of us run cars that unfortunately have expensive sized tyres, but that does not give us carte blanche to make our spending cheaper by fitting a cheaper sized tyre.

 

[Mr Pig]

I'd put the correct tyres on it and solve all your problems.

 

[SRGTD]

I'd always worry about fitting an alternative tyre size to any car I have, these cars have been homologated with a only a few different sizes of tyres and your insurance company will be aware of that, have you informed that that your car has a non preferred size of tyres on it, I think that you should check up, better now than finding out that they get unreasonable after you need to make a claim.

In reality, there is probably nothing wrong with using that size of tyre, but it sounds like it is not a preferred size for this car and that is the bit that could cause you trouble.

Many of us run cars that unfortunately have expensive sized tyres, but that does not give us carte blanche to make our spending cheaper by fitting a cheaper sized tyre.

I had a very similar discussion a while back with a member on a VW forum who’d fitted a set of different sized tyres to their car because they were cheaper than the original tyres fitted by VW on the production line. I was pretty much laughed at when I suggested they ought to inform their insurance company - their view was that they were only one size different and the insurance company wouldn‘t care. IMO fitting different sized tyres to factory spec is technically a modification and as you‘ve said, better to check now rather than finding out an insurance company gets difficult in the event of a claim.

When I fitted replacement wheels to my car last year, I took the opportunity to replace the factory Bridgestone tyres. They were replaced by a set of Michelin PS4 of exactly the same size and spec as the factory originals.

 

[Glosphil]

My 2018 Leon 1.4TSi (150) has covered 20k miles on its 225/40-18 tyres & the tyres are wearing evenly on 33/31 pressures. As the pressures are the same on a friend's FR on 225/45-17 tyres that should also suit your car.
Definitely inform your insurer you are running non-standard tyres. Your speedo will also be slightly under-reading.

 

[Dragonslock]

I'd always worry about fitting an alternative tyre size to any car I have, these cars have been homologated with a only a few different sizes of tyres and your insurance company will be aware of that, have you informed that that your car has a non preferred size of tyres on it, I think that you should check up, better now than finding out that they get unreasonable after you need to make a claim.

In reality, there is probably nothing wrong with using that size of tyre, but it sounds like it is not a preferred size for this car and that is the bit that could cause you trouble.

Many of us run cars that unfortunately have expensive sized tyres, but that does not give us carte blanche to make our spending cheaper by fitting a cheaper sized tyre.

I understand your message but two things.

I didn’t option to put the new tyre on it was only over the last few days that I found out that they were the wrong size. The garage that has done tyres for me before didn’t notice either.

In reference to having “ carte blanche” to put cheaper tyres on, that comment just doesn’t work when a 225/45 is running at near £30 a tyre more expensive than the tyres that should be on the car.

thanks for replying though and I’ll look at the insurance thing

 

[Dragonslock]

My 2018 Leon 1.4TSi (150) has covered 20k miles on its 225/40-18 tyres & the tyres are wearing evenly on 33/31 pressures. As the pressures are the same on a friend's FR on 225/45-17 tyres that should also suit your car.
Definitely inform your insurer you are running non-standard tyres. Your speedo will also be slightly under-reading.

Cheers very much.

I shall have a look at that. I think when they came from the garage they had like 38 PSI at the front which seemed excessive

 

[Dragonslock]

I had a very similar discussion a while back with a member on a VW forum who’d fitted a set of different sized tyres to their car because they were cheaper than the original tyres fitted by VW on the production line. I was pretty much laughed at when I suggested they ought to inform their insurance company - their view was that they were only one size different and the insurance company wouldn‘t care. IMO fitting different sized tyres to factory spec is technically a modification and as you‘ve said, better to check now rather than finding out an insurance company gets difficult in the event of a claim.

When I fitted replacement wheels to my car last year, I took the opportunity to replace the factory Bridgestone tyres. They were replaced by a set of Michelin PS4 of exactly the same size and spec as the factory originals.

Thanks for the reply but I haven’t opted for cheaper tyres.

the bigger profile tyre runs at £30 ish more a tyre.

it’s only the profile of the tyre wall that is larger but I will look at the insurance thing

 

[Mr Pig]

In reference to having “ carte blanche” to put cheaper tyres on, that comment just doesn’t work when a 225/45 is running at near £30 a tyre more expensive than the tyres that should be on the car.

I think he was meaning people in general, not you. But you are correct. The right tyre size for your car is a common size and tyres prices are good. My son has an Ibiza with 17'' alloys and my daughter a Toledo with 16'' alloys and both of those have uncommon tyre sizes. The same tyres on those cars are much more expensive. When I looked at tyres for my son's car good ones were as much as forty pounds more per tyre, for a smaller size.

 

[Dragonslock]

I think he was meaning people in general, not you. But you are correct. The right tyre size for your car is a common size and tyres prices are good. My son has an Ibiza with 17'' alloys and my daughter a Toledo with 16'' alloys and both of those have uncommon tyre sizes. The same tyres on those cars are much more expensive. When I looked at tyres for my son's car good ones were as much as forty pounds more per tyre, for a smaller size.

Yeh,

I get that people do try and go for cheaper alternatives for cars in general.

I’m not that type of person though. It’s more about durability and wear for me. When I spoke to the garage about the different profile and looking around all the difference a 45 over a 40 would really make is a more comfortable ride due to the higher profiling of the tyre but it would increase my ride bight and have a slight impact on handling. I didn’t think that it would probably knock the speedo off a bit but I’m ok with that

it’s just trying to work out which pressures to go for

 

[Mr Pig]

It’s only the profile of the tyre wall that is larger but I will look at the insurance thing

It was a common thing years ago. Lots of boy racers put odd sized tyres on their cars. They either wanted to fill the arches or lower the car.

It definitely can cause you bother because it changes the spec of the car. The spedo will be out but the car will also accelerate a little better on smaller tyres. I'm pretty certain your insurance company will grumble about it. We put winter tyres on the car and they asked me if the tyres were the same size and speed rating as the spec for the car. Even then I had to call them twice a year and notify them that I'd changed the tyres over. Eventually they said I didn't need to call, they would just make a record that I was doing it.

They're not that bothered about chasing you up on these things, the onus is all on you. You can mod the heck out of your car, don't tell them and what do they care? They get your money but if you crash? They inspect your car and if it's not right, they can just walk away. So win win. They get your money put don't have to pay out. You do not feck with these people!

 

[martin j.]

I’d start the tyres at the standard recommended pressures and see how it feels, her car now has Uniroyals fitted rather than the oe offerings, we are now 3 psi over the unloaded setting and the car feels better, tyres wearing evenly and temps stable across the tread.

 

[RUM4MO]

I can still remember when our new next door neighbour's son drove into the rear of my wife's Fiesta 1.6SI 2 days after we moved house, his(mother's) insurer's assessor spent 20 minutes checking all the tyres for sizes, pressure, wear and general condition, same for the brakes and searching under the bonnet - and only gave the damaged area a 2 minute look over - and that was for an accident where the "not to blame" party's car was stationary at a roundabout and was driven into accidentally by a young driver that misinterpreted the wet condition of the road. Any "get out of jail" ticket works for them.

 

[KXL]

I normally put the PSIs at the higher end of the recommended pressures for (3 passenger some luggage), and realease air my way down where necesary. I have one of those portable tyre pressure things. Easier to release air (it's free) than to put air which needs a trip to the fuel stn. I usually end up settling between 'comfort' and 'Eco' pressures. Usually in the mid 30s PSI.

 

[SamM2342]

I'm a tyre guy I'd definitely agree insurance if there's an accident could be dodgy I know if it was Ireland and you had accident and didn't tell them your tyres were wrong size they'd assess they accident and your car see that and just say giid luck... So your car is modified you've got to tell the insurance as side from all the other possible problems tyre pressure I would go around 38 psi maybe even 40 there not a small tyre...

 

[SuperV8]

Hi all

so I have a Mk3 Leon FR but I can’t figure out my tyre pressures.

so I do have different tyres than it should have on it. I should have 225/40/R18 but when I got the car it had 225/45R18’s on it.

I have stuck with the 45’s rather than the 40’s but as it’s not a conventional tyre to hae on the car I can’t figure out what pressures I should be set to.

at the moment I have set 36 PSI (2.5 bar) front and 33 PSI (2.3 bar) rear

thanks

I would start at the standard pressures, and maybe have a play around + & - a few PSI to see how it feels.

you may find this interesting regarding pressures/sizes & contact patches:

AutoSpeed - Tyres, Grip and All That...

 

[SamM2342]

I'd go 36psi all around