angel1368

iTrader: (1)

im currently on 40mm profile tyres and the arch gap looks pretty big and ride is very harsh so wondering going upto 45mm make much difference?

fat-thomas

iTrader: (4)

about 5mm difference

cookstar

iTrader: (6)

Or 5%

dazsti72

And they will look ****e..

kevfawcett

iTrader: (7)

As cookstar illuded to, the 40 profile is actaully a percentage of the tyre width not mm.

So a 225/40/18 will actually have a sidewall profile of 90mm or so

angel1368

iTrader: (1)

ahhh now i never knew that thank you Kev, i have 215,40,17 on and was told 225,45,17 would be better so was wondering if ive been told truth

kevfawcett

iTrader: (7)

That would be an increase of around 15mm tyre wall, which is a lot. That will also translate to a 15mm ride height gain. As well as that, your speedo will read around 5% different to what it does now.

What is the standard tyre size? you want to stick as close to that with the rolling radius as possible

ClassicEddie

The other way around maybe otherwise that'll be quite a difference in overall diameter. 40% of 215 is a 86mm side wall. 45% of 225 is a 101.25mm side wall = 15.25mm difference!

The difference between 215/45 and 225/40 is only 6.75mm. I think this would just about take out he 10% over-reading on the standard speedo so should read about right. In theory you'll see lower revs at cruising speed and slower acceleration but in reality you won't notice.

angel1368

iTrader: (1)

Thank you very much Eddie, if i swap them to 225,45,17 from the 214,40,17 thats on it should it look better?

ClassicEddie

That's a bit subjective really mate. It might be better to lower it and get some spacers if you're paranoid about the gap and filling the arch in a particular way. I think it will all detrimental to the driving characteristics though.

But, thinking about it, 15mm isn't really much. I'd just go with whatevers the cheapest fitment. Then you need to worry about what width yoru wheels can take...

kevfawcett

iTrader: (7)

I think you (or I) misunderstood what Eddie was saying. To go from a 215/40 to a 225/45 is a massive change in tyre size. Your speedo will be 5% different to what it currently reads. Are you sure your current tyres are 215/40?

Yeah, buy a 'performance' car then buy whatever is the cheapest size tyres to go on it, great advice. Also, quite a strange comment to make, considering you have just said lowering it will be detrimental to how it drives!?

angel1368

iTrader: (1)

Hi Kev yes i have just double checked and they are definatly 215,40,17 but as i say been told on these wheels i have it should be 225,45,17 car definatly looks abit wrong with these tyres

kevfawcett

iTrader: (7)

Yeah, they are far too small for them wheels and that car. The mistake was whoever put those tyres on in the 1st place. When you said you were told 225/45 "would be better", I didn't realise you meant because they were the standard size for the wheel. Like I said in a previous post, try and keep the rolling radius to the same size as the original. You can't get much closer than exactly the same

ditchmyster

iTrader: (7)

They are the wrong tyres for those wheels mate, I have the same wheels on mine at the moment and they want to be 225/45 17, your speedo will be right, it's currently wrong. 40 profile would be for 18's.

cookstar

iTrader: (6)

Looks like those wheels were previously fitted to a classic?

Have you bought them recently?

angel1368

iTrader: (1)

yes i have bought them recently but i saw them come off a blob, definatly wrong sixe though, if i put the right tyres on i shouldnt need to lower it should i?

The Trooper 1815

iTrader: (31)

If you have the wrong suspension set up (coilovers/stiffer springs/shortened springs) you may struggle to get any comfort. You may even compromise the driving capabilities of the car.