Technical 18" alloys 225 width any probs??

[Steely]

Just a quick one,

looking at some 18" alloys... matt black

tire size being EDIT 225/40/18

fit to my stilo 1.6 5 door...

it already has 15" fiats which are 195 width...


any problems that i should know about ...

they are fitment 4x100 so going to have to use wobblys..

cheers

 

[ChrisMClark]

it already has 15" fiats which are 195 width...

What's the second digit in the tyre size, IE: 195/??/R15

There's a really handy calculator here. You should try and keep the rolling radius +/- 2.5% or it could really screw your speedo readings up. Also if you go to large with your wheels then you'll actually kill performance as it'll take more power to get the wheels moving, it's all to do with intertia etc. Have a shufty at it, any more questions post 'em up.

 

[Steely]

What's the second digit in the tyre size, IE: 195/??/R15

There's a really handy calculator here. You should try and keep the rolling radius +/- 2.5% or it could really screw your speedo readings up. Also if you go to large with your wheels then you'll actually kill performance as it'll take more power to get the wheels moving, it's all to do with intertia etc. Have a shufty at it, any more questions post 'em up.

ones fitted are 195/65/15...

ones im after are 225/40/18

(edit 40) .48 % difference.. so should be ok... cheers



cheers

 

[ChrisMClark]

Don't know if you used that calc Steely, but if you did you'll see you;ve got a difference in rolling radius of 3.97%, with means when your speedo reads 70, you're actually doing closer to 74. Doesn't sound much, but if you imagine going up a dual carriageway doing that extra little bit over 70, then imagine what that extra little bit will actually be when you're already doing 74, then imagine going through a gatso...see what I'm saying? I've got 17's with 215/45 and they look fine. See my gallery for pics.

EDIT: DOH! put in 45 instead of 40 lmao, so disregard what I said. I'll leave it there though, for anyone else who's interested lol.

 

[Steely]

Don't know if you used that calc Steely, but if you did you'll see you;ve got a difference in rolling radius of 3.97%, with means when your speedo reads 70, you're actually doing closer to 74. Doesn't sound much, but if you imagine going up a dual carriageway doing that extra little bit over 70, then imagine what that extra little bit will actually be when you're already doing 74, then imagine going through a gatso...see what I'm saying? I've got 17's with 215/45 and they look fine. See my gallery for pics.

EDIT: DOH! put in 45 instead of 40 lmao, so disregard what I said. I'll leave it there though, for anyone else who's interested lol.

my bad.... i put 45 in the first post,. im good at confusing people... cheers for the advice !!

 

[bozzy]

My concern here would be turning 18" wheels with a 1.6. I think that's a lot to ask.

 

[ChrisMClark]

It's a difficult one to call. The overall tyre & rim combination isn't that much larger than what's already on, and alloys have a lower 'unsprung' weight than pressed steel rims, but with 18" allys compared to 15" pressed steel I'm not sure what the weight difference would be. I suppose there's a lot to take into consideration, what with the gyroscopic effects of a larger wheel too. I'm not all that clued up with wheels, all I really know are the few scraps of info I've picked up here and on other tuning/modding sites and shops.

That said my 1.2 turns 17" rims without batting an eyelid.

 

[Steely]

sorry forgot to mention... they are 15" FIAT alloys already fitted...

might look at some 17" then.... only reason i was after the 18's was for the 225 width...

 

[Dax]

sorry forgot to mention... they are 15" FIAT alloys already fitted...

might look at some 17" then.... only reason i was after the 18's was for the 225 width...

I have 17" Fiat alloy wheels with 225 45 Michelin Pilot Sport tyres fitted.

https://www.fiatforum.com/gallery/showphoto.php?photo=29302]

 

[wing1200a]

I've got 19s on mine (with 215/35/19 tyres), but am looking to increase the profile to 225/40/19 as there is loads of room left. You should be fine with 225s on the 18s

Steve

 

[PNL]

I wouldn't go over !7s on the stilo and with the 1.6 you will get drive losses and put the transmission under more strain ..

 

[ABZSTILO]

:yeahthat:

I'd stick to 18's max and preferably 17's, lots of nice Fiat own 17's out there that'll fit. Must admit the 18' Schumi wheels look cool though

 

[wing1200a]

I wouldn't go over !7s on the stilo and with the 1.6 you will get drive losses and put the transmission under more strain ..

Why? If the profile of the tyres is lower (very similar circumference between 215/45/17 and 215/35//19) and aftermarket alloys (if good ones) are lighter than oem so confused with this comment:worship:

 

[PNL]

OK what I am referring to is basically you will be turning a bigger wheel with regards to the amount of rubber and the J size of the wheel ..all mods come with some problems and this will put a lot of extra stress on the drive train of the car ..I can tell you of one stilo owner that fitted 19s on here car and is sorry she ever did ..

 

[wing1200a]

I can understand what you are saying about changing J size. However, the standard 17s have a 7 inch width, my 19s have a 7 inch width, the offcentre is 38 so the only thing that has changed (very slightly by about 1%) is the circumference. This would give a change to the indicated mph of 71 when travelling at 70 if the speedo were accurate to start - it isn't and has been measured with standard fitment 17s at 64 with an indicated 70.