Technical Which tyres?

[Alex1985]

So I am finally getting round to fitting some pepper pot style wheels to my motor and need some assistance on tyre size? The wheels I have are the ones below:

Now I recall being told that I can put a larger tyre on with additional spacers?

Anyone any thoughts?

Cheers.

Alex

 

[mephastophele]

I had new tyres fitted on that model of wheel yesterday and I went for the stock tyre size of R13 165/70. That is the size the cars were shipped with and in my opinion gives the best balance for a standard unmodified car.

As long as your hubs have the factory spacers attached then you can fit R13 185/60 tyres. I used to have those but I prefer the sharper more nimble feel the stock tyres give.

I doubt you can get anything wider than 185 crammed on to those 5J rims and if you could you would need more spacers because they would definitely rub.

 

[Sausage]

Sorry about hijacking this thread, but for some reason I cannot create a new thread, maybe cos I am new and need to post a certain number of times before I can do so?

anyway....

I am hoping to get some new alloys + tyres for my grande punto today from an online retailer.

I am a bit of a thicko so need some help....

I would like some sexy rims but I want to make sure I am going to get lower profile tyres with the rims otherwise there is no point. Is it a general thing that the larger the rims the more lower profile the tyres will be....otherwise if the tyre sizes don't decrease you could end up with some hella massive wheels?

My current tyres are 175 65 and sit on 15 rims.

175 is the bredth of the tyre from tread to tread and 65 is the percentage of the 'profile' bit of the tyre in relation to the bredth (175) so 65% of 175 = 113.75mm (the size of the 'profile' part of the tyre.

I would like some 17 rims but I want to make sure I am getting this right...

With 17" rims I think they generally sell 205/45/17 tyres:

This means the profile size is: 92.25mm which is of course lower profile than my current ones by a few cm's.

Will this make much difference in giving the lower profile look?

Also what do you think of these rims and what do you think of just getting the cheapest 'economy' tyres (scroll down on that link):

http://www.wheelbasealloys.com/17_Inch_Team_Dynamics_Sword_Anthracite_Alloy_Wheels__1679

 

[mephastophele]

Sausage
The diameter of your new wheel/tyre combination must be within a small percentage of the stock wheel/tyre. Don't quote me on it but I think 5% difference up or down is allowed. If you change the overall diameter by too much it changes the gearing of the car,your speedo will be reading wrong not to mention it will be illegal.
So, if your wheel is getting bigger then the tyre wall must be a lower profile to keep the rolling diameter within the allowed percentage.
Did Fiat offer 17" rims as an option for the GP? If so, your best bet might be finding out the exact measurements of that factory wheel tyre combo and then you know what sizes to look for.

Don't forget to take the width of the new wheels/tyres into consideration too. You have to make sure your new choice of wheels have an offset dimension works with your car without rubbing the supension/wheel arches etc.

Sorry I haven't answered your specific problem. My advice is don't jump in and buy new wheels online until you are sure of your calculations.

 

[rattystilo]

Sausage,

if its any use i bought a set of wheels that had been on a GP. they had 215/35/18 tyres on so your 205/45/17 should be bang on. just check the centre bore size and make sure you get the correct size spigot rings.

 

[brigguscoop]

I've run 185/60s on my Gran Finale OZ rims without problems. They fill the arches better but alter the handling a tad towards more grip which I prefer but I can understand why others may not. I don't know which brands are available these days in this size for 13" rims. Mine are Yokohamas but I've had them years.

 

[jimbro1000]

Did Fiat offer 17" rims as an option for the GP? If so, your best bet might be finding out the exact measurements of that factory wheel tyre combo and then you know what sizes to look for.

The GP wheels use a GM stud pattern (100x4 instead of 98x4 PCD) so they dont fit very well but all the other Fiats in the range use 98x4 and there are plenty of 17" options but don't expect them to fit.

You can check tyre size online at places like Miata.net using a tyre size calculator.

As long as the speedo does not under read (ie says you are going slower than you actually are) you are ok. The X1/9 speedo generally over reads by about 15% (some are much worse) so you actually have quite a bit of scope. It does mess with gearing though so you have to keep it fairly close.

What you must ensure is that the wheels do not protrude beyond the limits of the bodywork (in the UK anyway) so there are very real practical limits on how wide you can go. Furthermore the wheels must not rub the bodywork (an MOT failure) which limits the sizes even further.