[Peertantyb]

Hello FMers!

Got a couple of car questions for you! I've got a '94 Civic hatchback that currently has 13" steelies on it (155/80 tyres). Yesterday I bought a set of 15" alloys from the later shape VTI (EK4 '98), these have 195/50 tyres on I think.

Questions:
Do I need to use different wheel nuts for the alloys? (I haven't tried to fit them yet, but I want to be sure first because having improperly fitted wheels could be very dangerous!)
Do I need a different air pressure to my current 29psi when I fit the new wheels/tyres? If so how do I know what it should be? My car is lighter than the VTI models so they will probably have slightly higher pressures.

Thanks!

[Garry Richardson]

I would pressurize the tIres to whatever they're rated for. It'll be listed on the tIre itself. Not all tIres are the same.

As for the nuts I'm not 100% sure. I don't see any reason why you would use a different nut.. I mean.. the threading didn't chage or anything. I've just never heard that question asked before so I can't give a solid answer.. but I'd say probably not. I don't think I've ever seen normal car rims that weren't mounted like all the rest.

[Peertantyb]

Thanks for the reply.

The tyres would take much more pressure than would be suitable for them. By this I mean I'm sure the tyres would take over 40 psi but I'm sure this would not be a good pressure to run them at!

I have put 35 psi in them for now and they are actually 195/55 not 195/50. Not sure if this is right now but it should get me on the road!

As for the nuts I think they will be alright (from a brief visual inspection) but my dad said something about possible issues from the different types of metal.

PS: I am a brit, so tyres is correct to me, no need to capitalise the I in 'tires'.

[intifatry]

I believe that most tire manufacturers recommend that you follow the tire inflation guide for the specific vehicle that you use. I'm not sure if anything should be changed if you change the tire size, though.

[engacenus]

i'm pretty sure new bolts should be put in if you have gone from steelies to alloys as the bolts are of a harder metal than the new wheels and can score/damage them when tightened and cornering hard... not 100% on this but go into your local car shop and ask

pictures?

also according to this: http://www.miata.net/garage/tirecalc.html site your new tyres have a 3.0% bigger circumference so when your speedo is at 60mph you are actually going 61.8mph

[Quigoxito]

I would pressurize the tIres to whatever they're rated for. It'll be listed on the tIre itself. Not all tIres are the same.

That's the maximum tire pressure what is listed on the tire itself.

Here is a PDF file that gives an indication of your front and rear tire and with empty and loaded car:

http://www.hetnieuwerijden.nl/pdf/ba...tabel_2002.pdf

The pressure is listed in BAR, sorry.

[Tw1anJOO]

I only changed the nuts of the wheel because they weren't long enough and I scratched my new rims a bit, I went out and bought aftermarket lugnuts, only 30-40 bucks and you get a special key for the pattern.

You'll be fine as long as it fits.

[mr.videomen]

Alloy wheels DO require their own nuts. They usually have a built in washer-thingy on them. Also, it's very important that you know the thread numbering/sizing of the hubs for the nuts as if you buy the wrong ones and they happen to fit, you could be in for a serious accident.

[jamisi]

Usually alloys do need different nuts than normal steel wheels, adviseable to get locking nuts too if you like the alloys of if theyre worth something.

I generally put 32psi in my tyres (17" ford alloys)

[Siliespiriulk]

Some* alloys use the same angle nuts/bolts as the steel rims and, if so, you "may" be OK. However, there is a good chance that the hex on the 'steel' nuts may mark the alloy as the seat will be wider and for this reason it is usually a good idea to get a good set of correctly sized nuts - plus a set of locking nuts as the tea leafs are likely to take a liking to the rims.

*As has been mentioned, many aftermarket rims use a parallel nut and washer and you will need to check not only the thread but the hole diameter, depth and washer are correct for the rim - usually sourced from the same company.