Hello their

I just recently have new clutch and CV joint.

and not to long ago a new tyre.

the steering wheel wobbles ever slightly and Wondering if the cv joint isnt done correctly?

or are my wheels out of balance?

but my new tyre has more PSI in then the rest as i never bothered to add any extra when i purchased my alloy / tyre package,

could the difference in psi between the tyres casue the steering to wobble?

any help would be great.

Wobbles under what conditions? If it only happens around 100km/h it's wheel balance and you need to have the wheel with the new tyre taken off and rebalanced.

Tyre pressure difference won't cause wobble, but it will cause bad handling and braking.

An incorrectly fitted CV joint, well, I can't easily think how you could fit that incorrectly unless you've done something like leaving a bolt undone in which case the car will fall to bits as you drive round the first corner.

So if the wobble occurs at low speed I would look first for a bent wheel on one side or the other.

Inflate (/deflate) both tyres to recommended pressures when cold.

Edit: actually if you have new larger than standard alloys the recommended pressures are no longer applicable. Could be the size/offset of the wheel also?

what preasure should i have mine at?

i'm running 195/45/15's

What's the "correct" tyre pressure?

How long is a piece of string?

Seriously though, you'll be more likely to get a sensible answer to the length of a piece of string than you will to the question of tyres pressures. Lets just say a good starting point is the pressure indicated in the owner's manual, or the sticker inside the driver's side door pillar.I say 'starting point' because on every car I've owned, I've ended up deviating from those figures for one reason or another. On my Subaru Impreza, as outlined above, I got much better gas mileage and no difference in tyre wear by increasing my pressures to 40psi. On my Honda Element, I cured the vague handling and outer-tyre-edge wear by increasing the pressures from the manufacturer-recommended 32/34psi front and rear respectively, to 37psi all round. On my Audi Coupe I cured some squirrelly braking problems by increasing the pressure at the front from 32psi to 36psi. On my really old VW Golf, I cured bad fuel economy and vague steering by increasing the pressures all-round to 33psi.

So what can you, dear reader, learn from my anecdotes? Not much really. It's pub-science. Ask ten Subaru Impreza owners what they run their tyres at and you'll get ten different answers. It depends on how they drive, what size wheels they have, what type of tyres they have, the required comfort vs. handling levels and so on and so forth. That's why I said the sticker in the door pillar is a good starting point. It's really up to you to search the internet and ask around for information specific to your car.

The Max. Pressure -10% theory.

Every tyre has a maximum inflation pressure stampd on the side somewhere. This is the maximum pressure the tyre can safely achieve under load. It is not the pressure you should inflate them to.

Having said this, I've given up using the door pillar sticker as my starting point and instead use the max.pressure-10% theory. According to the wags on many internet forums you can get the best performance by inflating them to 10% less than their recommended maximum pressure (the tyres, not the wags - they already haves inflated egos). It's a vague rule of thumb, and given that every car is different in weight and handling, it's a bit of a sledgehammer approach. But from my experience it does seem to provide a better starting point for adjusting tyre pressures. So to go back to my Subaru Impreza example, the maximum pressure on my Yokohama tyres is 44psi. 10% of that is 4.4, so 44-4.4=39.6psi which is about where I ended up. On my Element, the maximum pressure is 40psi so the 10% rule started me out at 36psi. I added one more to see what happened and it got better. Going up to 38psi and it definitely went off the boil, so for my vehicle and my driving style, 37psi on the Element was the sweet spot.

Car Bibles : The Wheel and Tyre Bible Page 2 of 2

Wobbles under what conditions? If it only happens around 100km/h it's wheel balance and you need to have the wheel with the new tyre taken off and rebalanced.

.

yes it occurs around 100km maybe more, so maybe it needs all balancing?

will it cause any damge to the car this wobble?

many thanks

so maybe it needs all balancing?

Sounds as if the front - at least - needs it. Probably all four wheels if they were fitted by the same place.

will it cause any damge to the car this wobble?

Not quickly, though I suppose in the end it could shake something loose. It will damage your nerves, though!

Tyre pressure: my rule of thumb is a 6-inch-long contact patch on the road. Any car, any tyre. That said, it's all a bit of a compromise. More pressure will give a more positive ride in the dry but can stitch you in the wet, as I once found to my cost. Start with the manufacturer's rated pressure and then suck it and see a few PSI either side.

In extreme cases, an out of balance vibration can wear out wheel bearings and/or ball joints or suspension bushes. Most people have too much mechanical sympathy to let it get to that stage though.