Tyre size for spiders on a 4.2

[BspokeNI]

I just got a new set of 18" spiders from power for my 97 cerb 4.2, im just not sure on what tyre size. I did a quick forum search and only found 1 result saying - 225x35x18 front and 255x35x18 rear, the post saying this is over 5 years old so I just wanted to see if anyone had and thoughts or different views on this..

Thanks Shane..

[pmessling]

That's what I currently have on my spiders. So is correct

[yosini]

Hi,

Exactly the same as I have on my 1997 4.2 spiders - however the drivers side rear rubs so I'm wondering if the offset is wrong - the fronts give no problems so maybe rear and front are on the wrong way - is there any way of telling without taking a wheel off?

Cheers

Joe

[DJR 7]

yosini said:

Hi,

Exactly the same as I have on my 1997 4.2 spiders - however the drivers side rear rubs so I'm wondering if the offset is wrong - the fronts give no problems so maybe rear and front are on the wrong way - is there any way of telling without taking a wheel off?

Cheers

Joe

Cerbera wheels are the same offset front and rear, I believe this to be 42. (iit'll be stamped on the inside of the wheel)
Tuscan rears are 33, it maybe that you have a replacement wheel from a Tuscan on your rear?

[TVdinneR]

yosini said:

Hi,

Exactly the same as I have on my 1997 4.2 spiders - however the drivers side rear rubs so I'm wondering if the offset is wrong - the fronts give no problems so maybe rear and front are on the wrong way - is there any way of telling without taking a wheel off?

Cheers

Joe

Hi,
Quickest way of telling whether your spiders have different offsets , without taking the wheels off, is to take a look at the gap between the wheel mounting face and the disc - see pics.



The larger gap wheels, ET33, are the "rear" and should be stamped so on the back of the rim.
My sons 4.5 has ET42 fronts all round whereas mine has the ET33 on the rear with no rubbing problems.
Tyre sizes exactly as mentioned above - 225x35x18 front and 255x35x18 rear.

Edited by TVdinneR on Thursday 5th January 08:38

[FarmyardPants]

The OEM tyre size for the fronts is very skinny, you can run 40 series which fits the rim a bit better, gives a better ride and will protect your wheels a bit better. They are also easier to come by than 225x35. I thought the rears were 30 but probably wrong.

[yosini]

Hi,

Thanks for that - very useful, and meant I didn't need to take a wheel off and the certain scuffing of knuckles that would have involved.

I've just had a look though - hoping my wheels to be on wrong, but unfortunately it looks like that are correct. I have the bigger gap on the rears, and slim gap at fronts.

So, how do I stop it rubbing without resorting to the angle grinder....?

Cheers

Joe

[FarmyardPants]

You could try adding a bit of negative camber on the rear to give you a few mm horizontally, and hence more vertical translation before they start to rub.

[TVdinneR]

yosini said:

Hi,

Thanks for that - very useful, and meant I didn't need to take a wheel off and the certain scuffing of knuckles that would have involved.

I've just had a look though - hoping my wheels to be on wrong, but unfortunately it looks like that are correct. I have the bigger gap on the rears, and slim gap at fronts.

So, how do I stop it rubbing without resorting to the angle grinder....?

Cheers

Joe

Read one suggestion somewhere, some time ago, not necessarily on this forum, that a good engineering workshop could machine a few mm from the mounting face of the wheel ie changing the offset from ET33 to whatever - possibly down to ET42 as per the fronts - or just enough to bring your rears in a bit.
Another option is to go for a different size tyre on the rear.
According to the handbook, the original tyre size on the 4.2 rears were 245/45/16.
If you were to put 245/35/18 on the rear instead of the 255`s, the diameter and rolling circumference would actually be closer to the original than the 255`s, and may solve the rubbing problem.
245/45/16 - diameter 626mm, rolling circ 1967mm - speedo reads 70 actual speed 70
245/35/18 - diameter 628mm, rolling circ 1973mm - speedo reads 70 actual speed 70.22
255/35/18 - diameter 636mm, rolling circ 1998mm - speedo reads 70 actual speed 71.11

Edited by TVdinneR on Friday 6th January 16:08

[DJR 7]

I changed my rear tyres to 245/35/18 and it did the trick, where are you based? Happy to drop one of my wheels on to yours and see if it clears

[yosini]

Hi,

Thanks for the offer - it doesn't seem to rub on the passenger side although there are vague rub signs on the tyre side - the drivers side (more so after all that turkey) rubs quite a bit. So maybe 245s would sort it, the tread on current tyres isn't fantastic so fresh rubber might be good soon anyway and it would be reassuring to know that 245s would work. I'm in SE London, Greenwich if that is close by - or I could head to you?

Cheers

Joe

[DJR 7]

I'm in Aylesbury Buckinghamshire, if you fancy a trip down Pm me and we'll arrange.
D

[Mr Cerbera]

Some of these comments are starting to remind me of the TopGear christmas special to India.

Are you guys nuts ?? (Silly question for Cerbera owners)

[DJR 7]

Totally ...... Aren't you

[TVdinneR]

Mr Cerbera said:

Some of these comments are starting to remind me of the TopGear christmas special to India.

Are you guys nuts ?? (Silly question for Cerbera owners)

Absolutely
Wheel nuts