New Tyres

OwenP · Post by **OwenP** » 10 Nov 2006, 10:05

I am starting to look at new tyres for the 405, looking at National tyres website, they reckon that I should be using either 175/70 or 185/65. When I got the car it had a mix of 175/75s and 180/60s ( I think) I replaced them with 185/65s as it says on the door.

What do you guys reckon? Given that on the make I'm looking at the 175s are nearly £40 cheaper than the same make (different "model") in 185.

Adstar · Post by **Adstar** » 10 Nov 2006, 10:16

The 170 and 185 concerns the width of the tyre, the bigger the number the bigger the contact patch. The 70 or 65 refers to the side wall size whcih is a % or ratio of the width compared to the rolling radious, or something like that!

There are tools available on the internet to show how different sizes effect the rolling radious of the wheel and tyre package. unfortunately I have lost the link to the best one I found!

My personal opinion, is if the car and wheel are designed to take the wider tyre, then I'd go for that. Purely for the greater contact and grip and the reduced flex in the tyre wall (which gives better accuracy of handling, but has the effect of firming the ride a little).

Ross_K · Post by **Ross_K** » 10 Nov 2006, 11:28

Adstar wrote:There are tools available on the internet to show how different sizes effect the rolling radious of the wheel and tyre package. unfortunately I have lost the link to the best one I found!

This one maybe?

http://www.miata.net/garage/tirecalc.html

Adstar · Post by **Adstar** » 10 Nov 2006, 12:15

I prefer this one. unfortunately they have got rid of the list of wheel sizes that fit various cars! including offset and bore! but the comaprison tool is good!

http://www.tyresave.co.uk/tyresize.html

OwenP · Post by **OwenP** » 10 Nov 2006, 14:23

OK I think I'll stick with 185s in that case.

Also has anyone heard of/ had any experience with Barum Bravuris as a tyre make and model?

droylsden dave · Post by **droylsden dave** » 10 Nov 2006, 20:54

Ive no real experience of that tyre as such, but i did own a vectra and just before i got rid, ihad to replace a worn tyre as to pass MOT. Im sure it was a barum one what was put on, and it looked to have plenty of tread on. And no different to the lot dearer dunlops on offer. HTH

caveman_si · Post by **caveman_si** » 12 Nov 2006, 14:33

Ive had barums on my car for ages and there good much better the rubbish i used to have on there. And from time to time i do like to energeticly drive if the conditions allow it

The rear have done 10k miles and look really good the front have done 20K ish and still look ok. No tyre rotation just checking the pressures every other week. I should easily see a good few more miles before I have to change them again. And they are normally on nationals buy one get one free deal too in the 185/65 r14 size.

OwenP · Post by **OwenP** » 12 Nov 2006, 15:28

Right thats a fairly solid yes vote for them. The reviews of them seem to contradict each other fairly well, so I'm now ignoring them and listening to what people I "know" (i.e. real life or on here) are saying.

Think I'll book it in esp as the front left has a nice bulge in the side of it as well as a 1-2 inch crack!! only appeared this morning when I checked the pressure and put them back up to normal.

It was national I was looking at £144 for 4 tyres, not bad at all.

Gnerk · Post by **Gnerk** » 13 Nov 2006, 21:48

I'm probably teaching grannies to suck eggs, but here goes on the tyre sizing.

Take an example: 185/65 R14

185 is the tyre width in millimitres (i.e. the width of the tread)

The R14 means that the tyre is intended to fit a wheel of a rim size of 14 inches.

65 means that the tyre profile height is 65% of the tyre width (i.e. 185 mm) - so in this case 120 mm. Therefore, the total tyre diameter should be approx. 14" plus 2x 120mm.

Lower profile tyres tend to look cooler and distort less under high cornering loads. Higher profile tyres tend to give a more comfortable ride.

There is usually a speed rating suffixed after the tyre size code - T rated, H rated, etc. The 405 would need either T or H rated - although I have always suspected that H rated tyres were an excessive specification. I can't imagine a regular 405 would need V rated or better - maybe a 4x4 Mi16 or something (heavier and faster).

T rated is cheaper than H rated.

Smaller width, higher profile is cheaper (usually) than greater width, lower profile.

The 205/40R17's on my old Subaru used to look ridiculous and were > £100 a pop. Glad I bought a Citroen (repeat till I believe it).