16' Spare Will Explode If Used Over 80kph!

[Guest]

Basically,

Made a quick call to enquire about the reason why the spare 16inch is rated to only 80kph. Since the tyre is Dunlop Monza 300, with a specification rated for regular passenger use, and since I will have to be using mine for a couple days, why only 80kph???

After hearing my question, Service advisor over the telephone said that the tyre, although a Dunlop Monza, is 'different kind' and has a 'special rating' and can't be used to travel at freeway speeds.

McHeady: 'Really mate, what would happen'

Service Advisor: 'It could actually blow up from underneath'

McHeady:'............. ...............'

(sat there in silence, didn't know what to say or do, as I coudn't tell if he was being serious or taking the pi$$) :wassat:

He was serious...thanked him ended the call.

Speed Dial 012: Beaurepairs Maroubra Junction.

Quickly spoke to my friend..... :w00t: .....he laughed, passed me onto the manager, ....... :w00t: ...... he pissed himself Had to ask me three times if I was serious.

But just to be sure, double checked the catalogues, and .....................................

there was no 'special rating' released in that tyre. The steel is more than capable as it's used on the taxi pack falcons and futura wagons.

Eighty Schmatey, why brew up a story that diesn't even sound half believable, crikey some retreads can withstand up to 140kph!!!!

Service Advisor or not, makes you wonder.

Darren

[cqae]

my thinking as to why it says 80kph or less is because of the diff. different rolling diameters would result in damage to the diff at high speed for prolonged periods cos the wheels wouild rotate at different speeds

[ZAP]

Daz,

I think the reason it is rated to 80km/h is due to a slight difference in the rolling diameter of the 16" over the 17&18" wheels.

This will stuff the LSD on the rear if driven fast for long periods of time.

I could be wrong, but seem to remember this is the reason for the speed limit.

[tab]

Nah, bugger the LSD theory. Blowing up sounds much more fun

[Guest]

Rolling diameter?

Dunlop Monza: 225 / 55 / R16

Dunlop SP3000: 235 / 45 / R17

Width Different, but Rolling Diameter same? or is there other factors such as, sidewall (?) to consider.

Darren

[Lumpen]

Here you go heady...

The sidewall is a percentage of the width, so 55% of 225mm + 16" = rolling diameter and ((.55x225) + (16x2.54)) x Pi = Rolling Circumference...

OR:

Lumpy

[seventytwo]

hey lumpy where did you find that little gem

[driftpig01]

  McHeady said:

Eighty Schmatey, why brew up a story that diesn't even sound half believable, crikey some retreads can withstand up to 140kph!!!!

Retread can go alot faster than that on dragsters, not much chop for going arounf corners.

[Lumpen]

  seventytwo said:

hey lumpy where did you find that little gem

←

Tyre Size Calculator

Awesome little Java App

Lumpy :kdubb:

[Damo]

I was wondering the same. A few weeks back I went through a pothole which killed two tyres (huge bubble in one sidewall, actually tore a hole in the rear). So I had to put the spare on and was confused when I read the 80km/h max. I guess it was a diff thing (I have optional LSD).

But why not tell you the real reason?! Based on the reasoning you've been given you'd call a few places and go "well that's wrong" and just drive normally on it. Idiots.