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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Pre LeMans tyre check

I am off to Le Mans on Thursday and thought I should check my spare tyre as I have only had it out of the boot (whole?)once since I have owned the car...

Now, I understand most things about tyres but can't find an explanation with a quick google. The tyres on the car are Bridgestones and are "145/13 75T" I understand 145 and 13 and 75 is the profile. First question is if it is a 75 profile tyre what is does the "T" stand for.

Second question is; the spare is a brand new no name make and says "145/13 74s" on the side. So is that a 74 rather than 75 profile tyre and what does the "s" mean?

And finally if these are a 75 and 74 profile tyres they should be ok to run together in an emaergancy, right?

Every day I find something else in life I don't understand!

Mark
Mark '59 Frog

ok so I now realise they are 80 profile on the car so what is the 75 and 74 for?
Mark '59 Frog

Mark,

The T and S are I think the speed rating and either are fine for your car.
When and where on Thursday are you sailing/tuneling from
G Lazarus

D'oh! I knew that if I had thought about it, but what about 74 and 75? Have others off the car now and can see the 75s are slightly wider in fact about 1cm different, but they are more than 74-75 cm wide!I am sure it will be fine as a spare I won't need it anyway (touching the wooden desk top!).

We are going Portsmouth to St Malo overnight think we sail at 2030.. you ?

M
Mark '59 Frog

I leave Dover on Speedferries 10.45am Thursday morning.
G Lazarus

http://www.car-videos.net/info/tirespecs.asp
Mike G

Dee yo at the circuit! We are bound to bump in to each other... We are going in teh Frog and Steve's midget. Four of us but I have no idea where abouts we are staying! may make teh aprade thing on Friday...

I have jsut found the number means the load the tyre can carry at the speed. 74 = 375kg and 75 = 387kg just some useless info!

Mark
Mark '59 Frog

Ta Mike!
Mark '59 Frog

Did you by any chance happen to have a glass or two of wine with your dinner?

"Dee yo at the circuit! We are bound to bump in to each other... We are going in teh Frog and Steve's Midget. Four of us but I have no idea where abouts we are staying! may make teh aprade thing on Friday..."
G Lazarus

Started the LM spirit a little early :D
Dean Smith ('73 RWA)

I may have had a sniff of the bar maids' apron and coupled with the fact that I type as quickly as I talk, well accidents will happen. You got the message though I am sure!

Hope you enjoyed the Ace tonight? Great weather for it, but car needs to ready for Thursday... Hope the M&S community did us proud!

Mark "not a drop has passed my lips today officer" Hall
Mark '59 Frog

Mark,
The profile figure is the tyre wall height, always expressed as a percentage of the tread width. The standard 80 (originally 82) was a tyre with a wall height 80% of the tread width.
Your spare with a 74 or 75 profile, if that is what the number is, should represent the tyre wall height is 74% of the 145mm width. 74 or 75 would make so little difference as not to matter at all,

BUT
I am not convinced that these are actually your profile figures. They are usually to the nearest 5%, i.e. 55, 60, 65, 70 or 80

Guy
Guy Weller

Guy

you are right and your 82 profiel explains something else...

The old spare which is in amazing condition must be an 82 profile as it is taller than the tyres on the car. It doesn't have a profile number anywhere on it at all. However although it is says 145/13 it is around 1 cm narrower than the Bridgestones on the car. Not sure why this is!

The 74s and 75T I am now convinced are load and speed markings useful info here

http://www.kwik-fit.com/writing-on-my-tyres.asp and

http://www.kwik-fit.com/assets/jpg/graphics/tyre-sidewall.jpg

A simple guide even kids can understand but very helpful!

So I think I will get a new one tomorrow - if I nee dto use it I will be safer than a tyre fractionally taller and 1cm narrower.

Mark
Mark '59 Frog

This thread was discussed between 09/06/2008 and 10/06/2008

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.