spare tyre size

aadix · 3rd April 2004, 22:07

hi guys
yesterday when my parents were coming back from the farm, my dad accidently went over a huge rock, and the rear tyre bursted
the tyres i am using on one of the safaris is yokohama 265/70 15 inch(tubeless)
i have a brand new michellin , which was from our old merc s class(94 model) it is a 265/65 15 inch(tubeless) as the spare tyre? say to run abt 10kms to go to the tyre puncture walllah?
what would happen if i used it for say abt 20 to 30kms at a strech???
would that 5 cms(guess) diff make any diff or harm the car in any way??, should i keep the pressure higher in that tyre,so that the over all profile remains the same?
i would use it say abt for the next two months, after that my dad's planning to shift to mrf zvrls of the same size
does any one have a used 265/70??
thx
aaditya

Rehaan · 3rd April 2004, 22:41

Hey Aadix,

Technically the different between a 265/70 and 265/65 is 1.3cm till the hub. (1.3cm x 2 in totaly diameter).

"say to run abt 10kms to go to the tyre puncture walllah?"
Sure. I dont see this as a problem. Just take it a bit easy as the car might pull very slightly.
20-30kms is also a possibility, but u have to be careful.
Dont over inflate the tire, but u could do maybe 2-4psi more depending on how much the other tires are filled.

Using a slightly mis-sized tire temporarily is not too much of a problem on a safari, maybe it'll just give the rear differential a bit of a workout, BUT if the car had ESP or ABS or any such other electronic goodies it might have caused them to freak out as the smaller wheel will be rotating slightly faster, and hence it'll keep applying the brakes to that wheel thinking its about to loose traction etc etc!

Also, if your tubeless tire is ruined from hitting the rock, and it gets fixed it might still be dangerous/weak.
Try to minimize driving with the 265/65.
And check at a large tire shop if they have a used 265/70 in good condition that u can pick up (i suggest international tires at opera house (mathew road) if you are in bombay)

Hope that helped.
Cya
Rehaan.

GTO · 3rd April 2004, 22:47

Aadix,

The Yokohamas you speak about have a sidewall height of 185.5 mm. The Michelins you intend to replace the damaged tyre with are 172.25mm. Keeping this difference in mind, I think that you are asking for fatal damage to your differential - front or rear. In addition, it can complicate matters for your braking system...and more importantly the handling of your Safari.

The same size tyre MUST be used on the same axle. Period. My suggestion to you is to prepone the arrival of those MRF zvrl's or source a second hand tyre of the same size for two months. If you are in bombay, PM me...I have a tyre chap who can source almost anything secondhand for almost any car.

GTO

Dippy · 4th April 2004, 04:37

Hey aadix I have a friend whos totally into tyres .. If you need anything just buzz

Cheers

aadix · 4th April 2004, 10:42

hey rehaan, dippy, gto
thanx guys! for offering ur help, but i live in hyderabad
so will no use that tyre, can i use the std 235/70 tyre?

? or a 215/70

?
rehaan,dont worry i am not goona use that damaged
tyre,man
dad wont take the zvrls soon man, the tyres which r currenlty running have been just put on before dussera(after which it ran close to 19k) so he will only change it at 25k, he may buy a single zvrl, but the mrf guy is asking close to 7k for one tyre and 5.6 each when all the set of 5 is taken!!!!

Rehaan · 4th April 2004, 13:06

Quote:

Originally Posted by [b

Quote[/b] (aadix @ April 04 2004,10:12)]so will no use that tyre, can i use the std 235/70 tyre?

? or a 215/70

?

NO !

Aadix, u are correct in thinking that the "70" is the sidewall height, BUT it is a relative measurement, ie it is the sidewall height represented as a %age of the tread width.

egs.
265/70R15 > 265mmx70%=185.5mm is the sidewall height
265/65R15 > 265mmx65%=172.25mm "
235/70R15 > 235mmx70%=164.5mm "
215/70R15 > 215mmx70%=150.5mm "

I still think that a short 10-20km trip with a 265/65 pumped a few psi extra wont be too bad for the car, as long as u take it easy. Afterall the differential is used to tires spinning at different rates on corners etc!

cheers
Rehaan

toyota · 4th April 2004, 18:02

Just take care and drive , even for 20 k or 30 k it is not a problem .

aadix · 4th April 2004, 19:02

thx rehaan! and toyota
will tell all this to my dad and let him decide!

Ravibm · 29th October 2006, 23:50

Hi, aadix,

I agree with Reehan, he has given perfect technical explanation to the tyre specifications. The side wall aspect ratio is given in terms of 70 / 80/ 65/ etc. This has to be read in percentage to the width of the tyre that is 265 or 275 etc.

Having a sliggtly lower aspect ratio for an emergency will be safe and no damage to the car diffrential. If you have noticed, most of the european cars are deliverd with a small tyre with a small dia and a samller width for emergency purpose. If any damage would happen to the car diffrential no one would dare to supply such a tyre.

You are OK pal, go ahead and use it for an emergency. Just take care not to speed up as this may cause a small pull to the side where you have fitted the tyre. Other than this no side effect will be felt by you.

Any thing else you need on tyres, please let me know. I will help you out.

Ravi

3rd April 2004, 22:07	#1
aadix Senior - BHPian Join Date: Mar 2004 Location: hyderabad Posts: 1,597 Thanked: 17 Times	hi guys yesterday when my parents were coming back from the farm, my dad accidently went over a huge rock, and the rear tyre bursted the tyres i am using on one of the safaris is yokohama 265/70 15 inch(tubeless) i have a brand new michellin , which was from our old merc s class(94 model) it is a 265/65 15 inch(tubeless) as the spare tyre? say to run abt 10kms to go to the tyre puncture walllah? what would happen if i used it for say abt 20 to 30kms at a strech??? would that 5 cms(guess) diff make any diff or harm the car in any way??, should i keep the pressure higher in that tyre,so that the over all profile remains the same? i would use it say abt for the next two months, after that my dad's planning to shift to mrf zvrls of the same size does any one have a used 265/70?? thx aaditya
	() Thanks

3rd April 2004, 22:41	#2
Rehaan Team-BHP Support Join Date: Feb 2004 Location: Bombay Posts: 24,196 Thanked: 36,071 Times	Hey Aadix, Technically the different between a 265/70 and 265/65 is 1.3cm till the hub. (1.3cm x 2 in totaly diameter). *"say to run abt 10kms to go to the tyre puncture walllah?"* Sure. I dont see this as a problem. Just take it a bit easy as the car might pull very slightly. 20-30kms is also a possibility, but u have to be careful. Dont over inflate the tire, but u could do maybe 2-4psi more depending on how much the other tires are filled. Using a slightly mis-sized tire temporarily is not too much of a problem on a safari, maybe it'll just give the rear differential a bit of a workout, BUT if the car had ESP or ABS or any such other electronic goodies it might have caused them to freak out as the smaller wheel will be rotating slightly faster, and hence it'll keep applying the brakes to that wheel thinking its about to loose traction etc etc! Also, if your tubeless tire is ruined from hitting the rock, and it gets fixed it might still be dangerous/weak. Try to minimize driving with the 265/65. And check at a large tire shop if they have a used 265/70 in good condition that u can pick up (i suggest international tires at opera house (mathew road) if you are in bombay) Hope that helped. Cya Rehaan.
	() Thanks

3rd April 2004, 22:47	#3
GTO Team-BHP Support Join Date: Feb 2004 Location: Bombay Posts: 71,833 Thanked: 321,562 Times View My Garage	Aadix, The Yokohamas you speak about have a sidewall height of 185.5 mm. The Michelins you intend to replace the damaged tyre with are 172.25mm. Keeping this difference in mind, I think that you are asking for fatal damage to your differential - front or rear. In addition, it can complicate matters for your braking system...and more importantly the handling of your Safari. The same size tyre MUST be used on the same axle. Period. My suggestion to you is to prepone the arrival of those MRF zvrl's or source a second hand tyre of the same size for two months. If you are in bombay, PM me...I have a tyre chap who can source almost anything secondhand for almost any car. GTO
	(1) Thanks

4th April 2004, 04:37	#4
Dippy Senior - BHPian Join Date: Feb 2004 Location: Mumbai, India Posts: 7,740 Thanked: 4,117 Times	Hey aadix I have a friend whos totally into tyres .. If you need anything just buzz Cheers
	() Thanks

4th April 2004, 10:42	#5
aadix Senior - BHPian Join Date: Mar 2004 Location: hyderabad Posts: 1,597 Thanked: 17 Times	hey rehaan, dippy, gto thanx guys! for offering ur help, but i live in hyderabad so will no use that tyre, can i use the std 235/70 tyre?? or a 215/70? rehaan,dont worry i am not goona use that damaged tyre,man dad wont take the zvrls soon man, the tyres which r currenlty running have been just put on before dussera(after which it ran close to 19k) so he will only change it at 25k, he may buy a single zvrl, but the mrf guy is asking close to 7k for one tyre and 5.6 each when all the set of 5 is taken!!!!
	() Thanks

4th April 2004, 18:02	#7
toyota BHPian Join Date: Feb 2004 Location: bangalore Posts: 148 Thanked: 3 Times	Just take care and drive , even for 20 k or 30 k it is not a problem .
	() Thanks

4th April 2004, 19:02	#8
aadix Senior - BHPian Join Date: Mar 2004 Location: hyderabad Posts: 1,597 Thanked: 17 Times	thx rehaan! and toyota will tell all this to my dad and let him decide!
	() Thanks

29th October 2006, 23:50	#9
Ravibm Newbie Join Date: Oct 2006 Location: Bangalore Posts: 5 Thanked: Once	Hi, aadix, I agree with Reehan, he has given perfect technical explanation to the tyre specifications. The side wall aspect ratio is given in terms of 70 / 80/ 65/ etc. This has to be read in percentage to the width of the tyre that is 265 or 275 etc. Having a sliggtly lower aspect ratio for an emergency will be safe and no damage to the car diffrential. If you have noticed, most of the european cars are deliverd with a small tyre with a small dia and a samller width for emergency purpose. If any damage would happen to the car diffrential no one would dare to supply such a tyre. You are OK pal, go ahead and use it for an emergency. Just take care not to speed up as this may cause a small pull to the side where you have fitted the tyre. Other than this no side effect will be felt by you. Any thing else you need on tyres, please let me know. I will help you out. Ravi
	() Thanks