Mismatched tyre sizes: any advice?

[raffles]

I've had a couple of flat tyres and I can't find tyres the same size as what I need where I am right now. I have 275/70R16 tyres but the spare alternatives I have are 265/75R16 or 265/70R16. Both are worn, so after doing a bit of maths have decided to put the 265/75 one on (front right). Even though it's a bigger size, being pretty worn out should not be a huge difference.

I'll have to drive about 300km to the next town where I can get new tyres. Will driving that far be a problem for the car? Am I likely to damage anything, say if I drive over a certain speed?

 

[Chas]

I'm sure there are more knowledgeable than me but I wouldn't think the width would cause a problem it would be the diameter that would.

 

[StarCruiser]

The 275/70 R16 are 31.2" diameter new.
The nearest you have is the 266/75R16 at 31.6" new.

I would have thought you wouldn't even notice it and I doubt the truck would have any problem at all with those sizes.

 

[AndycruiserguyLomas]

Seconded, you wont even know and neither will your truck.

 

[joinerman]

When i bought my 80 it seemed tight in the drive train & the auto box was holding gears, long story short my boy noticed it had 265/7016s on the back & 275/70/16s on the front all nearing the end of their lives, new set of 275s & it drove perfect after

 

[Dave2000]

When i bought my 80 it seemed tight in the drive train & the auto box was holding gears, long story short my boy noticed it had 265/7016s on the back & 275/70/16s on the front all nearing the end of their lives, new set of 275s & it drove perfect after

Does your 80 have the VC? If so that would answer why the drive train was binding up.

regards

Dave

 

[joinerman]

Don't know Dave haven't got it anymore, Byron's got it.

 

[Dave2000]

Don't know Dave haven't got it anymore, Byron's got it.

What year was it? I am guessing late 92/early 93 onwards? With no VC I doubt you would have noticed any problems until the CDL was engaged.

regards

Dave

 

[chapel gate]

My spares actually a 275, im on 285s at the mo. Worst case, diff working a bit harder??

 

[joinerman]

Twas a 94 Dave

 

[IRLGW]

I have a 93 Manual with a VC. I got a puncture/tear right on top of the ALp d'huez in the day before the tour de france arrived and was going to be stuck there for over a week before anyone could get a tyre in. The first prick in the closest garage said that it had to be the same size and I argued that so long as the differentials were all open that it didnt matter, but he disagreed and wouldnt give me different tyre ( incidentally he also drove an 80 series but it was a heap). I found another garage down the hill a bit which was run by an older guy and showed him my sketch at which point he went ' ah oui' and climbed up onto the roof of his office and threw me down a used 265/60/16 and only charged me 10euro including fitting. I drove back to ireland on the same tyre with no issues. If anyone has ever had to rely on a VC (like when my front drive flange broke) it will only provide drive for a about a mile when cold. It does not provide continuous power to both axles as when the fluid heats up it the viscosity becomes too low and allows the plates/rotors to slip.

It may be a problem however on new vehicles with automatic electronic diffs or whatever they use as the ECU may take the different rotational speeds as wheel slip. If anyone has one of those in their 80 I suggest they rip it out...

 

[Towpack]

It shouldn't present any problems for unlocked diffs. Unless you never drive round corners the diffs are constantly 'working' anyway. Even the VC will cope with the minimal slippage with a difference in tyre sizes so small, not the same as trying to put all the drive through the VC with no drive to one axle due to a component breakage. JMO

 

[Dave2000]

Twas a 94 Dave

Makes sense, the VC picking up the difference rotational speed of the propshafts.

Agree with IRLGW and Towpack, the difference is minimal, most of the rotational difference being taken up by the axle differential, minimal going back to the VC. Re modern vehicles fitted with electronic traction control, they have to be setup to allow a certain amount of difference between wheel speeds, if they did not you would not be able to use the little 'space saver' spares we commonly see.

Mike, I would not be worried about using the spare as a get you to a garage option. There would have to be some research put in, which you can bet someone else has already done for us anyway. But the rolling radius of say a new tyre (8mm tread depth) and a legal (1.6mm) tyre has to be catered for, the differential would easily cover that.

regards

Dave

 

[chapel gate]

 

[Dave2000]

Replying to Shayne's post about his tread wear but, although I have the email with the link to this page, the last post showing is Chapel Gate, I have no #2 page

Anyway, no worries if the trailer has mismatched tread depths IMO.

regards

Dave

 

[Shayne]

Cheers Dave
I deleted having answered the question myself by buying a tread gauge , another lesson learned is not to trust a garage print out on tread depth turned out when i measured each tyre 4 times at different locations and averaged it , i have two at 4mm which will do for the trailer , 11mm on the driver side rear and the spare is 10mm so the worst worn 3mm will do as a spare .

So all good and yes i agree such little difference in size shouldn't matter on a trailer i just wondered if there were anything i had failed to consider .

Thanks for taking the time to reply

 

[Dave2000]

no problem, I often get weird happenings on this site from Spain, Crispin has put in some time on it but I still get odd glitches, I just wondered if this was one of them, now the k on my eyboard only wors with a really good push, not site related, just something else to fuc me off and get on my nerves.


regards

Dave