Tyres

haydn callow · Post by **haydn callow** » Mon Mar 12, 2007 4:45 pm

Just had fitted 4 new tyres. The old ones were jap winter/snow. Different sizes front/back as per book. Now then!! Chap at the tyre depot said fine, fit different sizes if you want but what's wrong with same size all round? He commented that as the Bongo was full time 4 wheel drive surely the rolling circumferance of each tyre ought to be the same or there would be a certain amount of conflict between the axles. This made sense to me so I elected to fit 215/65 all round. I know other bongos have done this and it does make life a bit easier and wheel/tyre rotation is now a option.
Any thoughts anyone???? Oh! and by the way. Will what I have done affect the speedo reading?

dp bradford · Post by **dp bradford** » Mon Mar 12, 2007 4:52 pm

I need to get some new tyres as mine are showing signs of old age - cracking in between the treads. I've got 215/65 R15 all the way round and will be replacing with the same size - roughly how much did you pay?

haydn callow · Post by **haydn callow** » Mon Mar 12, 2007 4:54 pm

£210 for 4x Kumho

mikeonb4c · Post by **mikeonb4c** » Mon Mar 12, 2007 4:57 pm

Just entered 'wind AND tyre' into Search (the 'wind' is to do with differential wind-up) and got lots of reading matter from previous threads

mikeonb4c · Post by **mikeonb4c** » Mon Mar 12, 2007 4:59 pm

Cor, must have struck lucky then. I got 4 x Bongo steel wheels with virtually new Kumhos on them for £100 off evilbaby a while back

David Edwards · Post by **David Edwards** » Mon Mar 12, 2007 5:15 pm

I have used four 215's since I bought mine 3 years ago, no difference in handling, mine are Nangkang make fully fitted at £39.00 each. Happy motoring.

bigdaddycain · Post by **bigdaddycain** » Mon Mar 12, 2007 7:17 pm

Yep, my old tyres were the same size all round 165/70/15's and are the same on each corner now i,m on 18"s 245/45/18... had the bongo nearly four years now, no probs so far...( touchwood )

trevd01 · Post by **trevd01** » Mon Mar 12, 2007 8:40 pm

The recommended tyres (different front and back) have rolling circumference that is only 1% different each other. For all practical purposes they are the same circumference.

Changing to the same size all round will make no difference to the transmission they obviously will have the same rolling circumference. Also makes no practical difference to the speedo (can you see a 0.7 mph difference at 70 mph?)

The reason Mazda fitted different tyres (different width and aspect ratio, NOT different diameter), we assume, is to provide 'safer' understeer characteristics, with the front tyres having less rubber on the road, and maybe breaking away at the front in extreme cornering, rather than the back end breaking away into a potential spin.

Many of us have the same size fitted front and rear - (we do).

haydn callow · Post by **haydn callow** » Mon Mar 12, 2007 9:08 pm

O.K. I think that answers my worries. Thanks lads.

Peg leg Pete · Post by **Peg leg Pete** » Mon Mar 12, 2007 9:51 pm

My tyres had fine cracks in tread, had a nasty blowout, get them changed A.S.A.P.

dp bradford · Post by **dp bradford** » Mon Mar 12, 2007 10:33 pm

I'm having them fitted on Saturday morning - there's loads of tread left, but now I've noticed the cracking they are going

Cheers, Peter - definitely not worth the risk.

ebygum32 · Post by **ebygum32** » Mon Mar 12, 2007 10:54 pm

had a set of khumos fitted when i first got my baby over two years ago and only just replaced them, done best part of 70k on them mostly motoway could not falt them at all but decided to try some 205/70/r15 bridgestone duelers 694 all terrain tyres, ready for all this snow and rain we are gonna get, the tyres are ok and look good ( have a thing for tyre tread must be a man thing as the wife does not get it when i get excited about different tread patterns) so we will just wait and see, got them from http://www.mytyres.co.uk also try http://www.blackcircles.co.uk

dandywarhol · Post by **dandywarhol** » Tue Mar 13, 2007 12:07 am

trevd01 wrote:
The reason Mazda fitted different tyres (different width and aspect ratio, NOT different diameter), we assume, is to provide 'safer' understeer characteristics, with the front tyres having less rubber on the road, and maybe breaking away at the front in extreme cornering, rather than the back end breaking away into a potential spin.

Many of us have the same size fitted front and rear - (we do).

I'm really not so sure about this one now Trevor - since reading that Land Rover have a similar viscous setup and they have a different final drive ratio front and rear I reckon the difference in size is to do with ALLOWING a tiny amount of speed differential front and rear to have the viscous constantly "loaded" to enable "FULL TIME 4WD"