Tyres
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- haydn callow
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Tyres
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?
Any thoughts anyone???? Oh! and by the way. Will what I have done affect the speedo reading?
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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).
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).
Last edited by trevd01 on Mon Mar 12, 2007 9:09 pm, edited 1 time in total.
- haydn callow
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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
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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"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).
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