Does tyre circumference really matter with 4wd?

[dandywarhol]

All the bleating on over the years has been backed up by a bloody Volvo of all things!!!

[keycare]

To add some real world experience, my bongo front diff exploded in a plume of black smoke when I had just 10mm rolling radius difference between the front and rear tyres. That was after 50 miles of motorway driving and was quite spectacular. I now have the same size all round (the larger of the two standard sizes supplied from factory) and did over 3000 miles in 3 weeks on a European tour in the summer with no problems at all.

One more thing to point out was that tyres have a weight rating, the tyres that caused my diff to explode were not rated high enough for a 2.5t vehicle fully loaded for a camping trip, even when the tyre pressures were upped a bit to compensate for the extra weight and motorway driving the tyre walls were just too soft and effectively reduced the rolling radius further.

When replacing tyres - get van load rating.

Cheers,
Rich.

[chiefster1976]

o.k chaps,very interesting post an each post has confirmed that same tyres are paramount..
I have 2 bongos...

One has Maxxis 751 all round..... 215/75R/15 102S 850KG... And are in good nik...

the other tyres on the other bongo that need replacing are Federals(all round) 215/70R/15 98T 750kg...

The 75 Profile fills the arches very well and looks alot better than the 70 profile...

Will the 75 profile damage the VC/transfer box etc???should i be worried???

Im looking at getting the best price for low cost tyres here in OZ, but wondering which is the MORE COMMON SIZE tyre
that i can safely put on the BONGO??
(make of tyre doesnt interest me...)
1. 215/70R/15 98 Load upwards?
2, 215/75R/15 98 Load " " " ?
3. 225/70R/15 98 " " " " "" " "?
4. 225/75R/15 98 " " " " " " " " ?


These campers will be converted.... Id like to go 225/75/15 if i can... Looking in the MEMBERS area someone has put on 225/70/15 with no dramas rubbing etc aparantly....
What do you guys think???? thanks,,Gav ....

[dandywarhol]

Won't cause any more strain on the VC if ALL 4 tyres are 75 aspect ratio.