front and back?

[silage]

Q: I have a 4WD Bongo. Recently my front differential overheated and was totally destroyed. I replaced it but this also over heated. I have been told that it may be due to incorrect tyre sizes, but I have checked and mine are 195/70/R15 on the front and 215/70/R15 on the rear. (Craig from Falkirk)

A: They are not the correct tyre sizes. The correct rear tyres should be 215/65/R15. The middle number is the tyre profile. Yours is 70 and should be 65. This means your rear tyres are standing too tall, which, over time, knackered your diff. The fact that a second diff experienced the same problems means you may have also damaged your transfer box and viscous coupling. This will need to be checked thoroughly.

I read this post from a newsletter last year and assume the front and rear tyres should be 215/65/R15 on my 4wd bongo? sorry to sound thick.

[JoeC]

Standard sizes ...

f - 195/70 R15 92S (30 PSi)
r - 215/65 R15 96S (34 PSi)

[Simon Jones]

Originally, the Bongo was fitted with narrower tyres on the front but due to the way tyre sizing works they are exactly the same rolling circumference as the wider ones on the rear (this is critical for the 4WD system). There's no problem with that, but if you want to swap tyres around to spread the wear, or have a full size spare, it starts to get tricky as you must not have different size tyres on the same axle: it's an MOT failure (as would be turning up with a space saver fitted). What many folk do is fit 215's on all four corners and the same for a spare and you have no problems.

Different variants were fitted with different sizes, so this is the official spec for my 2002 V6 which differs to what the sticker on JoeC's Bongo shows:



The official pressures are also much lower than any of use would want to use: 26.1 psi (front) and 34.8 (rear).

[Cab-ova pete]

Hi Simon I'm an apprentice bongonaut and wondered where that plate is situated, passenger door frame of the bongo, I think I saw one there???

[Bob]

Just a thought, have a look on the N/S door pillar.

[cmm303]

Somebody posted elsewhere that 215/65R15 is the largest tyre that fits in the spare wheel space. This would dictate the tyre size for a "same at each corner and spare" setup and stop you putting on 215/70R15 whose diameter is 0.85" more than the /65.
I haven't got a /70 to try this out for myself.

[Simon Jones]

I think you can get bigger tyre in the spare wheel space as there is a metal bracket that acts as a stop and this could easily be bent if required. Another factor that may reduce the space is a towbar but I've had no probs before my LPG tank was fitted with towbar and 216/65 R15 tyre as a spare so that would suggest at least 4 inch capacity for extra radius.

[silage]

Sorry Simon, are you saying it ok to run all four the same or thats what they do to get it through the MOT? slightly confused?
or should it be as Joec replied?

[Simon Jones]

There are no problems for MOT with using the original tyre sizes, but many people fit same size all round for convenience and cost reasons. More info in the factsheet: http://www.igmaynard.co.uk/bongo/member ... /tyres.pdf

[JoeC]

I have 4WD and all my tyres are 215/65/15.

[silage]

thanks for all the help, must get use to checking the fact sheet area first

[fluffy]

If one were to fit 215/70/R15 tyres all round, what would the front tyre pressures be please?

[Gasy]

34 - 40 psi
Closer to 34 on the front
Closer to 40 on the back
That's what I run mine at

I do 38 front and 40 rear
But I carry weight and tow a caravan

[fluffy]

Thanks Gasy, much appreciated.