Tyre Pressures

Technical questions and answers about the Mazda Bongo

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tony163

Tyre Pressures

Post by tony163 » Sun Jan 31, 2010 1:13 pm

I have just been checking the tyre pressures on the Bongo.

It has 195/80/R15 96S on the front and 215/70/R15/98S on the back.

After reading previous posts on the topic (which to some extent left me more confused than I was before I read them) I have decided that the recommended pressures in the hand book were probably too low and have put them to 36psi front and 38 psi rear. I will then drive the vehicle for a while to see how it feels.

Does this sound reasonable/

tony
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Re: Tyre Pressures

Post by francophile1947 » Sun Jan 31, 2010 1:26 pm

It's a good starting point :D After a while try an extra couple of PSI in each, to see if that feels better. I've got 225/50x17 tyres at 40PSI all round. The original recommendations are generally thought to be to low, as they're based on the old Japanese tyres.
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Re: Tyre Pressures

Post by mikexgough » Sun Jan 31, 2010 1:51 pm

Sound advice from John....... I'm (hands up and declares - ready tp be shot down... :lol: ) 38F / 40 R...... I prefer it like that....did try 40/40 & 40/42....
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Re: Tyre Pressures

Post by mister munkey » Sun Jan 31, 2010 3:46 pm

There really is no definitive answer though. No two Bongos are the same. I have a set of low profiles on 18" RX8 alloys that prefer to run at 45/40 but also have 15" alloys when on the same van they sit happiest at 38/36.

It really is a case of Suck It & See to find the right levels for your particular set-up.
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Re: Tyre Pressures

Post by splitpin » Sun Jan 31, 2010 5:28 pm

Mine are 215/65 all round and I have them at 38 front and 35 rear, if I put any more in the rears they feel very hard and bouncy and I found the middle of the treads were wearing quicker when they were at 38. As already stated it's a case of trial and error to find best setup for your van.
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Re: Tyre Pressures

Post by Alison01326 » Sun Jan 31, 2010 8:01 pm

I've got four Dunlop Le Mans RV 215/70R15 98H and have them at 36 front and 38 rear, having tried various other pressures. This seems to suit my Bongo and my driving style. The Bongo is unconverted although I have a removable kitchen which makes my rear passenger side tyre look soft (but only at the bottom :lol: ) The limit on my tyres says 40psi anyway.
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Re: Tyre Pressures

Post by stilldesperate » Sun Jan 31, 2010 8:13 pm

splitpin wrote:Mine are 215/65 all round and I have them at 38 front and 35 rear, if I put any more in the rears they feel very hard and bouncy and I found the middle of the treads were wearing quicker when they were at 38. As already stated it's a case of trial and error to find best setup for your van.
It takes a lot of miles at the same pressure to realise this, Splitpin, and it's expensive on tyres.

This is what over/under pressure does

Cross section


As you say, to high and it's hard and bouncy, (and can loose traction quickly with little warning).
Too soft will tend to "squirm" more on the corners.
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Re: Tyre Pressures

Post by splitpin » Sun Jan 31, 2010 10:51 pm

stilldesperate wrote:Cross section


As you say, to high and it's hard and bouncy, (and can loose traction quickly with little warning).
Too soft will tend to "squirm" more on the corners.
Good diagram stilldesperate, shows ata glance the effect of too much or little, your right about squirming on corners if underinflated specially on the fronts.
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Re: Tyre Pressures

Post by mister munkey » Sun Jan 31, 2010 11:04 pm

Another to look out for.

If too low - the edges will wear real quick.
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Re: Tyre Pressures

Post by Rob101 » Mon Feb 01, 2010 10:20 pm

mister munkey wrote:Another to look out for.

If too low - the edges will wear real quick.
Exactly that happened to our shiny new Toyo's at 36psi on the rear...
Now running at 40 - u live and learn.. #-o
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Re: Tyre Pressures

Post by Bin Bongoed » Tue Feb 02, 2010 7:35 pm

I'm higher than that, about 40/45, tyres if anything a little rounded. But it hugely improved the fuel consumption. and drives better as far as I'm concerned. I guess the weight of the van changes things too, if you it's loaded with a full conversion, and food, water, tents etc., as ours is.
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Re: Tyre Pressures

Post by David Edwards » Wed Feb 03, 2010 12:40 am

Interesting thread this, there seem to be so many variants on tyre pressures, mine is running on 215's all round and on the pressures as on the door panel (cant remember what tho) lol, it would be interesting if peeps put thier sizes and pressures on for comparison, I am gonna check mine again in the morning and depending on tread wear try a bit more,lol.
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Re: Tyre Pressures

Post by stilldesperate » Wed Feb 03, 2010 1:03 am

[quote="David Edwards"]Interesting thread this, there seem to be so many variants on tyre pressures,......[\quote]

I guess it's what you consider "value for money" at the end of the day. If you put loads of pressure in tyres, the rolling resistance is reduced so I guess the mpg will get better, the disadvantage (long-term) is that the tyres will wear (in the centre) faster, also there's the danger that grip on the road is reduced, and there's the possibility of an accident.
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Re: Tyre Pressures

Post by The Great Pretender » Wed Feb 03, 2010 1:48 am

stilldesperate wrote:
David Edwards wrote:Interesting thread this, there seem to be so many variants on tyre pressures,......[\quote]

I guess it's what you consider "value for money" at the end of the day. If you put loads of pressure in tyres, the rolling resistance is reduced so I guess the mpg will get better, the disadvantage (long-term) is that the tyres will wear (in the centre) faster, also there's the danger that grip on the road is reduced, and there's the possibility of an accident.
Got it about right there SD,.....but........running at the optimal pressure is what we are looking for. In motorsport a probe is inserted into the tyre across the width, sides and centre.
Ok so most Bongo owners don't have access to that equipment but after a motorway run of 20ml or so, stop on the hard shoulder of the slip road and feel the tyre across the tread. You can feel if the outsides or centre are at different temperatures. Data logging with pinkies.........simpelsssssss.
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Re: Tyre Pressures

Post by missfixit70 » Wed Feb 03, 2010 1:49 am

Yay, another excuse to play with my laser thermometer :wink:
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