Correct Tyre Pressures Yet Again........!

[Mrs Miggins]

Hi All

New to the Bongo scene having just bought our Bongo a couple of weeks ago and still very very excited!

I know this question has already been asked but the answers were a little unclear so I'm none the wiser now.

The tyres on our Bongo were looking a little on the flat side and we felt every little bump when we hit bumps/potholes/changes in road surface, yet when we checked the tyre pressures, they were correct (I think!) according to the plate written in Japanese just inside the drivers door. (26 and 35 respectively)

The tyres we have on are:

Front = 195/70 R15C
Rear = 215/65 R15 96H

It's a 2WD Diesel 2.5 if that's of any help. We just carry stuff like extra seating, basic awning and food supplies with us mostly (oh and 2 adult sized children in the back on occasion!)

Means not a lot to a newbie like me but I have seen that some people are driving round on far higher pressures, particularly in the front. The tyres seemed ridiculously flat on the pressures I had so, when I went to get some fuel today I put more air in. 35 up front and 38 in back. The journey home seemed far smoother and less bumpy as a result but I've only done this based on what few recommendations there are on here. Is there a correct pressure or is it just a case of try it and see? Bit wary of doing damage to tyres/other parts. First recorded mileage was 26.6 mpg done mainly on a run. Kind of hoping I can improve on that a little with correctly inflated tyres.

Please help!

Mrs M.

[missfixit70]

You've pretty much answered your own question There is no right & wrong as such - it depends on the tyres/load etc, as long as you are not over inflating the tyres (they may have a maximum pressure stamped on them, or you should be able to check it online or by phone from the manufacturer if not). Generally the pressure stated in the door frame is a bit low for uk tyres, it seems Jap tyres are a softer compound or sumat.
I run my 17"s at somewhere between 38 & 42 depending on load.
Welcome to the forum BTW

[David Edwards]

Just out of interest a lot of us run our bongos on 215's all round, I find it gives better handling, one thing tho it tends to make the speedo run about 5mph faster than you are actually doing, fine for speed cameras etc,lol.

[missfixit70]

Just out of interest a lot of us run our bongos on 215's all round, I find it gives better handling, one thing tho it tends to make the speedo run about 5mph faster than you are actually doing, fine for speed cameras etc,lol.

The width ie 215 has no bearing on the speedo, it's the profile (ie height of the tyre wall) of the tyre ie the 65 bit that affects the diameter & therefore the speedo. As the original fitment of narrower 195 tyres on the front has a higher percentage profile of 70 to give the same rolling diameter as the rear, it should not affect speedo rating just because you are running slightly wider tyres on the front, it just means your speedo is inaccurate

[Bob]

For what it is worth mine over reads by a good 5mph.

That doesn't help Mrs M though, but I run about 38/40.

[New Forest Terrier]

I run 225/45 ZR17 on my alloys. Tyre make ECSTA SPT only ones with the correct speed and load rating I could find for a V6. They were very rare four years ago when I bought the Bongo and the tyres. They have worn very well and evenly all round and after about 25k still have half the tread depth.

They do give a hard ride and I find need a higher pressure. Before I had the conversion I ran at 40psi all round. Any lower and you feel every pothole. Since I got the rear conversion I now use 42 on the rear to get the same level of comfort.

[New Forest Terrier]

I run 225/45 ZR17 on my alloys. Tyre make ECSTA SPT only ones with the correct speed and load rating I could find for a V6. They were very rare four years ago when I bought the Bongo and the tyres. They have worn very well and evenly all round and after about 25k still have half the tread depth.

They do give a hard ride and I find need a higher pressure. Before I had the conversion I ran at 40psi all round. Any lower and you feel every pothole. Since I got the rear conversion I now use 42 on the rear to get the same level of comfort.

[Mrs Miggins]

So, let me get this right then, I'm in the right ballpark with perhaps a little room to inflate a bit more, could maybe benefit from the same sized tyres all round but basically it's just guess work and going by what feels right? Hmmmmm...........

I think I can feel a Bongo trip coming on!

[TerryG]

["New Forest Terrier"] Before I had the conversion I ran at 40psi all round. Any lower and you feel every pothole.

Eh? That doesn't make sense. Higher pressure = less sidewall compliance = harder ride.
Lower pressure = more sidewall compliance = softer ride (unless you run the pressure so low that the rims bottom out )
There are consequences of running lower pressures, but harder ride isn't one of them.

BTW, does anyone have any substantive evidence that tyres for use on Bongos in Japan are constructed differently from tyres elsewhere in the world, as several threads on this forum suggest as justification for running pressure other than recommended in the Bongo handbooks? This would be very unusual as tyre manufacturers do all they can to make their products suitable for global markets. I suspect it is an urban myth but would be happy to be proven wrong.

Me, I'm running my V6 on 28 front (195 x 70s) and 36 rear (215 x 65s) and have no inclination to do otherwise.

[teenmal]

["New Forest Terrier"] Before I had the conversion I ran at 40psi all round. Any lower and you feel every pothole.

Eh? That doesn't make sense. Higher pressure = less sidewall compliance = harder ride.
Lower pressure = more sidewall compliance = softer ride (unless you run the pressure so low that the rims bottom out )
There are consequences of running lower pressures, but harder ride isn't one of them.

BTW, does anyone have any substantive evidence that tyres for use on Bongos in Japan are constructed differently from tyres elsewhere in the world, as several threads on this forum suggest as justification for running pressure other than recommended in the Bongo handbooks? This would be very unusual as tyre manufacturers do all they can to make their products suitable for global markets. I suspect it is an urban myth but would be happy to be proven wrong.

Me, I'm running my V6 on 28 front (195 x 70s) and 36 rear (215 x 65s) and have no inclination to do otherwise.

Exactly

[missfixit70]

So explain to me why, when I have tried bongos on the Mazda stated pressures on tyres bought in the uk (not van tyres either) they have virtually been sat with the rims on the ground & would have destroyed the tyres in no time, let alone been dangerous to drive on?
As I have said before, I am no tyre expert, I am just going on what I see/feel & understand from the vehicles ride & from others experience on here.

[helen&tony]

Hi
It's always intrigued me, this tyre pressure argument...I run 32 PSI all round...tyres look right, wear well, don't show uneven wear, and get good mileage????...If I have a heavy load on, I just add a bit more air!
Cheers
Helen

[TerryG]

So explain to me why, when I have tried bongos on the Mazda stated pressures on tyres bought in the uk (not van tyres either) they have virtually been sat with the rims on the ground & would have destroyed the tyres in no time, let alone been dangerous to drive on?
As I have said before, I am no tyre expert, I am just going on what I see/feel & understand from the vehicles ride & from others experience on here.

Dunno. Faulty pressure gauge?

Or maybe because they weren't van tyres?

I've never really thought that looking at tyres was a particularly effective way of assessing the correct pressure but having said that mine look fine, with a cute little bulge, and they are not showing uneven wear.

[missfixit70]

So explain to me why, when I have tried bongos on the Mazda stated pressures on tyres bought in the uk (not van tyres either) they have virtually been sat with the rims on the ground & would have destroyed the tyres in no time, let alone been dangerous to drive on?
As I have said before, I am no tyre expert, I am just going on what I see/feel & understand from the vehicles ride & from others experience on here.

Dunno. Faulty pressure gauge?

Nope

Or maybe because they weren't van tyres?

Not supposed to be (although there's nowt wrong with fitting them if you want), & if they were, I thought van tyres usually ran at higher pressures? - again - I'm no expert here.

I've never really thought that looking at tyres was a particularly effective way of assessing the correct pressure but having said that mine look fine, with a cute little bulge, and they are not showing uneven wear.

I've found that looking at tyres is a bloody good way of seeing that they are flat or damn near to when runnning at the stated pressures, but obviously that's just me

[David Edwards]

Helen hit it right, you would be surprised at how many people do not adjust tyre pressure to cope with load, I usually run mine at 32 or 34,lol, depends on weather etc.