Tyre Pressures

[Jac]

Have looked at previous threads and am still a bit confused.....we have stuck to the different tryres on front and back, have a full side conversion and packed up with stuff while travelling around.....what should our front and back pressures be currently have them at 34 & 36 but to us they still look underinflated, have checked the pressures when tyres cold.....

[mikexgough]

there are plenty of threads on this topic......too many to link to, do a search "Tyre Pressures".....

I have Van tyres on my Bongo and find 38 Front and 40 Rear is good for me........ others here will tell you what they run on ........

[Jac]

Yeah thats what I did initially on the forum, is this a silly question but how do I know if I have van tryes, not had van long but they did replace one when we bought it and we have had to buy one the other day on our travels in Spain and they just matched what we had????At the minute we've hit a cool spell but we have had hot temps, how much does this affect tyres/pressures??? Thanks...

[Ron Miel]

I use 36 fron/38 rear, with Japanese tyres still on it, and they're fine, if a bit sensitive to road surface feedback on the steering. They're not the original Mazda fit tyres, though - they're 215 width all round, Dunlop Japan sidewall-reinforced Le Mans RV502 tyres, intended for on road/occasional off road, 4x4 use, so they are strong enough to not look under-inflated at those pressures (at least, I think that's the reason). Other peeps, presumably not using reinforced tyres, sometimes seem to need to go to higher pressures to avoid sidewall bulge.

[mikeonb4c]

I use 36 fron/38 rear, with Japanese tyres still on it, and they're fine, if a bit sensitive to road surface feedback on the steering. They're not the original Mazda fit tyres, though - they're 215 width all round, Dunlop Japan sidewall-reinforced Le Mans RV502 tyres, intended for on road/occasional off road, 4x4 use, so they are strong enough to not look under-inflated at those pressures (at least, I think that's the reason). Other peeps, presumably not using reinforced tyres, sometimes seem to need to go to higher pressures to avoid sidewall bulge.

That could be me writing! I generally run my Pirelli P7 215/55/17s at 36 front and 38 rear (maybe 40 when loaded up) and they seem to be wearing fine. Bongo doesn't like poor road surfaces though and lets me know (anyone else find Bongos are great on a decent road but a bit rattly on a poor one?)

[Ron Miel]

I use 36 fron/38 rear, with Japanese tyres still on it, and they're fine, if a bit sensitive to road surface feedback on the steering. They're not the original Mazda fit tyres, though - they're 215 width all round, Dunlop Japan sidewall-reinforced Le Mans RV502 tyres, intended for on road/occasional off road, 4x4 use, so they are strong enough to not look under-inflated at those pressures (at least, I think that's the reason). Other peeps, presumably not using reinforced tyres, sometimes seem to need to go to higher pressures to avoid sidewall bulge.

That could be me writing! I generally run my Pirelli P7 215/55/17s at 36 front and 38 rear (maybe 40 when loaded up) and they seem to be wearing fine. Bongo doesn't like poor road surfaces though and lets me know (anyone else find Bongos are great on a decent road but a bit rattly on a poor one?)

Not you writing Mike but I think we oftern are on the same wavelength aren't we? Coming to Southport then?

[aitch]

I'm running with 17" alloys and put 40 psi in all round seems fine and the tyres are still going strong three years down the line!!! of ownership

[karlos]

Not being a bongo expert but a bit clued up on more clued up on settings of vehicles for specific reasons.

On tyre wall there is usually (on road vehicles) a max psi reading. You are best sticking to the manufacturers recommendations.

Because these run alloy wheels it is possible to run car tyres, or buy wheels from a car/have been fitted in the past. Van tyres normally have higher psi rating so I presume a thicker wall/stronger tyre which is to compensate for weight, As these are quite large vehicles I would recommend a van/commercial tyre. Car tyres may not be safe although some big cars are quite heavy. Performance tyres carrying a rating for speed like (z) So I presume there is a spec. Best just ask local tyre centre.

A bit pointless running a car tyre that will probably get hot or wear quick unless you want to do the numburg ring. Car tyres typically run around mid to late 30 psi, vans late 40 to 50psi ish.

I can sort you out with some sticky ones if you want, should last about 10miles or so!

[karlos]

Oh and temps,

Temperature will effect psi readings not so much the ambient temp, although this will factor.

You should check your tyre pressure when the tyres are cold, before driving to far. If you want to be specific. A bit accurate for a van though - a general reading is usually good enough.

The harder you drive/corner, with a lower tyre pressure plus warmer the day/tarmac the hotter the tyre will get(the higher the pressure reading will get)

If you were racing I could see your point, tyre pressures go up alot then.

I would expect maybe 2/3psi or less difference in a cold reading tyre to a warm one on a hot day, not that that should really matter if your just worried about tyre buldge.

"Pump them up to what it states on the tyres If they are still buldging more than a little they probably are not rated for the weight." Let a couple psi out for a bit more ride comfort or grip in the bends, put a couple in for better fuel economy or correct ware. To little or too much is bad.

Strictly speaking if you want to go into it that much, you should look a ride height, caster camber, toe and suspension settings. (lol) - I find an infer red heat gun helps to check the tyre temps when trying to bring your lap time down- maybe some data loggin.

karl-new boy-

[missfixit70]

For standard 15" wheels I'd recommend a minimum of 38 on the front & 40 on the back. Some people run up towards the high end of the 40's, giving a firmer ride & better handling.
There's a load of tyre info re the load & speed ratings on the forum & in the members area factsheets karlos, basically an absolute minimum of 92 S on the front & 96 S on the rear.
Tyres & wheels must be the second most often & heatedly discussed subject on the forum behind coolant/overheating issues

[karlos]

Sorry,

I dont need help when it comes to tyres, thanks for the offer.

Telling people generic info is a load of bull. All manufacturers tyres are rated differently and size doesnt mean pressures will be the same. The tyre has psi ratings and despite what any one states to stray to far from that to high or low is a bad thing -as I said in my previous thread all other factors apply- ITS NOT COMPLICATED follow the manufurers spec/rating.



I take a vechicle and hone it to do something better than it would before, this can compromise something else, but it requires a greater knowledge and understanding than any numpty before.

Hence why race teams have experts in specific areas to tackle issues. I'm still learning about setup but now form a drivers perspective but I have a good idea and have built up quite an understanding over the years whilst assisting as a race engineer on a team briefly and assiting a local company with testing, also carring out manufacturing equipment upgrades for some of the biggest teams in the world, getting advice from world ranking professional competitiors and doing my own projects -some published-

You start with basic knowledge - say what little a car tyre shop understands- " urr a wheel is a round thingey " may have- or a car mechanics understanding of a particular area and build on it until you understand how how why and what things do for what reason the physics and science involved. Avon have people that can look at wear markings on tyres and deturmin why or what cause a crash, to much throttle/to much heat etc. etc.(no not what police do)

Thats why I have an engine builder, because it's far to complicated to do everything on such a precision level.

I dont know every thing but what I do know I will defend with honour - Its annoying when someone talks to you who clearly knows nothing and wants to tell you how it is- weve all met them.

I dont tell david beckham how to play football, but I bet there are plenty of guy's who sit on there couch out of shape saying, cross it. Or down the pub with a pint, pack of crisps with- the team manager being interviewed commenting on "why did he do that".

Couch potato armchair sports fans - my Dad is one - I'm not, I'm a doer, like to live, learn and understand and participate my self. (not read magazines and listern to fictional opinons down the pub, I find out from the source and only make my mind up when I see the proof/have done it myself)

If some one asks for Info on something I know, I will tell them. If I dont know I will say i'm not sure, I think but check or I dont know. Not spectulate!

[missfixit70]

When you say you follow the manufacturers instructions, which manufacturer? the tyre or the bongo? if you follow the bongo manufacturers instructions, the pressure will be too low for modern uk spec tyres.
Driving & running a bongo has absolutely nothing to do with driving race cars - we get that you do that & love it, but you can't necessarily apply race car thinking to a bongo. The pressures I stated are tried & tested by myself & many others if you read through the forum (not speculation) & well within the tyre manufacturers maximum, but the stated maximum on the tyre doesn't tell you what an individual vehicle should run at.

Telling people generic info is a load of bull

isn't that what you did in your earlier post on this thread in your comparison of car tyres/pressure & van tyres/pressure?
You obviously don't know as much as you think you do about tyres as you seemed to gloss over the issue of load & speed rating which is VERY important. I am not a tyre expert & will happily admit that, but as you say IT'S NOT COMPLICATED

[Ron Miel]

When you say you follow the manufacturers instructions, which manufacturer+ the tyre or the bongo? if you follow the bongo manufacturers instructions, the pressure will be too low for modern uk spec tyres.
Driving & running a bongo has absolutely nothing to do with driving race cars - we get that you do that & love it, but you can't necessarily apply race car thinking to a bongo. The pressure I stated are tried & tested by myself & many others if you read through the forum(not speculation) & well within the tyre manufacturers maximum, but the stated maximum on the tyre doesn't tell you what an individual vehicle should run at.

Telling people generic info is a load of bull

isn't that what you did in your earlier post on this thread in your comparison of car tyres/pressure & van tyres/pressure?
You obviously don't know as much as you think you do about tyres as you seemed to gloss over the issue of load & speed rating which is VERY important. I am not a tyre expert & will happily admit that, but as you say IT'S NOT COMPLICATED

Well said, Kirsty. Among oither things our new friend doesn't appear to know that physics is a main element of science, in many ways, the underpinning of all science. "...physics and science involved..." indeed! Shan't feel so bad when I occasionally say something silly on here in future

[mister munkey]

Getting back on thread for a moment, Jac was asking about tyre pressures I seem to remember.

34/36 are too low, esp with a conversion. No danger involved but you'll find the outer edges wear pretty quickly.

I did the same & trashed my fronts in around 9000 miles, although mine are 18" RX8s not sure if that makes any difference . . . .



40 all round has slowed the damage but I wish I knew then what I do now.

[missfixit70]

Good illustration of the actual effects of underinflation there MM.

Yeah thats what I did initially on the forum, is this a silly question but how do I know if I have van tryes, not had van long but they did replace one when we bought it and we have had to buy one the other day on our travels in Spain and they just matched what we had????At the minute we've hit a cool spell but we have had hot temps, how much does this affect tyres/pressures??? Thanks...

If it doesn't say anything on the tyre regarding whether or not yours are a van/commercial tyre, then just do an online search on the make/type of tyre, or stick all the info on here & someone'll help you out with the right info Jac.