Tyre Pressures 255/45/18
- Thread starter DaveF
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- 18” 255/45/18 tyre pressure
I think that list is only giving max allowed cold pressure, and some conversion done from bar to psi, and rounded, and later conversed back to bar, and again rounded. Speedcode given in place of the usual R of radial.
On other plate I saw 255/45 R XL 103.H
Is maxload 875 kg/ 1929 lbs AT 2.9 bar / 42 psi upto 160 kmph/ 99 mph.
Maxcold is then only given on sidewall between 3.0 bar / 44psi and 3.5 bar / 51 psi, and an ocacional XL 4.25 bar/ 60 psi.
Can make you a cold pressure/ axleloadcapacitylist, with build in maximum reserve, at wich comfort and gripp is still acceptable.
For that, I give 90% of calculated axleloadcapacity for max 160 kmph/ 99mph.
On other plate I saw 255/45 R XL 103.H
Is maxload 875 kg/ 1929 lbs AT 2.9 bar / 42 psi upto 160 kmph/ 99 mph.
Maxcold is then only given on sidewall between 3.0 bar / 44psi and 3.5 bar / 51 psi, and an ocacional XL 4.25 bar/ 60 psi.
Can make you a cold pressure/ axleloadcapacitylist, with build in maximum reserve, at wich comfort and gripp is still acceptable.
For that, I give 90% of calculated axleloadcapacity for max 160 kmph/ 99mph.
Here the list for your tyre 255/45R18 XL 103H
In front of cold psi in lbs, and behind in kg.
Gives 90% of calculated axleloadcapacity for the cold psi for max speed to yse 160 kmph/ 99 mph.
Now you "ONLY " have to determine the axleloads in your use 99% acurate, the most tricky part, and your responcibility.
The 5 puppets and truncs on the plates , max permissable axleloads are used with no reserve, but for max technical carspeed, wich shal not be above 190 kmph for your car, because T speedrated given as lowest on one size.
For the 2 puppets and one trunc, the carmaker determined the expected axleloads, and used them to calculate pressure , again with no reserve build in.
Axleload LBS / cold psi/ axleload KG
In front of cold psi in lbs, and behind in kg.
Gives 90% of calculated axleloadcapacity for the cold psi for max speed to yse 160 kmph/ 99 mph.
Now you "ONLY " have to determine the axleloads in your use 99% acurate, the most tricky part, and your responcibility.
The 5 puppets and truncs on the plates , max permissable axleloads are used with no reserve, but for max technical carspeed, wich shal not be above 190 kmph for your car, because T speedrated given as lowest on one size.
For the 2 puppets and one trunc, the carmaker determined the expected axleloads, and used them to calculate pressure , again with no reserve build in.
Axleload LBS / cold psi/ axleload KG
1634 | lbs/ | 18 | psi | / | 741 | kg |
1713 | lbs/ | 19 | psi | / | 777 | kg |
1791 | lbs/ | 20 | psi | / | 812 | kg |
1869 | lbs/ | 21 | psi | / | 847 | kg |
1946 | lbs/ | 22 | psi | / | 883 | kg |
2024 | lbs/ | 23 | psi | / | 918 | kg |
2101 | lbs/ | 24 | psi | / | 953 | kg |
2179 | lbs/ | 25 | psi | / | 988 | kg |
2256 | lbs/ | 26 | psi | / | 1023 | kg |
2332 | lbs/ | 27 | psi | / | 1058 | kg |
2409 | lbs/ | 28 | psi | / | 1093 | kg |
2486 | lbs/ | 29 | psi | / | 1127 | kg |
2562 | lbs/ | 30 | psi | / | 1162 | kg |
2639 | lbs/ | 31 | psi | / | 1197 | kg |
2715 | lbs/ | 32 | psi | / | 1231 | kg |
2791 | lbs/ | 33 | psi | / | 1266 | kg |
2867 | lbs/ | 34 | psi | / | 1300 | kg |
2943 | lbs/ | 35 | psi | / | 1335 | kg |
3019 | lbs/ | 36 | psi | / | 1369 | kg |
3095 | lbs/ | 37 | psi | / | 1403 | kg |
3170 | lbs/ | 38 | psi | / | 1438 | kg |
3246 | lbs/ | 39 | psi | / | 1472 | kg |
3321 | lbs/ | 40 | psi | / | 1506 | kg |
3396 | lbs/ | 41 | psi | / | 1540 | kg |
3472 | lbs/ | 42 | psi | / | 1575 | kg |
3547 | lbs/ | 43 | psi | / | 1609 | kg |
3622 | lbs/ | 44 | psi | / | 1643 | kg |
3697 | lbs/ | 45 | psi | / | 1677 | kg |
3772 | lbs/ | 46 | psi | / | 1711 | kg |
3846 | lbs/ | 47 | psi | / | 1745 | kg |
3921 | lbs/ | 48 | psi | / | 1778 | kg |
3996 | lbs/ | 49 | psi | / | 1812 | kg |
4070 | lbs/ | 50 | psi | / | 1846 | kg |
4145 | lbs/ | 51 | psi | / | 1880 | kg |
4219 | lbs/ | 52 | psi | / | 1914 | kg |
4294 | lbs/ | 53 | psi | / | 1947 | kg |
4368 | lbs/ | 54 | psi | / | 1981 | kg |
Would like to know your max permissable axleloads and vehicle loads. Can be found on VIN plate somewhere on car, I is front , II is rear.
The lower pressure behind then front, indicates lower MPAW rear then front.
For vans its mostly higher rear then front, then plate is wrong. I think they placed the van-image above, the wrong way around.
The lower pressure behind then front, indicates lower MPAW rear then front.
For vans its mostly higher rear then front, then plate is wrong. I think they placed the van-image above, the wrong way around.
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The top tyre pressure plate is from my T28. Max axle weights are front 1600kg and rear 1550kg with max mass of 2800kg.
On the weigh bridge the unloaded van (full camper conversion) weighs 1280kg front and 1000kg rear, so slightly higher pressure in the front makes sense. Loaded up the weight should end up pretty even assuming the additional weight is spread to a degree and not all behind the rear axle. Therefore even pressures front and rear is close. Even tyre wear over the last couple of years backs up these pressures.
Then I read wrong.
Fully loaded is the same front and back, and 2 puppets is front higher, as expected for motor in front.
1550 front and 1600 rear are that close, that same recomended.
My list gives 42 and 43 psi , is with max reserve for max 160 kmph/99mph.
Plate 45 psi , then for max technical carspeed, but with no reserve.
Fully loaded is the same front and back, and 2 puppets is front higher, as expected for motor in front.
1550 front and 1600 rear are that close, that same recomended.
My list gives 42 and 43 psi , is with max reserve for max 160 kmph/99mph.
Plate 45 psi , then for max technical carspeed, but with no reserve.
