Re:Tyre Pressure on Gen4 w BFG K02 - still a bit confused
- Groenewald
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I am still a bit confused about the ideal tyre pressure on my Gen4 with 215/70/15 BF Goodrich K02s...
On Stock 195/80/15s : 1.8 Bar front and 1.9 bar rear (26 / 27.5 psi)
Now working from this, the pressure should probably be lower: ??
Are these assumptions correct?
The 215/70s are about the same diameter, but wider which equals more air, meaning lower pressure?
The BFG tyres have a heavier construction and what looks like much heavier sidewalls, also meaning lower pressure?
From my research on the forum there seems to be quite a range for the PSI. Some suggestions I got:
(Just about all are lower than the suggestion for the stock 195/80s)
User1 - 1.65 Bar (24 psi)
User2 - 1.6 front 1.8 rear (23/26 psi)
User3 - 1.4 (20 psi)
User4 - 1.7 (25 psi)
User5 - 1.6 (23 psi)
User6 - 1.6 front 1.8 rear (23/26 psi)
User6 - 1.65 front 1.85 rear (24/27 psi)
Looks like the sweet spot is around 1.65?
I am looking for a basic all round tyre pressure meeting the following requirements:
- Important: Wont wear out or overheat tyre ensuring longevity
- Important: Rim wont bottom out over speed bump or potholes
- Provides a comfortable reasonably cushioned ride on tar
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All tyres have a maximum load at a given pressure written on the side wall. This information can be used to determine the appropriate pressure of the tyre for the maximum weight of the vehicle as provided by the axle weights on the vin plate. Alternatively if you are able to weigh your Jimny accurately you can calculate the pressure for as used weight. It requires some simple mathematics to determine the pressure the tyre will need to support 1 kg and multiplying that by half the axle weight.
Short answer. 22 to 23 psi will be fine for general use and then go lower depending on the off road conditions.
Temeraire (2018 quasar grey automatic)
One of the last 200ish of the gen3s, probably.
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- jackonlyjack
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- Bill Portland
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- Roger Fairclough
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Standard tyres have load rating of 710 kg.@ 44psi.
2 x 710 divided by 680 = 2.09
44 divided by 2.09 = 21 psi.
recommended pressure = 26 psi This is front and back light load.
Car makers determine tyre pressures to cope with static, braking and cornering loads but they start with a simple physical test. The tyre is marked across the tread with an even chalk line approx. 50mm wide and it is then run across a flat smooth surface. The greater the line imprinted on the board, the greater the load. They change the pressure to obtain an even spread of the load across the tyre.
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Bill Portland wrote: I'm sure this has been discussed on here before but doesn't reducing pressures below about 24psi mean you have to live with the constant tpms warning?
You can't really live with it. When it activates it dominates the central screen and it'll show nothing else. Stupid design really. Suzuki should be embarrassed by it!
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- Groenewald
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A thing that I have noticed is that with some speed bumps I get a hard knock from the front end.
We have some speed bumps over here with a table top (non rounded) profile.
It almost sounds like the tyres are bottoming out.... Either that or the suspension.
Anyone experienced tyres bottoming out with lower pressures (say around 24/25 psi)?
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Temeraire (2018 quasar grey automatic)
One of the last 200ish of the gen3s, probably.
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- Groenewald
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Lambert wrote: I'd be surprised if you are deflecting the tyre that much on a speed bump at anything like town speed limits. With some of the speed bumps round here it's almost as if the tyre size is just in a sweet spot it's big enough to miss the bottom transition but not tall enough to just crest the top and it slamming into the face of the bump. I have learnt which these are and really slow down for them. Others are barely noticeable.
Excellent way of putting it:
"Slamming into the face of the bump" describes 100% what I am experiencing....
Will slow down for them as well.
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Black 2019 Jimny SZ5
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