jscan tire pressure

[NachoRuby]

Does jscan not let you do anything but multiples of 5, or is it somewhere else? I am trying to change my tire pressure setting, but I only want to change it if I can change it back to 37. Looks like it just counts by 5s

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[NachoRuby]

@ShadowsPapa , I know you know all about jscan. Can you set to increments that aren't multiples of 5 for the tire pressure somehow? I set mine to 35, since now I see you can revert it. But I'd really like to do 34 or 33.

 

[jjdustr340]

@ShadowsPapa , I know you know all about jscan. Can you set to increments that aren't multiples of 5 for the tire pressure somehow? I set mine to 35, since now I see you can revert it. But I'd really like to do 34 or 33.

If not mistaken, I believe you’re running 315s on yours correct? Just curious as to what pressure you’re running.

All the 315s I’ve ever run were anywhere from 28 to 32 psi.
I run my current 295/70R18 at 32 and set Jscan for 25. If I would set it for say 30, then a cold morning would be enough to set of the alert and I don’t want that. Setting 7-10 psi below my normal running pressure will only give the warning if my tire is actually going low.
Just some food for thought friend.

 

[NachoRuby]

If not mistaken, I believe you’re running 315s on yours correct? Just curious as to what pressure you’re running.

All the 315s I’ve ever run were anywhere from 28 to 32 psi.
I run my current 295/70R18 at 32 and set Jscan for 25. If I would set it for say 30, then a cold morning would be enough to set of the alert and I don’t want that. Setting 7-10 psi below my normal running pressure will only give the warning if my tire is actually going low.
Just some food for thought friend.

Yes, correct. I'm running 315s. I've been running them at 34 for a while, but I started playing with it again recently. 34 seems like too much when we get a heavy rain. It's breaking loose and losing traction too easily when it rains hard and it's hot out.

 

[Geoarch]

Yes, correct. I'm running 315s. I've been running them at 34 for a while, but I started playing with it again recently. 34 seems like too much when we get a heavy rain. It's breaking losing traction too easily when it rains hard and it's hot out.

Did you do a chalk test? I have 315 Kanatis and running 34 but that looks like too much, I.e. higher in the center. I’m going to test tomorrow.

 

[jjdustr340]

Yes, correct. I'm running 315s. I've been running them at 34 for a while, but I started playing with it again recently. 34 seems like too much when we get a heavy rain. It's breaking losing traction too easily when it rains hard and it's hot out.

If you do intend to run at 34, I’d suggest setting the TPMS to 25, 30 at most.
Remember, the rule of thumb is 1 psi pressure drop for every 10 degrees temp change. So if your at 34 and it’s 80 out, a temp drop down to high 30s or low 40s can set off the alert when set to 30.
Also, not to turn this into a pressure thread, but 34 may be too high for your tires.

 

[NachoRuby]

Did you do a chalk test? I have 315 Kanatis and running 34 but that looks like too much, I.e. higher in the center. I’m going to test tomorrow.

No. I'll do it to tomorrow, if it's not raining. I'll borrow some of my kid's chalk. I did figure out how to manually input a psi setting on jscan. You have to turn it on under app and adapter settings.

 

[Geoarch]

No. I'll do it to tomorrow, if it's not raining. I'll borrow some of my kid's chalk. I did figure out how to manually input a psi setting on jscan. You have to turn it on under app and adapter settings.

Which OBD did you get?

 

[NachoRuby]

Which OBD did you get?

I already had one from before that I used on my old car. It's a Carista, and it works with jscan, but I wouldn't recommend it, just because there are cheaper options. My old car required a different app, and the Carista was needed for it. For jscan, you can get a cheaper obd tool.

 

[ShadowsPapa]

@ShadowsPapa , I know you know all about jscan. Can you set to increments that aren't multiples of 5 for the tire pressure somehow? I set mine to 35, since now I see you can revert it. But I'd really like to do 34 or 33.

I haven't worked with the tire pressure - yet..........
My stock tires ran at 38
These tires run at about 36.
The bad - in the winter the tires almost always drop to below 30 psi (normally on a really cold day they drop to about 29) and trigger that danged alert. I'd like to set it to say, 28 psi.......... but haven't looked into it yet.
I know the tire size was defaulted in jscan to something like .25" increments, and I'm more picky than that. The truck's BCM tracks dynamic circumference in mm.

I did figure out how to manually input a psi setting on jscan. You have to turn it on under app and adapter settings.

LOL - I see you figured it out - and I'm thinking as I read that post - I bet I already did that and forgot all about that setting since it was over 2 years ago.

Remember, the rule of thumb is 1 psi pressure drop for every 10 degrees temp change.

Yeah, but that will vary some from the largest tires people here run compared to the stock tires or tires like I run that aren't huge tires.
1 to 2 pounds change, or 2% is typical (according to Goodyear and Tirerack)

If you are running 30 psi that's roughly 1/2 pound
If you are running 38 psi like a stock tire, that's 3/4 pound

Mine went from 38 psi down to 29 psi from summer to winter.
That's 9 pounds with a 70 degree drop in temp.
On the other hand, at 65 degrees if mine are running 36 psi, I can see them at 39 to 40 on a hot day.

Goodyear recommends airing them up to proper pressure in the winter.

I tried the chalk test on mine - wild results. The pattern was the same whether I ran 32 psi or 38 psi. I saw no difference. So I'm using what the General tire engineer told me to run - and the tires are wearing evenly across the face - even though on the front there's a weird feathering on the edges -
but more research said that's likely a combination of caster and toe not being perfect.
We'll see how they do on this new truck.

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