Tire Pressure

[rastus]

I am a real novice and need help. I have 185-65-R15 tires front and back on my 1961 split bus. A Karman Ghia rear end so it sits low to the ground.

What tire pressure do you recommend I put in my tires. I presently have 35 psi and I get a bumpy ride.

Thanks for your help.

[jadatis]

Googled the sises of your tire and have maximum load of 560kg/1235 lbs .
Most likely standard load so AT 35 or 36 psi.
So if you can determine the actual axle loads , or better sperate tire-loads , I can calculate a save lowest pressure for you.
If you can also give your maximum speed you use and wont go over for even a minute, I can even give a better advice.
But also look on sidewall of tires to chech the data, if you find XL/Extraload or Reinforced, the AT-pressure is 41 psi or 42 psi and maximum load is also more. Googled that too and gave LI 92/630kg/1390lbs maxload .
I find the European tires so AT 42 psi, but American system would give 1 LI step lower AT 41 psi , then P-before the sises.

[rastus]

Thanks for taking the time to help the helpless. It says Radial LL 65 on the side of my tires. As to speed, it varies from 30 m.p.h to 60 m.ph.

Gene

[ronjonlasvegas]

This is what the owners manual says for tire inflation. I am not sure if this is still correct as when the bus was new it would have had Bias Ply tires and modern tires are much different. Someone with more experience than me will need to answer that part.

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September 1964 Standard Sunroof walk through SWR/BG original paint.

[EverettB]

The bias ply tire pressures apply but you should add 3 psi for radials.
This is mentioned in the later manuals where you could get either tire.
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[NUTSFORBUSES]

I use 1500 + load tires (radial) I think that is needed for my liking/bus. I use my race car discipline for tire pressure: don't ever exceed the rec. pressure and "test" the pressures front and back-write it down. It takes time, but worth every minute, as long as you have a good pressure gauge. My ride has much improved using this technique. Tires have changed so much since the bus was built, and street radials are more trial and error than an "off road/heavy sidewall" type tire that many Bus owners use. I like the cush and quite ride.
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kaiser kills kids.com

[Who.Me?]

There's an explanation of how to calculate tyre pressures on the SSVC Technical page...

https://www.ssvc.org.uk/phpbb/viewtopic.php?p=893128#p893128

Having said that, it came up with a very low number for my truck, so I ended up going with the original bias ply tyre pressures from the manual. They look about right, but I can's say I do a lot of miles in the truck.

https://www.ssvc.org.uk/phpbb/viewtopic.php?p=897810#p897810
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Andy


Looking for info on my truck's history. Are you from Campbell California or nearby. Do you recognise it? ... http://www.thesamba.com/vw/forum/viewtopic.php?t=636786

[jadatis]

[Murt]

Sorry to resurrect an older thread, but I’ve been searching on here regarding tyre pressures.
Came home to a flat on my rear passenger side (LHD Kombi) today. OK, so tried putting some air in, and wasn’t sure of how many PSI to put in, so checked the driver’s side, and it only had 24psi in it 😩 anyway, pumped the flat up, and just went out, and yes, she’s flat again 🤬 no drama, as I have a spare, so my question is as per this thread. What pressure is good for a modern tyre set up ?
I’m not lowered in anyway
I’m running 5.5J x 205 ET20 alloy wheels
Wheels are fitted with 195/70/15 Vredestein Comtrac tyres, and clearly marked as 450 kPa/65 psi MAX Pressure 😱
And probably looking at driving the Bus maybe 2000 miles per year ?

So chaps, what’s your thoughts ? I’m planning on getting 2 new rears. The existing tread looks good, but the sidewalls look at bit cracked, there’s a good choice of tyres over here, Michelin Agilis, Continental, Hankook, Nankang, and also Falken which I quite like, as run them on my Bug. You guys have any preferences?
As for pressure, I’m tempted to say, that as has been mentioned, going original bus manual pressures +3 psi for radials ?? Help Please 😂😂😂😂
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1966 VW Beetle ‘Jules’
1967 Kombi Splitscreen ‘Barney’
2018 VW Caddy Maxi R Line
2017 Golf GTD saloon
2008 VW EOS 2.0 TFSi

[mandraks]

your problem is that you do not drive enough to see what your pressure needs to be.

start with the recommended bias ply plus 3 pounds and look at your tires.

do the look bulged out at the bottom?

I like lowering my pressures until i see a difference in wear pattern after some driving.

pressure too low: tires wear on the outsides.
pressure too high: tires wear in the middle only.

Most people tend to run their tire pressures quite high, making them uncomfortable. this is relatively safe as far as the life of the tire is concerned, but i can make a bus drive really sketchy.

as i said, start with the recommendation and work your way down from there. that is my recommendation.
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regards

Uli

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'53 3-Fold Oval, L35 Metallic Blue, looking for a narrow hatch panel

[hitest]

Tire pressures aren't the only factor diagnosing a bumpy ride in a Lowered bus. Are the shocks shorter (correct) - or just stock ones mashed down tighter?
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[Tizian]

[Murt]

Some interesting responses, and definitely food for thought

I'm sort of in a pickle now, as that flat upon closer examination looks absolutely great tread wise, and apart from a little crazing on the sidewall to all intents and purposes looks perfectly good.

The reality is somewhat different, I have realised that the date stamp on the tyre wall is 4608 !! Yes, manufactured week 46 0f 2008 the other rear is from 2019, and can't decipher the fronts !!

Bottom line is that I definitely think I need to replace all of the tyres now, as I can't definitively say they're OK to drive with.

This bus is new to me, I've only had it a month, and I'm learning new stuff about the Busses every day. Good and Bad

Found tons of good stuff on the Samba here, so feel in good hands, and I'm also pretty comfortable with the advice on tyre pressures now

Just to re-iterate, currently I’m not lowered in any way

I’m running 5.5J x 205 ET20 alloy wheels, and they are currently fitted with 195/70/15 Vredestein Comtrac tyres.

I'll probably be looking at only driving the Bus maybe 2000 miles per year as I also have my beetle as well? 😱

So, as I want to change the wheels anyway from the 'empi' style to Fuchs reps, I now have the option of adding a tyre package.

There's currently a good deal on the wheels and tyres, but the tyres in the package deal are 185/65/15, which will take my current tyre diameter of 25.74" down to 24.46" and a speedo error of 5.3% and also a loss of overall speed ?

Hi Tizian
I'm going to have to look at the shocks as well, as now I've seen tyres that are 14 years old, I'm probably going to need new shocks as well
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1966 VW Beetle ‘Jules’
1967 Kombi Splitscreen ‘Barney’
2018 VW Caddy Maxi R Line
2017 Golf GTD saloon
2008 VW EOS 2.0 TFSi

[Eric&Barb]

You really want to get 1,525 Lbs. or higher weight rated tires for any 1955-67 bus that will be traveling on the highways. We used to run beetle tires with about 1,200 Lbs. (sold to us by tire shop because that was what they sold for VWs) rating and got pushed side to side in windy weather in places like the Columbia river gorge thru the Cascade Mtns. or even by any bow wave of a semi truck passing us. We are talking sudden lurch changing lane action that made for white knuckle stressful driving that tired one out all too quickly. Now barely notice side winds, and only slight steering adjustments in worst situations is all that is needed to keep in the lane.
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[mandraks]

[Murt]

Thanks mandraks
I'm certainly going to look at the Red Koni shocks, heard good things about them
_________________
1966 VW Beetle ‘Jules’
1967 Kombi Splitscreen ‘Barney’
2018 VW Caddy Maxi R Line
2017 Golf GTD saloon
2008 VW EOS 2.0 TFSi

[Tizian]

[Murt]

Hi there
I've just put the shocks in my basket, and they look to be $460
Are you suggesting going for the KONI 80-1350 front and rear then ? as I have been going for these, but haven't bought them yet ?

_________________
1966 VW Beetle ‘Jules’
1967 Kombi Splitscreen ‘Barney’
2018 VW Caddy Maxi R Line
2017 Golf GTD saloon
2008 VW EOS 2.0 TFSi

[Tizian]

[Murt]

Finally fitted my new Fuchs repop wheels last night.
The tyres I went with were a good value tyre.

Uniroyal Rain Max3 195/70/R15 C104/102, as per advice from Eric and barb above 👆 wanted a decent load rated Van tyre, and these are 900kg/1984lbs. I’m off on a decent 60mile run tomorrow, and have set tyres at 31psi on the front and 36psi on the rear, and will see what a difference it makes. Hopefully 🙏 night and day, as I was horrified by the fact that the front tyres were older than the 2008 one on the rear, and were stamped on the inners at 2006 😱
I have also bought a new set of shocks, and after a lot of looking around, finally went with a really good deal on a set of Bilstein Shocks, for standard suspension. They were actually cheaper than the Koni ones ($460) and the offer came in at ($412) planning on fitting probably next weekend.

_________________
1966 VW Beetle ‘Jules’
1967 Kombi Splitscreen ‘Barney’
2018 VW Caddy Maxi R Line
2017 Golf GTD saloon
2008 VW EOS 2.0 TFSi