MY72BUG
Hey VW world; it's MY72BUG making a general inquiry.   A humble subject perhaps, but where do people stand on the topic of tire pressures?  I don't mean exotic racing stuff or off road, but where are you on 15 " standard stock VW rims with stock width modern radial tires?  I had  a bit of an epiphany courtesy of the glove compartment sticker.  I had roundly ignored it until I did some work on another Bug and noticed that the tires were, in my opinion, way under inflated.  I then noted that these ( 17 PSI front and 27 PSI rear) were recommended pressures even for radials.  All of my training came from the crank-em-up school of tire pressure.  I run my Voyager at 35 PSI so I kept MY72BUG at 32 all round.  I fought and 90% won the battle of front end "Super Shimmy" doing new neoprene bushings, new wheel bearings, new tires and balance, steering dampner and eventually front disc brakes.  This week came the forehead slapper - " If VW calls for such radical differences in front and rear tire pressure; could there be a reason?"  The notion of weight distribution crossed my mind.  As an experiment, now that the Canadian driving season is all but over, I dropped my front tires to 23 PSI and the rears to 28.  Knowing that mushy rides were " in " back in the day stopped me from going whole hog to 17 - I could not do that to my radials!  OK Tonight some results.  More rubber on the road - better steering.  Lower pressure - less transmission of road surface irregularities to the suspension and an absolute end to the last vestiges of " Super Shimmy ".  There may be a price to pay in mileage and tire wear but at 1200 miles/ year a price I can afford.   Any similar experiences??  Dan in Goderich, Ont.


I'd rather have a partial bottle in front of me than a partial frontal lobotomy.
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Wayne

I run my radials at the recommended tire pressure as listed in the glove box without a problem. I think it's 18/28? The extra pressure in the back is obviously due to the extra weight of the engine. When I first got the Bug I over inflated the front tires and found that the handling suffered and it did not grip the road as well.

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Ryan

Tire pressure is 100% dependant upon the weight you put on them.  So as you've already considered, a VW is pretty light and doesn't need that much pressure.  The numbers on the sidewalls are MAX figures, i.e. MAX pressure for the MAX weight load.  Set that up as a ratio and set it equal to your 'running' pressure over your 'running' weight.  Running weight is acutally the corner weight each tire carrys.  If you do all this and plug in stock weight numbers and the specs for a stock tire, you magically come up with the same numbers listed in your glove box.

Even when tire size changes, the pressure doesn't change all that much, maybe a pound or two at most.  But your correct, tire pressure plays a big role in the Super shimmies simply because it puts more tire in contact with the road.  Another 'less known' contributor to the shimmies is the torque on the lug bolts.  They only take 90 ft*lbs, any more and the steel wheel will often distort and warp, completely throwing your wheel balance.  Never let an impact wrench get anywhere near your wheels.  No matter what the tire buster says, it will always be too much torque, they really have no clue.  --Ryan

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Friedle

Glove box sticker reads: front radial-19psi; rear radial-27psi, cold.  I put 20psi front they wear even, 29psi rear because my torsions springs are a little weak just to wear the tire more even, and toward the center  

 

Patrick.

'72 Super. Paint-7/20/09, 400+k miles, New engine case "41" Brazil, rebuilt German heads, new Bosch electrics, new Solex German carb. new German silencer. Built by Steve Tims Performance/Enterprises, Riverside CA. '73 OEM airfilter, (Fram elemement), chrome stock wheels, daily driver, 25.46-27.50mpg, driven 20+years.
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68autobug

Hi,

I was talking to an ex VW trained Mechanic today and He quoted 17 & 23 PSI for a Beetle's tires...

but that was probably for cross ply tires not radials..

I've always used 18 psi front and 28 psi rear pressures..

and that seems to work OK...

as there isn't much weight in the front of a beetle...

and I presume that a Supers front end is lighter than a Non Supers front end...

if anyone has taken the front torsion bar beam assembly off a Non Super beetle can tell You...

 

I have even heard of a Beetle owner putting 40 PSI front and back...  now thats even way too high for the small front wheel drive sedans these days..

I would say it wouldn't handle like a beetle at all...??

Maybe like a roller skate??

 

cheers

 

Lee Noonan - 68autoBug - Australia -

 

http://community.webshots.com/user/vw68autobug

 

Lee Noonan
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vwrod

I had new tires put on this weekend and they put 32 lbs in the front and rear. I went home and dropped the pressure down to 18 front and 28 rear, much better ride.

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68autobug

Hi,

It looks like the tire change guys never let the pressures down once they apply pressure to bead the rims,

otherwise don't let enough out..

 

but it seems most vehicles that have New tires fitted always come out with high pressures...

never the correct pressure, and all late model vehicles have a tire pressure sticker somewhere...

 

I have let the high pressures out of a few non VWs where I normally fill up..

the have all been woman... and I've noticed on the air pressure digital readout what pressure they are putting in their tires...

If someone has been there before them with high pressure Off Road tires etc and have left the gauge set at 35-45PSI...

 

Back to VWs... I've run some VWs at 22-32 PSI...

but at the moment I use 18 - 28 PSI...

the front tires will always look flat at 18 psi...

and I drive over rough sealed roads all the time...

so I don't want a rougher ride...

never had any trouble with wear on the front tires...

 

Lee - 68AutoBug - Australia -

 

http://community.webshots.com/user/vw68autobug

 

Lee Noonan
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68AutoBug - helping keep air cooled Volkswagens alive in Australia & around the World -

http://community.webshots.com/user/vw68autobug
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Ryan

I don't see irregular wear untill I drop below 12 lbs up front, there's just not enough weight up there to make a difference.  That said, I run 20/28.  --Ryan

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cyanide_music
nah, your all wrong lol!!! i run roughly, between 29-32PSI on the Rear and 27-30PSI in the Front.

the car is deadly in the wet, + drive down the motorway you get blown sidetoside but it gives good MPG and thats good for me! esspecially for lots of Motorway trips.
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cyanide_music

lmao, actually one day i was curious, checked out my Max PSI on the tyre. filled it up 2 that. 44PSI that was a fun drive, but yea...v scary!

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76fisedan
the only tire that should have that much psi is the spare for wiper fluid i do 19/22 around town but will change to 23/23 for the highway works the best for me and my driving style but use what works for you thats always good advice
1976 fuel injected standard is new to me but its my baby
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