ground clearance - tyre pressure effects?

[ryan]

Don't worry about it.

Just go slow over big humps next time.

Everyone gets scrapes from time to time in the forum... as long you don't bang it so hard that it sends shudders through your spine, you should be fine

Cheers and welcome to the forums.

Oh yes..We have nut asses who run 19" (like Azrielsc, but don't say i say one..) and use sports suspension as well, i think he scrapes everytime he drives out of his home... :laughlik:

 

[Azrielsc]

Hahaha! Thanks for the "recommendation" BRO! :ehhh:

My car not so low lah... Only scrapes when I go to Golden Mile Complex... That place is definitely a No-No except for freakin' SUVs!!

Melo, sometimes it may not be your undercarriage or bodykit but could be the 2 flaps that are in front of your front wheels. U could be scraping those instead!

Cheers!

PS: I was thinking of lowering it a teeny bit more leh... :thinking:

 

[ryan]

Hahaha! Thanks for the "recommendation" BRO! :ehhh:

My car not so low lah... Only scrapes when I go to Golden Mile Complex... That place is definitely a No-No except for freakin' SUVs!!

Melo, sometimes it may not be your undercarriage or bodykit but could be the 2 flaps that are in front of your front wheels. U could be scraping those instead!

Cheers!

PS: I was thinking of lowering it a teeny bit more leh... :thinking:

 

[Azrielsc]

Wait till i get my car back from servicing!

Think another 5mm down on the fronts would be the sweet spot!

 

[melo]

Hi ryan and Azrielsc

thanks for the replies and welcome. :wavey:

I've been reading up in the forum, which is why I have been super careful when driving over humps and on steep slopes. I was very surprised that the car had no problems clearing the ikea carpark (heard horror stories about scrapes going down there) and all. Looking back, I suspect the tyres were on higher pressure then, so could be why there was no incident. Never had problems with such things on my dad's old 5 series. but that one was on 15" wheels and normal suspension.

After being assured that the undercarriage should be fine (thanks again guys!), my last concern is to figure out if the tyre pressure could be a factor. After last night my dad rushed out this morning to adjust the pressure back to the 4 passengers level. Anyone else have this view/theory that tyre pressure would affect ground clearance a little?

 

[melo]

Melo, sometimes it may not be your undercarriage or bodykit but could be the 2 flaps that are in front of your front wheels. U could be scraping those instead!

Hi azrielsc

I dunno man, I really hope so? But the grind seemed to come from closer to my seat than footwell so i think it was the undercarriage. :verysad: But i'll keep my fingers crossed that it was the flaps instead.

although... scrape any part of the car my heart will feel pain so maybe doesn't make much difference. i still wanted to lie on the road and cry :screwedu:

 

[E46]

1 other place I noted was a shopping centre in bishan. Some freaking smart a** contractor thought drivers are going to clock 300mph when they come out from the basement carpark, hence they placed a huge hump immediately after the exit. :screwedu:

The problem is the exit slope is at a almost 35 degrees upslope and placing another hump will simple make things worst ! I've actually glinded my undercarriage as I was carrying 4 pax while driving at walking pace. And we are talking about a stock 320.

 

[Azrielsc]

Melo, i felt the same as well when i kenna my 1st couple of scrapes, BEFORE i lowered my ride... Now, its lowered and I hardly scrape! :thinking:

Playing with tire pressure because of scrapes don't seem to be the wise choice. Here's a quote from Tire Rack for u to ponder over:

"While the drivers thought that the properly inflated tires provided responsiveness and predictable handling, they quickly realized that the same tires in an underinflated state left a lot to be desired. The underinflated tires required more steering input to initiate maneuvers and were slower to respond. The underinflated tires also felt out of sync during transitions; instead of moving in unison, the rear tires' reactions lagged behind the front tires, resulting in a detached sensation being transmitted to the drivers.

The underinflated tires delivered acceptable steady-state cornering force once they stabilized on our test track's skid pad, but the car was uncooperative anytime it was asked to change directions. It proved to be over 2 seconds slower around our test course (2 seconds represents about a 7% loss of handling performance).

In other words, the performance that tire manufacturers build in, low tire pressures can take away."

The rest of the articles can be found at TireRack: http://www.tirerack.com/tires/tiretech/general/airpress_vs_dryperf.jsp

 

[melo]

Melo, i felt the same as well when i kenna my 1st couple of scrapes, BEFORE i lowered my ride... Now, its lowered and I hardly scrape! :thinking:

Playing with tire pressure because of scrapes don't seem to be the wise choice. Here's a quote from Tire Rack for u to ponder over:

Thanks for the article, Azrielsc. Told my dad not to play around with the tire pressure anymore. When I get the guts i'll try that slope again. But right now I still glare at that spot whenever I drive by... :furious:

I'm curious, if someone were to change their wheels to a bigger diameter? Is the risk of scraping higher as well?

 

[Azrielsc]

But right now I still glare at that spot whenever I drive by... :furious:

Hahaha... that's damn funny...

 

[jon2367]

Re: ground clearance - tyre pressure effects?

Hi ryan and Azrielsc

After being assured that the undercarriage should be fine (thanks again guys!), my last concern is to figure out if the tyre pressure could be a factor. After last night my dad rushed out this morning to adjust the pressure back to the 4 passengers level. Anyone else have this view/theory that tyre pressure would affect ground clearance a little?

Lower pressure does not have an appreciable effect on ground clearance. It does allow the tire to compress more when it hits the bottom of the hump. Thats probably the reason you scraped. You also stand a higher chance of bending your rims and suffering tire damage if you hit a pothole.