Rough ride, RFT at 31/33 PSI ok?

spuck · 06-28-2010, 10:45 AM

I have a 07 335xi with OEM Style 159 17" rims and Bridgestone RFT. I live in Montreal where it's impossible to find a decent patch of pavement and this car is driving me crazy with the roughness on choppy roads. At this point, I'd put 15" rims if they would fit over the calipers.

Is it safe/acceptable to drop the PSI from 35/38 to 31/33 (F/R), I did this yesterday and it made a massive difference.

I'm a little worried about damaging the side walls of the RFTs with the lower PSI, but then again tires are way cheaper than replacing worn out shocks/springs, constant realignments or dented rims.... so maybe I shouldn't be too concerned.

Any advice or suggestions on softening up the ride?

Firefly6 · 06-28-2010, 11:41 AM

Had those same tires. When pressure was low I noticed a noisier ride and sloppier handling. I wouldn't recommend it.

I switched to Continental RFTs and the ride is definitely much less harsh.

stratplaya06 · 06-28-2010, 11:57 AM

How much tread do you have left on those tires? Unfortunately you got the crappiest tires offered with the 17" wheels (the contis are much better, but still not great). I say run those pressures provided you're not pushing the car over 100mph and you don't mind a little wear to the tires. Whatever you do, don't replace them with the same tires. If you must stay with the RFT's, get the contis, and if you are willing to leave the "runcraps" get a nice set of regular tires. Your ride will be smooth as glass.

spuck · 06-28-2010, 08:58 PM

Quote:

Originally Posted by stratplaya06

How much tread do you have left on those tires? Unfortunately you got the crappiest tires offered with the 17" wheels (the contis are much better, but still not great). I say run those pressures provided you're not pushing the car over 100mph and you don't mind a little wear to the tires. Whatever you do, don't replace them with the same tires. If you must stay with the RFT's, get the contis, and if you are willing to leave the "runcraps" get a nice set of regular tires. Your ride will be smooth as glass.

What would be a good non run-flat replacement in 17"? I don't want "sportier" tires, my average speed is 40km/h driving around downtown montreal. I do want a descent tire with emphasis placed on ride quality. I've read about the Michelin PS2, but everyone's perspective is different... and i assume most people are driving PS2's on good roads with emphasis on handling not comfort.

One more thing, is there any chance I can upgrade to 18" non run-flat tire/rim setup that is more comfortable than OEM 159/17 RFT (even slightly better would do)?

cb4 · 06-28-2010, 09:16 PM

If comfort is what you are after stick with 17s. Get yourself some conti dws for tires.

06-28-2010, 10:45 AM	#1
spuck New Member 7 Rep 18 Posts Drives: E90 335xi Join Date: May 2010 Location: Montreal iTrader: (0)	Rough ride, RFT at 31/33 PSI ok? I have a 07 335xi with OEM Style 159 17" rims and Bridgestone RFT. I live in Montreal where it's impossible to find a decent patch of pavement and this car is driving me crazy with the roughness on choppy roads. At this point, I'd put 15" rims if they would fit over the calipers. Is it safe/acceptable to drop the PSI from 35/38 to 31/33 (F/R), I did this yesterday and it made a massive difference. I'm a little worried about damaging the side walls of the RFTs with the lower PSI, but then again tires are way cheaper than replacing worn out shocks/springs, constant realignments or dented rims.... so maybe I shouldn't be too concerned. Any advice or suggestions on softening up the ride?
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06-28-2010, 11:41 AM	#2
Firefly6 Lieutenant 12 Rep 412 Posts Drives: 2018 330i Xdrive Join Date: Aug 2007 Location: New Jersey iTrader: (2)	Had those same tires. When pressure was low I noticed a noisier ride and sloppier handling. I wouldn't recommend it. I switched to Continental RFTs and the ride is definitely much less harsh.
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06-28-2010, 11:57 AM	#3
stratplaya06 Captain 46 Rep 967 Posts Drives: 2008 E92 335xi-SOLD 5.0 Miata Join Date: May 2008 Location: Maryland iTrader: (10)	How much tread do you have left on those tires? Unfortunately you got the crappiest tires offered with the 17" wheels (the contis are much better, but still not great). I say run those pressures provided you're not pushing the car over 100mph and you don't mind a little wear to the tires. Whatever you do, don't replace them with the same tires. If you must stay with the RFT's, get the contis, and if you are willing to leave the "runcraps" get a nice set of regular tires. Your ride will be smooth as glass. __________________ \| PROcede Rev3 \| Vishnu Meth \| DCI \| BMW Perf. Exhaust \| AR Coated/Catless \| CP-E FMIC \| Quaife \|
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06-28-2010, 09:16 PM	#5
cb4 Captain 60 Rep 910 Posts Drives: 2008 335xi Join Date: Jul 2009 Location: Massachusetts iTrader: (1)	If comfort is what you are after stick with 17s. Get yourself some conti dws for tires.
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