honda civic EH, flex too much with 15inch wheels

**NA15BS** · 16-02-2011 08:59 PM

i got a honda civic 4 door sedan, with SS tein coilovers set to max stiff, oem front and rear swaybars, car been lowered just enough to clear the fenders. but when i put my 15inch 6.5 width wheels wrap with 205/50/15 toyo r888 on the front and falken tyres on the rear, my car bounch okay but flex too much, i ended up putting a hardrace full kit bushes but didnt solve the problem. my car is dangerous to drive on more than 80khp. especially when changing lane i have to slow down. i checked my coilovers for oil leaks and and their okay bought them brandnew 2.5yrs ago. but when i put my 17inch wheels with 205/40/17 back on my car for testing all the flexing problem are all gone. Any of you guys have the same experience or maybe some advice how to solve this problem would be much appreciated...coz i like my 15inch than my 17inch wheels..... thanks in advance...

**NA15BS** · 16-02-2011 09:03 PM

forgot to mention alignment also been checked, and tyre pressure on 15inch wheels is 36psi..

**jdmEG5** · 16-02-2011 09:09 PM

steering problem? :s

**V73C** · 16-02-2011 09:11 PM

Bounch okay but flex too much ?

**NA15BS** · 16-02-2011 09:18 PM

bounch okay but flex left n right... i check for any loose bolts and nuts but everything is okay...
steering problem, i realy dont know coz i when i put my 17s everything is back to normal...

**string** · 16-02-2011 09:20 PM

I'm sure I'm not the only one who sees a problem with R888's on the front and "falkens" on the rear. R888's are about as anti-flexy as they come -- they're a competition tyre. A lower profile 17 is going to have a higher cornering stiffness than your 15" "falkens" much closer to that of the front (but likely still nowhere near). What you mean by "flexy" probably has nothing to do with tyre cornering stiffness though...

1) Mismatched tyres. This can sometimes be acceptable but you definitely can't run an R-compound on one axle and not on the other.
2) You have cheap coilovers set on full-stiff. The chance of full-stiff being optimal for what you want is basically 0%. What is optimal? Iterate through the settings until you figure out what they do. This can't be explained in one post, and real knowledge in this area will either cost you a whole bunch of time (provided you have the appropriate background to allow for such knowledge) or a whole lot of money.

**NA15BS** · 16-02-2011 09:45 PM

i like r888 tyres, i never have problem with them even in cornering they grip really well, already tried different dumper settings but doent solve the problem that why i end up setting max stiff. if i turn the adjustmen like 8clicks it will get worse. i mean flexy, too much shaking left and right for a small movement on the steering and it sways too much or roll to much when cornering. now i got my 17inch never had a problem... went to a mechanic yesterday , he test drive the car and he felt the same way. he was thinking my coilovers..

**jdmEG5** · 16-02-2011 09:55 PM

have you done your wheel alignment for front and back? I would recommend you to do it after changing rims from larger size to smaller or vice versa and also you should align them also if you raise/lower your car.

**dougie_504** · 16-02-2011 10:59 PM

Are you putting the new wheels on with the balancing weights in the right spot? 'Flex' from changing lanes is kinda extreme.

And you're not referring to body flex, right?

**mugen_ctr** · 16-02-2011 11:27 PM

Originally Posted by dougie_504

Are you putting the new wheels on with the balancing weights in the right spot? 'Flex' from changing lanes is kinda extreme.

And you're not referring to body flex, right?

Prbs mean as in how the tires side walls flex, what about tire pressure?? seems u mite be running low tire pressure causing the sidewalls to flex alot

**NA15BS** · 16-02-2011 11:46 PM

yah i think side wall flex of the tyres, im running 36psi each tyres... yap wheel alignment been check changing from 17 to 15 and vice versa at jack tyres liverpool. should i put 40psi or more?

**jdmEG5** · 16-02-2011 11:55 PM

Originally Posted by NA15BS

yah i think side wall flex of the tyres, im running 36psi each tyres... yap wheel alignment been check changing from 17 to 15 and vice versa at jack tyres liverpool. should i put 40psi or more?

nah 36 sounds right for 15" tyres..

have you taken it to the mechanics? can it be your bushings? to me it might sound like your powersteering man..

Because on my brother's EG, i noticed it has an electronic plug for the powersteering (its located on the powersteering lines behind the motor) and i read something from here that says the plug is used for activating the power steering on low speed or something...
or a sensor/switch to loose the pressure on the fluids on high speed so steering wont be as light?

sorry very shit description.. lol