question for the handling experts

[MMamdouh]

i have a 1.5 SOHC lanos with a few suspension upgrades...

- got a front strut bar
- front springs from lanos 1.6 version
- a set of Monroe shock absorbers (a bit stiffer than OEM)
- 15" rims
- 195/50/15 kumho ecsta MX tires

after doing all of the above the car does handle much better... less body roll in curves, more high speed stability, better braking, less wheel spinning at launch and that is all great and have enhanced the driving experience very much indeed...

i also feel that the car became more "nervous" and requires more attention to what i am doing on the road if you know what i mean... for example:

- i am known for heavy braking so if the steering wheel is not dead center during my braking the car will tend to go diagonally down the road
- a throttle lift off from WOT during a fast corner will trigger rear end break away (scary as hell if you are not paying attention)
- going sharp in some corners will trigger rear end break away as well...

i know this is normal to happen during those driving conditions but that was not easily triggered prior to the upgrades... i still drive my dad's lanos (100% stock 1.5 lanos) and those things doesn't happen that easy... OK i can't brake that car as hard as mine or go into corners as fast or as sharp as i do with my woo yet this is very noticeable on my car

is this normal with cars that have similar suspension modifications?

or is it just me gaining too much confidence with my upgraded woo and driving to the limits and being a bit reckless?

i admit that when i drive my dad's car while still in "my woo mode" i did have some unpleasant surprises such as less effective (AKA worthless) brakes. less responsive steering and loads of under-steer but i never experience any of the above nervousness described above.

since we mentioned steering... my woo now is more reactive to road surface imperfections.. the steering wheel will try to follow the road surface if it is not 100% smooth and this effect is boosted if i am under braking... is this normal with 195/50/15 tires and 15" rims??

MMamdouh

[gse_turbo]

two things come to mind in this case...

under the same conditions, test the brakes of the two daewoos and then check the temperatures of the rotors. the issues from deceleration sound a little like a stuck caliper. if the rotors on the modded woo are hotter then it is possible that the caliper is constantly causing friction.

the other thing that comes to mind is the strut mount being in backwards. there is an "upright" and "layed back" possition so to speak. this comes to mind because of how you describe the steering going where it wants. the large opening in the strut tower is oval shaped and the strut mount should be towards the back of the large opening. if the strut mount is to the front of the opening you will get sharper steering and even understeer as you are discribing. if the mount is to the back, you will bet better straight line handling. this is were my money would be if I were a betting man, especially after having swaped out front suspension as you have.

Cheers,
Garrett

[benzino]

tyres could play a massive part in these things too

i noticed when i got new tyres that they were jumpy and skiddy

this is because they are hard as F cheap chinese tyres... i think they will have legal tread on them in 20 years, they are that hard.

[MMamdouh]

i assume from your answer that what i am experiencing is not a normal thing for a car with the above mentioned mods and i defenatly have something wrong with my suspension... right?

two things come to mind in this case...

under the same conditions, test the brakes of the two daewoos and then check the temperatures of the rotors. the issues from deceleration sound a little like a stuck caliper. if the rotors on the modded woo are hotter then it is possible that the caliper is constantly causing friction.

that is a possibility indeed but wouldn't this cause the car to pull to the same side every time?... what i am experiencing is a pull towards the direction of the steering wheel as well as "follow road surface" symptom.

the other thing that comes to mind is the strut mount being in backwards. there is an "upright" and "layed back" possition so to speak. this comes to mind because of how you describe the steering going where it wants. the large opening in the strut tower is oval shaped and the strut mount should be towards the back of the large opening. if the strut mount is to the front of the opening you will get sharper steering and even understeer as you are discribing. if the mount is to the back, you will bet better straight line handling. this is were my money would be if I were a betting man, especially after having swaped out front suspension as you have.

Cheers,
Garrett

my mounts are in the correct position... i checked the pics i got after the strut bar installation





what else in the suspension system can cause that?? i remember i measured the ride height of all 4 wheels before and found out that the front right side is 1.5 cm higher than the front left... can this be a reason for what i am experiencing?

MMamdouh

[MMamdouh]

tyres could play a massive part in these things too

i noticed when i got new tyres that they were jumpy and skiddy

this is because they are hard as F cheap chinese tyres... i think they will have legal tread on them in 20 years, they are that hard.

i have got a set of Kumho Ecsta MX tires with less than 10k kms on them... those tires got great ratings on every tire review website i came acroos and their only downside is noise on highways but on the performance side they are excellent



MMamdouh

[benzino]

tyres could play a massive part in these things too

i noticed when i got new tyres that they were jumpy and skiddy

this is because they are hard as F cheap chinese tyres... i think they will have legal tread on them in 20 years, they are that hard.

i have got a set of Kumho Ecsta MX tires with less than 10k kms on them... those tires got great ratings on every tire review website i came acroos and their only downside is noise on highways but on the performance side they are excellent

MMamdouh

they are a good tyre! much better than mine

directionals do tramline, some worse than others
that's pretty normal and nothing to do with suspension (or very little)

[gse_turbo]

hhmmm, I'll have to think about it. for you to get understeer isn't very common. I've done most of the same things and haven't had an issue like these.

[benzino]

hhmmm, I'll have to think about it. for you to get understeer isn't very common. I've done most of the same things and haven't had an issue like these.

but at the same time, it could be roads and driving style

[MMamdouh]

hhmmm, I'll have to think about it. for you to get understeer isn't very common. I've done most of the same things and haven't had an issue like these.

but i am not getting under steer.. i just feel that the car became more jumpy and probably more "on a knife edge"... not sure if this is because of the modifications or its just me getting too much confidence and being so close to the limit.

MMamdouh

[MMamdouh]

tyres could play a massive part in these things too

i noticed when i got new tyres that they were jumpy and skiddy

this is because they are hard as F cheap chinese tyres... i think they will have legal tread on them in 20 years, they are that hard.

i have got a set of Kumho Ecsta MX tires with less than 10k kms on them... those tires got great ratings on every tire review website i came acroos and their only downside is noise on highways but on the performance side they are excellent

MMamdouh

they are a good tyre! much better than mine

directionals do tramline, some worse than others
that's pretty normal and nothing to do with suspension (or very little)

i have searched for the term "tramlining" and this is what i got... seems pretty much what i am experiancing with the steering following road surface variances given my tire size and type:

The term "tramlining" is being used to describe when directional control is disrupted by the vehicle's tendency to follow the longitudinal ruts and/or grooves in the road. It's name could be compared to the tram or trolley driver who does not steer because his vehicle follows the path established by the tracks.

Any vehicle can exhibit tramlining on certain areas of the highway because of uneven pavement or severe rutting. And all vehicles tramline to some degree rather than obediently following the driver's steering input. For example, there's usually at least a small change in steering resistance felt through the wheel when crossing an uneven expansion joint or asphalt junction during lane changes.

Noticeable increases in tramlining are frequently uncovered when drivers living in the snowbelt make the seasonal changeover from winter tires to summer tires, or when any driver upgrades the performance of their tires using either the same size or going to a "Plus Size" tire and wheel package. The reason that it becomes more pronounced then is because neither the typically narrower and softer handling winter tires nor the Original Equipment tires generate as much grip or responsiveness as the higher performance summer tires. Since the vehicle's suspension works as a complete package, a higher performance tire will also uncover any previously unnoticed looseness in the rest of the suspension.

[MMamdouh]

also found this info:

High performance tires with short sidewalls that develop lots of cornering power at lower slip angles will be more susceptible to tramlining than standard All-Season passenger tires that develop less cornering force until their slip angle increases. A wider treaded tire will encounter more longitudinal ruts and/or grooves in the road than a narrow treaded tire. A tire with large tread blocks that transmits the driver's input to the road with great precision will also transmit the road's imperfections back to the vehicle's suspension. And because tires become more responsive as their tread depth wears away (which is why tires are shaved for competition and track use), a tire will become more likely to tramline as it wears.

this is precisely describing the Ecsta MX tire... ultra high performance tire with low sidewall and big ass tread blocks

Usually the amount of offset change is kept to a minimum and vehicle tracking remains relatively unchanged. However it the offset is significantly different, it will alter the way the road forces are transmitted through the tire and wheel to the suspension. Therefore, large changes in wheel offset will increase the likelihood of tramlining.

i think the factory offset for a lanos is 49mm... my current rims got 35mm offset... is that relatively a big change?

If you experience tramlining, the main thing you want to remember is to keep both hands on the steering wheel in the proper "9- and 3-o'clock" positions. This will help you make the precise steering inputs that will help keep your vehicle on course. You sacrifice precise control if you drive with one hand on the wheel or both hands in the wrong place.

i do hold the steering wheel with both hands now if i am going a bit fast or going sharp into corners... and obviously under heavy braking... i hold the steering wheel at the "2 and 10 o'clock" position though... i feel more in control at this position and more comfortable as well

MMamdouh

[benzino]

remember offset depends on width. Offset is mm away from the middle of the wheel looking at it side on.

Say you had a 100mm wide wheel, the centre would be at 50mm. +40 would be 90mm. -40 would be 10mm. So therefore a 150mm wide wheel would have a 0 offset of 75mm. If it had an offset of +15 it would also be 90mm like the narrow wheel at +40 but there would be more wheel on the other side of the hub because it is wider.

So in conclusion, the higher the offset (+) the more the wheel is tucked. The lower the offset (-) the more the wheel sticks out from the guard.

[PrecisionBoost]

- a throttle lift off from WOT during a fast corner will trigger rear end break away (scary as hell if you are not paying attention)
- going sharp in some corners will trigger rear end break away as well...

If the rear end swings out that is oversteer as opposed to understeer, which is not normal for a FWD car.

Have you checked the alignment since your changes in suspension ?

I find it very strange that you would get oversteer, especially with this type of trailing arm suspension, usually you have to get the car up on three wheels before this happens.


I think your bang on with respect to thinking offset may be an issue with your car pulling in different directions, that is a significant change and I have had the exact same issue with other vehicles that have had their offset changed.

You will eventually get use to the pulling left and right, but I also had a few "scary" incidents under braking and turning where the wheel was nearly ripped from my hands as the tires tried to follow a groove in the road.

[MMamdouh]

If the rear end swings out that is oversteer as opposed to understeer, which is not normal for a FWD car.

Have you checked the alignment since your changes in suspension ?

twice... once after the shock absorbers change and the other after the 15" rims and at both times the car didn't need any adjustments

I find it very strange that you would get oversteer, especially with this type of trailing arm suspension, usually you have to get the car up on three wheels before this happens.

i can't confirm if the rear wheel was raised or not during that...

I think your bang on with respect to thinking offset may be an issue with your car pulling in different directions, that is a significant change and I have had the exact same issue with other vehicles that have had their offset changed.

i thought of a combination of that and sporty tires that have high tendency for tramlining... also a bit of wreckless driving can be a reason as at both times this significantly showed i was on some 90 degree down sloping bend.. once taking over a slower car and then stuck behind another slow car thus lifting off and braking fast and the other time i chickened out mid corner and lifted the throttle from WOT

You will eventually get use to the pulling left and right, but I also had a few "scary" incidents under braking and turning where the wheel was nearly ripped from my hands as the tires tried to follow a groove in the road.

i am now used to holding the wheel firmly specially under braking to avoid any unpleasant surprises...

as for the oversteering i am more aware now that this can happen so i am more cautions during driving... i have tried a bendy road last monday and deliberately lifted on some fast corners to train myself and i am now better at anticipating it and catching it with the steering wheel... also tried catching it with the throttle and it works too... as long as you have more road to do so

MMamdouh

[mr_g]

Lower tire profile, and different ET (wider tire) can cause what you have...

You should put lower front strut bar. It is more important then front upper strut bar...