Keep an eye on this thread...I'll post my outcomes....

Kenchan....in all seriousness.....how low do you think I could go - and still be safe (in psi)?

 

33.5psi normal street driving with 1-2 passengers (of normal weight )

I would not go lower then that. use at your descression.

 

I'll go let another two psi out....

In fact...I think I'll go for a drive in my freshly washed car...

 

I'm going to post this for the benefit of current and future readers - at the expense of a bit of a bruise to my ego...

I went outside a few hours ago to let some more pressure out on the tyres....and I noticed something strange....

Front right tyre - 36psi
Rear right tyre - 36psi
Front left tyre - 40psi
Rear left tyre - 40psi



I wondered how that could be, and realised that while I was adjusting the pressures after i'd fit the wheels, I'd recieved a long phone call!!!!! I'd forgotten what I where I was at and didn't finish letting down the other two tyres!!



Anyway....I went for a drive with 33 psi in...the ride is considerably better. It still isn't as good as the 215/40/17's i'm used to though. I think I'll go back to 34 psi, and leave it at that. I did notice that the ride feels a bit 'mushier' at turn-in.

I had a friend visit tonight with his 03 MCS who has 215/40/17 Yokohamas at 36psi on H&R suspension. I got to drive his car (which also has a Sparco Evo II bucket for the drivers side *drooool*). The car transferred every bump and lump like the 18's did before today, except each and every bump wasn't a dramatic traumatising event like it was in the 18's. His car felt more planted and direct than mine does - it gave me the false impression that I could probably go around any corner as fast as I wanted....

I was probably left with even more of an impression of the seat - man...was it comfortable....!

Other Thoughts (anyone, please add yours...)

In two weeks I'm putting my wheels on another MCS with eibachs - I'll drive that around a bit to see if that makes any difference.

Another thing I've been looking at is changing the tyres. The Falkens that came with the wheels are low-grade as it is, and I'd prefer to spend some money on some good tyres. Perhaps more Toyo Proxes (I've been very happy with my current 17's) or Michelin Pilot Precendas.

I'm thinking of 205/40, 215/40 or 225/35 - all of this depends on availability, price, and whether or not they are likely to fit under my arches....225/35's are likely to rub, but interestingly, they are also the closest rolling diameter to stock, and therefore the most accurate on the speedo. The sidewalls for those sizes are 3.2, 3.4, 3.1 inches respectively...so by that rationale the 215/40 is likely to be the most 'shock absorbant', but also the most incorrect on the speedo.

One other thought I had tonight is that it might be worth investing in some control arms so I can have less negative camber at the back...

Either way it turns out, I'll report back here for that one person who happens to use the search function and hopefully finds this discussion useful.

 

One other thought I had tonight is that it might be worth investing in some control arms so I can have less negative camber at the back...

For what reason???

 

At one point minihune commented that having less neg camber on the rear
of his car provided better comfort. but i am not sure what he is after.
I think he is thinking about getting some pizza while he's at it too.

 

I'd think that your first and lowest-cost experiment would be to borrow some lightweight wheels/tires and determine whether the ride issue for you can be corrected by reducing wheel weight.

To answer a question from an earlier post, Yes, wheel/tire (i.e. unsprung weight) weight is a Major factor in ride comfort, as well as in cornering and acceleration and braking. It's the biggest single change you can make to the car.

The heavier the parts hung outboard of the springs, the more jolt gets transmitted to the frame when you hit a bump.

 

There is some truth to that notion if the camber adjustment affects the angle of the spring/damper assembly; a spring and damper in an absolutely upright position will not change its speed as it compresses. A spring and damper assembly set at an angle will compress progressively faster as the suspension compresses. Just make a simple model with straws or sticks.

...camber thrust increases with greater camber angles too; an upright wheel in a suspension arrangement that allows only verticle movement will absorb a bump and transmit the force in a linear fashion, especially one with an upright damper/spring assembly - this is a good theoretical place to begin since this arrangement does not exist. Now, excessively camber the wheel (negatively). The motion of the wheel is no longer completely linear or up and down. Some of the force is transmitted sideways. And, if the car in question has an aggressive camber curve, it will become progressivley more negative as the suspension compresses accelerating the speed of the wheel as it moves thru its arc and therfore increasing camber thrust.

The problem with a Mac strut is that changing camber affects both the speed of the wheel, and, the speed the spring and damper. With a SLA set-up, only the camber curve is changed and therefore only the speed of the wheel - the pick-up points for the damper and spring do not change.

...adding more negative camber lowers the car too...

I love pizza! Mozzarella, gorgonzola, figs, presutto, onions, whole basil leaves and big garlic cloves - no suace...mmmmmmm good!

 

or, he might have been just feeling too much of the inner tire sidewall.

 

If you say so... I certainly don't agree with you though.

I'm still baffled at the tire pressure, camber, wheel weight, etc comments - as if something was wrong with his car. What some of you apparently fail to understand is that 1) the mini is a rough riding car 2) aftermarket springs on stock dampers sucks 3) low profile tires reduce ride quality.

To conclude, take a rough car, slap on some springs and low profile tires and this is EXACTLY what's supposed to happen. Some people fool themselves into thinking their car rides good, maybe some just like bumpy rides. Add to that, a poster who's content to complain about the ride, but not motivated to do anything meaningful (large change in wheel size - or change in suspension) to change it, and you've got yourself a meaningless thread.

 

and one meaningless post.

>1) the mini is a rough riding car

No, it is not if you know how to tune it. It is a tad choppy ride for some
on the factory linear rate springs.

>2) aftermarket springs on stock dampers sucks

No, mine doesn't. (03 + Hsports)


>3) low profile tires reduce ride quality.

No, Im running 35 profile S03's on my G35C with modded suspension.
the ride is butter smooth and no jarring or choppy ride.

You just have to know how to tune it correctly.

And... tire pressure does make a huge difference in ride quality.

 

Jeffs,

Part of teaching is patience and learning. My son knows everything and I'm a moron. But that does not stop me from gently nudging him.

 

My comments and questions in this thread are here for a couple of reasons.

1. I know the Mini, by it's nature, isn't a big-ol-comfy cruiser. My idea of what rough ride is in the mini, is based on my experiences in the car when it had stock suspension and with my previous 17 inch setup. I wasn't talking about a firm ride, I was talking about every single bump in the road being an uncomfortable event.

2. I understand that aftermarket lowering springs, heavy wheels and low profile tyres will affect the ride quality of the car. It's one thing for the car to feel firm, it's another for it to feel 'wrong'.

3. I stated at the start of this thread that this was the first car I've modded and I'm learning. I'm happy to admit I've made a mistake, and happy to admit that a mod that I've done has made my car worse, not better. That seems to be something that is rare around here.

4. I like the look of the wheels on my car, and will make a compromise, if that's possible. If I was a track fiend or 100% focussed on performance, I would not go out and buy 18 inch rims. I drive the car on the street 99% of the time and I care about how it looks almost as much as I care about how it handles - that might sound shallow but not everyone is a performance nut (I will not make/keep a visual mod that jeoparises the safety of the car though). My problem is one of compromise. I will consider taking the wheels off 'if all else fails'...

5. Other people on the boards have mentioned that they are running 18 inch wheels without ride problems like these - therefore, this makes me think that perhaps there's something wrong with my setup, and so I ask the question....

6. I find this statement not useful, as this is a forum. I was putting my it to other members of the forum to get advice and comments. To say I'm "content to complain, but not motivated to do anything meaningful" does not make sense, as I've put up this thread to help work out what my best course of action would be - keeping in mind that I'm happy to make a bit of a compromise for the look of the wheel.

Another thing to point out is that i'm not in the US or UK. Therefore, if I'm going to order anything for the car, it takes time - weeks to get parts. So we, far far down here in Australia have to be confident that what we are ordering from overseas is what we are after - because after-sales support tends to be useless for us all the way down here. I can't just drive down the street and buy some mini bits like you guys can.

The wheels have only been on for just over a week. I'm not about to throw a set of wheels out straight away just because the ride is bumpy (as I don't have money to throw away). I'm going to try work out what I can do about the problem first before I go straight to getting rid of them.

So say this is a meaningless thread is useless. I went searching on here, before and after I picked up the wheels, for info on 18 inch wheels, tyres, suspension etc. Someone like me may make a search like this again, read it, and perhaps gain some insight into my experiences with lowered suspension and 18 inch wheels. In fact, you may have noticed there is a poster on this thread who's about to get a set of 18's and has mentioned to me he'd be interested in my outcomes, as it may affect what he does with his car.

And finally, it is an embarrassing thing to admit your mistakes in a public forum like this. I did it so that people who were reading this thread in interest, got the whole story. I screwed up, and am happy to admit it. Someone might learn from my mistakes...

 

Tit- considering modding a car is all trial and error, you haven't made any
mistakes other than talking on your celphone while pumping air into the
tire.

 

watch this space, ill be posting if i made one of these mistakes with m7 springs and 18" rims! lol

 

Hey Tit,

thank you for openning this thread, if you did not i would have, because I just ordered a set of 18x7 OZ superturismo WRC rims from OZ Racing USA, and am currently running on h-sport springs. I am closely following this thread, because it is going to be a challenge for me to minimize the comprimise in comfort for handling and cool factor gains. I do not want to make a mistake on my tire choice nor having problems with the car. In addition to this, people should have patience and understanding or get the hell out of the thread and move on to the next one....

Ken (kenchan) is a good source for the right desicions, lots of experience, (no he did not pay me ) so do like i do, send him pms....

 

Ah...see...I recieved a call and walked away from the car.....

So...todays lesson....don't take any phone calls while you are working on your car... Especially if you're a scatter brain like me...

You know what they say..."a fool learns from his own mistakes, smart people learn from the mistakes of others"

 

...fools don't learn from anyone. Learning from other's mistakes is shrewed but removes the struggle and responsibility - makes for arrogant type folk...learning from your own mistakes reveals your true nature and ability, humbling qualities.

 

berky- hahahaha

which tires did you get with those turismos?

 

I have not yet, the rims are on the way. you want to exchange them with your SSRs? I think it is fair, from a price point. Anyways, i am seriously in trouble for the tires. As you know, bigger the rim, more expensive the tire, and i really don't want the 35s, but there is 4-5 manufacturers that supply 205/40/18s and 215/40/18s are a little off. Keep in mind i have to consider the rubbing too. Now Sensei, enlighten me

 

If it was my MCS running 18's and going for dressup only,
i would run 215/35/18's ParadaSpecII's. they use a soft
silica compound and the ride is actually more comfortable
than others. not the cheapest nor extremely good performing
tire, but probably one of the better all rounders for street use.

I would use 33.5 to 34psi, and cruise.

I would also use H-sport front springs, but swap the rear
with Whiteline rear springs. I would use OE dampers unless
i can find a set that is simultaneously adjustable.

Finish off with a nice booming heavy stereo system in the
boot to make it even more softer riding and to lower the
boot a tad more than what the Whitelines would do just
by themselves.

whalla, theoretically, you got yourself a soft riding 18"
cruiser that will turn heads. well, at least by
calculation it would. if the ride is still too firm, I would
suggest 205/40/18's Pilots and run 33psi.

 

yeah, we are all talking on paper, i think i will stick to 205/40/18s. 33psi front 34 back?

 

yah you don't take me seriously do you? berky berkie berkee

 

heh heh heeeeee

nah, not at all, Ken

I just don't want to make a mistake on this, BTW, do you have a spare in your car? Always been curious, now i am switching to non-runflats, and am worried about millions of things, my God, am I bitching so much? I should be happy....Anyways, seriously do you have a donut? If yes, where did ya get it?(won't take Krispy Kream or Dunkins Donut for an answer )

 

donuts are for wimps. i carry an air compressor, fix a flat, and a
celphone.

BUT... if i was gonna take the car cross country i will pop out my
BassLink and throw the donut off my 04 Civic in there.
or just run my R90's with the DSST's... or just take the Legacy.