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Technical Spring rates?

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Technical Spring rates?

MarkThompson4

MarkThompson4

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I have a 1.2 Stilo and plan on lowering it on coilovers. I have 15's on 185/45 tyres and they look tiny in the Stilo arches but from a previous photoshop I know they will look the business when the car is suitably lowered ;) I've done my measurements and I need a 100mm drop to take it to where I want it, and that's leaving 15-20mm to the arch. I've phoned around a few places and so far all I've had is them saying that most coilovers are adjustable up to 60mm tops which obviously isn't enough for me :( 60 seems more than what most people go but trust me 60mm isn't enough for this Stilo! Is what they've said true? But the main question is; I've came across these on Demon Tweeks and thought if I could get the right spec for the springs then I can get custom springs that are shorter?

http://www.demon-tweeks.co.uk/motorsport/competition-springs/eibach-competition-springs

Or there's also these that seem a bit better?

http://www.demon-tweeks.co.uk/motorsport/competition-springs/tein-racing-springs

Anyone have an idea about this or done it before? Need opinions on this :)
 
185/45r15 must be way out. Is it a typing error? Standard is 195/65r15 so a 60 mm drop will fill the arches much more than 185/45r15. How is your speedo coping with this?
 
Last edited:
MarkThompson4 said:
Nope, might be 185/55r15 in fact :s definately was 195/65r15 originaly though but I put lower profile tyres on
Click to expand...

Hm... If you want lower profile, you should get bigger wheels, like 16" or 17". Using 185/45 (or 55) will get your speedometer reading 100 km/h but you are actually travelling below 90 km/h.

When going from 195/65r15 to 185, the profile should be 65 or 70 (if 70 exists on 185 wide tires).

If you drop your stilo 100 mm on your existing tires, I guess the exhaust would face the asphalt constantly. And I can imagine the strain on axles, bushes and joints.
 
17's on a 1.2? Nah don't think so :LOL: less work for my wee engine to do with 15's :p

It's really common for Stilos to have 17's on them I think, I'm trying to do something a little different, and if I get it right I think it will look sweet. Plus I think 17's look too big on a Stilo with no side skirts so that's why I'm avoiding bigger wheels, plus 15's would look lost in the arches if I had skirts on it :/

trust me, when it's done it will look awesome, just wait ;D
 
Old tyre size, the jack's holding it at that height as I was putting the rear spring back in :eek:

028.JPG

New tyres. They definately look smaller than the previous ones :confused:

182.JPG
 
still dont get it lol.

i dont understand why you would want smaller tyres than its suppsoed to have.. it will have incorrect speedo readings and be harsher and noiser.. unless there cheaper :p


i was meaning with the 17" on a 1.2. 205/45 is very similar to 195/65 so would make nearly no difference.
 
I worked it out on a website one time and it was something like 6% difference to the speedo it makes, which I can live with :)

It is a bit harsher but not louder really

I think it's more of a styling issue to me, I really like the wheels I've got, something about them I think they're really cool :p If I got 17's I would want side skirts because as I've said they look a bit big on Stilo's without skirts, but 15's on a stilo without skirts looks just right to me - once it's on its arse! :D

Plus 17's are bigger and heavier :p I remember driving the Stilo with the old tyres on and it felt hopeless, 3rd barely happened on small gradients! lol now with the smaller tyres I have noticed it picks up a hell of a lot better ;)
 
cool. nice to know. :). i know there abit sluggish with the 1.2 but once they get going ive herd there fine :).

i like you wheels tbh. shocked there 15" though.
 
MarkThompson4 said:
I worked it out on a website one time and it was something like 6% difference to the speedo it makes, which I can live with :)
Click to expand...

You already have 5-8% speedo error, in addition to the new...

lol now with the smaller tyres I have noticed it picks up a hell of a lot better ;)
Click to expand...

Simple physics...

The car looks like an 80's rollerskate with those small tires on, but it's genious if you want to brag about driving way to fast all the time, and never get caught speeding. :D:D:D
 
MarkThompson4 said:
How was my speedo 5-8% out before put the smaller tyres on? :s or is that taking inaccurate fiat technology into account?
Click to expand...

Most speedometers are inaccurate. Mine is about 7% off constantly on summertires (215/45/17) - even after I changed my instrument cluster, so the fault is not there. On winter tires (195/65/15) it's about 6% off. Try testing yours against a GPS. It's not a FIAT special, it's quite common, and very annoying, but also a quality, as it is difficult to maintain constant speed, so if you accidentally speed a bit too much, you are within the limit anyway. (y)

Is that a compliment? it will look the part when it's dropped 100mm!
Click to expand...

80's rolleskates are cool, especially on tan women with hotpants.

And I missed the part where I bragged about driving too fast?
Click to expand...

Back to the speedometer error due to your small wheel diameter in addition to the already calculated speedometer reading. When you put on 185/45/15 on your Stilo it is about 14% difference to the 195/65/15. This means it will also show 14% faster speed on your speedometer. And then add in the already speedometer difference. I guess you could drive in 75 mph and you speedo shows 60 mph. This way you can always be a concealed "speeder". :D

M.
 
Morty Mort said:
Most speedometers are inaccurate. Mine is about 7% off constantly on summertires (215/45/17) - even after I changed my instrument cluster, so the fault is not there. On winter tires (195/65/15) it's about 6% off. Try testing yours against a GPS. It's not a FIAT special, it's quite common, and very annoying, but also a quality, as it is difficult to maintain constant speed, so if you accidentally speed a bit too much, you are within the limit anyway. (y)



80's rolleskates are cool, especially on tan women with hotpants.



Back to the speedometer error due to your small wheel diameter in addition to the already calculated speedometer reading. When you put on 185/45/15 on your Stilo it is about 14% difference to the 195/65/15. This means it will also show 14% faster speed on your speedometer. And then add in the already speedometer difference. I guess you could drive in 75 mph and you speedo shows 60 mph. This way you can always be a concealed "speeder". :D

M.
Click to expand...

Ah... but I'm not a woman, I certainly don't have a tan, and don't wear hotpants :/ that's the sort of people I want my car to attract though :devil:

I think that's pretty cool :) Shows a higher speed than it is, always the law abiding motorist then :D

I did worry at first about the fuel consumption going up as the revs at a given speed would be higher with smaller tyres, but I'm still able to get intp the mid 50's on the motorway :D

Do smaller wheels in general make a difference to acceleration? I genuinely feel there is a slight improvement in mine after it, though I wouldn't imagine 20's on a 1.2 would help :eek:
 
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