225/45 18" tires anyone?

[Mac]

i was wondering if i could fit the 225/45 tire on my 18" instead of the 40 height tire
thinking of this because roads here are real shi7e so it could help soften a bit the ride

considering buying the koni fsd shocks but it wont be enough i think

right now on winter tires 205/55R17 ride has improved a lot so that's why i am thinking of 45 high tires for the 18
what do you think?
here are the differences in speed, diameter etc.

 

[Jarre]

As long as you understand the difference in speedo accuracy then I don't see why not. Although I'm not sure how much difference the profile size will make to comfort. My 18s aren't really less comfortable than the 17s on my old car

 

[Paulki]

If you want to improve the ride on a pre/fl FR then I would stick with the 40 profile tyres as 45's won't make much difference. Get the FSD's along with Eibach Pro Lines or Sport Lines depending on how much you want to lower it: the ride will be transformed!

 

[Mac]

the KONI FSD can go with maximum 20mm lowering springs, not more

 

[Jarre]

Standard shocks with eibach sportline lowering springs should provide you with a more comfortable ride

 

[Paulki]

the KONI FSD can go with maximum 20mm lowering springs, not more

I have had my Koni FSD's fitted with Eibach Pro's with a 20-30mm drop for nearly 7 years with no problems at all and I'm sure there are several members here using them with Sport Lines with a 40mm+ drop.

 

[Mac]

Koni replied to me that maximum 20mm is allowed in order for them to work well
they said to mount them with original springs

 

[Paulki]

Koni replied to me that maximum 20mm is allowed in order for them to work well
they said to mount them with original springs

This is from their FSD FAQ page:

"Q: How far can I safely lower my car?

A: KONIs are designed to fit standard height cars and can work with lowered cars as long as they don't bottom out internally and become damaged. Unlike some shocks, KONIs are not position sensitive so they will work properly anywhere in their stroke range providing they are not bottoming or topping out. Different vehicle suspension designs have different stroke travels but a good rule of thumb is that most vehicles can be lowered acceptably about 30-40 mm, beyond that the possibility of bottoming increases rapidly although some longer stroke cars can go lower. Most vehicles are equipped with bump stops to keep the shocks and springs from bottoming out. When lowering a vehicle be sure to reuse your bump stops as they are cheap insurance to avoid bottoming damage. Remember also that severely lowered vehicles typically also have a negative effect on suspension geometry, ride quality and handling, and tire and suspension part wear."


The alternative option is to just change the springs to Eibach's or other progressive rate springs and keep the standard shock absorbers, this will also give a better ride quality.