Height on 17" alloys

[Nauxcorolla]

What height would i want my car on 17" wheels. Should i go coilovers or springs. Friend of mine had 40mm springs didnt look low enough but could be just bad springs. Any suggestions? 

[Cookeh]

Coilovers will be much better for your cars handling and for reducing wear and tear on the suspension and tyres. Regarding height, that is entirely subjective and depends on what you think looks best aesthetically.

[JRCorolla2]

I have some 17" alloys on 225/45/17 tyres, im only going 30mm lower on Eibach Springs in a couple of weeks, i know coilovers will sit nicer but thats too low for me 

[Cookeh]

Its will also have a negative impact on your handling - lowered springs will have different compression ratio and damping/rebound to the shocks you're pairing them with; this leads to issues with handling and increased wear and tear on the shocks. If you're going with springs, at least match them to the shocks and if not go for coilovers.

[Nauxcorolla]

Ya will just go for coilovers for the sake of 200 more

[JRCorolla2]

3 hours ago, Cookeh said:

Its will also have a negative impact on your handling - lowered springs will have different compression ratio and damping/rebound to the shocks you're pairing them with; this leads to issues with handling and increased wear and tear on the shocks. If you're going with springs, at least match them to the shocks and if not go for coilovers.

a few people have said that lowering a PFL t sport by 30mm on the standard shocks is okay, however any lower then coilovers/new shocks are needed?

[Cookeh]

It will be okay, in that it will lower the car and it will still drive. It will, however, still have a negative impact on ride, handling and grip though. Lowering springs in general are a pretty bad way of going about dropping your car if you are doing it for anything other than aesthetics.

To briefly go into it, aside from the fact you have no adjustment with lowering springs, they also result in less grip due to the fact the spring will be much stiffer (sounds counter intuitive but there is a fair bit of math behind it that you can check up on).

Of more importance/concern is that the spring will have a different damping rate to the shock, which will reduce the shock's travel and reduce its damping ability - again less grip, much worse ride. This is because the shock will be tuned for a softer spring that will have more travel, so in stiffening and shortening the spring you reduce the travel of the suspension, increase it's preload and so impact damping - so the car can be crashy and have poor small-bump sensitivity (i.e. be harsh), as well as being more likely to bottom out.

The third negative associated with lowering springs is that they can and will increase the rate of wear and tear on the shock and will damage it. Obviously a damaged shock costs money to replace and it still won't have the same damping rate as the spring and so will still get damaged again. So whilst in the short term lowering springs seem cheaper, they can easily work out to be more costly.

Coilovers, on the other hand, are height adjustable, they have matching spring and damping rates, the damping and rebound of the suspension can be tuned and adjusted and they won't suffer from the same issues attributed to lowering springs.

 

 

[SanaYusuf]

30mm springs will be fine with the standard shocks and will improve handling as attested to by many on this forum. Obviously coilovers will make a much bigger difference but then you have all the hassle of setting them up right and also maintaining them. 

Only issue you might have with the springs is if your shocks are dying a slow death then adding lowering springs will speed up that death.

Personally I would go with the springs and a updated ARB (my next mods).

[Cookeh]

Lower springs and an ARB will further affect the handling...

Anti-roll bar on a FWD will increase understeer (and decrease grip) by increasing the slip angle of the wheels as you corner and through the increased weight over the front of the car. Admittedly you can counter this by decreasing the spring rate on that axle....except you've increased that with a lowering spring. A stiffer/bigger ARB will also reduce the independence of the suspension which again reduces grip. Sure, you'll get less body roll but also decrease grip and have crashier suspension cos every pothole/bump/stone/whatever you hit with one wheel will be transferred across the whole front end.

 

As said, 30mm drop will not stop your suspension from working, and will decrease body roll cos of stiffer shocks so I guess that could be classed as an improvement to the handling, but then worsening the ride and grip hardly seems like an upgrade.

[SanaYusuf]

I take your point, but a fair few owners have lowered with springs and fitted ARB on pre-facelift T sports and have said it totally transforms the car-for the better.

So in your opinion ARB's are not the way to go with just springs?

(I'm talking rear ARB).

[Cookeh]

Rear ARB will reduce roll slightly at the rear and won't encourage understeer. It will still have the same other negatives, however, such as decreased grip (not really what you want, especially as oversteer is harder to correct than understeer!) and reduced independence/ride quality at the rear. Honestly, from a performance POV I just don't see the advtange for lowering springs, if you want to gain performance handling wise its tires and coilovers that you should be looking at in my opinion (and in that order!). I also wouldn't pair an arb with springs, personally - though for a tracked car I would add them alongside coilovers. For normal road use I would just go for coilovers as the suspension upgrade.

This is of course just my opinion though, looking at it from an engineers POV and putting grip and ride quality as the most important factors.

[JRCorolla2]

14 hours ago, Cookeh said:

It will be okay, in that it will lower the car and it will still drive. It will, however, still have a negative impact on ride, handling and grip though. Lowering springs in general are a pretty bad way of going about dropping your car if you are doing it for anything other than aesthetics.

To briefly go into it, aside from the fact you have no adjustment with lowering springs, they also result in less grip due to the fact the spring will be much stiffer (sounds counter intuitive but there is a fair bit of math behind it that you can check up on).

Of more importance/concern is that the spring will have a different damping rate to the shock, which will reduce the shock's travel and reduce its damping ability - again less grip, much worse ride. This is because the shock will be tuned for a softer spring that will have more travel, so in stiffening and shortening the spring you reduce the travel of the suspension, increase it's preload and so impact damping - so the car can be crashy and have poor small-bump sensitivity (i.e. be harsh), as well as being more likely to bottom out.

The third negative associated with lowering springs is that they can and will increase the rate of wear and tear on the shock and will damage it. Obviously a damaged shock costs money to replace and it still won't have the same damping rate as the spring and so will still get damaged again. So whilst in the short term lowering springs seem cheaper, they can easily work out to be more costly.

Coilovers, on the other hand, are height adjustable, they have matching spring and damping rates, the damping and rebound of the suspension can be tuned and adjusted and they won't suffer from the same issues attributed to lowering springs.

 

 

 

12 hours ago, SanaYusuf said:

I take your point, but a fair few owners have lowered with springs and fitted ARB on pre-facelift T sports and have said it totally transforms the car-for the better.

So in your opinion ARB's are not the way to go with just springs?

(I'm talking rear ARB).

Ive done a bit of research and the Eibach 30mm drop springs (re branded TTE's) are designed to work around the standard shocks, apparently they just added the same spec spring onto the standard shocks with the facelift version of the t sport. Alot of people have said that a 30mm drop on the standard PFL shocks wont cause any issues, any lower then what you are saying about the shocks wearing faster and dramatically less grip etc would be a given. If i were driving on a track every day then maybe but its standard driving and with 17"s on 225/45/17 the ride should be great.

[Nauxcorolla]

I think ill just get springs until the summer is finished up. What springs would ye recomend on standerd shocks and any links. Ive only a 1.4 but im fairly sure the facelift are lower than the pre facelift

[JRCorolla2]

7 minutes ago, Nauxcorolla said:

I think ill just get springs until the summer is finished up. What springs would ye recomend on standerd shocks and any links. Ive only a 1.4 but im fairly sure the facelift are lower than the pre facelift

If you're using standard shocks the best springs to go for are the Eibach, as they are designed to work on the standard shocks. Any other springs or going lower than 30mm then it seems the general consensus is to get new shock too, or coilovers, or you may experience all of the issues listed above by Cookeh.

[Nauxcorolla]

No bother thanks