So I want to stiffen my suspension

[Xantho]

Currently my 2008 135i has a set of rims and tires that are quiet aggressively stanced this is due to some higher offset wheels. I’m happy with the ride height and the overall look of the car at the moment, but when driving on the “wonderful” roads of my Midwest state the rough transitions cause me to rub. I’ve considered getting lower offset wheels but I also want to make the car more aggressive handling wise as well. So can I stiffen the suspension but keep stock ride height? I’m newer to how it all works so would I need different springs? And if I change springs would sportier dampers also help stiffen the suspension? Thanks to any one who responds, I look forward to potential options.

[nachob]

Originally Posted by Xantho

Currently my 2008 135i has a set of rims and tires that are quiet aggressively stanced this is due to some higher offset wheels. I'm happy with the ride height and the overall look of the car at the moment, but when driving on the "wonderful" roads of my Midwest state the rough transitions cause me to rub. I've considered getting lower offset wheels but I also want to make the car more aggressive handling wise as well. So can I stiffen the suspension but keep stock ride height? I'm newer to how it all works so would I need different springs? And if I change springs would sportier dampers also help stiffen the suspension? Thanks to any one who responds, I look forward to potential options.

135i suspensions were designed for run flats so they are softened a bit to reduce harshness. With that said having lower offset wheels than were intended for the car can have the effect of softening the suspension on top of that. If you can imagine the suspension arms pivot and the farther out you go from the pivot point gives you mechanical advantage. Like when you use a pry bar. If you grab it close to the pivot it takes a lot of force. The farther away you go the less force required. So when you go into a corner with wrong offset the mechanical effect pushes springs up with less force. So if you plan to change both at same time it can be a drastic change especially if you run run flats. So I would first decide on proper rims and tires first and see how you like it. Then you can pick up some bmw performance shocks and springs from 135is or a coil over kit. Also don't forget sidewall aspect. If you are running 18" you can also go stiffer but 19s also impact ride and performance. It's a system meant to work together not separately. So I recommend you go with proper offset 18s with non runflat high performance tires first. Then see how you like it. Stiffer is not always better and I can tell you the interior plastics in our car are not very good so be ready for a lot of creaking and rattling if you go stiff. Best wishes

[Esteban]

Originally Posted by nachob

135i suspensions were designed for run flats so they are softened a bit to reduce harshness. With that said having lower offset wheels than were intended for the car can have the effect of softening the suspension on top of that. If you can imagine the suspension arms pivot and the farther out you go from the pivot point gives you mechanical advantage. Like when you use a pry bar. If you grab it close to the pivot it takes a lot of force. The farther away you go the less force required. So when you go into a corner with wrong offset the mechanical effect pushes springs up with less force. So if you plan to change both at same time it can be a drastic change especially if you run run flats. So I would first decide on proper rims and tires first and see how you like it. Then you can pick up some bmw performance shocks and springs from 135is or a coil over kit. Also don't forget sidewall aspect. If you are running 18" you can also go stiffer but 19s also impact ride and performance. It's a system meant to work together not separately. So I recommend you go with proper offset 18s with non runflat high performance tires first. Then see how you like it. Stiffer is not always better and I can tell you the interior plastics in our car are not very good so be ready for a lot of creaking and rattling if you go stiff. Best wishes

The 135is has the same M Sport suspension that the standard 135i came with. The Performance shocks and springs you mentioned are part of the BMW Performance suspension for the 1 series. There were some 135is owners who added the Performance suspension to their cars after purchase, but no 135is (or any 135i) came standard with it. It had to be purchased separately. I have it for my 135i. BTW, I'm pretty sure the BMW Performance suspension is NLA, as are several other Performance parts for the 1 series. Sadly, they are being discontinued.

[Xantho]

Originally Posted by nachob

135i suspensions were designed for run flats so they are softened a bit to reduce harshness. With that said having lower offset wheels than were intended for the car can have the effect of softening the suspension on top of that. If you can imagine the suspension arms pivot and the farther out you go from the pivot point gives you mechanical advantage. Like when you use a pry bar. If you grab it close to the pivot it takes a lot of force. The farther away you go the less force required. So when you go into a corner with wrong offset the mechanical effect pushes springs up with less force. So if you plan to change both at same time it can be a drastic change especially if you run run flats. So I would first decide on proper rims and tires first and see how you like it. Then you can pick up some bmw performance shocks and springs from 135is or a coil over kit. Also don't forget sidewall aspect. If you are running 18" you can also go stiffer but 19s also impact ride and performance. It's a system meant to work together not separately. So I recommend you go with proper offset 18s with non runflat high performance tires first. Then see how you like it. Stiffer is not always better and I can tell you the interior plastics in our car are not very good so be ready for a lot of creaking and rattling if you go stiff. Best wishes

I already have wheels and performance tires (non runflat) that are the proper offset (no offset) I had an extra set of rims my cousin had on a 5 series, I took them and put proper sized winter tires on it expect they have 30 mm of offset making the car look mean but rub the fender on bad bumps. I was hoping to get away with using the wheels but they seem to be slowly destroying my new winter rubbers.

[HP Autosport]

Originally Posted by Xantho

Currently my 2008 135i has a set of rims and tires that are quiet aggressively stanced this is due to some higher offset wheels. I’m happy with the ride height and the overall look of the car at the moment, but when driving on the “wonderful” roads of my Midwest state the rough transitions cause me to rub. I’ve considered getting lower offset wheels but I also want to make the car more aggressive handling wise as well. So can I stiffen the suspension but keep stock ride height? I’m newer to how it all works so would I need different springs? And if I change springs would sportier dampers also help stiffen the suspension? Thanks to any one who responds, I look forward to potential options.

You can certainly change just the struts and shocks only to improve handling. Koni is one of the best in business. If you are looking to change ride height, a good linear rate sport spring with quality struts and shocks is what you want. Beyond that, you are looking at coilovers. Ther are coilovers out there allowing stock ride height so you don't have to sacrifice ground clearance.