Stock Ride Height

[Gangplank]

I did a search and surprisingly didn't find any good info on what the stock ride height is supposed to be for the 135i.

I just recently did coilovers so I measured mine before & after

Before = stock ride height Msport suspension w/ 55k miles.

Front 337 mm (arch to center) or 578 mm (arch to bottom of rim)
Rear 343 mm (arch to center) or 583 mm (arch to rim bottom)

Anyone willing to measure theirs? If so please post up your ride height/fender gap and mileage.

Thanks.

[beattiecj]

I am going to install ohlins coilovers this coming weekend and will measure if you are willing to wait that long. Currently running stock suspension on a 2012 135i.

Not sure what your use is, do you mind sharing your setup i.e. camber, toe, castor etc if you have it available?

[bbnks2]

Originally Posted by beattiecj

I am going to install ohlins coilovers this coming weekend and will measure if you are willing to wait that long. Currently running stock suspension on a 2012 135i.

Not sure what your use is, do you mind sharing your setup i.e. camber, toe, castor etc if you have it available?

yes, please post.

you can find the "target" ride heights on a dealer (BMW) alignment sheet, but I am not sure how accurate it is since it's a range. Each car is slightly different in springs and packages that might affect ride height. Also, BMW provides ride height measurement as taken from the bottom of the wheel to the fender... not from the wheel center. And technically this is a poor way of measuring ride height as GROUND CLEARANCE is what you should be using to measure rake... not fender gap clearance. Fender measurement is just a quick way for the dealer to inspect for a sagging suspension.

Gangplank what was the "before" measurement? Seems like you have a lot of rake dialed in... From what I remember, the stock ride height provided for 8mm higher front measurement then rear.

Here is a dealer sheet I found:

http://www.1addicts.com/forums/attac...1&d=1313087067

Front 599mm/ Rear 592mm (with 16" wheels apparently)

[Gangplank]

Originally Posted by beattiecj

I am going to install ohlins coilovers this coming weekend and will measure if you are willing to wait that long. Currently running stock suspension on a 2012 135i.

I just installed the Ohlins kit Saturday.

Originally Posted by bbnks2

Gangplank what was the "before" measurement? Seems like you have a lot of rake dialed in... From what I remember, the stock ride height provided for 8mm higher front measurement then rear.

Front 599mm/ Rear 592mm (with 16" wheels apparently)

The above actually is my before measurement for 135i Msport suspension w/ 55k miles on it. That is why I was asking others what their stock ride height is b/c mine seemed to have some rake from the factory. I ended up with a -3/8" or -9.5 mm drop all around from stock but I did't actually change or add any rake.

The BMW numbers seem strange. Why would it be higher in the front vs. the rear? In this post by fe1rx in another thread http://www.1addicts.com/forums/showp...34&postcount=2 the Stock ride height for the 135 is listed as Front 592 mm / Rear 584 for 18" rims (measured from top of arch to bottom of rim). Same 8mm squat (reverse rake) which I don't see looking at other stock 135i's. I'm trying to figure out why mine had rake built in on the stock msport suspension?

Interestingly the sheet linked by Fe1rx also lists the BMW Perf. Suspension as dropping the rear 10mm but leaving the front resulting in 10mm more squat F 592 / R 574 but that doesn't seem right either.

Using the BMW method my ride height was Front 578 mm / Rear 583 mm.

[bbnks2]

It's pretty simple... The arch is a useless point to measure to. Like I said, it's just how dealer techs measure suspension sag. They don't care about rake when you go in for service. What really matters for performance is ground clearance and that is what you measure rake by.

If you measure ground clearance you'll see you have over 1/2" of rake with the rear sitting higher. Yes, rake can be used to tune handling but the car was delivered with close to 0 rake for a reason (front arch sits a bit higher than the rear). It makes perfect sense because weight distribution. Desoite popular belief, very few if any cars run rake. They chassis itself is naturally raked to improved aero rather than physically running the rear suspension geometry higher. You wouldn't need to dial out understeer with rake if you've tuned it out by squaring up the tires and other means.

[Gangplank]

Ok, now you have me curious. Where should I take the measurements from to determine the ground clearance ride height and rake?

Why would the car be delivered with close to zero rake?

I may try to run a 245 or 255 square set up and more front camber which would be needed to do that.

[bbnks2]

Originally Posted by Gangplank

Ok, now you have me curious. Where should I take the measurements from to determine the ground clearance ride height and rake?

Why would the car be delivered with close to zero rake?

I may try to run a 245 or 255 square set up and more front camber which would be needed to do that.

You measure from the ground (on a level surface) the the bottom of the side skirt (right next to the jack points). Ideally, you would measure from the lower control arm pickup point, but the sideskirt is close enough.

The car does come with a slight positive rake despite the front fender sitting a bit higher than the rear. It's just enough positive rake to offset the squat of acceleration. I can't speak too much more on it other than my car handles way better with 1/4" rake then it did with 3/4" take. Then again, I am running different spring rates then most.

Pretty much every BMW I see at hpde runs 0 rake. This creates a look as if the front is sitting higher when it's really not.

[Gangplank]

Ok so your saying the stock 135i has some positive rake from the factory. And we should dial it out to get a flat stance?

Please explain what effect this will have on handling - better corner entry? Reduce mid corner float? Reduce corner exit understeer?

[bbnks2]

Originally Posted by Gangplank

Ok so your saying the stock 135i has some positive rake from the factory. And we should dial it out to get a flat stance?

Please explain what effect this will have on handling - better corner entry? Reduce mid corner float? Reduce corner exit understeer?

How much rake you want is your decision and is entirely setup dependent. All I was trying to say is that you were measuring rake wrong and you may want to revisit your ride height settings now that you know where to measure from.

[Gangplank]

The point of this thread is to find out what the stock ride height is on a 135i with Msport suspension. You happened to point out that you think my car has excessive positive rake.

I'm not doubting what you say but I'm also not going to accept it without understanding it. I'm trying to learn about suspension set up. I've tracked motorcycles for years and am learning about cars.

If others can post up their measurements to compare stock ride height we'll have more info to work with.

[swagon]

AFAIK, mine was on both axles over 340 mm on the left side of the vehicle. I'd say like 343 to 345 mm. Stock everything @ 10k miles.

[bbnks2]

Originally Posted by Gangplank

The point of this thread is to find out what the stock ride height is on a 135i with Msport suspension. You happened to point out that you think my car has excessive positive rake.

I'm not doubting what you say but I'm also not going to accept it without understanding it. I'm trying to learn about suspension set up. I've tracked motorcycles for years and am learning about cars.

If others can post up their measurements to compare stock ride height we'll have more info to work with.

Why don't you start by measuring as I recommended to get your actual rake? No one knows how much rake you actually have dialed in, nor do we know your entire suspension setup... I already explained how the front fender is molded in a way that makes it useless for measuring actual rake.

Rake is typically used to gain an aero advantage, but it comes at the expense of disturbing the cars suspension geometry and weight distribution especially so when you consider dynamic situations like slowing down while entering into a corner. The 135i chassis is designed in a way that, at a flat ride height (0 rake), the rear bumper is naturally raked and the rear trunk lid also sits higher than the front hood. This generates down-force even without a proper diffuser which could provide even further benefits... In essence, the chassis is designed with aero in mind.

If you were to put a fancy diffuser on the rear bumper to generate even more downforce, you would not want to have excessive rake either. Too much rake would place the diffuser higher off the ground and decrease its effectiveness. You would then need to move to a diffuser with an EVEN GREATER angle to capitalize the extra rake. No aftermarket diffuser that I know of is design to be used with a high rake angle. You want just enough static rake so that under acceleration the chassis sits relatively flat at. Add a wing and you'll need to dial in a bit more rake to offset that downforce... in a non-aero car, you are far better off with 0-1/4" of rake for the aforementioned reasons. Or, you may need rake to get the car to rotate if you completely botch up your suspension setup with aftermarket parts

You can google rake yourself for more information. I am no expert. I just think people dial in rake without having a clue why and I have yet to see a production race car with a high rake angle (purpose built cars are a different story): "Cars are normally set up to have the front ride height of the car (measured at the front axle) lower than the rear ride height of the car (measured from the rear axle). This relationship is known as "rake". It ensures the undertray of the car produces downforce and not lift. There is an optimum rake at which cars run though and there is a point beyond which any extra reduction in ride height may actually increase drag and promote lift."

"A potential downside of this philosophy has always been that as the speed falls as the car enters into the corner and the ride height increases, it causes a big balance change - because the gap between track and the leading edge of the floor has increased, but there is not much compensation from the increased rake (as you get with a high-rake car - ie a high-rake car is even higher-rake as the speed comes down)."

http://www.skysports.com/f1/news/324...es-and-ferrari
https://www.caranddriver.com/feature...y-suck-feature

[BimmerAg]

Originally Posted by bbnks2

Rake is typically used to gain an aero advantage, but it comes at the expense of disturbing the cars suspension geometry and weight distribution especially so when you consider dynamic situations like slowing down while entering into a corner. The 135i chassis is designed in a way that, at a flat ride height (0 rake), the rear bumper is naturally raked and the rear trunk lid also sits higher than the front hood. This generates down-force even without a proper diffuser which could provide even further benefits... In essence, the chassis is designed with aero in mind.

I know this is being a little nit-picky, but rake doesn't really have all that big of an effect on weight distribution like you suggest. If we assume a stock weight distribution of 52%F/48%R, we can calculate the position of the vehicle's CG along the x-axis (1382.7mm from the rear wheel).

For simplicity's sake, I assumed the CG height to be 1/2 of the car's overall height; this is likely higher than the actual CG height and will exaggerate the effect of rake.

For a fairly extreme rake of 25mm, the rake angle, and it's effect on CG position can be calculated. The rake angle is 0.56°, and the CG moves forward by 6.85mm.

From this, we can calculate that the resulting weight distribution is: Front=52.26%

Obviously, the relationship between ride height and suspension geometry is very important, but I'd argue that rake that's slightly higher than stock isn't really the big deal that you make it out to be.

[bbnks2]

Originally Posted by BimmerAg

Obviously, the relationship between ride height and suspension geometry is very important, but I'd argue that rake that's slightly higher than stock isn't really the big deal that you make it out to be.

#1 - I didn't make it out to be a big deal. I was simply correcting his statement that he has "6mm" of rake as based off his measurements from wheel center to fender which is false.

#2 - Weight distribution is not the only affect of rake. You are also making a change to the instantaneous roll center. Whether or not it is favorable is setup dependent and could result in un-wanted bump-steer.

#3 - Your assessment of weight distribution completely ignores down-force and how raking a non-aero vehicle will more than likely result in a reduction in rear down-force.

#4 - Why are you calculating based on wheel-base? Overhang and the overall length of the vehicle would change your COG calculations, but I get your overall point.

You also seem to assume that I am trying to present an argument AGAINST rake when I am not. I am simply doing as he requested and explaining why you MAY NOT WANT to dial in rake and trying to explain why that is. This is especially true when you don't know how to measure it.

Thank you for the bit of information/math though as many here believe that you can't use math to tune suspension.

As for op's question, what is the stock m-sport ride height?, here is the technical info... it varies by a lot of things so getting forums users to post their ride heights seems futile... Measure like BMW does, from bottom of the wheel to the fender (https://www.newtis.info/tisv2/a/en/e...nsion/FaPCnH1_), and then compare to the stock values as follows:

Front: https://www.newtis.info/tisv2/a/en/e...ension/6h97aRc
Rear: https://www.newtis.info/tisv2/a/en/e...-guide/61Xf0Co

BMW says it's normal to have up to 10mm difference from left to right in an unloaded car ("normal position") so don't expect to land at exactly the defined ride height.

I am guessing "Low-slung sport suspension" is for cars that came with the S704 "M-Sport" package (anthracite headliner, shadow-line trim, style 261m wheels)

18" stock M-sport wheels (261m) stock ride height should be:
Front: 592mm
Rear: 584mm

Having re-found the TIS info, I now remember why I never bothered asking this question on the forums. Too many variables to even get the "right" number... and it's all provided by the above TIS articles.

[Gangplank]

Wow quite a roundabout here but now that we've come full circle - bbnks2 the info you linked to is the same as the info I linked to posted by Fe1rx in another thread. It seems this thread went sideways when I used the term "rake" in regard to the measurements I was taking on my car. You are correct that wheel center or bottom of rim is not a good measurement to determine actual rake of the suspension set-up.

BTW - all US spec 135i come with the low slung sport suspension (aka Msport).

The real point of this thread was for comparison to find out if my before numbers are different from others with stock suspension. Using wheel center to fender arch is a great way to compare easily.

18" stock M-sport suspension
Front: 592mm
Rear: 584mm

My stock measurements w/ 55k miles were:
Front 578 mm (arch to bottom of rim)
Rear 583 mm (arch to rim bottom)

So my suspension was sitting 14mm low in the front & 1mm low in the rear vs. spec.

So anyone out there with stock Msport suspension want to post up their measurements for Front & Rear ride height.

[bbnks2]

Originally Posted by Gangplank

Wow quite a roundabout here but now that we've come full circle - bbnks2 the info you linked to is the same as the info I linked to posted by Fe1rx in another thread. It seems this thread went sideways when I used the term "rake" in regard to the measurements I was taking on my car. You are correct that wheel center or bottom of rim is not a good measurement to determine actual rake of the suspension set-up.

BTW - all US spec 135i come with the low slung sport suspension (aka Msport).

The real point of this thread was for comparison to find out if my before numbers are different from others with stock suspension. Using wheel center to fender arch is a great way to compare easily.

18" stock M-sport suspension
Front: 592mm
Rear: 584mm

My stock measurements w/ 55k miles were:
Front 578 mm (arch to bottom of rim)
Rear 583 mm (arch to rim bottom)

So my suspension was sitting 14mm low in the front & 1mm low in the rear vs. spec.

So anyone out there with stock Msport suspension want to post up their measurements for Front & Rear ride height.

I know people have demonstrated that the stock front strut mounts permanently compresses over time causing suspension sag. That could be your 14mm right there. Possible you added some weight with an aftermarket intercooler as well?

Originally Posted by Gangplank

BTW - all US spec 135i come with the low slung sport suspension (aka Msport).

M-sport is actually a completely separate package. Not all 135i are M-sport. But, I get what you mean that both a base and an M-sport 135i get the same struts and springs. I believe the sways are the only thing that is different, based on another thread. Then again, where is the proof that the struts and springs are the same on both cars? I've seen at least 3-4 different spring codes...

[BimmerAg]

Originally Posted by Gangplank

So anyone out there with stock Msport suspension want to post up their measurements for Front & Rear ride height.

Yeah sorry for the thread derailment...I'll try to remember to get some measurements for you this evening!

[gjm120]

Originally Posted by Gangplank

I just installed the Ohlins kit Saturday.


Interestingly the sheet linked by Fe1rx also lists the BMW Perf. Suspension as dropping the rear 10mm but leaving the front resulting in 10mm more squat F 592 / R 574 but that doesn't seem right either.

I think that is a typo as it only shows for 18" wheels.

[Gangplank]

Originally Posted by bbnks2

I know people have demonstrated that the stock front strut mounts permanently compresses over time causing suspension sag. That could be your 14mm right there. Possible you added some weight with an aftermarket intercooler as well?

M-sport is actually a completely separate package. Not all 135i are M-sport. But, I get what you mean that both a base and an M-sport 135i get the same struts and springs. I believe the sways are the only thing that is different, based on another thread. Then again, where is the proof that the struts and springs are the same on both cars? I've seen at least 3-4 different spring codes...

I have a 135i sport (not Msport) and it has the "704 M SPORT SUSPENSION". No intercooler. Just stock motor.

Originally Posted by BimmerAg

Yeah sorry for the thread derailment...I'll try to remember to get some measurements for you this evening!

No worries. I enjoyed the info & I learned something new. I still need to go back and measure underneath clearance to determine my actual rake as suggested by @[bbnks2];(22921965)

Originally Posted by gjm120

I think that is a typo as it only shows for 18" wheels.

Agreed.

[Gangplank]

Anyone out there willing to measure their stock Msport ride height??

If so please post your ride height and mileage on your car.

Trying to collect some data.

Thanks.

[gjm120]

I think all springs are fitted based on the car and it's options (like BMWP springs which have been much discussed). I've seen at least 4 front spring codes on 1 series. My guess is the tolerance on the OE ride height sheets linked above are due to the fact that a car just over the edge D5 is going to sit higher than a car just below D6.

It would contribute to the collective knowledge base if people could also post their spring codes and vehicle options.

For what it's worth, I'm at 588 / 576 front / rear. My strut mounts have only about 7,000 miles so that partially explains the relatively high front end. Also I'm on D6 front and L3 rear springs that I think would have been standard on a 135i with AT. My car is lighter than a 135i spec'd the same so the spring codes explain some of the ride height also.

Also, squatting down next to the car in the garage with a tape measure is not completely accurate.

[gjm120]

Since I suggested we post vehicle options I guess I should note mine:

AT, power seats, Nav, HK sound, sunroof, xenon lights