Suggest Suspension, Wheel, Tire, Brake Modifications?

E28 technical advice asked and given! Troubleshooting, modifications and more.
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jyl
Posts: 138
Joined: Jun 02, 2016 8:59 PM
Location: Oregon

Suggest Suspension, Wheel, Tire, Brake Modifications?

Post by jyl »

I realize that describing how a car rides and handles is difficult and subjective. That said, I’m still hoping I can get some guidance.

I have a stock ‘86 535i with 15” wheels. The intended use is as a fast, comfortable roadtrip car, where the road might be freeway, curving and rolling secondary road, or mountain curves. I want it to be as comfortable, quiet, and compliant a ride as stock. With that primary requirement, I’d like it to handle the curves and rollers and twisties in a smooth, planted, rapid, predictable manner. Maximum cornering grip and quick direction charges are not high priorities. Think Grand Touring rather than autocrossing, tracking, or canyon racing. I’d also like it to sit about 1” lower than stock, for looks if naught else. And I think the 15” wheels look a little small.

Given those criteria, what - if anything - would you do to suspension, wheels, tires, brakes?
Blue Shadow
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Joined: Feb 12, 2006 12:00 PM
Location: SE PA

Re: Suggest Suspension, Wheel, Tire, Brake Modifications?

Post by Blue Shadow »

16" wheels cause anything larger screws up driving dynamics.
205/55-16 tires all around because bigger isn't better.
Gotta be some brake info copied from m535i.org here somewhere listing all the different upgrades using BMW parts from other vehicles. But 540 E34 fronts and rears are one good option.
Last edited by Blue Shadow on Dec 01, 2021 12:40 PM, edited 1 time in total.
Blue Shadow
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Re: Suggest Suspension, Wheel, Tire, Brake Modifications?

Post by Blue Shadow »

M535i.org
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FAQ & Tech Help
E28 FAQ & Tech Articles
Brakes

Read what you need and start looking.
jyl
Posts: 138
Joined: Jun 02, 2016 8:59 PM
Location: Oregon

Re: Suggest Suspension, Wheel, Tire, Brake Modifications?

Post by jyl »

Thank you!

What is the best way to lower the car 1" and still meet the goals of comfort and handling? I have read about lowering springs but wonder if they will add harshness.

I'm not going for a luxobarge here, but I have another car for the boy-racer duties . . .
Tiit
Posts: 290
Joined: Oct 06, 2017 6:27 AM
Location: Canberra

Re: Suggest Suspension, Wheel, Tire, Brake Modifications?

Post by Tiit »

If you want the car to be as comfortable, quiet, and compliant a ride as stock, then keep it stock. 15” wheels are already bigger than stock.
tn535i
Posts: 5585
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Location: Middle Tennessee

Re: Suggest Suspension, Wheel, Tire, Brake Modifications?

Post by tn535i »

Stock wheel on my 535 was a 390 metric which works out to 15.35" with a 200/60VR390 tire. So a 15" wheel is really slightly smaller and it's well agreed on mye28.com that a 16" wheel is the better choice. Possibly the most important reason to move up to a 16" wheel is the incredibly better choices of tires. The 205/55-16 tire size has so many great options and this one thing may have as much bearing on your goal as anything else you might do. I'm a great fan of the General GMax AS05 for a touring tire on a budget and it's basically a Conti DWS in disguise. The Pirelli P Zero's I find quieter and smoother and better at the limit and have them on my M6. My son has had the Michelin UHP tires on his 330Ci and while crisper handling I find them to generate more noise, more than I like.

You can lower your car by cutting stock springs and it will increase the rate slightly and lower it at the same time, maybe 1/2 coil off the top and bottom so you don't loose some of the tuck built in. I did that on my M6 when converting the rear from hydraulic self leveling and it was just right I think. I would upgrade to Bilstein all around and replace all the spring pads and mounts. In the rear you have different perches to choose from but up front there is a watch out. All new front strut mounts I've seen tend to raise the car maybe 1/2" and are made slightly different from the originals, however, you can offset that with e90 hats that have a deeper dish than std e28/30/24 hats. It works just fine.

IMO lower it about 1/2" and with the right 16" wheel and modern tires it looks just right and rides like stock with better handling. In this case you would stick with Billy HD's. If you go and inch or more lower and use different springs you might need to switch to Billy Sport. The major difference is the height before max travel is reached. There are numerous threads about all these subtle differences and many opinions on springs and sway bars and tires and so on... It's really hard to improve greatly on what BMW did at the onset.

Well that's my 2 cents based on my limited experience.
jyl
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Joined: Jun 02, 2016 8:59 PM
Location: Oregon

Re: Suggest Suspension, Wheel, Tire, Brake Modifications?

Post by jyl »

That is a ton of information - thank you very much!
Blue Shadow
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Location: SE PA

Re: Suggest Suspension, Wheel, Tire, Brake Modifications?

Post by Blue Shadow »

tn535i wrote: Dec 01, 2021 6:26 PM I'm a great fan of the General GMax AS05 for a touring tire on a budget and it's basically a Conti DWS in disguise.
I wonder how many people are clued up on this? Consumer's Reports liked the AS05 more than the Conti and they sell for less.
John in VA
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Re: Suggest Suspension, Wheel, Tire, Brake Modifications?

Post by John in VA »

Rod was a fan of Generals ages ago!
ScottKendall
Posts: 65
Joined: Jul 07, 2015 10:01 PM
Location: Kentucky

Re: Suggest Suspension, Wheel, Tire, Brake Modifications?

Post by ScottKendall »

To corroborate what some others have said:

1. I have 16" wheels. That is a limit IMO. I have to set the air pressure at 30 psi. At 32-35 psi, the ride goes to hell.

2. I had 225s and they rub the strut. I went to 205/55 and they are perfect!
RonW
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Joined: Feb 12, 2006 12:00 PM
Location: Long Island, NY

Re: Suggest Suspension, Wheel, Tire, Brake Modifications?

Post by RonW »

I have E32/E34 brakes on my 535is. They fit 15" E34 basketweaves (which is what I use) and the stock TRX wheels. I'm fine with the stock E28 master cylinder, though you can certainly upgrade to the E32 part.
Alberto89
Posts: 129
Joined: May 04, 2021 5:24 AM
Location: Netherlands

Re: Suggest Suspension, Wheel, Tire, Brake Modifications?

Post by Alberto89 »

tn535i wrote: Dec 01, 2021 6:26 PM Stock wheel on my 535 was a 390 metric which works out to 15.35" with a 200/60VR390 tire. So a 15" wheel is really slightly smaller and it's well agreed on mye28.com that a 16" wheel is the better choice. Possibly the most important reason to move up to a 16" wheel is the incredibly better choices of tires. The 205/55-16 tire size has so many great options and this one thing may have as much bearing on your goal as anything else you might do. I'm a great fan of the General GMax AS05 for a touring tire on a budget and it's basically a Conti DWS in disguise. The Pirelli P Zero's I find quieter and smoother and better at the limit and have them on my M6. My son has had the Michelin UHP tires on his 330Ci and while crisper handling I find them to generate more noise, more than I like.

You can lower your car by cutting stock springs and it will increase the rate slightly and lower it at the same time, maybe 1/2 coil off the top and bottom so you don't loose some of the tuck built in. I did that on my M6 when converting the rear from hydraulic self leveling and it was just right I think. I would upgrade to Bilstein all around and replace all the spring pads and mounts. In the rear you have different perches to choose from but up front there is a watch out. All new front strut mounts I've seen tend to raise the car maybe 1/2" and are made slightly different from the originals, however, you can offset that with e90 hats that have a deeper dish than std e28/30/24 hats. It works just fine.

IMO lower it about 1/2" and with the right 16" wheel and modern tires it looks just right and rides like stock with better handling. In this case you would stick with Billy HD's. If you go and inch or more lower and use different springs you might need to switch to Billy Sport. The major difference is the height before max travel is reached. There are numerous threads about all these subtle differences and many opinions on springs and sway bars and tires and so on... It's really hard to improve greatly on what BMW did at the onset.

Well that's my 2 cents based on my limited experience.
I also want to realize this. But you are talking about dishes from an E90. I spoke to someone who had experience with that of an E60. Would drop about an inch. Are you familiar with that?
tn535i
Posts: 5585
Joined: Jul 14, 2006 1:30 PM
Location: Middle Tennessee

Re: Suggest Suspension, Wheel, Tire, Brake Modifications?

Post by tn535i »

http://bmwfans.info/parts-catalog/E90/E ... ing_parts/

Part #9 in the link. It's used in a few different cars. This is the only one I have any experience with. Some have argued it puts the hat or upper plate too close to the mount. This might be true with old original mounts but with new ones I've seen no problem. If the e90 is even deeper there might be an issue with old or new. I'm sure to some extent the hat and the mount are designed to go together as there needs to be some kind of gap between them or as you raise the hat to lower the car you crash the hat into the mount.
Alberto89
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Joined: May 04, 2021 5:24 AM
Location: Netherlands

Re: Suggest Suspension, Wheel, Tire, Brake Modifications?

Post by Alberto89 »

Hmm.. I will inform you again thanks. Do you happen to have before and after pictures?
tn535i
Posts: 5585
Joined: Jul 14, 2006 1:30 PM
Location: Middle Tennessee

Re: Suggest Suspension, Wheel, Tire, Brake Modifications?

Post by tn535i »

Realize I said something wrong above. Meant to comment if the e60 hat is even deeper than the e90 hat it might be too close to the mount.
Alberto89
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Joined: May 04, 2021 5:24 AM
Location: Netherlands

Re: Suggest Suspension, Wheel, Tire, Brake Modifications?

Post by Alberto89 »

Ah okay!
tn535i
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Location: Middle Tennessee

Re: Suggest Suspension, Wheel, Tire, Brake Modifications?

Post by tn535i »

From memory those parts were < $15 if ordered online. If you are local to a dealer who had all the parts in stock it would be interesting to see how they differ and document that for those who might be looking to do the same.

And No I don't have any before/after pictures. I remember comparing the old original strut mounts I had to new ones and they did move the point of contact to the spring perch or hat down (raising the car) but with the e90 hat there was ample clearance between the hat and mount and it brought the spring back up closer to the mount again. So maybe it was a wash. old+old = new+e90 hat

Others have documented putting new strut mounts on their car with no other changes had raised the front end slightly.
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