ThatRatRodProject Posted October 24, 2016 Report Share Posted October 24, 2016 So I am using a e30 rear end and sub frame. For my hot rod build. Know that the rear breaks are under powered and not big enough. I started thinking if the front brakes from a 325i e30 would fit. They both have the same size hub centric ring to locate the rotor on the wheel bear which is a plus. So then knowing that the front rotor fits I grab my front caliper. I all ready know that I will need a adapter to mount the caliper. But there is not enough room. For one it didn't sit far enough on the rotor and two there was not enough clearance on the a-arm. So at this point I know I need a 4x100 lug pattern and a bigger size rotor with the same size thickness rotor. Which made me think that there was very few options available. Well I used to own a Mini Cooper S and remembered I had a set of rotors sitting on my shelves. So I grab one from the rack and started comparing them. So everything checks out but one thing. The hub centric ring on the rotor is bigger then the wheel bearing which is not the end of the world. I will have to use the set screw that holds the rotor on when the lugs are not in place. But any who is used the lugs to locate for now. And I am quite impressed with as little work that needed to be done so far. So with everything being said. I think this is a very possible option. And obviously the e brake is no longer available. I still need to collect some measurements and draw up a proto type but it should take very little modification to make work. Thought and opinions would be great. If any one is truly interested. I am willing to make up a extra set of brackets after I get everything test fitted. But I will not be able to test them till my project is complete. Which will be a reasonable amount of time. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
B C Posted October 25, 2016 Report Share Posted October 25, 2016 Very interesting, most folks reach for FC rx7 brakes for budget 4x100 upgrades Quote Link to comment Share on other sites More sharing options...
ThatRatRodProject Posted October 25, 2016 Author Report Share Posted October 25, 2016 Very interesting, most folks reach for FC rx7 brakes for budget 4x100 upgrades I wonder how close they are to each other Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
straight6pwr Posted October 25, 2016 Report Share Posted October 25, 2016 saying the e30 rear brakes are under-powered is a bit of a internet myth. with upgraded pads are very capable of locking up the brakes without much effort. however, if your rat rod is going to weigh more than a stock e30 its a good idea. either way, I love creative ideas and will love to see this accomplished. Quote Link to comment Share on other sites More sharing options...
m42b32 Posted October 25, 2016 Report Share Posted October 25, 2016 Interesting idea! It definitely would be a nice option since there really isn't a 'cheap' rear brake upgrade. One thing I would recommend is using some sort of machined spacer/ring to take up the space between the rotor and the hub and properly center the rotor. If you just rely on the lugs you could get some nasty vibration because the rotor won't self center when you have a wheel attached Quote Link to comment Share on other sites More sharing options...
ThatRatRodProject Posted October 25, 2016 Author Report Share Posted October 25, 2016 Interesting idea! It definitely would be a nice option since there really isn't a 'cheap' rear brake upgrade. One thing I would recommend is using some sort of machined spacer/ring to take up the space between the rotor and the hub and properly center the rotor. If you just rely on the lugs you could get some nasty vibration because the rotor won't self center when you have a wheel attached I do agree with you on the locating. I believe I had mentioned that I would use the original hole to hold the rotor in location after the lugs are not in place. yes I will have to add the hole in the correct location Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
patsbimmer1 Posted October 25, 2016 Report Share Posted October 25, 2016 I think he's talking about some kind of hub spacer. Even using the screw to hold the rotor on won't guarantee it's centered correctly. Honestly, you don't even need that screw in there if the rotor is hubcentric. Those screws are usually only there for manufacturing purposes so it doesn't hit someone in the head going down the line. GM uses virgin clips instead of the screw. m42b32 1 Quote Link to comment Share on other sites More sharing options...
ThatRatRodProject Posted October 25, 2016 Author Report Share Posted October 25, 2016 I think he's talking about some kind of hub spacer. Even using the screw to hold the rotor on won't guarantee it's centered correctly. Honestly, you don't even need that screw in there if the rotor is hubcentric. Those screws are usually only there for manufacturing purposes so it doesn't hit someone in the head going down the line. GM uses virgin clips instead of the screw. Correct it won't guarantee that it's in the exactly the correct location but I feel confident that it would be with in + or - .010 which will be well within centered. I do also agree that the screw is not needed. And is mostly for the assembly line. But I was trying to think of options with doing a budget build. The rotor is only about .03 to .04 a side bigger on the hub where it locates so make a spacer would be extremely hard to manufacturer and to ensure that the spacer would be parallel and round. In the event that this does work. Haveing to make a spacer would increase the price of the swap. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
ThatRatRodProject Posted October 26, 2016 Author Report Share Posted October 26, 2016 saying the e30 rear brakes are under-powered is a bit of a internet myth. with upgraded pads are very capable of locking up the brakes without much effort. however, if your rat rod is going to weigh more than a stock e30 its a good idea. either way, I love creative ideas and will love to see this accomplished. They are not under powered but in track use the suffer from heat soke Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
straight6pwr Posted October 26, 2016 Report Share Posted October 26, 2016 making a 'spacer' should be pretty easy. think of it as a shim. buy some steel strips of the correct thickness, cut to the correct length (circumference), then just tap it in. ThatRatRodProject 1 Quote Link to comment Share on other sites More sharing options...
patsbimmer1 Posted October 26, 2016 Report Share Posted October 26, 2016 Fyi, maximum allowable runout is typically .002". Quote Link to comment Share on other sites More sharing options...
ThatRatRodProject Posted October 26, 2016 Author Report Share Posted October 26, 2016 Fyi, maximum allowable runout is typically .002". Run out on the diameter or being true to its self Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
jc43089 Posted November 3, 2016 Report Share Posted November 3, 2016 .002 would be side runout spec or axial runout. Radial runout is not going to be that tight of a tolerance. It would be easy to use feeler gauges around the hub and lock the assembly screw to hold it in place until the wheel is on. You would easily be +/- .005 using feeler gauges. Then you could verify axial runout with 2 lug bolts installed to make sure your rotors are in good shape. ThatRatRodProject 1 Quote Link to comment Share on other sites More sharing options...
jc43089 Posted November 3, 2016 Report Share Posted November 3, 2016 ThatRatRodProject 1 Quote Link to comment Share on other sites More sharing options...
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