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Yea, the one thing I'm unsure of is material. I'm not sure if steel is necessary for the housing. I'm wondering if it'd be possible to do it out of 7075. The job of the housing is just to keep the bearing located to the upright. In a sense you could just think of it as an extension of the upright. I have a hard time believe the OEM bearing is made out of anything more exotic than a mild steel. The evo and the normal lancer share the same rear bearings so there's no way Mitsu would splurge that much money on exotic bearings for standard lancers.
And the failures we see on track are of the ball bearings and races, not the housing. So I don't think we need to go crazy overboard on the housings with this, as long as it can safely keep the bearing located it should be sufficient.
I definitely have a lot of thinking to do with this but I'll likely order up a front lancer bearing here soon and start measuring for a housing.
No I wouldn't use aluminum to create a billet bearing housing on a steel hub. Dissimilar metals, galvanic corrision, and thermal conductivity are some reasons why not to do this. IMO, Aluminum can be used to save weight but this is not the right application.
I am going to analyze both approaches I have read about to try and compare options as a prospective consumer.
Dallas' Bearing Solution:
4 OEM GTR Front Bearings at $190 = $760
2 Custom Rear SSB Uprights
2 Custom Rear Axles From DSS
Pros
1. Stronger OEM solution to prevent track use bearing failure
2. Bearings are interchangeable between Front and Rear.
3. Parts Availability is high if production is guaranteed.
4. Could be a one and done purchase.
Cons
1. Higher Initial Cost
2. Depending on construction and assembly there could be QC issues. (Develop QC process?)
3. Supply Chain issues with materials and Driveshafts from DSS
Pros:
1. Works with OEM Rear Axles.
2. Ceramic Bearings are more durable and reliable.
Cons:
1. Does not solve initial issue of Bearing failure. (Potential to repeat purchase of bearings)
2. Depending on construction and assembly there could be QC issues. (Develop QC process?)
3. Upfront cost for materials.
4. Parts can be discontinued.
Both directions are viable, definitely. A con to the GTR rear is the E-brake would definitely have to go. I still haven't figured out what to do about that part.
Class rules require an ebrake separate from normal brake hydraulics, I use the ebrake launching at ProSolo, and its nice to have loading in the trailer.
No I wouldn't use aluminum to create a billet bearing housing on a steel hub. Dissimilar metals, galvanic corrision, and thermal conductivity are some reasons why not to do this. IMO, Aluminum can be used to save weight but this is not the right application.
Galvanic corrosion isn't a concern here. If that were the case, Dallas' aluminum uprights would be rusting my stock wheel bearing housings and every bolt that threads into them. As for thermal conductivity, aluminum is better. it pulls heat out of the bearing faster than steel and transfers it away instead of insulating all of the heat in the bearing.
The main concern with aluminum is modulus of stiffness and yield strength, we obviously don't want it flexing more than the stock housing because that can affect dynamic wheel alignment. But if the stock housings are a mild steel like 1018 or something similar using 7075 aluminum would be marginally weaker, but would make manufacturing considerably easier. We need to determine if the factory housings are actually flexing. One of the beautiful parts about making a new bearing housing is we can increase the wall thicknesses on it to make it stiffer etc. so it's possible to make a beefier aluminum housing that's stiffer than the factory housing.
Responses in red.
Originally Posted by deylag
I am going to analyze both approaches I have read about to try and compare options as a prospective consumer.
Austin's Bearing Solution:
Pros:
1. Works with OEM Rear Axles.
2. Ceramic Bearings are more durable and reliable. For cost reasons, I'd likely stick with steel. Ceramic bearings would bump cost considerably. But if the uprated steel bearing didn't fix the failures, ceramic likely would.
Cons:
1. Does not solve initial issue of Bearing failure. (Potential to repeat purchase of bearings) The lancer front bearing has a 22% higher load rating than the stock rear. I can try to find a load rating for the GTR bearing but I don't expect it to be worlds higher than the lancer bearing. I consider both solutions to be potentials for resolving bearing failures, and to be frank, the amount of guys experiencing rear bearing failure is a small number.
2. Depending on construction and assembly there could be QC issues. (Develop QC process?) I have complete faith in my machine shop for something like this. They've been in business longer than I've been alive and they buy new updated CNCs every few years to stay ahead of the curve. Their capability is up there with the best. I have the same faith in Dallas, his work already speaks for itself. Beyond the machining of the housings the only steps to assembly is pressing everything together.
3. Upfront cost for materials. Either Dallas or I would be selling these through our respective companies, I don't see it affecting customers.
4. Parts can be discontinued. With this solution even if the housings are discontinued, the customer is still able to convert back to stock bearings without having to change any other parts.
I do appreciate you input as a potential customer. I like getting critical feedback like this!
Galvanic corrosion isn't a concern here. If that were the case, Dallas' aluminum uprights would be rusting my stock wheel bearing housings and every bolt that threads into them. As for thermal conductivity, aluminum is better. it pulls heat out of the bearing faster than steel and transfers it away instead of insulating all of the heat in the bearing.
Galvanic corrosion might be mitigated if the mechanical properties of 7075 aluminum match the alloy for the OEM upright. Honestly needs more research to prove that is true or not. Thermal conducitivity is not the right word lets switch over to thermal expansion. If 7075 doesnt expand as fast as the steel alloy then what will happen?
Galvanic corrosion might be mitigated if the mechanical properties of 7075 aluminum match the alloy for the OEM upright. Honestly needs more research to prove that is true or not. Thermal conducitivity is not the right word lets switch over to thermal expansion. If 7075 doesnt expand as fast as the steel alloy then what will happen?
Almost all aluminums expand faster than steels. When you're talking something this small and two components operating at similar conditions the growth difference is negligible.
After some more reading around on NTNs site I found the housing is made from 1053 steel. 1053 has a yield strength of 63 ksi. 7075 has a yield strength ranging from 63-73 ksi depending on how it's tempered. So a 7075 aluminum housing would be stronger than the stock steel housing.
Almost all aluminums expand faster than steels. When you're talking something this small and two components operating at similar conditions the growth difference is negligible.
After some more reading around on NTNs site I found the housing is made from 1053 steel. 1053 has a yield strength of 63 ksi. 7075 has a yield strength ranging from 63-73 ksi depending on how it's tempered. So a 7075 aluminum housing would be stronger than the stock steel housing.
Yield strength is fine and dandy but arent we considering more factors than that. Usually in case like this I would run some simulations in a CAD program to double check the claim. Convince people with the colors of FEA and determine the safety factor or something.
7075 is some good stuff, UTS, yield strength, and hardness similar to low carbon steels and normalized/annealed high carbon or chromolys. Its also dramatically easier to machine. Downside is its temperature dependent (we dont really get into the heat zone that it matters here), and all the modulus are 1/3rd of steel. So that means stiffness as well, but if you have space you just need to make it "cube root of 3" thicker. <-- This is one of my interview questions for new engineer hires.
7075 is some good stuff, UTS, yield strength, and hardness similar to low carbon steels and normalized/annealed high carbon or chromolys. Its also dramatically easier to machine. Downside is its temperature dependent (we dont really get into the heat zone that it matters here), and all the modulus are 1/3rd of steel. So that means stiffness as well, but if you have space you just need to make it "cube root of 3" thicker. <-- This is one of my interview questions for new engineer hires.
Hmm, cube root of 3 thicker than a comparable part made of steel. You have a point there.
almost all aluminums expand faster than steels. When you're talking something this small and two components operating at similar conditions the growth difference is negligible.
After some more reading around on ntns site i found the housing is made from 1053 steel. 1053 has a yield strength of 63 ksi. 7075 has a yield strength ranging from 63-73 ksi depending on how it's tempered. So a 7075 aluminum housing would be stronger than the stock steel housing.
Originally Posted by deylag
yield strength is fine and dandy but arent we considering more factors than that. Usually in case like this i would run some simulations in a cad program to double check the claim. Convince people with the colors of fea and determine the safety factor or something.
Originally Posted by dallas j
7075 is some good stuff, uts, yield strength, and hardness similar to low carbon steels and normalized/annealed high carbon or chromolys. Its also dramatically easier to machine. Downside is its temperature dependent (we dont really get into the heat zone that it matters here), and all the modulus are 1/3rd of steel. So that means stiffness as well, but if you have space you just need to make it "cube root of 3" thicker. <-- this is one of my interview questions for new engineer hires.
Pros:
1. Works with OEM Rear Axles.
2. Ceramic Bearings are more durable and reliable.
Cons:
1. Does not solve initial issue of Bearing failure. (Potential to repeat purchase of bearings)
2. Depending on construction and assembly there could be QC issues. (Develop QC process?)
3. Upfront cost for materials.
4. Parts can be discontinued.
I looked into this, as I wanted to machine front uprights with integral bearing housing to avoid bolting on the bearing unit, and just press the hub into the bearing. Looks like a real neat solution until I cut apart the OE bearing/hub unit. Since the inner bearing race is actually machined out of the same piece as the hub, that means the OE front hub is much stronger and stiffer than the rear one (that is just pressed into the bearing)... decided to avoid that idea.. shame, as the upright design was just so neat and slim..
EDITED In.. DAMN just figured you are talking a bout rear hubs.. sorry..
Ive only ever changed mine once. is it the climate you guys are in or something?
Also, Why not just pull the bearing out of the original housing and press a new bearing into it?
You can try going higher quality but size is the main limitation on bearing life.
The ER endurance evo uses bearings every few races IIRC. I had a bearing finally go bad last year, took 11 years of racing AX on it to finally have a bad one.
Ive only ever changed mine once. is it the climate you guys are in or something?
Also, Why not just pull the bearing out of the original housing and press a new bearing into it?
The bearing is integral to the housing. The outer races are the housings so there's nothing to press out. This is why I'm' suggesting the design of a housing that takes a stronger press in bearing.
Realistically, the amount of people that would benefit from stronger rear bearings is extremely small.
sigh. seems like i'm losing a touch of coolant when i drive the car. apparently no milkyness in the last oil change (RS did it) so hoepfuly that means it's not head gasket. Where else could I be losing it from?
I tried to look around but nowhere immediately obvious as far as I could tell, though there is an odd spot of fluid pooled up here (top of trans right by the reverse sensor. Any thoughts? Car is kept in a temp stable garage when the coolant level is measured.
Dec 3, 2021 | 02:27 PM
