Question about CRX hubs and development...

[chrisb]

What is it exactly that fails on CRX hubs? ie. Where does it break? Would aftermarket hubs be legal and if the answer is technically no, would it really be enforced or noticed? I have been taking a number of machine classes and now am taking MasterCam (A very popular CAM program). I need to come up with a first project and was considering creating hubs. They could be machined out of stainless and then heat treated. I am sure they would much stronger than stock. The only hitch is cutting the splines. I think that would require purchasing a special tool. Anyway, if anyone has some info to share about these hubs let me know. Thanks, Chris

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[Todd Reid]

hi chris!

i think there is already a company or two making strengthened hubs for the crx (opm, maybe?).

if you make a set yourself, i think you would want to broach the splines.....

good luck

todd

[GBRacing]

Chris,
From what I understand, the hub typically fails when the hub bearing fails. I could be wrong but that's what I've been told. Now, as far as making stronger hubs, what they do is take an OEM hub and kryo treat it. So, same material just tighter bond.

[jisu009]

OPM hubs are not OEM hubs, they are machined from a higher rockwell stock.

SBMS hubs are OEM hubs that have been heat treated.

That being said, if you could make a hub that is within spec (OPM wasn't able to in my case) and offer it with good customer service (somthing lacking with the other guy)....then I think you might be onto something.

The average rockwell of an OEM hub was around 19, which is pretty soft. They OPM unit rockwell was 32 and was consistant throughout the unit.

[Tyson]

this is how mine (both of em) failed. the hub separates from the bearing. once that happens, its just the rotor in the caliper keeping the wheel from flying off the track.

[RineRacing]

If I'm not mistaken I believe stainless is supposed to be weaker then non-stainless. I remember in one of Caroll Smith's books saying that Stainless hardware should not be used on anything critical or something like that.

[Kaan]

stainless will warp/break down faster under extreem heat ... in a non heated structure its very strong.

[Andrew240z]

We had a rear hub actually break and we lost a wheel last year. They were on the Integra but I believe they are the same. We replace them every year. It is costly but losing a wheel could be more so. We use Honda factory parts. Dont know what the one was that broke, it was on the car when we bought it.

[chrisb]

Wow! I can't believe that part breaks like that. I know on my Integra hub there is a little bit of a radius between the bearing surface and the hub but I guess there is still a pretty big stress riser there. That is scary. I am a big fan of OEM parts but it seems in this case there is a need for something better than stock. I was not aware that OPM uses an aftermarket part. That is cool.

I have not taken my materials classes yet and obviously I am ignorant about the proper material to use. Luckily I have a mechanical engineer from Ga Tech and my professor as resources. I may choose a "safer" and simpler part as my first project but this is definitely something I would like to do. I would think with better material, better quality control, heat treating etc. a part that is stronger than stock with a stock fit could be produced.

[Tyson]

OPM hubs are pretty much race proven. im not saying theyre indestructable either. they going to be better than OE. you should replace your bearings also, and repack them with synth grease. dont reuse your hubs, thats what i did and thats what happened above. OLD, original OEM hubs will fail. before the hardened aftermarket hubs were available, racers would replace the hubs at least once a season, so im told.

after going thru this myself, i wouldnt recommend anyone go to the track often with the 10+ year old car without replacing the hub and bearings.

[Andrew240z]

Yes it is scary, I dont know anything about OPM stuff. what is the cost compared to Honda parts? The Honda parts are usually pretty darn good. I have heard about fronts breaking as well, but I have never actually witnessed it.

[phat-S]

Originally Posted by Andrew240z

Yes it is scary.... I have heard about fronts breaking as well, but I have never actually witnessed it.

Well, you got a witness! Guess you didn't ask "can I get a witness?" though

Two different cars in one race about 30 minutes apart - one a very fast ITA CRX Si, the other a very well sorted ITS GS-R (former Nonemaker car IIRC - same build that King-Rat's GSR came from I believe). The former lost the front left spindle due to the failure braking (or attempting to) into Roller Coaster. The latter occurred in the same race exiting South Bend. I was first stint so I just "witnessed" the GS-R's failure as the car remained in the infield grass, nose in the dirt, for the remainder of the race, the CRX came in on a flat bed where the evidence was pretty obvious.

Tyson, not sure I follow your "should not reuse your hubs" comment. We always mic'd the hubs and if they were still true, we certainly reused them ... that seems to be the point to buying the hardened hubs in the first place. I would always check them but I don't think I'd throw out a hardened hub unless it had signs of damage or some other concern. I do believe we were pretty religious about replacing the front left wheel bearing every 6 races and the front right every 2 front lefts. As for rears, they seem to have a pretty good indicator they are going bad.

There was a time when we could not get the hardened hubs due to (hell it might have been Mr. Tyson that bought the last off the shelf ) supply and ran OEs for a full season. We just made even more certain we were not missing a maintenance cycle on the bearings.

[Tom Blaney]

I use factory new hubs that are sent off to a heat treating service, peened and then returned to me before I sent them to my customers. I opted to use factory instead of custom built for both consistancy and availabilty.

I have had 3 hub failures at the bearing radius prior to starting to offer heat treated hubs, and wanted to have quality parts with a realistic turnaround time available as part of my product line.

Tom Blaney
SBMS Racing Inc
http://www.sbmsinc.com/race_shop.html

[Tyson]

phat, yeah, my statements were a bit jumbled, like my thoughts.

i meant to stress that if youre going to replace the original bearings, dont think you can get away with reusing your ORIGINAL hubs. which is what i did, and got the above result.

sorry, didnt mean to say not to reuse your hardened hubs. i wonder tho, how many times you could reuse even those OPM hubs after puttinga new bearing on.