IrocZ'85

iTrader: (9)

I'm in the process of converting my front brakes to C5 with the help of bigbrakeupgrade.com. In case anyone is thinking of converting, I highly suggest it and Scott from bigbrakeupgrade is awesome to deal with!

Anyways, after much searching, I bought C5 wheels. They are hubcentric wheels and I purchase 2 inch hubcentric spacers as well. They will fit my stock thirdgen hubs in the rear and fit the wheels fine....however these spacers DO NOT fit onto the newly converted C5 hubs for the fronts. The ID of the spacers are just shy of the OD of the hubs. Does anyone know where I can get the appropriate spacers from? I could have a shop widen them out but I'd rather not. Maybe i should have used lugcentric spacers instead for the fronts?

I'm waiting for a response from Scott in the meantime, but since alot of TGO members have done this conversion, I figured someone might know what spacers to get. Thanks! I can include pics if anyone is interested.

EDIT: for reference, can anyone confirm 70mm?
http://forums.corvetteforum.com/c5-t...dimension.html

//<86TA>\\

iTrader: (15)

stock is 70.3mm you can get 70.2mm and 70.3mm rings what did you buy?

are they not fitting the machined part of the hub or are they bottoming out of the rest of the protruding hub? If they are too small, have them opened up a but. It should be 70.3mm

70mm and 70.3mm is a noticeable difference, its not "close enough" you will be able to feel noticeable slop in the connection.

IrocZ'85

iTrader: (9)

If you bought the C5 front brake upgrade from BigBrakeUpgrade and want the short version of this post to cut to the chase, then DO NOT purchase the 2inch HUB CENTRIC spacers from ezaccesory.com. Now, that is not to say that the lugcentric spacers won't work, but the hub centric ones most definitely do not fit that conversion.

Now for the long part of the post. This first picture shows what I have:


Those spacers are specifically the HUB CENTRIC 2" adapters from EZaccesory, listed here: http://www.ezaccessory.com/Hub_Centr...475-5475hv.htm

So, this is what happens when I put those spacers on the conversion hub:



This is roughly the bore of the spacer itself, the most restrictive portion:

Around ~60mm

The bottom side of the spacer has the taper and comes more in line with the ~70.2 or ~70.3 standard bore as was mentioned by the previous poster ^, as you can see here:


Top diam of the conversion hub:


Bottom of the conversion hub:


Lastly, here is the hub centric spacer mounted to the OE-wheels deepdish C5 wheel I bought. However, the spacer lip and the wheel itself have some play between the 2 bore diameters...a noticeable amount just like the previous poster mentioned...which leads me to believe that either the spacer lip OD was not really machined to the right spec...or these wheels are not made for a factory C5 hub OD. I'm not sure of the last part because I've never brought the wheel to autozone and asked to see a C5 hub for fitment of the two. Also the possibility that C5 wheels are infact lugcentric? As usual I can never get a succinct answer on that question no matter what forum I check.

In any case, I will be calling EZaccesory to confirm what ID they have on their NON HUB CENTRIC spacers, versus these that I purchased. I'm guessing those are what's considered a "lugcentric" spacer as the wheel will no longer have contact on a bore, but will be hopefully centered well by the acorn nuts, and properly torqued and retorqued. The other option is to have a shop turn the spacers and open up that ID.

So, for anyone else with this same specific circumstance, in which you've bought the c5 conversion from bigbrakeupgrade you should have what I have in the pics. The large hub on the conversion interferes with THIS particular HUB CENTRIC spacer from ezaccessory, so these 3 components do not work together. I cannot speak for any other C5 hub design which might be smaller in height, or any other conversion kit. Let me know your thoughts!

IrocZ'85

iTrader: (9)

Apparently I wasn't the only one who bought the hubcentric spacers from ezaccesory and had issues. Here was RPOL98's problem...pretty much identical to mine:
https://www.thirdgen.org/forums/post...06-post42.html

I spent the better part of yesterday slowly spinning the spacer while having my friend use a drill and a sanding bit from a Dremel until we finally removed about 100-120micron of material...since it was undersized to begin with. My machinery's handbook lists a tight clearance fit for this particular inside diameter as being between 70.33-70.39mm as hubcentric is considered a locating surface. So, the spacer we have is just enough oversized to fit snugly...and be easily removed and put back on! I'm satisfied with the results, especially since it was cheap...but EZAccesory needs to get their act together and at least hire 1 engineer who knows how to spec a damn clearance fit....

A line to line interference fit(or undersize) should not happen on a piece like this..give me a break. I think i might do the other 3 spacers by hand since I don't believe a typical machine shop lathe will take 60 microns off as tool pressure alone from contact will drive the cutter deeper than 1 mil. Well Anywho, Good luck to anyone who buys these in the future, they're not perfect as of today!

87350IROC

iTrader: (2)

Best bet for this kind of stuff is to go the custom route. That way you can specify every dimension.. I have found Motorsport Tech to be great to work with. They are willing to build them the way you want.

Also, I'm not sure I like the way you expanded your hole. How can you be sure you removed equal material all the way around? I think a better option would be to have a machine shop hone it out.

IrocZ'85

iTrader: (9)

Good point, i agree about having it honed out as well. I mainly used the sandpaper/diegrinder just to see how much material needed to be removed, I'll have a local shop do the other 3 spacers like you mentioned. That way they can keep concentricity and remove it equally too. I'll check out motorsport tech too, thanks!