I need to upgrade to 17"+ wheels for my 13" brake upgrade and want to use low cost Vette wheels, so I need the 4 3/4" pattern. This upgrade is normally done with welding a larger flange to the backside of the fiero wheel bearing flange. This path works, but I would prefer to use a larger bearing, so this is where I will make the S10 wheel bearing fit.
A couple of quick measurements. The wheel bearing hole in the 88 upright is 2.798". The edge of the tapered surface is 3.264"
The thinnest part of the S10 wheel bearing is 3.180"
The stepped surface then grows to 3.622"
There is no way a 3.180" bearing is going to fit into a 2.798" hole, so the first plan of attack will be to make the bearing smaller and to bore the hole in the upright larger.
After pressing the wheel studs out, I used one of the fiero bearing bolts to lock the wheel bearing together. Also wrapped the gap between the flange and housing with some tape to keep the metal shavings out.
After a little bit of time, the S10 wheel bearing no longer is stepped. The 3.622" portion and the rest of the surface was turned down to 3.125 (just the first portion of the machining, more will be remove).
Now how thin can the wall surface be? The wall is supported by the wall of the upright, so it can be relatively thin. A stock fiero rear wheel bearing has a wall thickness of .117"
The S10 wheel bearing after the phase 1 of machining has a wall thickness of .190"
So if I want a 33% (just a random #) thicker wall thickness than the fiero wheel bearing, I can remove another .035" from the thickness (or .070" from the OD) which would take the bearing OD down to 3.055". At this OD, I would need to bore out the ID of the 88 upright by .257 (or .1285" of material from each edge). Since the edge of tapered surface is 3.264", this modification would remove about 1/2 of the tapered area.
Now what about bolting the bearing to the upright. I am planning to keep the stock 88 wheel bearing pattern and use its bolts. This means I need to drill the S10 wheel bearing for the new pattern, but is there room for the pattern to fit the body of the bearing. The S10 body is 3.603" at the base by the mounting flange:
The heads of the 88 wheel bearing bolts are .754"
From the Timken catalog, the flange bolt circle pattern for the 88 rear wheel bearing is 4.02". Subtract the head thickness = 3.266". So when I drill the new pattern, I will have to cup the 3.603" wall about 3/16" around the bolt holes. I will also need to drill the access hole in the flange for attaching the wheel bearing bolts (and access for the endmill to cup/clearance the housing.
The wheel flange depth is deeper on the S10, and the housing mounting flange is thicker as well. I am planning to back cut the mounting flange to make it closer to the thickness of the stock fiero wheel bearing. This will help keep the rotor/brake caliper alignment correct. Also, removing material from the back side will make the whole area a machined surface allow me to possibly be able to rotate the new mounting flange pattern to clear the existing S10 one. Worst case the bolt holes will be slotted, but if I can keep them separate, then I will.
It is going to take machining the wheel bearing and boring the upright to install the S10 wheel bearing, but it should work out just fine. It will take me a week or two to build the mounting fixture to hold the upright for the boring process (I want to be able to use 1 fixture for both sides). I will also have to build a mounting fixture to hold the wheel bearing for drilling the fiero mounting flange.
Nice, same bolt pattern as Firebirds, too. Would increase the number of available wheel options exponentially from the ridiculously limited selection of 5x100's
Very nice. Since the rear of the 88 uses the same wheel bearing as the earlier years, this should work for all year Fiero's more or less. Looks like this wheel bearing uses different splines compared to the stock Fiero Axles, are you planning on building something larger for the F40? I was looking at a 97 S10, is this the correct bearing?
Very nice. Since the rear of the 88 uses the same wheel bearing as the earlier years, this should work for all year Fiero's more or less. Looks like this wheel bearing uses different splines compared to the stock Fiero Axles, are you planning on building something larger for the F40? I was looking at a 97 S10, is this the correct bearing?
for pre 88's an A-body front spindle/upright with an s10 wheel bearing is a near bolt in affair, no need for machining. http://www.fortunecity.com/.../switch/67/id205.htm My centurt had this spindle, you need to check if the car has the proper brake code.
I figured this would be an 88 only thing because the 84-87's have the option of doing this modification with the pontiac 6000 upright with minimal work (slight machining and slotting of holes), but the 88's can't just swap out the uprights.
The 88 fronts will just be drilled to match, but probably will not live a long life due to the 8 1/2" front wheels. If need be, I can do the bubbajoe bearing upgrade for the 88 fronts.
This bearing uses the 27 spline, so the axle ends will need to be swapped out.
The reason for this mod is to have low cost options for wheels in the 17/18/19 diameter and 8 1/2 to 10 1/2" wide... about $300 - $400 for a used set, or $600 - $700 for a new set.
[This message has been edited by fieroguru (edited 01-23-2012).]
for pre 88's an A-body front spindle/upright with an s10 wheel bearing is a near bolt in affair, no need for machining. http://www.fortunecity.com/.../switch/67/id205.htm My centurt had this spindle, you need to check if the car has the proper brake code.
No kidding, I didn't know about this, thanks. Is there any thing for the front of the 84-87?
No kidding, I didn't know about this, thanks. Is there any thing for the front of the 84-87?
Swap the front hub with corvair hubs... If you are an 84-87 guy, you need to read bubbajoes newest project thread (in the construction zone) start to finish once per year. He covers the corvair upgrade, corvette caliper upgrade, the S10 bearing in the rear, and lots, lots more... There is a table of contents on page #1 and page 9 covers the Corvair hub upgrade. //www.fiero.nl/forum/F...3/HTML/000007-9.html
[This message has been edited by fieroguru (edited 01-23-2012).]
Fieroguru, you may have just solved my 09 Cobalt SS axle problem
It is funny you should mention this... I have the specs for the 09 cobalt SS printed out on my desk at home. Not a fan of the 110 bolt pattern. But I seem to remeber it being slightly smaller than the S10. I can get you the important dimensions this evening.
However, while looking them over, I notice the standard cobalt 4 x 100 front bearing is small and pretty close to the size of the 88 front bearing (flange depth is still about .100" too high for a perfect fit, but it is .100 closer than the other 5x100 options). Redrill for 5x100 and some minor machining (might take the .100 off the upright) it should be able to work as a stock replacement for the 88 fronts for those who want to retain the 5x100 pattern... not sure if there is room for the redrill or if there is an access hole that would get in the way.
Swap the front hub with corvair hubs... If you are an 84-87 guy, you need to read bubbajoes newest project thread (in the construction zone) start to finish once per year. He covers the corvair upgrade, corvette caliper upgrade, the S10 bearing in the rear, and lots, lots more... There is a table of contents on page #1 and page 9 covers the Corvair hub upgrade. //www.fiero.nl/forum/F...3/HTML/000007-9.html
Wow, didn't realize this, I thought it was just the build thread for that awesome Northstar Indy. Thanks.
Yes, I'm a 84-87 guy because I don't HAVE any 88's.
Thanks again Guru. If this works out, is this something that we can pay you to do for us? In other words, send you a set of 88 spindles, and S10 hubs, and pay for the service? If you get to it, down the road, maybe also doing the work to the front hubs and putting it in this thread, so we have it all documented into one place.
Originally posted by 1fatcat: I'll take anything you can give me. Thanks Fieroguru!
code:
Application bolt circle Flange offset Hub Pilot Hub Pattern Spline 88 Rear 5x100 1.66 in 2.80 in 4.02 in 33 - small 88 Front 5x100 1.42 in 2.76 in 3.74 in None S10 4x4 5x4 ¾ 1.86 in 3.62 in 4.75 in 27 Cobalt 4x100 1.53 in 3.35 in 4.33 in 33 - small Cobalt SS 5x110 1.53 in 3.35 in 4.33 in 33 - Large?
The thing I am concerned with is the Timken catalog lists the same bearing for the SS from 2005-2009, which from your experience isn't correct. Can you confirm the spline for the outboard end? I suspect it is 30 vs. the large 33... GM tends to be getting away from the large 33 from what I have seen and going with 30.
As you can see, the hub pilot diameter is smaller on the Cobalt bearings, so there would be less material needed to be removed. It would be nice if it could be turned down to 2.80 and avoid the modification to the upright...
[This message has been edited by fieroguru (edited 01-23-2012).]
Thanks again Guru. If this works out, is this something that we can pay you to do for us? In other words, send you a set of 88 spindles, and S10 hubs, and pay for the service? If you get to it, down the road, maybe also doing the work to the front hubs and putting it in this thread, so we have it all documented into one place.
Rob
I need to prove it works and figure out how much time/effort the modification takes. I have 4 spare sets of 88 rear uprights on the shelf, so I could offer an exchange with a core charge to make sure I get the stock ones back... more to come on that.
The fronts I plan to redrill for the 5x4 3/4, but I will post that process here as well. I might check into having some drill rings made up with the 5x100 and 5x4.75 pattern. Then you bolt the ring to the bearing and use it to drill the new pattern.
[This message has been edited by fieroguru (edited 01-23-2012).]
The thing I am concerned with is the Timken catalog lists the same bearing for the SS from 2005-2009, which from your experience isn't correct. Can you confirm the spline for the outboard end? I suspect it is 30 vs. the large 33... GM tends to be getting away from the large 33 from what I have seen and going with 30.
My 09 Cobalt SS axles have an outboard spline count of 30.
[This message has been edited by 1fatcat (edited 01-24-2012).]
one other issue with the outter CV on the 08-10 Cobalt SS axle on my car, with Held tubular A-arms, is the clearance between the SS outter CV and the lower ball joint. The Fiero outter is 3.25" Dia. and the SS is 3.75". I only have .125" of clearance with the Fiero outter. Might this be unique to the Held suspension? I think this, http://shop.zzperformance.c...4-ZZP-LSJ-Axles.aspx will be my solution since my Series 1 doesn't have much HP, or options to increase it.
Also, I need to stay with the 5x100 pattern. I have very expensive compomotive wheels, (and a wife), that I would like to keep.
------------------ 67 GT-40 Mark II, 3800 S/C auto, 85 Fiero based (ASPP) kit. Held suspension and coil-overs all around with 2" dropped spindles. Mike's leather interior. And a whole lot more...
[This message has been edited by GT40 3.8 SC (edited 01-24-2012).]
First post. Finally registered. Been meaning to register and ask a hub question, but this post has almost answered it.
The question is: what is the best hub you can put on an '88 Fiero? Both front and rear. Any bolt pattern. And by best, I mean strongest. Looking into road racing a Fiero. Stock hubs won't do. ("Don't do it" isn't what I'm after here. I've been road racing for about 15 years, and around Fieros since 1985 when I worked at the plant. I have had my '88 Formula since 1990.) I have read quite a few of the hub posts here, lots of great info.
My thoughts so far: S10 hub should be strong. 4x4.75 might be tricky as I have to stick with 15" wheels. I want to stay close to stock offset to help the bearing situation. Cobalt 4x100 sounds tempting, 4x100 15x7 wheels are plentiful. Are the 4 and 5 lug Cobalt bearings the same? Is the Cobalt a good upgrade? What other options might be out there? Cruze? Solstice? Corvette?
16x8 Grand Prix wheel seems like the obvious choice for a stock appearing 16" wheel. 5x115, FWD offset. There was a flyer on the wall from a guy with a brand new stock set a little bit ago....I'll look if it's still up.
if I ever score a Wide Body I'm puting a set of those wheels on the back. I've been wanting to do that to a fiero for a couple years.
Seems less than efficient to me to go to all the trouble of building the widebody (and it's a LOT of work) and only install 8" wheels when 11's would fit.
Only had about 2 hrs to spend in the garage today, but I was able to tear down the upright for the other side and get it bored as well:
Also, looked into the possibility of installing a modified S10 wheel bearing in a modified front 88 upright. In this pic, the calipers are set for the 3.062" dimension that the S10 wheel bearing is turned down to.
The 88 front bearing bolt pattern is 3.74" diameter and a M12 bolt is .472". So the inner edge of the bolt threads will be at 3.268". With the 3.063 hole, the wall thickness would be .103"... not too much.
The other issue, is the bolt heads are .754"
The ID of the bearing housing (where the balls are) is 2.743"
So by the time the front side of the bearing housing is clearanced for the bolt heads, the wall thickness would be reduced to .122" at the notched portion.
The stock bearing wall thickness for the 88 rear wheel bearing is .117", which is thinner than the .122" the modified S10 bearing will have at the notched for the mounting bolts. The modified S10 bearing has .160" wall thickness with it turned down to 3.062", so I could turn it down some more (.040" more) and increase the wall thickness of the upright at the bolts to .143" from .103"
The last issue would be the flange protrusion depth. The S10 wheel bearing would push the wheel flange out .44" on each side... and there really isn't mush of an opportunity to trim down the bearing (1/8" max) and the upright (probably another 1/8" max). There are 4 Timken part #'s for 4 3/4" wheel bearings that have a 1.66" wheel flange depth (vs. 1.86" on the S10 and 1.42" on the 88 Front wheel bearing), they only come with ABS and I do not know how that would impact modifying the bearing housing.
For the time being, I will probably just redrill the stock 88 front wheel bearing flanges for the 5 x 4 3/4".
[This message has been edited by fieroguru (edited 01-28-2012).]
Have you considered the Bubbajoe hybrid bearing mod to get 5x4.75 up front?
Yeah, that is my current plan once the stock 88 front bearings give up... in all my years with multiple 88 fieros, I have only had 1 front wheel bearing go bad.
Turned down the 2nd bearing, so now I have a matched set of uprights and bearings. Now I need to figure out how to mount the bearings to the mill and clearance the flange side for the mounting bolt heads.
[This message has been edited by fieroguru (edited 01-29-2012).]
The mount bolt holes on the flange of the S10 wheel bearing are tapped, so I modified 2 of the bolts to fit into the T-slot of the mill.
Once everything was indicated in, I drilled through the wheel flange and enlarged the hole to 3/4". Then used a 3/4" end mill to clearance the side of the bearing housing for the bolt head and to flatten the casting at the base.
Then went back though with a 1/2" end mill to drill the new holes (for the fiero upright pattern):
The two locating bolts were sacrificed for the drilling process:
Bearing all modified:
Bolted in place on the 88 Fiero rear upright:
Now I just have to finish the 2nd one...
[This message has been edited by fieroguru (edited 01-29-2012).]
The work to install the modified S10 wheel bearings into a modified 88 rear upright is now complete. The only part left for this project is swapping the outer CV for one from the S10 (27 spline).
It has to be great having easy access to all that tooling. It's good to see you put it to good work.
Thanks!
Everything is in the basement/garage and it stays 50+ down there all winter long. The tools are a perk and a poison... they greatly increase the modifications I can play around with, which is often times a significant distraction from other projects. They also take up pretty much 1 full bay of my 2 car garage, so space it tight.
I need a larger garage... (and more/larger tools).
