Spherical Bearings for Fox Vanilla Shox

[Mike Shaw]

what kind of spherical bearings are yall pressing into your shox? i need a bearing with a bore of 0.25" dia for our 1/4" bolts.

our cost report from last year says they used Aurora COM-4, but i know those dont fit. the eye hole for the 2004 Fox shox is 0.59" dia (same as last year, i think), and the COM-4 are 0.656" dia.

i talked to a dude from last year's team, and he said they found some spherical bearings in teh cabinet that fit perfect, but dont know where they came from.

i then ordered some Aurora AIS-4 b/c they have a smaller race, and they are 0.61" dia, 0.02" bigger than the hole and making for a big interference fit.

i called Fox, and they played dumb and acted like they didn't even know what spherical bearings were.

what are yall doing? i'd rather not machine these shox to get these bearings to fit, but time is ticking away and our car is set to roll out tomorrow.

[Brent Howard]

Com 4's with pressed in 1/4" inserts (Aluminum).

Brent

[Frank]

just to be different..

ge6's with single pressed in steel sleeve

the seeve gets a light - medium interference
the spherical gets a medium interferance (it wont move.. cause it only sees purely axial load.. if you have them at each end)

just be careful with your spacers (conical?) connecting the spherical to the rocker or chassis.. you need to make sure the shock can float and not bind, throughout the range of movement of the suspension



http://skf.com/skf/productcatalogue/catalogue/productPropertiesPage.jsp?prodid=183200006&designation=GE+6+C&lang=en&imp=false&pafurl=%252Fportal%252Fskf%252Fhome%252Fproducts%2 53Bjsessionid%253DLQ1RT2TCXHNWFQFID0LCFE15AAAACIV0 %253Fpaf_dm%253Dshared%2526paf_gm%253Dcontent%2526 paf_gear_id%253D4400006&extra=true

[Mike Shaw]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Brent Howard:
Com 4's with pressed in 1/4" inserts (Aluminum).

Brent <HR></BLOCKQUOTE>

that doesn't help. the spherical bearings are too large, they dont fit. inserts wont help, the bore size on the COM-4 is 1/4" dia, the race is 0.656" dia.

i need a bearing that has a race slightly larger than 0.59" dia (up to 0.005"), and a bore for a 1/4" bolt.

i know a number of people are using the Fox Vanilla RC shox, so some of yall had to come across this issue.

if all else fails, i'll just bore out the holes so the Aurora bearings fit (the 0.61" ones).

[ben]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Frank:
just to be different..

ge6's with single pressed in steel sleeve

the seeve gets a light - medium interference
the spherical gets a medium interferance (it wont move.. cause it only sees purely axial load.. if you have them at each end)

just be careful with your spacers (conical?) connecting the spherical to the rocker or chassis.. you need to make sure the shock can float and not bind, throughout the range of movement of the suspension



http://skf.com/skf/productcatalogue/catalogue/productPropertiesPage.jsp?prodid=183200006&designation=GE+6+C&lang=en&imp=false&pafurl=%252Fportal%252Fskf%252Fhome%252Fproducts%2 53Bjsessionid%253DLQ1RT2TCXHNWFQFID0LCFE15AAAACIV0 %253Fpaf_dm%253Dshared%2526paf_gm%253Dcontent%2526 paf_gear_id%253D4400006&extra=true <HR></BLOCKQUOTE>

Glad that woks! My GE6s arrived last week and I'm planning to fit them at the weekend :-)

Ben

[NJM.]

Mike,

Couple of choices here. First Aurora had made a special run of spherical bearings for those Fox shocks at one time. They were just the bearings you have with smaller outer races. Maybe they discontinued those but in any case you can still use what you have.

First, i have heard of teams boring out the shock eyes for the smaller bearing you have. I know that this will work but I am not sure i would recommend it because you may bore through one of the oil passages and ruin your shock.

Second you can turn up a jig that you can chuck in your lathe and bolt your bearings to in order to turn the outside of the bering down to .595 or whatever. Remember your jig needs to hold the outer bearing race true to the lathe. I have heard of teams doing this with no problems.

Maybe a combination of the two is the best bet.

Hope this helps.
NJM

[Mike Shaw]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by NJM.:
Mike,

Couple of choices here. First Aurora had made a special run of spherical bearings for those Fox shocks at one time. They were just the bearings you have with smaller outer races. Maybe they discontinued those but in any case you can still use what you have.

First, i have heard of teams boring out the shock eyes for the smaller bearing you have. I know that this will work but I am not sure i would recommend it because you may bore through one of the oil passages and ruin your shock.

Second you can turn up a jig that you can chuck in your lathe and bolt your bearings to in order to turn the outside of the bering down to .595 or whatever. Remember your jig needs to hold the outer bearing race true to the lathe. I have heard of teams doing this with no problems.

Maybe a combination of the two is the best bet.

Hope this helps.
NJM <HR></BLOCKQUOTE>

Thanks for the help. we just ended up using a dremel with a sanding attachment to bore out the eyes a little bit -- that sounds gorey, hehe. but, only took like 15 min and works great. two shocks are done, two more to go.

[Frank]

If your interested in whats indside your shock..

go down to the vet department at your uni

and get them to x-ray the shock

60 kVa , about 100mas, @ 1000mm on fine grain film
theres an exposure to get you started

you'll notice that you do have room to bore them a little (the drilled passage is the worry)

although if your going to bore them, id only do it to put a sleeve in the full width if the shock

dont bore them and run a spherical on the ally

i hear mountain bike guys say that when they're ridden for a while the rebound knob gets "stiff"

i think this is the ally yielding tightening the threads of the rebound knob

i'll try and scan the x-rays of our "risse" shocks and post them here

regards

Frank

[JadgPzIV]

For our last car we used SIB-3 Spherical Bearing press fit mount in a sleeve. This sleeve was press fit in the Vanilla RC.

With AN3 Bolt we never got any problem!

[ben]

GE6s went in fine. Respect due to our team machining god for getting the sleeves correct.

Ben

[Gumby]

Frank

What Risse shocks are you guys using? We are looking at buying a set and it would be good to get some insight.

[Frank]

http://www.uq.edu.au/fsae/7-E-01.htm

they've got heaps of travel, externally they are basically identical to fox

get them direct from risse, big disount available when we got 'em

as for dyno plots, and modifying the internals, we'll be getting to that very soon

we just went straight into histograms lasy year, which was a silly waste of time

[jack]

as i was reading this forum, i looked over at my bike, and thought hey, i have a fox shock, with a bell crank type setup, and no spericals, and it works great, along with everyone else's mtb bikes. why are people using sphericals, if you can set up suspension without it? our car doesnt use bellcranks or spherical, so i dont really understand the setup fully.

[Mike T.]

On a mountain bike, the whole assembly is in plane, meaning the bolts mounting the shock ends will always be perpendicular to the shock. However, on most FSAE cars, the assembly is sometimes slightly out of plane, which causes the shock mounts to bind if sphericals are not used. Binding of the shock ends, in addition to causing unwanted resistance to motion, will cause the shaft of the shock to bend, which can do internal damage and wear the shocks out more quickly. I noticed on your new car that you have pull through shocks and no sphericals, and initially thought the setup would cause the shocks to bind. It seemed though, after further inspection, that it is situated in such a way that no binding would occur since motion of the outboard pickup is in a plane perpendicular to the shock rotation axis. If that is the case, that is why you all don't need them.

[Denny Trimble]

Yeah, Carroll Smith nailed us on bushings instead of sphericals in '99. We argued "the bellcrank and shock are in-plane, and this is how it's used on bikes", but he replied:
-Is it "perfectly" in-plane?
-Does it stay in-plane when you apply loads to it?
-How much friction force is developed if you apply a bending load on the shock?

And his summary was "it won't kill you, but it sure won't help".

[Jarrod]

if you aren't using sphericals, are you using a pin connection, rather than a bolt? If you have a bolt done up tight on the bushing, it will clamp it, adding a lot of friction that you cannot control. If it is not done up tight, you will have some degree of slop. Using sphericals eliminates all of this. Any bind, stick, or slop in your suspension is ugly. Just my thoughts.

[ben]

Regardless of how in plane your suspension is, a coil-over unit will always have an out of plane load due to the buckling of the coil spring.

Ben

[jack]

yes, its true out of plane loading will screw things up. but, here is some more food for thought; in mtb'ing those shocks certainly get laterally loaded, i know this may not seem like it makes sense, if you have never downhill mtb'ed yourself, you would know. my kona, and allmost every other frame design will put a healthy bending load (side to side) on the shock in a severe bump. why do bike manufacturers keep doing this? because, at least on a mtb, it doesnt matter at all. on another note, if you put my rear wheel on 90 degrees to how it should be, you would have a nice pushrod/bellcrank setup, all in one plane, with none of this bending the shock bussiness. if i was going to design a suspension, i would probably do this, only use a tortion bar instead of a coil spring.

...on another note i just looked in the ferrari book to see what they do, and they dont use sphericals on the shock between the two rear pushrods, makes sense, the whole system is in one plane...so this got me thinking...everything that has to do with anything on the ferrari is in double shear, but on most fsae car, the bellcranks are in single shear, this is probably where that bending that carroll was getting at comes from.

so if you put your bellcranks in double shear, no need for sphericals??

[Schumi_Jr]

[QUOTE]they dont use sphericals on the shock between the two rear pushrods, makes sense, the whole system is in one plane...so this got me thinking...everything that has to do with anything on the ferrari is in double shear, but on most fsae car, the bellcranks are in single shear, this is probably where that bending that carroll was getting at comes from.QUOTE]

I think that Ferrari are holding slightly tighter tolerances than your typical FSAE car...

[Denny Trimble]

Our bellcranks were in double shear in '99 when he commented that, and they still are on the new car.

I just made a quick jack with inline skate wheels that are mounted on bolts in single shear, and I feel dirty. But it was quick and easy and it's not part of the car http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Charlie]

Jack, from your post it sounds like you can justify a design by looking at something else and how they do it, without knowing the background of thier design choices. Say it ain't so. http://fsae.com/groupee_common/emoticons/icon_wink.gif I don't think thats how you mean to say it but that's what it sounds like.

In a mountain bike you are doing something quite a bit different. In a racecar the driver is feeling the car through the shocks, especially low piston speeds. You want as little stiction as possible, including stiction caused by side loading.

Also we are interested in preventing seal blowouts like we've had in the past. http://fsae.com/groupee_common/emoticons/icon_redface.gif

This is my take on a possible reason, I'm no shock expert so if anyone wants to correct me please do!

I don't doubt that there have been FSAE cars with single-shear bellcranks and shocks at some point, but I certainly hope that is not the norm! I shudder at the thought. We've done some stupid things in the past but never putting our shocks in single shear.