And now, a not so stupid question., Wheel spacers/offset effect on bearings Options

[Dr. Roger]

So now I expect the new rear 11" hollow spoke turbo twisties to come in tomorrow.
Then I will figure the spacer width required.
Then I worry about what I thought I heard about crazy bearing wear rates if I go too spaced out. (IMG:http://www.914world.com/bbs2/html/emoticons/smoke.gif)
I think I want to use my Sheridan flares but.........
If I use them I will need to space the wheels a substantial amount.
I'm guessing >3"...

Aren't all the guys using Sheridan flares either spacing out their fat rubber or using huge positive offset wheels?

I'm looking for feedback from people who've actually seen or done this before.

Thanks!
Roger

[dweymer]

Wouldn't that need low, or negative offset? I am also trying to figure out how to run 17x10, 17x8s on mine.

http://members.rennlist.com/1976c38/index.html

[wbergtho]

Hello,

I have a Sheridan Body kit on my LS6 V-8 street car and I am running 993 Twin Turbo Hollow spokes 18x10 & 18X8s. I have 1 1/2" rear spacers and 2 1/2" spacers on the front. I have had no bearing problems...although I can say I have only put about 3K on the car since 2004. I installed all new bearings on all four corners as cheap insurance. I expect that it will last a while...

Regards,

Bill

[Andyrew]

Roger, Your flares are to big... Cut em down till you like it, and fiberglass them back straight...

btw... you'll have to do it anyways (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

Andrew

[SirAndy]

QUOTE (rogergrubb @ Feb 20 2006, 09:20 PM)

Then I worry about what I thought I heard about crazy bearing wear rates if I go too spaced out. (IMG:http://www.914world.com/bbs2/html/emoticons/smoke.gif)

yes, there will be more load on the bearings, no question ...

how much, i can't say. the bearings come with plenty of margin from the factory, so, they *can* handle quite a bit of additional load.
i'm sure someone somewhere (at the factory?) has exact numbers.

i'd say, run them wheels and check the bearings on a regular base.
(IMG:http://www.914world.com/bbs2/html/emoticons/smash.gif) Andy

[Dr. Roger]

QUOTE (wbergtho @ Feb 21 2006, 01:20 AM)

Hello, I have a Sheridan Body kit on my LS6 V-8 street car and I am running 993 Twin Turbo Hollow spokes 18x10 & 18X8s. I have 1 1/2" rear spacers and 2 1/2" spacers on the front. I have had no bearing problems...although I can say I have only put about 3K on the car since 2004. I installed all new bearings on all four corners as cheap insurance. I expect that it will last a while... Regards, Bill

Bill,

Do you have a progress thread on your ride?
Many guys here love your car and I'm no exception.

I'm particularly interested in your Sheridan rear quarters integration and brake setup.

It appears that I may have the "wide body" rear quarters.

What do you think?

Much thanks,
Roger

(IMG:http://www.914world.com/bbs2/uploads/post-2-1139007086.jpg)

[wbergtho]

Hi Roger,

I don't have a build thread...but should probably piece something together. If you click on all my posts...there is a fair amount of info & pics. Also, just pm me or e-mail me at: wbergtho@pressenter.com if you have any questions. I'd be happy to answer them if I can.

I just went out to the garage to measure the distance between the outside of my rear Sheridan Standard flair to the inner wheel well. I took a tape measure and held it horizontally to the inner wheel well structure and came up with 13". If you're measurements are within a 1/2" of this (you haven't glued it and fitted it yet) you most definitely have the Standard kit. By looking at your photo, they appear to be Standard. They don't look overly squarish like the wide body flairs. I have about 1/2" on either side of my tires for clearance. It'll be interesting to see if your 11" wide wheels will fit. Let us all know???

[wbergtho]

Hi Roger,

I don't have a build trhread but probably should have one. I went out to the garage and measure my flairs for you. The measurement from the rear flair (outside of bodywork) to the inner wheel well structure...where you might weld in a chassis stiffening kit) is 13". I held the measuring tape horzontally from the outer wheel lip to the inner fender. I have less than 1/2" clearance on either side of my 18x10 hollow spokes (running 285/30/ZR18). Your pic looks like a stndard body to me. It isn't overly square & extra extra wide. Take the measurement and tell us all what you came up with??? I'll be interested to see if your 11" wide wheels & tires will fit comfortably. I hoope they do...so I will have a reason to upgrade (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

Regards,

Bill

OOPS! I thought I lost the 1st post...So i posted again (IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif)

[Eric_Shea]

I'm with Andy,

You'll see some extra load and you'll probably wear them out twice as fast meaning... every 50k miles? (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

930's used 30mm spacers and had the larger bearings. Some 914 control amrs have been cut for larger bearings but I 'really' don't think that's a good use of time or money.

If you're racing maybe every other season??

[Dr. Roger]

QUOTE (wbergtho @ Feb 21 2006, 09:18 AM)

Hi Roger, I don't have a build trhread but probably should have one. I went out to the garage and measure my flairs for you. The measurement from the rear flair (outside of bodywork) to the inner wheel well structure...where you might weld in a chassis stiffening kit) is 13". I held the measuring tape horzontally from the outer wheel lip to the inner fender. I have less than 1/2" clearance on either side of my 18x10 hollow spokes (running 285/30/ZR18). Your pic looks like a stndard body to me. It isn't overly square & extra extra wide. Take the measurement and tell us all what you came up with??? I'll be interested to see if your 11" wide wheels & tires will fit comfortably. I hoope they do...so I will have a reason to upgrade (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) Regards, Bill OOPS! I thought I lost the 1st post...So i posted again (IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif)

Bill,

Could you please post a few pics of how you attached the rear quarters to the car?

Bonded or fastened?

Complete removal of steel fender or leave some for fastening?

Thanks, thanks, and thanks! (IMG:http://www.914world.com/bbs2/html/emoticons/cool.gif)

Roger

[Dr. Roger]

QUOTE (dweymer @ Feb 20 2006, 10:35 PM)

I am also trying to figure out how to run 17x10, 17x8s on mine. http://members.rennlist.com/1976c38/index.html

I know Leo and I did his car with 8"ers in the rear with Cookie cutters, whatever offest that is...

We had to roll those puppies before they would fit. Nice and tight. Looked great. (IMG:http://www.914world.com/bbs2/html/emoticons/smilie_pokal.gif)

I tried my 15X8's on the rear of my car and they fit just fine. (different offset than Leo's)

If you see the link to my progress thread you'll se that there's no way to get 10"ers under the rear fenders without substantial modification.

[dweymer]

Mine is way flared..just can't seem to find a good offset so I don't have to run 3" spacers. Nice car btw, both of them!

[Mueller]

QUOTE (dweymer @ Feb 20 2006, 10:35 PM)

Wouldn't that need low, or negative offset? I am also trying to figure out how to run 17x10, 17x8s on mine. http://members.rennlist.com/1976c38/index.html

pretty easy.....if using modern Porsche wheels you'll need spacers that'll give you 5" backspacing, more backspacing (with smaller spacers) and you'll hit the inside trunk wall/trailing arm

930s (911 turbo) used the same wheel bearings (at least on the front) that all of the '65 to '89 911s used...the front hubs of the 930 had an ~`1" spacer "built-in" to the hub like Eric mentioned.....

I guess you could try and find out if Porsche recommended more frequent service on the 930's than the regular 911's.....

[byndbad914]

I have the sheridan std kit with old school 15x8-1/2" right now that barely tuck inside the fenders due to the "deep dish" wheels. I have 4" b/space which sets the wheel and tire out a bit.

I don't think the backspacing really matters until you go passed the 1/2 way point ... if you use a deep dish wheel or a backspace with spacers, the issue is where the centerline of the load is in relation to the centerline of the bearing's reaction - standard kind of Force *distance (moment reaction) stuff. Now use a 6" b/s on an 8" wheel, and you move the reaction location out another 2" (increasing the d in F*d).

Deep dish wheels were also known as "bearing killers" back in the 70s because the tire centerline is so far away from the bearing centerline (this old timer mechanic told me I was crazy when I was 16 and put deep dish Cragars on my 70 Mustang because of all the wheel bearings he replaced on those 'crazy vans' with those wheels) (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

So, wider wheels that offset the centerline outward from the bearing centerline will always induce additional loading to the bearing surface due to the addition of moment to the equation. In the end, run the tire width and backspacing you think looks good and keep an eye on the bearings. I would personally try to keep the b/s no more than the 1/2 way point (4" on 8" wheel for example) as additional adds more moment. Less leaves the moment at the 1/2 way point no matter what.

If you race a lot, you should knock the car down annually and inspect everything anyway, so just replace the bearings (cheap really). If you don't race it a lot, or not at all, those bearings will last quite a while... probably 50K.

That is my guess, no real science or testing to it other that what seems to make sense. Then again 525HP in a 914 makes complete sense to me as well (IMG:http://www.914world.com/bbs2/html/emoticons/cool_shades.gif)

[byndbad914]

sorry, re-reading there was a point a bit misleading in the way it was worded... hard to explain sometimes...

Regarding the 6" b/s on the 8" wheel, it is worse assuming you have a 2" spacer in there to space the tire in the wheelwell correctly. If you have a 6" b/s on an 8" wheel with no spacer, different story. Just forgot to say more or less that larger than necessary b/s with a spacer is a worse idea in that case.

For the rear of my car, I could run a 10" wide wheel easily if I keep the "front" spacing the same and I would actually decrease moment at the bearing since the tire centerline would shift back inward.

that is probably as clear as mud...

[Leo Imperial]

QUOTE (rogergrubb @ Feb 21 2006, 01:56 PM)

QUOTE (dweymer @ Feb 20 2006, 10:35 PM) I am also trying to figure out how to run 17x10, 17x8s on mine. http://members.rennlist.com/1976c38/index.html I know Leo and I did his car with 8"ers in the rear with Cookie cutters, whatever offest that is... We had to roll those puppies before they would fit. Nice and tight. Looked great. (IMG:http://www.914world.com/bbs2/html/emoticons/smilie_pokal.gif) I tried my 15X8's on the rear of my car and they fit just fine. (different offset than Leo's) If you see the link to my progress thread you'll se that there's no way to get 10"ers under the rear fenders without substantial modification.

Sorry Roger, they are only 7"ers in the rear and 6"ers up front, but I didn't
have to roll. I fit 225ers on stock fenders... Remember (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

[Aaron Cox]

no such thing as an 8" cookie...

just 6's and 7's