| [GMCnet] Wheels with less offset [message #87764] |
Tue, 08 June 2010 13:12  |
Gary Casey
Messages: 448
Registered: September 2009
Karma: 0
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Someone posted that wheels from a Dodge 2500 or Ford F-250 will fit the front hubs and will result in about a 2 inch increased track at each side. I've been looking for a pair of these wheels, but I'm finding that the "standard" (whose standard? Ford? Dodge? GM?) bolt pattern changed in about 1996. Previous to that the bolt circle diameter was 6.5 as best I can tell and after that it changed to a metric pattern. True? If so, what trucks have the same pattern as ours? I'm getting confused.
Gary Casey
'73 23 with a narrow front end...
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| Re: [GMCnet] Wheels with less offset [message #87773 is a reply to message #87764] |
Tue, 08 June 2010 14:38  |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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Gary,
The wheels I used are Dodge 3/4-ton / single wheel 1-ton, 16" X 8" factory aluminum wheels of about '94 - 2000 vintage. They are two inches wider than the GMC drop center wheels and have close to two inches less backspacing. They are NOT hub centered (I'm not sure how much of an issue that really is with eight 9/16" lug bolts holding the wheel to the hub) which is important to some people. I am not the first person to use these wheels and got the idea from another GMCer. I am using them on the front only and they do have the effect of making the front track width the same as the back.
I may be wrong about this, but I think GM and Dodge still are using the 8 on 6-1/2 bolt pattern and only Ford has changed to a metric bolt circle that is somewhat less than 6-1/2". that should open up a lot of options in both factory wheels and aftermarket wheels. The 16" X 6(1/2)" wheels from GMC and Chevy trucks might also be an attractive option if you are not looking to run a wider tire (which I was).
The use of two different offset wheels might present a handling problem if I need to put my drop center spare on the front, but I think I will be able to live with that until I can get the other tire fixed or replaced in the event of a flat tire.
Here are some pics:
Mine;
<http://www.gmcmhphotos.com/photos/showphoto.php?photo=33299&title=dodge-front-wheels&cat=500>
<http://www.gmcmhphotos.com/photos/showphoto.php?photo=33300&title=dodge-front-wheels&cat=3>
<http://www.gmcmhphotos.com/photos/showphoto.php?photo=33302&title=dodge-front-wheels&cat=3>
Ozone3's;
<http://www.gmcmhphotos.com/photos/showphoto.php?photo=8360&cat=3731>
<http://www.gmcmhphotos.com/photos/showphoto.php?photo=8356&cat=3731>
<http://www.gmcmhphotos.com/photos/showphoto.php?photo=8359&cat=3731>
<http://www.gmcmhphotos.com/photos/showphoto.php?photo=8358&cat=3731>
JWID. May not be appropriate for everybody.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
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| Re: [GMCnet] Wheels with less offset [message #87802 is a reply to message #87764] |
Tue, 08 June 2010 20:40 |
Gary Casey
Messages: 448
Registered: September 2009
Karma: 0
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Senior Member |
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Carl,
Thanks a ton for the info. The wheels you picked look really great and I think I'll keep looking until I find a pair like that. I did find some from a late model Ford Excursion and they had a number of small holes that looked a lot like the Alcoa's with less offset. But then I found that the late model Fords used "metric" bolt circles and from then on I got more confused. And I don't see any problem running an original wheel as a spare, for a reasonable distance anyway. As for running the Dodge wheels in the rear, I have no real opinion one way or the other - except that would put you back in the mode of having different tracks front and rear.
Another comment: Way back when we at GM were having trouble with the life of CV joints and found that running them at a slight angle IMPROVED durability. The reason was that the inevitable wear was spread over a larger area. That delayed the clicking sound worn joints make on a sharp turn. By the way, the official service procedure to use if a customer came in with worn CV joints was to swap the shafts side-to-side. As long as the customer didn't do sharp turns in reverse under power he never knew. One thing that is important is that whatever angle the joints run it is important that they both are about the same. Unequal angles lead to torque steer.
Yet another comment: I see no reason to believe that A-arms should be parallel to the ground at a normal ride height. Sure, it might make the geometry simpler, but as for any functional advantage I see none. The GMC seems to have the upper arm parallel to the lower, but that is also not particularly important. Just my opinion.
Final comment: Here I'm going out on a limb, as I'm not an expert on the subject of castor angles. As I understand it the purpose of castor is to provide a straightening effect when in a turn. When going straight it has little effect except that when driving on a cambered road surface high castor angles will make it more difficult to keep straight. High castor angles increase lateral force deflection understeer and that is probably a good thing. When in a turn it takes more steering effort to keep it in the turn. Is it critical that the castor angle be a specific number? I don't think so. But then what do I know?
Gary
From Carl:
The wheels I used are Dodge 3/4-ton / single wheel 1-ton, 16" X 8" factory aluminum wheels of about '94 - 2000 vintage. They are two inches wider than the GMC drop center wheels and have close to two inches less backspacing. They are NOT hub centered (I'm not sure how much of an issue that really is with eight 9/16" lug bolts holding the wheel to the hub) which is important to some people. I am not the first person to use these wheels and got the idea from another GMCer. I am using them on the front only and they do have the effect of making the front track width the same as the back.
I may be wrong about this, but I think GM and Dodge still are using the 8 on 6-1/2 bolt pattern and only Ford has changed to a metric bolt circle that is somewhat less than 6-1/2". that should open up a lot of options in both factory wheels and aftermarket wheels. The 16" X 6(1/2)" wheels from GMC and Chevy trucks might also be an attractive option if you are not looking to run a wider tire (which I was).
The use of two different offset wheels might present a handling problem if I need to put my drop center spare on the front, but I think I will be able to live with that until I can get the other tire fixed or replaced in the event of a flat tire.
Here are some pics:
Mine;
<http://www.gmcmhphotos.com/photos/showphoto.php?photo=33299&title=dodge-front-wheels&cat=500>
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| Re: [GMCnet] Wheels with less offset [message #87969 is a reply to message #87802] |
Thu, 10 June 2010 16:39 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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""Yet another comment: I see no reason to believe that A-arms should be parallel to the ground at a normal ride height. Sure, it might make the geometry simpler, but as for any functional advantage I see none. The GMC seems to have the upper arm parallel to the lower, but that is also not particularly important. Just my opinion""
There's no reason to think that the A arms need to be parallel to the ground, nor do the upper and lowers need to be parallel to each other. Things like camber change, roll steer, ride steer are all engineered as a multi link assembly. Almost all vehicles are a bit different to suit the handling characteristics and packaging constraints. The only thing you need to worry about is that the ride height is correct and the rest falls into place. Now it does need to be symetrical side to side and the shop manual details what to look for.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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