b_have Posted February 16, 2006 Share Posted February 16, 2006 Just to clarify, I was looking for MINUS 20 offset for my Abflug rears. Quote Link to comment Share on other sites More sharing options...
wkdtime Posted February 16, 2006 Author Share Posted February 16, 2006 So, do you have a wheel with a +30mm offset, or -30mm offset? If its -30mm you have no chance of them fitting, with +30mm you might get them to fit but could need spacers. they are +30, whe i use the calculator on http://www.1010tires.com/WheelOffsetCalculator.asp it shows the the wheel extends towards the arch, see below before wheel config, 17 inch 9 rears, off set 50 new wheel config, 19 inch 9.5 rears, off set 30, Inner Clearance:14mm more, Outer Position: extend an extra 26mm, i think this means the wheel will extend toards the arch with a +30 offset, not more inwards towards the hub. am i reading this right? Homer you say i would need spacers with +30 offset whereas on previous threads and on what the above shows is that i may get rubbing occuring witht the arch. Quote Link to comment Share on other sites More sharing options...
wkdtime Posted February 16, 2006 Author Share Posted February 16, 2006 http://www.mkivsupra.net/vbb/showthread.php?t=53629&highlight=offset the above is the exact same question that i asked, Terry seems to think they will stick out too far, now what im confused about is what homer said, that i would need spacers to get the rears in! where as Terry seems to think that the wheels will be too far out. thanx for helping out guys. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 16, 2006 Share Posted February 16, 2006 Wheels are facing the same way, mounting hubs both on the inside left hand and centerline in the same place ...I'm a bit lost now but maybe this will clear it up. http://www.tomzwheels.com/offset1.jpg The picture shows a wheel with the positive offset. A positive offset will cause the wheel to set in or tuck into the vehicle. Originally you found positive offsets on just front wheel vehicles. Due to that some people refer to positive offset wheels as front wheel drive offsets. Currently there are many rear wheel drive cars and trucks with positive offsets. The higher the positive offset the less it sticks out from the vehicle and it will have a higher Backspace. And the website for you: http://www.tomzwheels.com/offset.htm Sorry but you still have it arse about face! the picture on that link is referring to a negative offset as a starting point! which will cause the affect you describe above:) Quote Link to comment Share on other sites More sharing options...
Miguel Posted February 16, 2006 Share Posted February 16, 2006 Correct! as basicaly the hub sits 20mm ( +30 offset) further in as opposed to a +50 offset ..pushing the out side rim edge towards the arch and the inside rim edge away from the strut. Positive offset Negative offset +50 > +40 > + 30> + 20> + 10 > 0 Outside rim away from arch. Outside rim towards arch Wheel hub outwards Wheel hub inwards Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 16, 2006 Share Posted February 16, 2006 Nooooo:blink: Quote Link to comment Share on other sites More sharing options...
Miguel Posted February 16, 2006 Share Posted February 16, 2006 Sorry but you still have it arse about face! the picture on that link is referring to a negative offset as a starting point! which will cause the affect you describe above:) LOL I never wrote that. It came from the same site as the write up CLEARLY stating it's a positive offset. yes i copied and pasted it. I Don't proffess to be an expert just reading up on it myself. So it says beans on the tin it must be beans. Click the link and read it for yourself Quote Link to comment Share on other sites More sharing options...
Homer Posted February 16, 2006 Share Posted February 16, 2006 I was completely wrong earlier, Migs got it right in his last post. Wkdtime, problem still remains though, not sure if you'll be okay with +30mm offset, could be too close the arch. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 16, 2006 Share Posted February 16, 2006 Either i'm going stupid in my old age or they have got that wrong on that site! which if you read the first part and then go on to read the last they have defiantly cocked up! i know from past tuning of front wheel drive vehicles that most run a negative offset, which is necessary due to steering angles to avoid torque steer, if you use a positive offset on FWD you will get bad torque steer and odd steering characteristics! are we agreed that this diagram is correct?? http://www.tireguides.com/images/offset.jpg Quote Link to comment Share on other sites More sharing options...
Miguel Posted February 16, 2006 Share Posted February 16, 2006 Either i'm going stupid in my old age or they have got that wrong on that site! which if you read the first part and then go on to read the last they have definatly cocked up! are we agreed that this diagram is correct?? http://www.tireguides.com/images/offset.jpg Yes it is correct Quote Link to comment Share on other sites More sharing options...
wkdtime Posted February 16, 2006 Author Share Posted February 16, 2006 cheers homer, bit more clued up now, so i have to worry about it rubbing with the arch. thanx guys. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 16, 2006 Share Posted February 16, 2006 Yes it is correct So in this case if you add more to the inside face of the mounting surface it will move the wheel more toward the wheel arch! as it also moves the outside rim surface toward the inside of the wheel arch!? are we in agreement ? Quote Link to comment Share on other sites More sharing options...
Miguel Posted February 16, 2006 Share Posted February 16, 2006 So in this case if you add more to the inside face of the mounting surface it will move the wheel more toward the wheel arch! as it also moves the outside rim surface toward the inside of the wheel arch!? are we in agreement ? Aha i see where your are coming from. That is Backspacing not offset. Backspacing is the distance from the back of the hub face to the the back side of the wheel. hence if you put spacers on you move the whole wheel outwards. offset is the relation of the HUB to the centerline of the wheel. EDITED as i made a boo boo and called PCD instead of offset Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 16, 2006 Share Posted February 16, 2006 Sorry but PCD refers to pitch circle diameter and is nothing to do with offset, but refers to the spacing of the stud holes! but i think you are getting my drift:) Quote Link to comment Share on other sites More sharing options...
Miguel Posted February 16, 2006 Share Posted February 16, 2006 Sorry me being a tit on PCD my bad. But yeah i get your drift. But it still does not affect that offset and back spacing are diferent. Positive offset like both them pictures will move the rim inwards from the arch and the hub outwards Negative offset moves the hub inwards and the rim outwards. Am i wrong ? who knows maybe my eyes are in reversal ...backspacing i've always taken as the relation from the hub to the back edge of the rim. Sorry on the PCD blonde moment. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 16, 2006 Share Posted February 16, 2006 One last try! i'm not meaning to be argumentative, i would just like get the whole wheel offset thing cleared up:) Aha i see where your are coming from. That is Backspacing not offset. Backspacing is the distance from the back of the hub face to the the back side of the wheel. hence if you put spacers on you move the whole wheel outwards. "In the same way that if you have more offset it is the same as adding spacers! Offset will always change the amount that the whole rim moves either in or out, providing that the rim width stays the same! i think that where the confusion is coming in is that people are talking about changing the rim width! in which case the offset needs to be changed to avoid the rim coming into contact with either the shock or brake, on the inside or the arch on the outside!" offset is the relation of the HUB to the centerline of the wheel. "so at the same time it must have an equal effect on the inside and outside of the rim" EDITED as i made a boo boo and called PCD instead of offset Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 17, 2006 Share Posted February 17, 2006 And sorry for the blatant hijack wkdtime:innocent: hopefully it will help clear thing up for you in the end;) Quote Link to comment Share on other sites More sharing options...
Miguel Posted February 17, 2006 Share Posted February 17, 2006 Er have I not been saying this since the start. You corrected me of that the 1st pic was negative offset and it was infact positve. The problem is also exagirated "like you say " when rim sizes are thrown in ..No im not in it to pick fights ..this is all edumacational. But correct me if i am wrong here ...Adding spacers and therefore bringing the hub in relation to the centerline of the wheel towards the back end of the rim is infact taking away positive offset and once past the the centerline and closer to the rear of the rim it's then into negative offset. Taking spacers out and moving the hub in relation to the centerline of the wheel forwards towards the outside face of the rim is positive offset. do you agree? If i am wrong then ibrar is wrong to then ? as going from a 50mm positive to a 30mm positive offset won't make the outside rim go towards the arch ? http://www.mkivsupra.net/vbb/showthread.php?t=29064&highlight=30mm+offset Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 17, 2006 Share Posted February 17, 2006 LOL see my edit to my last post:) like i said i don't mean to be argumentative either, in fact i'm enjoying the discussion, but i think we are coming at the problem from such different angles, i'm not altogether sure we can agree, in fact having just re read your last post i still think you have it around the wrong way! perhaps we need some outside input to try and get a different perspective? then again it will probably just confuse things more! so maybe we will have to just disagree:) Quote Link to comment Share on other sites More sharing options...
Miguel Posted February 17, 2006 Share Posted February 17, 2006 No not at all debating is good. As you can see I have added a link to Ibrar on my last post also that even says " and he is a wheel expert" that going from a 50mm positive offset to a 30mm positive offset will make them foul the arch. All im confused over TBH is that the 2 pictures depict the exact same thing positive offset yet you are convincing me that one of them is infact negative. As much as I look at them I cant see how. So i too would like to be educated. And I can't see how in relation to centerline of the wheel that if the hub is behind the centerline it's negative offset and if it's in front of it it's positive. The pics say it, every google I pull up says it yet your telling me otherwise ....I'm no wheels expert ( won't even pretend to be) just i keep getting info that sugests the oppsite to your coments. so which one of them pictures is wrong even though the show the same thing ? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 17, 2006 Share Posted February 17, 2006 I know what your saying and looked at that link, and i still can't get my head around how when its a + offset reducing the offset from 50 to 30 pushes the wheel farther out, i'm looking at it in this way, you have a wheel fitted to a car, and with a + offset totalling 50, made up of a 30mm offset built into the wheel and a 20mm offset made up by a spacer! if you remove the spacer which way does the wheel move?? now my logic says inwards! but i am seeing a + offset as the hub mounting face projecting beyond the centre line towards the inside of the wheel closer to the suspension therefore moving the wheel outwards towards the arch, and - offset as the hub mounting face receding from the centre line towards the outside of the wheel, so as offset is reduced from + to - the wheel moves further inwards! now to me that make perfect sense! but other info presented seem to point to the opposite??? Quote Link to comment Share on other sites More sharing options...
Miguel Posted February 17, 2006 Share Posted February 17, 2006 OK I'm with you on train of thought here. Here is the problem + offset is the distance from the center line of the wheel to the back face of the hub ....so if the HUB mating surface is further outwards from the center of the wheel then this is + so 50mm is futher away outwards from the center line than +30 is . So by your theory adding a 20mm spacers to a +30 mm wheel would make it a +10 wheel. If the hub is mating surface is inwards from the centerline then this is negative .Now i can see you spacer theory although you would have to be the other way round. If you start with a +50 wheel and add a 20mm spacer it would be +30 but then yes if you took the spacer off the wheel would move in and vice versa. But the spacer also makes the hub thicker and longer studs are needed. In order to make it a +50 wheel with a 20mm spacer you would need to start with a +70mm wheel Heres my take on it. Now wheels are manufactured with the same thickness hubs say for the supra ..so adding a spacer to bring the wheel out, effectively giving it less offset( bringing the hub inwards towards the centerline taking off + offset) means you would have to use longer wheel studs ( using spacers).Not the best way . So lets say the hubs are uniform and all the same thickness so you can use stock studs. How do manufacturers make the wheels in different offsets. They move the whole center section of the wheel in or out keeping the hub uniform. So lets take a split rim. The actual rim ( tyre mounted) stays the same size lets say 9" and i want to go from a +30 to a +50 i would make the centre split move outwards on the rim making it less of a deep dish wheel and the rim move inwards. If i say down the road wanted a wide body supra and i need to fill the arches the +50 rim would be too far in so i would want to move the whole inner section of the wheel inwards so the rim moved outwards but kept the same hub thickness. This would mean i would have to move the center section of the wheel inwards past the centreline and into negative offset . Same goes for if i wanted to go narrow body i could not shave the hubs to bring the wheel in for one they would hit the struts and two the hubs would get thin and weak. Then yes for the widebody i would have to add rim to the inside as the center section of the wheel would be so deep it would nearly be on the back edge of a 9" wheel but then thats when i would go to a wider wheel and throw all this above out. Do you see the angle of dangle ....Don't get me wrong i can see where you are and agree. But take Azev wheel all 9" wide and 17's I could line up every set of 17 azev A wheels identical in width and size but every one of them will have a diferent dish because of the offset. And spacers don't technicaly affect offset. What spacers do is make the Disk/car hub/ mounting surface of the car stick out further. The wheel is still the same offset it began with just what it mounts to is further out..bit like sticking a wider axle on. Quote Link to comment Share on other sites More sharing options...
Nic Posted February 17, 2006 Share Posted February 17, 2006 Have a read of THIS Quote Link to comment Share on other sites More sharing options...
Miguel Posted February 17, 2006 Share Posted February 17, 2006 Good find nick! Quote Link to comment Share on other sites More sharing options...
wkdtime Posted February 17, 2006 Author Share Posted February 17, 2006 OK I'm with you on train of thought here. Here is the problem + offset is the distance from the center line of the wheel to the back face of the hub ....so if the HUB mating surface is further outwards from the center of the wheel then this is + so 50mm is futher away outwards from the center line than +30 is . So by your theory adding a 20mm spacers to a +30 mm wheel would make it a +10 wheel. If the hub is mating surface is inwards from the centerline then this is negative .Now i can see you spacer theory although you would have to be the other way round. If you start with a +50 wheel and add a 20mm spacer it would be +30 but then yes if you took the spacer off the wheel would move in and vice versa. But the spacer also makes the hub thicker and longer studs are needed. In order to make it a +50 wheel with a 20mm spacer you would need to start with a +70mm wheel Heres my take on it. Now wheels are manufactured with the same thickness hubs say for the supra ..so adding a spacer to bring the wheel out, effectively giving it less offset( bringing the hub inwards towards the centerline taking off + offset) means you would have to use longer wheel studs ( using spacers).Not the best way . So lets say the hubs are uniform and all the same thickness so you can use stock studs. How do manufacturers make the wheels in different offsets. They move the whole center section of the wheel in or out keeping the hub uniform. So lets take a split rim. The actual rim ( tyre mounted) stays the same size lets say 9" and i want to go from a +30 to a +50 i would make the centre split move outwards on the rim making it less of a deep dish wheel and the rim move inwards. If i say down the road wanted a wide body supra and i need to fill the arches the +50 rim would be too far in so i would want to move the whole inner section of the wheel inwards so the rim moved outwards but kept the same hub thickness. This would mean i would have to move the center section of the wheel inwards past the centreline and into negative offset . Same goes for if i wanted to go narrow body i could not shave the hubs to bring the wheel in for one they would hit the struts and two the hubs would get thin and weak. Then yes for the widebody i would have to add rim to the inside as the center section of the wheel would be so deep it would nearly be on the back edge of a 9" wheel but then thats when i would go to a wider wheel and throw all this above out. Do you see the angle of dangle ....Don't get me wrong i can see where you are and agree. But take Azev wheel all 9" wide and 17's I could line up every set of 17 azev A wheels identical in width and size but every one of them will have a diferent dish because of the offset. And spacers don't technicaly affect offset. What spacers do is make the Disk/car hub/ mounting surface of the car stick out further. The wheel is still the same offset it began with just what it mounts to is further out..bit like sticking a wider axle on. Excellent read, for someone who claims not to know too much about wheels, that was serisouly nicely exaplined for the non techies! Quote Link to comment Share on other sites More sharing options...
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