| 04furesterXT | 01-12-2006 05:32 PM |
Swaybars hollow- solid
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I would like opinions on swaybar size recommendations. I have 7K springs front and rear and I like the balance I have now. Therefore, I would like to increase the sizes proportionately. My front is a 21MM solid and the rear is a 17MM hollow. I'm looking at a 27MM solid in front and I'm not sure what to go to in the rear.
Oh and I realize this is the motorsports forum but I don't track the car much.
Thanks.
Oh and I realize this is the motorsports forum but I don't track the car much.
Thanks.
| ratt_finkel | 01-12-2006 06:07 PM |
Why do they have to be the same size? Just get the bigger front, if you don't like it, add a bigger rear. Or just take it off.
| wrrrx | 01-12-2006 07:41 PM |
He didn't say they had to be "the same size"- just both increasing proportionally.
Hard to say... I think Whiteline pairs up a 24mm rear when using the 27mm front- that would be a 6mm increase front and 7 mm increase in the rear, which is quite a bit. I'd go for an adjustable one (22-24mm), that way you can fiddle w/ it until you're happy.
The fact that one is hollow and one solid shouldn't really affect performance- one's just lighter than the other.
Good luck,
Russ R
Hard to say... I think Whiteline pairs up a 24mm rear when using the 27mm front- that would be a 6mm increase front and 7 mm increase in the rear, which is quite a bit. I'd go for an adjustable one (22-24mm), that way you can fiddle w/ it until you're happy.
The fact that one is hollow and one solid shouldn't really affect performance- one's just lighter than the other.
Good luck,
Russ R
| Scooby921 | 01-12-2006 08:31 PM |
A solid bar is going to be stiffer than a hollow bar of the same diameter. There is more material and its able to handle more load.
From what I've read most people think you should get the biggest bar you can up front and adjust the rear until you like the way it drives. I personally have a stock front and 22mm solid rear. It performs pretty well. In an attempt to get better turn-in, but also maintain the reduction in understeer I currently have, I just ordered a 22mm front and 24mm adjustable rear. We'll see how it works out, but I have good feelings about it.
From what I've read most people think you should get the biggest bar you can up front and adjust the rear until you like the way it drives. I personally have a stock front and 22mm solid rear. It performs pretty well. In an attempt to get better turn-in, but also maintain the reduction in understeer I currently have, I just ordered a 22mm front and 24mm adjustable rear. We'll see how it works out, but I have good feelings about it.
| 04furesterXT | 01-12-2006 10:38 PM |
[QUOTE=wrrrx]He didn't say they had to be "the same size"- just both increasing proportionally.
Hard to say... I think Whiteline pairs up a 24mm rear when using the 27mm front- that would be a 6mm increase front and 7 mm increase in the rear, which is quite a bit. I'd go for an adjustable one (22-24mm), that way you can fiddle w/ it until you're happy.
The fact that one is hollow and one solid shouldn't really affect performance- one's just lighter than the other.
Good luck,
Russ R[/QUOTE]
Thanks.Correct on the proportional increase in size. The rear bar is 17MM HOLLOW so I guess I was also looking for a calculation for the solid equivalent. Otherwise I could just increase them a like amount and be close to the balance I have only at a higher grip level.
I was also kind of questioning what would work right with the spring rates I have.
Hard to say... I think Whiteline pairs up a 24mm rear when using the 27mm front- that would be a 6mm increase front and 7 mm increase in the rear, which is quite a bit. I'd go for an adjustable one (22-24mm), that way you can fiddle w/ it until you're happy.
The fact that one is hollow and one solid shouldn't really affect performance- one's just lighter than the other.
Good luck,
Russ R[/QUOTE]
Thanks.Correct on the proportional increase in size. The rear bar is 17MM HOLLOW so I guess I was also looking for a calculation for the solid equivalent. Otherwise I could just increase them a like amount and be close to the balance I have only at a higher grip level.
I was also kind of questioning what would work right with the spring rates I have.
| 04furesterXT | 01-12-2006 10:41 PM |
[QUOTE=Scooby921]A solid bar is going to be stiffer than a hollow bar of the same diameter. There is more material and its able to handle more load.
From what I've read most people think you should get the biggest bar you can up front and adjust the rear until you like the way it drives. I personally have a stock front and 22mm solid rear. It performs pretty well. In an attempt to get better turn-in, but also maintain the reduction in understeer I currently have, I just ordered a 22mm front and 24mm adjustable rear. We'll see how it works out, but I have good feelings about it.[/QUOTE]
Do you know what the SOLID equivalent would be to the 17MM hollow?
Your theory on picking the front bar first makes sense. My car is pretty neutral as it is, probably part from the even spring rates and also it sits with a bit of rake (13.75" from axle to fender lip F&R).
Thanks
From what I've read most people think you should get the biggest bar you can up front and adjust the rear until you like the way it drives. I personally have a stock front and 22mm solid rear. It performs pretty well. In an attempt to get better turn-in, but also maintain the reduction in understeer I currently have, I just ordered a 22mm front and 24mm adjustable rear. We'll see how it works out, but I have good feelings about it.[/QUOTE]
Do you know what the SOLID equivalent would be to the 17MM hollow?
Your theory on picking the front bar first makes sense. My car is pretty neutral as it is, probably part from the even spring rates and also it sits with a bit of rake (13.75" from axle to fender lip F&R).
Thanks
| wm07 | 01-13-2006 03:11 AM |
Not very sure, but I guess 17mm hollow is equivalent to 14mm or 15mm solid? I don't know, but isn't stocks around 19mm or so? and you actually have a smaller than stock rear swaybar? interesting...
| 04furesterXT | 01-13-2006 02:06 PM |
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That is what initially makes sense as an equivilant solid bar. I just want to be sure. Stock is a 17MM hollow. It's a Forester XT.
That is what initially makes sense as an equivilant solid bar. I just want to be sure. Stock is a 17MM hollow. It's a Forester XT.
| AUTOwrXER | 01-13-2006 02:42 PM |
[QUOTE=wm07]Not very sure, but I guess 17mm hollow is equivalent to 14mm or 15mm solid? I don't know, but isn't stocks around 19mm or so? and you actually have a smaller than stock rear swaybar? interesting...[/QUOTE]
You would be surprised by how much less additional force you get from a solid bar vs. a hollow of the same size. Without knowing the inner diameter of the hollow bar, you cannot answer the original question. My guess is that the equivalent solid bar would be 16.25 - 16.5 mm.
You would be surprised by how much less additional force you get from a solid bar vs. a hollow of the same size. Without knowing the inner diameter of the hollow bar, you cannot answer the original question. My guess is that the equivalent solid bar would be 16.25 - 16.5 mm.
| draggin wagon04 | 01-13-2006 04:37 PM |
If performance is the issue, hollow bars can have some weight saving advantages. Knowing the gauge of the tube is very important to figure on it's force. Try to find some Numbers from tests.
Pro-Hollow-
[url]http://www.hotchkistuning.com/bin/Misc/HollowSwayTech-D.pdf[/url]
If tubes get a kink or knicked, they -could- create a crease in the wall and can fail pretty quickly vs. a solid rod. If I was daily driving and not really concerned about track performance, and the price is close, I'd take piece of mind that if I hit road debris, rocks, etc., that the solid bar could take more everyday road condition abuse.
Pro-Hollow-
[url]http://www.hotchkistuning.com/bin/Misc/HollowSwayTech-D.pdf[/url]
If tubes get a kink or knicked, they -could- create a crease in the wall and can fail pretty quickly vs. a solid rod. If I was daily driving and not really concerned about track performance, and the price is close, I'd take piece of mind that if I hit road debris, rocks, etc., that the solid bar could take more everyday road condition abuse.
| 04furesterXT | 01-13-2006 05:14 PM |
Appreciate all the replys! I don't want to stray too far from my original question. I don't really care hollow or not, but mentioned hollow only in reference to my stock rear bar and finding an equivalent solid size but thanks for the info nonetheless.
If anything it seems as though I would have less fitment issues with the smaller O.D. of a solid bar. I know I can get the Strano to fit but it seems like in my case it would be like trying to stuff a large sausage into a small hole- fun but tricky.
If anything it seems as though I would have less fitment issues with the smaller O.D. of a solid bar. I know I can get the Strano to fit but it seems like in my case it would be like trying to stuff a large sausage into a small hole- fun but tricky.
| Porter | 01-13-2006 05:14 PM |
Solid bars FTW.
Read up here for some good info on hollow vs. solid:
[url]http://www.whiteline.com.au/docs/bulletins/Hollow%20vs%20Solid%20Swaybar.pdf[/url]
Read up here for some good info on hollow vs. solid:
[url]http://www.whiteline.com.au/docs/bulletins/Hollow%20vs%20Solid%20Swaybar.pdf[/url]
| 04furesterXT | 01-13-2006 05:19 PM |
Thanks for the PDF. Any suggestions on what sizes would work well with the 7K springs? Just canyons and a lot of daily driving. I love the balance as is, it just feels a little mushy with full throttle transitions.
At this point the 27MM Whiteline seems to be the chit and I guess an STi 21 MM stocker?
At this point the 27MM Whiteline seems to be the chit and I guess an STi 21 MM stocker?
| subieworx | 01-13-2006 05:45 PM |
I have never heard of the Foresters have a hollow rear bar.
In what way does it feel mushy?
In what way does it feel mushy?
| 04furesterXT | 01-13-2006 09:24 PM |
Well to be honest, I haven't cut it open but it sure feels light. I'm pretty sure it's hollow.
Maybe mushy wasn't the right word. Turn-in feels great- immediate and tight. It's when i'm really on it exiting a turn and when I change directions it almost feels like it has memory steer where it takes a second for it to react. I know it could be my steering rack or bushings.
My main reason for upgrading is at my height (13.75") the lower control arms are above parallel and even though it doesn't seem to have any quirks because of it(besides the aformentioned one) I'm thinking I should try and keep the alignment where it should be. It's a bit contradictory i'll admit.
Thanks.
Maybe mushy wasn't the right word. Turn-in feels great- immediate and tight. It's when i'm really on it exiting a turn and when I change directions it almost feels like it has memory steer where it takes a second for it to react. I know it could be my steering rack or bushings.
My main reason for upgrading is at my height (13.75") the lower control arms are above parallel and even though it doesn't seem to have any quirks because of it(besides the aformentioned one) I'm thinking I should try and keep the alignment where it should be. It's a bit contradictory i'll admit.
Thanks.
| kfoote | 01-13-2006 09:29 PM |
The rate of a hollow sway bar is also dependant on the wall thickness. For a 17mm hollow bar with a 1 mm wall thickness, it's equivalent to a 13.4 mm solid bar, for a 2mm wall thickness, a 15.3mm bar, and for a 3mm wall thickness, a 16.2mm bar.
The formula to determine the equivalent solid bar is ((outer bar diameter)^4-(inner bar diameter^4))^(1/4)
The formula to determine the equivalent solid bar is ((outer bar diameter)^4-(inner bar diameter^4))^(1/4)
| 04furesterXT | 01-13-2006 09:34 PM |
Thanks. Now all I need to do is cut it open!
| subieworx | 01-14-2006 08:02 AM |
I really think the bar is solid. I have never heard of Subaru making a hollow bar before. I know my rear on my 04 is a 17 mm solid and is very light. Especially in comparison to my 22mm aftermarket bar on there now.
| dave bruener | 01-14-2006 10:35 AM |
You can tell if a bar is hollow by looking at the ends of the bar. If you look at the ends of a hollow bar you can see a seam on the collapsed portion of the bar--you know where the end links bolt on. On a solid bar you can tell that the ends are flattned and the seam is not evident in the end.
As a side note, I have Honda Prelude and the stock bars on that are hollow. This is the only car I know of off hand that has hollow bars from the factory. I believe hollow bars are more difficult and expensive to produce compared to solid ones.
As a side note, I have Honda Prelude and the stock bars on that are hollow. This is the only car I know of off hand that has hollow bars from the factory. I believe hollow bars are more difficult and expensive to produce compared to solid ones.
| Porter | 01-14-2006 10:49 AM |
[QUOTE=dave bruener]As a side note, I have Honda Prelude and the stock bars on that are hollow. This is the only car I know of off hand that has hollow bars from the factory. I believe hollow bars are more difficult and expensive to produce compared to solid ones.[/QUOTE]
The stock bar on the rear of the Forester XT is hollow. Also, hollow bars are not necessarily more expensive to produce... it depends on many factors including the cost of raw materials, whether the extrusions are made in-house or sourced, the type of bender used, etc.
The stock bar on the rear of the Forester XT is hollow. Also, hollow bars are not necessarily more expensive to produce... it depends on many factors including the cost of raw materials, whether the extrusions are made in-house or sourced, the type of bender used, etc.
| AUTOwrXER | 01-14-2006 10:59 AM |
[QUOTE=Porter]Solid bars FTW.
Read up here for some good info on hollow vs. solid:
[url]http://www.whiteline.com.au/docs/bulletins/Hollow%20vs%20Solid%20Swaybar.pdf[/url][/QUOTE]
I disagree. The downsides of hollow bars cited in that article are related to manufacturing issues, which many manufacturers have been able to solve (Hotchkiss, Addco, etc.). Perhaps Whiteline does not have the equipment to manufacturer hollow bars correctly, so these are real issues to them. I'll take the weight savings of the hollow bar vs. a slightly smaller diameter solid bar any day. The one exception that I see is if space constraints do not allow a larger diameter bar.
To the original poster - If you can find the inner diameter of the stock hollow bar then I can tell you the equivalent solid bar diameter.
-Joel
Read up here for some good info on hollow vs. solid:
[url]http://www.whiteline.com.au/docs/bulletins/Hollow%20vs%20Solid%20Swaybar.pdf[/url][/QUOTE]
I disagree. The downsides of hollow bars cited in that article are related to manufacturing issues, which many manufacturers have been able to solve (Hotchkiss, Addco, etc.). Perhaps Whiteline does not have the equipment to manufacturer hollow bars correctly, so these are real issues to them. I'll take the weight savings of the hollow bar vs. a slightly smaller diameter solid bar any day. The one exception that I see is if space constraints do not allow a larger diameter bar.
To the original poster - If you can find the inner diameter of the stock hollow bar then I can tell you the equivalent solid bar diameter.
-Joel
| 04furesterXT | 01-14-2006 12:42 PM |
Thanks for all the replys! All valid points. I will try and at least find the inner diameter or wall thickness to calculate the exact solid equivalent.
So assuming i'm able to calculate a solid equivalent, am I wrong in thinking I can increase both the front and rear an equal amount to maintain my F. to R. balance? Or is there more to it than that? I realize that there are only a finite amount of options out there but was curious if this approach is correct or not.
Also i'm not sure if trying to pick swaybar sizes corresponding to spring rates has any validity or not.
Thanks again.
So assuming i'm able to calculate a solid equivalent, am I wrong in thinking I can increase both the front and rear an equal amount to maintain my F. to R. balance? Or is there more to it than that? I realize that there are only a finite amount of options out there but was curious if this approach is correct or not.
Also i'm not sure if trying to pick swaybar sizes corresponding to spring rates has any validity or not.
Thanks again.
| kfoote | 01-14-2006 01:53 PM |
[QUOTE=04furesterXT]Thanks for all the replys! All valid points. I will try and at least find the inner diameter or wall thickness to calculate the exact solid equivalent.
So assuming i'm able to calculate a solid equivalent, am I wrong in thinking I can increase both the front and rear an equal amount to maintain my F. to R. balance? Or is there more to it than that? I realize that there are only a finite amount of options out there but was curious if this approach is correct or not.
Also i'm not sure if trying to pick swaybar sizes corresponding to spring rates has any validity or not.
Thanks again.[/QUOTE]
You are incorrect. Assuming the geometry is the same, the bar rate is proportional to the diameter of the bar to the 4th power. If they are both solid, a 23mm sway bar is 44% stiffer than a 21mm bar, while a 19mm bar is 56% stiffer than a 17mm bar
So assuming i'm able to calculate a solid equivalent, am I wrong in thinking I can increase both the front and rear an equal amount to maintain my F. to R. balance? Or is there more to it than that? I realize that there are only a finite amount of options out there but was curious if this approach is correct or not.
Also i'm not sure if trying to pick swaybar sizes corresponding to spring rates has any validity or not.
Thanks again.[/QUOTE]
You are incorrect. Assuming the geometry is the same, the bar rate is proportional to the diameter of the bar to the 4th power. If they are both solid, a 23mm sway bar is 44% stiffer than a 21mm bar, while a 19mm bar is 56% stiffer than a 17mm bar
| Porter | 01-15-2006 02:11 PM |
[QUOTE=AUTOwrXER]I disagree. The downsides of hollow bars cited in that article are related to manufacturing issues, which many manufacturers have been able to solve (Hotchkiss, Addco, etc.). Perhaps Whiteline does not have the equipment to manufacturer hollow bars correctly, so these are real issues to them. I'll take the weight savings of the hollow bar vs. a slightly smaller diameter solid bar any day. The one exception that I see is if space constraints do not allow a larger diameter bar.
To the original poster - If you can find the inner diameter of the stock hollow bar then I can tell you the equivalent solid bar diameter.
-Joel[/QUOTE]
Well, functionally there is a significant space constraint. By going to the huge hollow bar that you were using you were forced (IIRC, correct me if I'm wrong) to go away from the stock-style endlink design entirely.
I honestly believe that the Whiteline 27mm bar is the highest effective springrate product on the market that fits in the stock location and uses the stock-design endlinks.
Has something changed in the last few months that makes this no longer true?
To the original poster - If you can find the inner diameter of the stock hollow bar then I can tell you the equivalent solid bar diameter.
-Joel[/QUOTE]
Well, functionally there is a significant space constraint. By going to the huge hollow bar that you were using you were forced (IIRC, correct me if I'm wrong) to go away from the stock-style endlink design entirely.
I honestly believe that the Whiteline 27mm bar is the highest effective springrate product on the market that fits in the stock location and uses the stock-design endlinks.
Has something changed in the last few months that makes this no longer true?
| 04furesterXT | 01-15-2006 06:45 PM |
[QUOTE=kfoote]You are incorrect. Assuming the geometry is the same, the bar rate is proportional to the diameter of the bar to the 4th power. If they are both solid, a 23mm sway bar is 44% stiffer than a 21mm bar, while a 19mm bar is 56% stiffer than a 17mm bar[/QUOTE]
Thanks Kevin. Figured it wasn't linear and wouldn't be a no-brainer. So as you can tell i'm dragging my ass as far as finding inner diameters and wall thicknesses. What would be a proportional increase in stiffness be if I went from a 21MM to a 27MM in front, and say my 17MM hollow is equal to a 14 or 15MM solid? 20-21MM? I'm just guessing.
Thanks Kevin. Figured it wasn't linear and wouldn't be a no-brainer. So as you can tell i'm dragging my ass as far as finding inner diameters and wall thicknesses. What would be a proportional increase in stiffness be if I went from a 21MM to a 27MM in front, and say my 17MM hollow is equal to a 14 or 15MM solid? 20-21MM? I'm just guessing.
| 04furesterXT | 01-15-2006 06:49 PM |
[QUOTE=Porter]Well, functionally there is a significant space constraint. By going to the huge hollow bar that you were using you were forced (IIRC, correct me if I'm wrong) to go away from the stock-style endlink design entirely.
I honestly believe that the Whiteline 27mm bar is the highest effective springrate product on the market that fits in the stock location and uses the stock-design endlinks.
Has something changed in the last few months that makes this no longer true?[/QUOTE]
Yes this was my reasoning for going with the 27MM Whiteline. The 32MM Strano sounds impressive and all but for that amount of increase in stiffness i'm thinking it's a lot less complicated to stuff a 27MM bar in there.
What's your thoughts on running this 27MM bar with 7K springs in front? Too stiff or in the ball park?
Thanks.
I honestly believe that the Whiteline 27mm bar is the highest effective springrate product on the market that fits in the stock location and uses the stock-design endlinks.
Has something changed in the last few months that makes this no longer true?[/QUOTE]
Yes this was my reasoning for going with the 27MM Whiteline. The 32MM Strano sounds impressive and all but for that amount of increase in stiffness i'm thinking it's a lot less complicated to stuff a 27MM bar in there.
What's your thoughts on running this 27MM bar with 7K springs in front? Too stiff or in the ball park?
Thanks.
| AUTOwrXER | 01-15-2006 07:22 PM |
[QUOTE=Porter]Well, functionally there is a significant space constraint. By going to the huge hollow bar that you were using you were forced (IIRC, correct me if I'm wrong) to go away from the stock-style endlink design entirely.
I honestly believe that the Whiteline 27mm bar is the highest effective springrate product on the market that fits in the stock location and uses the stock-design endlinks.
Has something changed in the last few months that makes this no longer true?[/QUOTE]
I designed the bar for an amount of force, and the space was there. It was not a constraint, though it would be if you wanted to go bigger than 35mm. The factory endlink design could have been retained, but why would you? I prefer the bolt and bushing attachment, and I can absolutely guarantee that it is providing more force than the Whiteline bar at significantly less weight. Sure, the Whiteline may give the most force using the stock endlinks, but who cares?
I honestly believe that the Whiteline 27mm bar is the highest effective springrate product on the market that fits in the stock location and uses the stock-design endlinks.
Has something changed in the last few months that makes this no longer true?[/QUOTE]
I designed the bar for an amount of force, and the space was there. It was not a constraint, though it would be if you wanted to go bigger than 35mm. The factory endlink design could have been retained, but why would you? I prefer the bolt and bushing attachment, and I can absolutely guarantee that it is providing more force than the Whiteline bar at significantly less weight. Sure, the Whiteline may give the most force using the stock endlinks, but who cares?
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