Suspension Arms
Discussion
Dear Ultima Friends
I need some information i want to build my Ult with Aluminium Uper and Lower A Arms front and rear
can anyone give me some measurements
For Each A Arm :
the with between the mounting points
the length between the hub mounting point and chassis
the heighth between the lower and uper A arm at the side of the hub
the weight of Each A Arm
and some advise who has experience with Alluminium A Arms
I need some information i want to build my Ult with Aluminium Uper and Lower A Arms front and rear
can anyone give me some measurements
For Each A Arm :
the with between the mounting points
the length between the hub mounting point and chassis
the heighth between the lower and uper A arm at the side of the hub
the weight of Each A Arm
and some advise who has experience with Alluminium A Arms
I'd guess he's going for ultra-low unsprung weight.
Keep in mind that a Vette's A-arms need to support about 160% more GVWR, so of course a Vette's A-arms should weight as much as an Ultima's, despite being alloy!
But I'm not sure if one can make any noticeable (to the driver) shedding of unsprung weight, especially in the A-arms. Perhaps mag wheels would offer more savings with less headache; custom jobs always hurt...
But if anyone goes custom, perhaps try improving the geometry, like Jay; if you did that well, too, I'd be your first customer for "aftermarket Ultima parts," LOL, at any reasonable price, if you kept a jig...
OTOH, every last bit of unsprung weight counts, and most performance-car makers have been using alloy (or other lightweight materials) on unsprung, rotating, and "near-the roof" weight -- before using alloy on most other car-parts -- for the obvious engineering reason: better performance:cost ratio. Why have alloy panels on the Ultima down-low, even before alloy was exhausted where the lightweight would be of most benefit? (e.g., A-arms, or the roll-hoops? ...i.e., the places where other mfr's have found it more economical to use alloy, than the body?)
>> Edited by jhr8 on Monday 28th July 09:16
Keep in mind that a Vette's A-arms need to support about 160% more GVWR, so of course a Vette's A-arms should weight as much as an Ultima's, despite being alloy!
But I'm not sure if one can make any noticeable (to the driver) shedding of unsprung weight, especially in the A-arms. Perhaps mag wheels would offer more savings with less headache; custom jobs always hurt...
But if anyone goes custom, perhaps try improving the geometry, like Jay; if you did that well, too, I'd be your first customer for "aftermarket Ultima parts," LOL, at any reasonable price, if you kept a jig... OTOH, every last bit of unsprung weight counts, and most performance-car makers have been using alloy (or other lightweight materials) on unsprung, rotating, and "near-the roof" weight -- before using alloy on most other car-parts -- for the obvious engineering reason: better performance:cost ratio. Why have alloy panels on the Ultima down-low, even before alloy was exhausted where the lightweight would be of most benefit? (e.g., A-arms, or the roll-hoops? ...i.e., the places where other mfr's have found it more economical to use alloy, than the body?)
>> Edited by jhr8 on Monday 28th July 09:16
jhr8 said:
I'd guess he's going for ultra-low unsprung weight.
Keep in mind that a Vette's A-arms need to support about 160% more GVWR, so of course a Vette's A-arms should weight as much as an Ultima's, despite being alloy!
But I'm not sure if one can make any noticeable (to the driver) shedding of unsprung weight, especially in the A-arms. Perhaps mag wheels would offer more savings with less headache; custom jobs always hurt...
OTOH, every last bit of unsprung weight counts, and most performance-car makers have been using alloy (or other lightweight materials) on unsprung, rotating, and "near-the roof" weight -- before using alloy on most other car-parts -- for the obvious engineering reason: better performance:cost ratio. Why have alloy panels on the Ultima down-low, even before alloy was exhausted where the lightweight would be of most benefit? (e.g., A-arms, or the roll-hoops? ...i.e., the places where other mfr's have found it more economical to use alloy, than the body?)
>> Edited by jhr8 on Monday 28th July 09:16
As unsprung weight includes ie rims, tyres etc and those heavy cast uprights, even if the A arms weighed in at zero, the percentage change would be minimal. Is it worth it except to say they are your design?
pashby said:
As unsprung weight includes ie rims, tyres etc and those heavy cast uprights, even if the A arms weighed in at zero, the percentage change would be minimal. Is it worth it except to say they are your design?
Actually the uprights are alloy, according to Ultima -- but yeah, that's exactly what I meant when I questioned whether it even be "noticeable...especially in the A-arms," and therefore worth the effort...?
They only weigh a few pounds each, as is, so I can't see much of a gain, for how *I* would use this car (and am trying to plan to use it). Still, while I agree that it seems silly for *most of us* to fabricate custom A-arms (in alloy), there are some who want even better performance over bumps (and the few hundred $$ and several hours of investment, for a pro-racer [or -fabricator], might someday pay off in thousands of $$)... Also, is there really any good reason that anyone should have to go *custom* for alloy A-arms, or is this an aspect which the factory can improve? The Ultima's body panels would also only weigh a few pounds each if those were steel...so why use alloy there, before using alloy for the A-arms...given that those alloy panels are static weight, resulting in less performance benefit, whereas every other mfr I'm aware of, seems to agree that using the alloy on the suspension members (and rotating assembly and areas near the roof, to lower Cg), if alloy is used anywhere, is the most worthwhile? It's not exactly as deep as asking the meaning of life
, but are Porsche, Chevy, etc. all wrong, and Ultima right, or is there a special circumstance that applies to Ultima, but not those cars? >> Edited by jhr8 on Monday 28th July 11:24
>> Edited by jhr8 on Monday 28th July 11:31
Bespoke suspension arms machined from alloy must be a lot more expensive than welded steel tube as used as standard. Ultima wishbones are light compared to wheel/tyre/brake assy so going for alloy must be a marginal benefit for the cost.
Not quite the same for issue volume HP car manufactures who can tool up and cast alloy suspension components in large numbers thus keeping costs down.
Not quite the same for issue volume HP car manufactures who can tool up and cast alloy suspension components in large numbers thus keeping costs down.
Given that many racers use tubular 4130 chrome-moly alloy for rollcages and A-arms (Just search google: "4130 alloy A-arms" "4130 alloy rollcage".), I doubt that the low-volume which the Ultima factory deals with should be a cost-efficiency issue, or else it should have been a cost-efficiency issue for those low-volume racers. (...because I'm not just talking low-volume, here, but talking grassroots, poor, weekend racers -- LOL, it's *not* as though alloy tubes cost so much more over steel tubes, yet, the Ultima's alloy body-panels don't cost so much more over steel panels: I'm not talking about people using this tubular 4130 in no-expense-spared cars, nor even cars that are necessarily even as valuable as an Ultima...)
But like I said, I don't mean for alloy A-arms to be thought-upon too deeply, nor for us to spend all day debating whether the factory is right and the conventional wisdom is wrong, because there are too many factors we might be unaware of which prevents the factory from using alloy A-arms. In the meantime, someone who knows Ted and wants alloys might want to ask if there's a reason, or they might consider offering alloy for the A-arms? It might just result in them deciding it's worthwhile to do...
Or, maybe the factory has already done (and/or would do) one-off alloy A-arms?? That may be alphaSteve's easiest route, and perhaps even the one for best performance...
(What I mean by the last, bold-text portion, is:
Jay's site noted that the suspension has some flaws, and at least some of his descrptions are commonly accepted as either flaws or *indicative* of flaws, but for all I know, the factory arms might correct for something like short A-arms [by compensating with, e.g., a really great length-RATIO of upper:lower, or great static angles], giving a nice camber-change over a broad range [and so, perhaps that's *not* a reason why its springs are "stiff," as he theorized], and for all I know, his definition of the springs being "stiff" might be a normal race-car frequency that he wasn't personally accustomed to. I'll only see, for sure, once I check one out instead of looking at photos -- and after reading Jeff's comments about how it handles over bumps in another thread [I'm just assuming those cars had factory A-arms.], I'm hoping to be pleasantly surprised. Because I would hope that the factory has sorted out its suspension geometry, at the least, over the years...but then again, I've read one too many stories [here and on build-sites] for me to blindly trust that the factory A-arms are well-sorted...stories about other components on the car not working right until third-party parts were used, which magically cured the problem that the factory's parts [and overall design] probably didn't deal with from the start, but should've [That's if third-party 'fixes' were available at all -- but admittedly, where those 'fixes' *weren't* available, I can't say that the flaw was anything major]. We'll see...)
But like I said, I don't mean for alloy A-arms to be thought-upon too deeply, nor for us to spend all day debating whether the factory is right and the conventional wisdom is wrong, because there are too many factors we might be unaware of which prevents the factory from using alloy A-arms. In the meantime, someone who knows Ted and wants alloys might want to ask if there's a reason, or they might consider offering alloy for the A-arms? It might just result in them deciding it's worthwhile to do...
Or, maybe the factory has already done (and/or would do) one-off alloy A-arms?? That may be alphaSteve's easiest route, and perhaps even the one for best performance...
(What I mean by the last, bold-text portion, is:
Jay's site noted that the suspension has some flaws, and at least some of his descrptions are commonly accepted as either flaws or *indicative* of flaws, but for all I know, the factory arms might correct for something like short A-arms [by compensating with, e.g., a really great length-RATIO of upper:lower, or great static angles], giving a nice camber-change over a broad range [and so, perhaps that's *not* a reason why its springs are "stiff," as he theorized], and for all I know, his definition of the springs being "stiff" might be a normal race-car frequency that he wasn't personally accustomed to. I'll only see, for sure, once I check one out instead of looking at photos -- and after reading Jeff's comments about how it handles over bumps in another thread [I'm just assuming those cars had factory A-arms.
], I'm hoping to be pleasantly surprised. Because I would hope that the factory has sorted out its suspension geometry, at the least, over the years...but then again, I've read one too many stories [here and on build-sites] for me to blindly trust that the factory A-arms are well-sorted...stories about other components on the car not working right until third-party parts were used, which magically cured the problem that the factory's parts [and overall design] probably didn't deal with from the start, but should've [That's if third-party 'fixes' were available at all -- but admittedly, where those 'fixes' *weren't* available, I can't say that the flaw was anything major]. We'll see...)Gassing Station | Ultima | Top of Page | What's New | My Stuff