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aluminum spindles

aluminum spindles

aluminum spindles

(OP)
i know applications such as honda use cast steel or iron spindles but does anyone make aluminum spindles and how feasible is it for a race application?

RE: aluminum spindles

Yes they do. ZF Lemforder are one manufacturer. Given the comparitively low loads that a circuit car sees compared with a production car there should be no problem.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

RE: aluminum spindles

Aluminum and titanium is used in racing spindles.  Al or Mg is often used for the hubs.  Rather costly alternative to steel for most racing classes, IMO.

www.mpdracing.com/spring_hubs.php-8k

Rod

RE: aluminum spindles

Well that did not go as well as planned.

www.mpdracing.com/  and look under sprint products.

Rod

RE: aluminum spindles

Your point about weight is a good one Rod, particularly on short spindles. The only time we see really significant weight savings is on tall spindle SLA designs, or, possibly, rear hubs, where the driveshaft needs a lot of structure to get around it. You might see a 20%-30% weight save going for forged aluminium compared with a cast or forged steel part, for a given level of stiffness and durability.  





 

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

RE: aluminum spindles

Apparently Coleman Racing Products will be offering a carbon fiber spindle, if that's of interest.  It's listed in the issue of Circle Track magazine that just came in the mail today as one of the top 40 new products on display at the 2004 SEMA show (Las Vegas) and PRI (Indy).  No price or other data available though.

Norm

RE: aluminum spindles

Norm, my issue came yesterday and I see the spindle.  More like a steel spindle with Al control arms mounted to a CF plate.  Looks WAAAAY too complicated for me.  In my own racing efforts over the years, I find that the more parts you have, the more likelyhood of a failure of one of them.

On lightweight racecars, the aluminum or titanium spindles with a Mg hub should be a good way of reducng unsprung weight---albeit, a really high dollar item.  I still think its a rather costly alternative to steel in most classes.

Rod

RE: aluminum spindles

I'll venture that a fabricated steel upright can approach the weight of a Aluminum forging w/o giving up any rigidity. Check out some of the uprights on Chaparral's.

RE: aluminum spindles

Spindle deflection is a drawback with aluminum.

RE: aluminum spindles

Racecar Engineering magazine has an article this month about spindle design

RE: aluminum spindles

I am really surprised that aluminum would be used for a spindle, but I guess if somebody tried it and it worked-----

A spindle is subject to bending stress, fatique, and it should not deflect too much. Aluminum is at a disadvantage in all of these. There is no definite fatique strength like there is with steel, and it has 1/3 the stiffness.

Weight should not be that big a factor if we are talking only about the spindle. The bulk of the weight is in the housing, control arms, and brake parts.

RE: aluminum spindles

(OP)
What about a cast titanium spindle?

RE: aluminum spindles

Shrugs. What advantage do you see in Ti, given that hubs tend to be stiffness limited?

jlwoodward. Um, I don't think you realise how much weight we are talking about. A tall spindle on a full size car or truck will weigh upwards of 12 kg, so a 30% weight saving (times 4) starts to look very attractive.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

RE: aluminum spindles

Are you guys talking about the stubby shaft that the wheel bearings slip over, or the whole unit (upright?) that the linkages and calipers connect to? I may have misunderstood.

RE: aluminum spindles

In our parlance a spindle is the thing that holds the brakes, wheel bearings and outboard ends of the suspension arms. You are describing a stub axle, or carrot.

If a spindle also has a driveshaft then we call it a knuckle.

A hub (these days) is the actual bit that holds the wheel bearings, typically bought in as an assembly.

eg Gen 2 or Gen 3 or Gen 4 parts in http://www.ntn.co.jp/english/product/lineup/menu2-4.html

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

RE: aluminum spindles

Thanks Greg

That cleared up few things in my mind re terminology.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: aluminum spindles

Don't even think about aluminum spindles unless you want to kill someone.  Read some basic information regarding the fatigue properties of aluminum and load cycling.  Unlike steel, aluminum eventually will come apart with repeated flexing at any load.  Steel fortunately has a load threshold below which repeated load cycling will not cause problems.

RE: aluminum spindles

(OP)
i know aluminum is not ideal for durability purposes, but for the advancement of a position in racing, an aluminum one that works for 1 race will be fine.  i also think about the possibilty of titanium to keep the strength up but weight down.  i also see that these would cost a lot, but for racing, once again there is no ceiling.

RE: aluminum spindles

In my experience, to reinforce Rob's point, spindle designs are stiffness limited, therefore titanium will not offer much of a weight advantage over steel, and aluminium won't offer much of a weight advantage over titanium. Nonetheless, you should see about a 15% improvement in weight for a given stiffness, for each of those two steps. The gotcha is, of course, that with aluminium you are also going to have to watch out for strength issues, as you will be much closer to its limits.

I don't see much point in being alarmist about the fatigue properties of aluminium, real engineers have been successfully using it in high cycle fatigue environments for a long time. If you can get away from welds I can see no reason not to use it, if designed properly.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

RE: aluminum spindles

Al is the last choice of material for a wheel spindle.
Carbon fiber? I just read an article in a science magazine about the tails comming off a certain aircraft, that are made of carbon fiber. So maybe it isn't as great as all think it is.  Better stick with good ole chrome moly for that application.

RE: aluminum spindles

This thread seems rather persistant.  I'll add one more comment, anyway.
Motorsports is a contest measured in hundredths of seconds or less.  A 15% reduction in weight?  Well I would think that IS significant. Most professional teams, especially F-1, would positively KILL, and invest millions, for a 1% advantage!

Rod

RE: aluminum spindles

Sure, the question becomes with aluminium, how are you going to make it, and how are you going to design it? With Ti it's easy, if it looks like the steel part it'll be strong enough, but with Al that won't work.



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

RE: aluminum spindles

(OP)
would carbon fiber have enough durability in that type of application where load is constantly varied.
Is carbon fiber becoming the answer to most strength/wieght issues?
I hope you guys will continue to respond to this thread.

RE: aluminum spindles

Yes it has the durability, when properly designed and made.
Not for mass production (cost), and not for small budgets (too hard to design and make). I think a spindle would be one of the worst things to make from CF, as it combines high loads, restricted packaging, and a lot of hardpoints in a small area. It can be done, obviously. Having gone to all that trouble you've saved maybe another 2 kg ie 0.5 kg per corner) on a short spindle car. There are much better weight saving opportunities on most cars.












Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

RE: aluminum spindles

Carbon fibre can have quite good fatigue resistance if designed correctly, it has a very high flex mod and good tensile strength. It compares with steel on a size for size basis and easily beats steel on a weight for weight basis.

HAVING SAID THAT, I do agree with Greg, specifically for the following reasons:-

It has VERY LOW ELONGATION AT BREAK, hence the design is extremely critical of even distribution of stress.

Packaging restrictions can force stress concentration areas into the design.

The resin that binds the fibres is degraded by heat, the extent of the degradation depends on the particular resin.

The properties are VERY DEPENDANT ON FIBRE ORIENTATION.

Properties quoted for a single fibre cannot be extrapolated into a composite structure, as the load is never shared equally with all the fibres in the cross section of the composite. Also the resin matrix plays a part in the properties of the composite.

Often data sheets quote the properties of a single fibre, not the properties of a composite.

Even data sheets quoting data for composites use data from a perfectly oriented sample, made under ideal conditions and with a test piece designed to optimise the properties. This is rarely if ever achieved in the real world, and many designs and processes fall far short of data sheet properties.

My recommendations.

Use good steel, remove as much excess from the design as possible, then use it to your hearts content.

Use aluminium, save some weight, but check it regularly for cracks.

If you have an F1 level of budget, experiment with carbon fibre prototypes, but expect breakages until, when and if you sort it out. Do extensive testing where neither life nor limb are threatened by a failure.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: aluminum spindles

Pat, we amature builders/racers cannot escape your logic.  Those of us who do not operate on $100,000,000 budgets per year (that's not an exageration!) would all tend to agree with you.  However...

Greg, based on Norm Peterson's post above...I looked at the photo and article...not practical IMO but then there are plenty of impractical solutions to auto design problems that sell rather well on the open market.  Racing tends to weed out those solutions in short order. Alternative material for critical components must, above all, work safely---cost is often secondary. In amature racing I see mostly steel, forgings or fabrications.  This is not to say that amatures do not use Al or Ti spindles, just that I have not personally seen them in common use.

Composites are great.  Carbon fibre body parts for my race cars would be wonderfull for much needed weight savings (I have grown rather large in my old age)---NOT on my racing budget, anyway.  

Rod

RE: aluminum spindles

The failure of a CF suspension part was very graphically demonstrated during the latest F1 race on the final lap.
K. Raikkonen was leading when he flat spotted a tire that caused a severe vibration in the right front suspension. The vibration resulted in a a very dramatic failure of the CF suspension.  If you were watching closely the initiation of the failure was vividly demonstrated by a flash as one of the upper suspension arms failed.  

I have seen this particular failure mode several times early on during the development of CF especially in high speed flywheels as they disintegrated with explosive force.

RE: aluminum spindles

Yeah, I watched it. Stupid rule, the tire change thing.  Could have caused a disaster.  
I also noted that my estimate of cost for a F-1 season was a bit low...$400,000,000 and UP seems to be the current fugure!!! Sheesh :-(

I watched the Indy and the Nurburg race and I found the F-1 still rather boring (a parade punctuated by brief "events") from a television point of view but the coverage was totally superior to the ABC (Absolutely Boring Coverage) broadcast of Indy.  I have been to both types of open wheeled racing and, in person (I "worked" Long Beach GP T-1 drivers right at the last F-1 race there in the 80's), F-1 racing is rather more exciting.  I also find NASCAR oval stuff totally boring, but the road racing is super!
I am NOT much of a spectator in motor sports.

Rod

RE: aluminum spindles

Aluminum spindles/knuckles:
GM is using them in late-model midsize fwd cars...(USA, anyhow)
Of course, being fwd, there is no 'carrot' to support the bearings, and the loads are applied to the heart of the piece.
I found out when doing a brake job on my '03 Buick Regal. Used a file on a parting line, just to meke sure it wasn't just a shiny coating. -Nope- it's Al!
cheers
Jay

Jay Maechtlen
http://home.covad.net/~jmaechtlen/

RE: aluminum spindles

How about we make the spindles out of Starmet (Aluminum/Beryllium)? It has the stiffness of steel.

RE: aluminum spindles

Check out the health hazards for beryllium. That's why it is banned from F1

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

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