stillracing Posted March 28, 2012 Share Posted March 28, 2012 Evening boys. Apologies for a bit of a techy post, but I thought it was worth sharing. Having fitted Rota Torque Drifts a while back, I noticed before fitment that the Rota's are about 3kg lighter each than the standard 2004 350z 18" wheels. Pretty impressive. Intrigued about the strength of the wheel, I produced a CAD model of it and put it through my FEA software. Forces Applied I went for the absolute worst case loads, which were a simultaneous combination of: Braking Acceleration : -1.5g (gives a torque of 1703Nm) Cornering Acceleration: 1.0g (gives a lateral 'force' of 300kg) 'Kerbing' Bump Event : 5.0g applied to quarter of the car's mass (gives a vertical 'force' of 3100kg) To give a visual representation of the results (where blue is low stress, going up to red which is high): http://i1063.photobucket.com/albums/t50 ... sFront.png http://i1063.photobucket.com/albums/t50 ... esRear.png This shows that the maximum stress seen is 99MPa. The ultimate (breakage) strength of the aluminium alloy used is likely to be between 150-200MPa. So I think it's safe to say that as designed, the wheel is very safe. The horror stories of people breaking wheels probably therefore comes about either by major manufacturing defects, or misuse. Hopefully of some interest! Rob Quote Link to comment Share on other sites More sharing options...
4RE Leather Posted March 28, 2012 Share Posted March 28, 2012 Evening boys. Apologies for a bit of a techy post, but I thought it was worth sharing. Having fitted Rota Torque Drifts a while back, I noticed before fitment that the Rota's are about 3kg lighter each than the standard 2004 350z 18" wheels. Pretty impressive. Intrigued about the strength of the wheel, I produced a CAD model of it and put it through my FEA software. Forces Applied I went for the absolute worst case loads, which were a simultaneous combination of: Braking Acceleration : -1.5g (gives a torque of 1703Nm) Cornering Acceleration: 1.0g (gives a lateral 'force' of 300kg) 'Kerbing' Bump Event : 5.0g applied to quarter of the car's mass (gives a vertical 'force' of 3100kg) There was a post on this in the 350.com USA site a while back. The guy driving felt the steering judder and pulled over to the kerb. Every spoke in his after market wheels on the front right alloy had cracked at the centre dropping the wheel down on the hub. It was only his quick thinking and knowledge of his car that saved his life. It transpires that all 4 wheels had been powdercoated and l think he paid peanuts for them. there is a lot to be learnt and one area you cannot skint on is wheels and wheel nuts! Good post! To give a visual representation of the results (where blue is low stress, going up to red which is high): http://i1063.photobucket.com/albums/t50 ... sFront.png http://i1063.photobucket.com/albums/t50 ... esRear.png This shows that the maximum stress seen is 99MPa. The ultimate (breakage) strength of the aluminium alloy used is likely to be between 150-200MPa. So I think it's safe to say that as designed, the wheel is very safe. The horror stories of people breaking wheels probably therefore comes about either by major manufacturing defects, or misuse. Hopefully of some interest! Rob There was a post on this in the 350.com USA site a while back. The guy driving felt the steering judder and pulled over to the kerb. Every spoke in his after market wheels on the front right alloy had cracked at the centre dropping the wheel down on the hub. It was only his quick thinking and knowledge of his car that saved his life. It transpires that all 4 wheels had been powdercoated and l think he paid peanuts for them. there is a lot to be learnt and one area you cannot skint on is wheels and wheel nuts! Good post! Quote Link to comment Share on other sites More sharing options...
bronzee Posted March 29, 2012 Share Posted March 29, 2012 Very interesting. Would also be really interesting to see the stock wheel strength and other popular model strengths. Quote Link to comment Share on other sites More sharing options...
docwra Posted March 29, 2012 Share Posted March 29, 2012 Its been a longtime argument, that Rotas particularly arent as strong as they are cheaper than brand name rims. Seeing as nearly every competition driftcar in the UK runs Rotas and regularly smashes over kerbs at full lock and IIRC we are yet to see a failure in competition, it suggests the boys at Rota have got it right Quote Link to comment Share on other sites More sharing options...
stillracing Posted March 31, 2012 Author Share Posted March 31, 2012 Yeah I well imagined they're engineered properly. It was just the weight difference to stock that surprised me. It kind of begs the question what the extra 3kg per wheel is doing on the stock wheel...Although saying that it could be a weaker material. Quote Link to comment Share on other sites More sharing options...
Chris`I Posted March 31, 2012 Share Posted March 31, 2012 They're cheaper as they copy other peoples designs. They let them do all the R&D and then just copy it. Simples. Lighter than OEM as OEM probably use cheaper material. the RAYS that come on the Zed will likely be the same or lighter than the Rotas. Do Rota do forged wheels yet? Quote Link to comment Share on other sites More sharing options...
350 Russ Posted March 31, 2012 Share Posted March 31, 2012 Here i found this which should be relevant viewtopic.php?f=113&t=29475 Quote Link to comment Share on other sites More sharing options...
stillracing Posted March 31, 2012 Author Share Posted March 31, 2012 Pretty impressive Russ! I won't feel too guilty when I hit a pot hole now then Quote Link to comment Share on other sites More sharing options...
docwra Posted April 1, 2012 Share Posted April 1, 2012 Lighter than OEM as OEM probably use cheaper material. the RAYS that come on the Zed will likely be the same or lighter than the Rotas. Do Rota do forged wheels yet? All Rotas are forged, and on weight they are comparable with a lot of aftermarket wheels too. The GTR-D isnt a copy of another design and is still cheap as chips too Quote Link to comment Share on other sites More sharing options...
lukekbrown Posted April 1, 2012 Share Posted April 1, 2012 I never understand Rota crtics to be honest. Yes Rota are comparable in design to a lot of brands out there, but the build quality is second to none and wouldn't say a set of 19 inch wheels for £1k is exactly cheap, my opinion is that If you go down to Halfords and pick a set of wheels up for £400, that is cheap. I like the Nismo LMGT4, but are basicly the same design as the Rota GTR (you just pay 4 times the price because of the Nismo brand), I think the value for money for a Rota is very good and that is why so many performance cars have them fitted. Maybe I'm bias because I just brought a set of Rota's But done my research, Rota for me can't be beaten for quality at the price they charge. Quote Link to comment Share on other sites More sharing options...
Chris`I Posted April 1, 2012 Share Posted April 1, 2012 All Rotas are forged, and on weight they are comparable with a lot of aftermarket wheels too. The GTR-D isnt a copy of another design and is still cheap as chips too Didnt know all Rotas were forged. When I got mine some years back I'm pretty sure they werent at the time. Now they are all forged and making a name for themselves I'm sure the prices will start to rise Quote Link to comment Share on other sites More sharing options...
ben@RARE RIMS Posted April 2, 2012 Share Posted April 2, 2012 Rotas are not forged, they're cast. Chris 'I you'll find the R&D in Rota wheels is there, they're similar to other wheels sure, but not identical as you cant just copy a forged wheel and make it cast and thus cheaper without making is significantly less strong. This was quite an interesting read the other day: http://custompinoyrides.com/2012/03/que ... ta-wheels/ Quote Link to comment Share on other sites More sharing options...
docwra Posted April 2, 2012 Share Posted April 2, 2012 Bollocks, word confusion issues. I didnt mean forged, I mean cast, Ive had this discussion with Ben a few times. How embarrassing. Quote Link to comment Share on other sites More sharing options...
Chris`I Posted April 2, 2012 Share Posted April 2, 2012 No doubt ROTA are up there for cast wheels, its why I got a set of GTRs. They're great for their money but they're not forged wheels if thats what you are after. So cast OEM vs cast ROTA, usually ROTA will be lighter I'd imagine, as OEM will just want to keep things as cheap as possible, but vs forged, you'd expect the forged to be lighter and about the same strength. Quote Link to comment Share on other sites More sharing options...
ben@RARE RIMS Posted April 2, 2012 Share Posted April 2, 2012 That's pretty well it Chris Forged wheels go 1 of 3 ways usually. They're the same size as a cast version, but lighter due to the increased strength allowing for less material to be used. Strength and load rating usually similar They're heaver than a cast wheel, but stronger - this is where race and rally wheels fall mostly The forged wheel is a blingy design that cannot easily be cast, often multi-piece. Weight and strength is similar to a cast wheel, but a more exciting design. The different techniques do give different properties in terms of stiffness and how they perform under damaging impacts, but both will be strong enough if VIA / JWL certified and tested. The time to be worried about a cast wheel is when it's made by somebody you've never heard of, and cant find out about. There's a large number of chinese manufacturers who do replica wheels, on alibaba you can get a replica of almost any wheel where a mould has just been taken of another wheel and it's copied, with the original manufacturers markings still in place. These are the scary ones - likely little or no testing is involved. There's no UK / EU standard or requirement for a wheel, so it's up to suppliers to make sure things are fit for purpose. When people are in it to make a quick profit you cannot always be sure on the quality of the products, like wheels with Forged Monoblock written on the side that actually aren't... Quote Link to comment Share on other sites More sharing options...
Chris`I Posted April 3, 2012 Share Posted April 3, 2012 Saw an interesting prog on the Beeb yesterday about the history of metal. Turns out that casting can be stronger than forging, in the case of Rolls Royce jet engines, they 'cast' their turbine blades, but from a single metal crystal. Very cool (and uber expensive), but makes the metal stronger than forging. Need to get some Rotas from a single crystal Quote Link to comment Share on other sites More sharing options...
ben@RARE RIMS Posted April 3, 2012 Share Posted April 3, 2012 Ha, single crystal casting sounds very exotic! Time for some iplayer action later me thinks! Quote Link to comment Share on other sites More sharing options...
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