Pete-B Posted November 12, 2012 Share Posted November 12, 2012 Hi, Being a numpty on this subject could someone explain, in easy speak, what the difference is between an Al-Ko chassis and the usual ones? Link to comment Share on other sites More sharing options...
Tracker Posted November 12, 2012 Share Posted November 12, 2012 If you google 'alko motorhome chassis' and then compare it to, say, 'fiat ducato camper chassis' and with 'fiat ducato chassis' all will become clear. Link to comment Share on other sites More sharing options...
747 Posted November 12, 2012 Share Posted November 12, 2012 A Fiat chassis is fine except that it has to be extended (at least in some cases) to accommodate the longer motorhome body. The Alko chassis comes in different lengths to suit the particular model. That is basically it but as usual, there is much more to it than that. Link to comment Share on other sites More sharing options...
Mel B Posted November 12, 2012 Share Posted November 12, 2012 A standard vehicle chassis is just that - it was produced by the original vehicle manufacturer, however some converters use a flat bed type chassis, whilst others use a 'grid' type chassis - basically steel box work. When a motorhome manufacturer requires something different from the standard chassis, they may use an Alko chassis - this is designed specifically for the purpose it is going to be used for and can vary for each motorhome model depending on what the final product will be, for example a twin rear axle motorhome would required an Alko chassis as this isn't available from the standard chassis manufacturer. A motorhome built on an Alko chassis doesn't have any of the original vehicle's chassis in it's build (normally) - only the cab itself it kept and the Alko chassis attaches to the rear of the cab base where the original chassis would normally extend from. These usually have different suspension to the standard vehicle chassis and the chassis itself is often set lower to the ground to allows for a lower floor level for the accommodation part (so it is easier to get in/out with less steps), or even permits a 'double floor' so that storage, water tanks, services etc, are all set within this double floor - often used for fully winterised motorhomes and the heating system is often ducted into it. Some manufacturer's offer the same layout of motorhome on either chassis (or at least they used to!), but obviously an Alko chassis adds to the cost of the motorhome, so usually you only find it on the higher end of the motorhome market. Below are images of a Fiat ladder and platform chassis and Alko single and twin rear axle chassis. Link to comment Share on other sites More sharing options...
Guest peter Posted November 12, 2012 Share Posted November 12, 2012 The Fiat chassis is dispensed with and replaced by the Alko one which is usually wider - longer and has independant suspenion by torsion bar as opposed to the Fiat cart springs, so it rides better. The Alko one is also lower, and a damn sight better, but more expensive, naturally. Link to comment Share on other sites More sharing options...
Mel B Posted November 12, 2012 Share Posted November 12, 2012 Below is a very 'bespoke' alko chassis! Link to comment Share on other sites More sharing options...
PJay Posted November 12, 2012 Share Posted November 12, 2012 Mel B - 2012-11-12 8:41 PM Below is a very 'bespoke' alko chassis! You shoudn't have weight carrying problems with! Could take every thing you think/might need in that!! Wonder how it corners? Link to comment Share on other sites More sharing options...
Wooie Posted November 12, 2012 Share Posted November 12, 2012 Mel B - 2012-11-12 8:41 PM Below is a very 'bespoke' alko chassis! You`d have thought they could have afforded " Alloys " for the front wheels as well ! Link to comment Share on other sites More sharing options...
George Collings Posted November 12, 2012 Share Posted November 12, 2012 Photoshop has a lot to answer for. Who would want to drive around in a scrubber? Link to comment Share on other sites More sharing options...
George Collings Posted November 13, 2012 Share Posted November 13, 2012 In addition to an Al-Ko chassis Fiat and Ford offer special motorcaravan chassies. The standard type has two top hat box sections welded together. The motorcaravan type only has the lower inverted top hat giving a lower floor line and slightly lighter unit. See pics (1) & (2) Converters can order cab units already adapted to take the Al-Ko conversion and for ease of handling they are delivered bolted back to back. See pic (3) Link to comment Share on other sites More sharing options...
crinklystarfish Posted November 13, 2012 Share Posted November 13, 2012 Repeated from the other thread as this one seems to be moving on better: I've always wondered, how do converters isolate torsional stresses from AL-KO chassis. Do they just use rubber bobbins or something more engineered. I imagine some of the longer versions twist pretty spectacularly when faced with a bit of cross axle stress. Those forces have to go somewhere - you can't twist a box (well not very much anyway). The images of the long versions above makes clear that there will certainly be a lot of torsional force at work. How do they dissipate it to stop it twisting the coachbuilt panels to bits? Or is that why leaks are so common? Link to comment Share on other sites More sharing options...
euroserv Posted November 13, 2012 Share Posted November 13, 2012 PJay - 2012-11-12 8:53 PM Mel B - 2012-11-12 8:41 PM Below is a very 'bespoke' alko chassis! You shoudn't have weight carrying problems with! Could take every thing you think/might need in that!! Wonder how it corners? Like it's on rails? Link to comment Share on other sites More sharing options...
pepe63xnotuse Posted November 13, 2012 Share Posted November 13, 2012 crinklystarfish - 2012-11-13 9:50 AMRepeated from the other thread as this one seems to be moving on better:I've always wondered, how do converters isolate torsional stresses from AL-KO chassis. Do they just use rubber bobbins or something more engineered. I imagine some of the longer versions twist pretty spectacularly when faced with a bit of cross axle stress. Those forces have to go somewhere - you can't twist a box (well not very much anyway). The images of the long versions above makes clear that there will certainly be a lot of torsional force at work. How do they dissipate it to stop it twisting the coachbuilt panels to bits? Or is that why leaks are so common?Crinkly..Now, play nicley with the lovely motorhome people.... (lol) (lol) Wasn't there someone on here quite a while back whose tag axle (Burstner,I think?)had developed "creases" in the side panels.....I do recall that they("they", being the dealers or Burstner)reckoned that the owner must have hit a speed bump too hard...?!?... :-S .Yeah right! *-) Link to comment Share on other sites More sharing options...
crinklystarfish Posted November 13, 2012 Share Posted November 13, 2012 Honestly didn't know about sidewall creasing - I drop in and out of here and miss most things. It doesn't surprise me in the slightest though. Looking at the images of those long chassis, I do know for certain that bolting a body directly to them will definitely end badly for the body / furniture etc, and could also lead to chassis failure if stress is concentrated in localised points. Link to comment Share on other sites More sharing options...
pepe63xnotuse Posted November 13, 2012 Share Posted November 13, 2012 crinklystarfish - 2012-11-13 12:38 PMHonestly didn't know about sidewall creasing - I drop in and out of here and miss most things. It doesn't surprise me in the slightest thoughThis isn't the actual discussion that I was remembering but it is touched upon here:http://www.motorhomefacts.com/ftopic-61412-days0-orderasc-0.html(..I knew it was a while back but I hadn't realised that it was that long ago though...?!...) Link to comment Share on other sites More sharing options...
crinklystarfish Posted November 13, 2012 Share Posted November 13, 2012 Interesting reading pepe, ta. That's what I'm on about. It seems several similar models on long AL-KO chassis developed mysterious creases in the body panels. What alarms me is in the case of 'motherbrown' was that none of the 'expert' damage assessors even had a punt at torsional stress as an issue - even though they couldn't come up with viable explanations. Now, either it clearly wasn't, or they weren't aware of the concept. I'll have a good poke and proddle next time I'm at a show to see how the major converters actually fasten bodies to AL-KO chassis. In the meantime, anyone who has mysterious damp ingress at panel joints, or whose furniture keeps working loose, you may have already met Mr Torsional Stress. He's an unforgiving chap. Link to comment Share on other sites More sharing options...
PeteH Posted November 13, 2012 Share Posted November 13, 2012 Hi How about?. Because the Alko chassis has torsion bar suspension rather that a semi live axle more of the torsion across the chassis may be absorbed by the movement of the wheels and less transmitted to the body work?. Having said that it`s still a likely hood that the (apparently) less torsionally rigid Alko chassis will tend to transmit more movement to the body shell unless compensated for by the methods of mounting the bodywork to the chassis? You don`t see much of this with American R-V`s. But then they are 90% on actual Truck Chassis!!! The one on the Winnebago is Massive!! Pete Link to comment Share on other sites More sharing options...
747 Posted November 13, 2012 Share Posted November 13, 2012 Or, how about. 99.9% of Alko chassis vans are not exhibiting any unusual symptoms. They are not kinked on the bodywork, leaking at joints (that seems to be the preserve of British made vans, leaky Kontiki for example). Their floors do not rot in the first few years (again British vans can, Swift for example due to their construction method). They do not turn into showers through the rooflight when it pours (Autotrail, as we all know too well on this forum). To be on the safe side, you could always do a selfbuild based on a Challenger 2 Tank. Mind you, the mpg will not be brilliant. :D Link to comment Share on other sites More sharing options...
crinklystarfish Posted November 14, 2012 Share Posted November 14, 2012 PeteH - 2012-11-13 8:47 PMHiHow about?. Because the Alko chassis has torsion bar suspension rather that a semi live axle more of the torsion across the chassis may be absorbed by the movement of the wheels and less transmitted to the body work?. Having said that it`s still a likely hood that the (apparently) less torsionally rigid Alko chassis will tend to transmit more movement to the body shell unless compensated for by the methods of mounting the bodywork to the chassis? ... Absolutely right, and all I was asking is can anyone with a (ideally) long chassis let us know how the body has been mounted, ie just how, if at all is stress: "compensated for by the methods of mounting the bodywork to the chassis" Torsion bar suspension will help, but won't eliminate chassis twist. Indeed if you look at the rolling road test on the YouTube video Derek posted on the other thread you can see the chassis rails deflecting out of each others plane at the rear whilst staying pretty rigid where they are joined to the cab.- and that's a short one! RVs notoriously self-destruct if treated to rough roads (and sometimes on smooth ones!), and the inexplicable creasing on the coachbuilt in question was a highly regarded German brand. I completely accept that in the vast majority of cases with the ever-so-gentle usage 'vans tend to be subject to it won't be a problem. I'm equally suspicious though that it's another area that converters just bodge over and that torsional stress is perhaps at the root of many of the longevity problems when it comes to water ingress from joints and creeping cracks etc etc. Just trying to raise awareness, most manufacturers build to maximise profit, they are not driven by philanthropy. How bodies are mounted could well be an important indicator of product quality. I stress this is not a criticism of AL-KO chassis, it's an open question regarding how manufacturers build onto said chassis. Link to comment Share on other sites More sharing options...
crinklystarfish Posted November 14, 2012 Share Posted November 14, 2012 At about 1:28 Link to comment Share on other sites More sharing options...
pepe63xnotuse Posted November 14, 2012 Share Posted November 14, 2012 ..yeah...and interestingly,that "motorhome like" vehicle being thrown through those cones,does not appear to be integral to the cab either...It just looks like a seperate box-body.. I would've thought that to fully test a suspension system,they should be using an "integral" motorhome type set-up.. :-S (..I know our's is "only" 7mtrs and on a Renault "platform chassis" thingie..but our's is just bolted rigid.. ..and it don't half creak'n'groan when pulling on and off our steep driveway.. *-) ) Link to comment Share on other sites More sharing options...
dikyenfo Posted November 14, 2012 Share Posted November 14, 2012 Ladder chassis of Alko type are useless for the job they are being used for as some sort of spaceframe has to fitted to make them fit for purpose. I still remember a bods face when he was charged 300 quid for a handbrake cable :D Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.