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My new van is it a light or maxi chassis?


rogermash

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The brochure says the standard delivery is on a 35L (non-maxi) chassis.

 

Some manufacturers give the option of building on a maxi chassis, but I can't see that for Sun-Living, and the lack of 16" wheels indicates that doesn't apply in your case.

 

Even though the light and heavy (maxi) chassis are often delivered at 3500kg MAM, the latter has higher maximum axle loadings both front and rear, and a higher potential upgrade to the MAM as a paper exercise. (largely achieved by use of heavier suspension, bigger wheels and tyres, and bigger brakes).

 

You can confirm the 35L diagnosis by checking the maximum axle loadings on the Fiat VIN plate under the bonnet - the values against 1 and 2 (Front and rear axle) should be 1850 and 2000 respectively.

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15 inch wheels are normal fit on a light chassis. The major difference is that the maxi or heavy chassis has 16 inch wheels with a 130 mm PCD for the thicker wheel bolts. The suspension is uprated with HD shock absorbers and springs, both the front and rear axle allowed loads are higher at 2100kg front and 2400kg rear.(1850 kg, 2000kg on the light chassis). The brakes have larger diameter disks with HD hubs. (300mm dia on the heavy, 280mm dia on the light). The tyres normally fitted are 225/75/16 load rating 121/120.

 

Mike

Sorry RH, was typing as you posted.

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I must admit, I thought the XLWB version was only available with "maxi" underpinnings (it was certainly the case when I bought my previous 'van).

 

Things might have changed since, but on Fiat's current price list I can't spot a non-maxi XLWB.

 

The Sun Living brochure is pretty clear, however, and the 15" wheels are a bit of a giveaway.

 

It wouldn't be the first time a special-order version had found its way to a converter.

 

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Thanks very much everyone. My main reason for asking was that the tyre pressures on the side of the passenger door frame were for 16" wheels. Als the speedo readings are very optimistic compared to the sat nav. An indicated 40mph is actually 34mph!
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I think I would be raising a query with the dealer.

 

I'm pretty sure that that difference in indicated speed is within the legal tolerance, but it is certainly high, and the 16" tyre inflation pressures doesn't look confidence inspiring.

 

The Sun Living price list shows the option of 16" steel or alloy wheels for the light chassis (they will fit the non-maxi hubs because they have different spacings) and one wonders whether there's been a miss-build.

 

(My van has the 16" wheels on a light chassis, but the tyre pressures in the door frame have been blanked out!)

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As mentioned the chassis is the 35L chassis for the 6.36m vans. Payload is c.598Kg but this does not include many of the main items so with full water, hab battery, awning, solar, carpets, MIRO weight variations and other stuff then your payload on paper will be 350kg available assuming that you can load the axles correctly.

 

You will need to take it to a weighbridge as you may struggle to use it legally at 3.5T.

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rogermash - 2020-06-20 5:28 PM

 

Thanks very much everyone. My main reason for asking was that the tyre pressures on the side of the passenger door frame were for 16" wheels. Als the speedo readings are very optimistic compared to the sat nav. An indicated 40mph is actually 34mph!

 

It is (literally) impossible for the 15” wheels that are standard original equipment on a Ducato X290 ‘light’ chassis to be fitted to a Ducato ‘heavy’ (Maxi) chassis. As mikefitz says, the hubs are different and, because a Maxi Ducato’s front brakes have larger-diameter disks, the 15” wheels won’t fit over the Maxi front disks. More information on the following link

 

https://www.tyremen.co.uk/guide/fiat-ducato-motorhome-wheels

 

Received wisdom is that, when Fiat decided to offer 16” wheels as a factory option for the X290 Ducato, the overall gearing took no specific account of this. So the gear ratios of my Rapido motorhome (based on a Ducato X290 ‘light’ chassis with 15” wheels ) are quite low and - although I’d rather have ‘undergearing’ on a motorhome rather than ‘overgearing’ - I wouldn’t mind a 7th gear that would be higher than the present 6th.

 

(My Ducato's speedometer is also well optimistic compared to my sat-navs. I just ignore the speedometer and drive on the sat-nav reading.)

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That's very odd, as Robin posted the XLWB's are normally only on a Maxi (H) chassis, so it must be a special for that convertor, but I did once have a list of variants available for the old x250, many where never listed on 'standard' price lists, I don't recall if there was a 35L XLWB.

What does the data plate show for axle loadings?

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hi

 

My last van a 2014 x250 Adria twin 640 slx was on the light chassis with 15" wheels and i'm sure my new sunliving v65sl is too but the speed seem's better with the 16" wheels.

 

When i was working we had panel vans on both chassis's a quick look seemed the light had two rear fog lights in light cluster and the maxi had a single rear fog light in plastic corner bumper (i'm not saying all are like that)

 

Paul

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There are a whole load of 6.34m PVCs which rest on the Light 35L chassis including the likes of Sun Living, Adria and Autotrail.

 

You normally see dozens of these heavily overloaded machines venturing in and around the Highlands & Islands with Scooters and all sorts on the back.

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paul2 - 2020-06-20 9:29 PM

 

hi

 

My last van a 2014 x250 Adria twin 640 slx was on the light chassis with 15" wheels and i'm sure my new sunliving v65sl is too but the speed seem's better with the 16" wheels...

 

Paul

 

This 2014 forum thread discussed Ducato 15” and 16” wheels

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/16-inch-wheels-fitted-on-Fiat-and-Peugeot-Van-conversions/36477/

 

When I asked the Fiat Professional techical rep at an NEC show whether the gearbox ratios of a Ducato ‘light’ chassis were altered when the optional 16” steel or alloy wheels were factory-fitted instead of the standard 15” wheels, he said “No”.

 

Motorhomes based on a Ducato ‘light’ chassis with 15” wheels will normally have 215/70 R15 tyres and, if the optional 16” wheels are specified, the tyres will normally be 225/75 R16 size. The latter tyres will have a rolling circumference around 6.5% greater than that of the former tyres, resulting in the motorhome’s overall gearing increasing by the same amount.

 

Let’s say (with top gear selected and with 15” wheels and 215/70 R15 tyres) that a motorhome's speed when its engine is turning at 1000rpm is 25mph. if the motorhome’s overall gearing is increased by 6.5%, the vehicle’s speed at 1000rpm would rise to 26.625mph. That may not sound much, but 3000rpm with 215/70 R15 tyres would be 75mph, while 3000rpm with 225/75 R16 tyres would be 79.875mph. So, if you are barrelling rapidly along a French autoroute, 16” wheels + 225/75 R16 tyres should make the experience more comfortable (less ‘busy’, less noise, etc.) and possibly more fuel efficient.

 

The trouble may come when a Ducato-based motorhome with an engine with a relatively low power output (eg. the 130 variant) is heavily loaded and the motorhome has the 16” wheels + 225/75 R16 tyres combination, as the vehicle may be unable to maintain the higher speed when faced with a long upwards gradient, forcing the driver to down-shift out of top gear.

 

My Rapido is on a Ducato X290 ‘light’ camping-car chassis with 15” wheels and 215/70 R15 tyres: it has the 150 motor and treats long motorway inclines with disdain. I’m sure it could cope with the 16” wheels + 225/75 R16 tyres combination on the flat, but, as it's the overall gearing that is on the low side, 1st to 5th (and reverse) gears are also lowish, which (in my view) is a plus with a motorhome.

 

Fiat’s Ducato specification 'naming conventions’ can be confusing, but this link provides a useful summary for panel vans.

 

https://www.parkers.co.uk/vans-pickups/fiat/ducato/2011-dimensions/

 

Assuming that the Parkers information is correct, although it used to be possible to have a XLWB ‘light’ version, this changed when Euro 6d Temp powerplants were introduced, with all XLWB vans (ie. vans with an overall length of 6.36 metres) then being built on the ‘heavy’ (Maxi) chassis with a gross vehicle weight of 3500kg, 4000kg or 4250kg.

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Derek Uzzell - 2020-06-21 8:46 AM

 

Assuming that the Parkers information is correct, although it used to be possible to have a XLWB ‘light’ version, this changed when Euro 6d Temp powerplants were introduced, with all XLWB vans (ie. vans with an overall length of 6.36 metres) then being built on the ‘heavy’ (Maxi) chassis with a gross vehicle weight of 3500kg, 4000kg or 4250kg.

 

I'm not sure that's a reliable source, Derek.

 

On every retail pricelist (both English and German) I've checked for the period 2015 to current (covering Euro5+, Euro6 and Euro6D temp engines), the XLWB van is notably absent in any form but the Maxi.

 

It doesn't mean that the converter couldn't get a set of "specials" supplied, though. I seem to remember we had a debate in the past about your (or possibly someone else's) Rapido lacking something that was a standard line fit at the time. (EBD or ESP or something?).

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Neverthess, as Roger’s 6.36m-long Sun Living V65 SL has 15”-diameter wheels, it is definitely not built on a Ducato Maxi chassis,.

 

As Bop has said above, there are plenty of 6.36m-long PVCs from other converters also with that size road-wheel and, hence, built on a Ducato ‘light’ base.

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Bop - 2020-06-20 10:02 PM

 

There are a whole load of 6.34m PVCs which rest on the Light 35L chassis including the likes of Sun Living, Adria and Autotrail.

 

 

Sun Living is, of course, Adria's second brand, so that wouldn't surprise me.

 

Autotrail, from impression, adopted the 16" wheel upgrade (and generally alloy) for its light chassis from a fairly early point in its availability. I can see that this was probably not the case with the "Tribute" range, but even they seem to have gone the 16" route now (though I suspect they also have/had access to a 35L XLWB, looking at the specs).

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Thanks, Everybody. I should have spent more time reading the spec, instead of watching youtube. I am very pleased with my purchase. It had done only 4600 miles . That was at the end of January. Thanks to lockdown, I have only done another 1000 miles . They were mostly for adding goodies, and a habitation service. This is our only vehicle so there are also shopping trips to add at 7mmiles a time. There are only two adults and a fat spaniel, so overloading shouldn't be an issue.

Roll on September when the kids will hopefully be back at school. We may be able to get a bar meal again by then!

 

Roger

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Just as an addition, I can't find this spec anywhere in the retail line, in any location, at any time.

 

Patently it exists in the motorhome channel, however.

 

Hymer, for instance, also offer it on their XLWB van conversion(s), with 15" wheels, though, knowing Hymer delivery practice I suspect few, if any, are actually built on that base without it being a user-ordered vehicle (all manner of chassis upgrades being available).

 

I suspect it will be a "special order" configuration made available to large-volume panel van converters.

 

I would, at least, check the applicability of the tyre pressures marked on the cab door opening, as the recommended pressures for 15" and 16" tyres can vary somewhat..

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It may be the case that mainstream motorhome converters are specially provided with XLWB Ducato ‘light-chassis’ panel-vans but, if so, the practice has been going on for a long time.

 

When my wife became infected with the ‘downsize-to-a-PVC’ virus in late-2014, we looked at quite a few 6.36m-long PVCs as one of the must-haves would have been a twin single-bed layout, though - as we wanted a left-hand-drive vehicle - we ignored UK-built models.

 

Two of the candidate PVC manufacturers were Globecar and Malibu and, when I checked the specification, it became evident that Globecar were building their XLWB PVCs on Ducato ‘heavy’ (Maxi) chassis, while Malibu were using the ‘light’ chassis. Although whatever was bought would need to have a Gross Vehicle Weight (GVW) of 3500kg, I wanted the Maxi big front disks if I could get them: consequently I would have preferred the Globecar over the Malibu for that technical reason alone.

 

Rapido has been building 6.36m-long Ducato-based PVCs for some years and those models have always had a no-alternative GVW of 3500kg. The Rapido “Van” catalogues have never included a road-wheel size/type choice - you got what you were given which was 15”-diameter steel wheels with plastic trims.

 

What is interesting is that all the past catalogue photos show those 15” wheels, whereas the photos in the 2020 “Van” catalogue (where the motors are Euro 6d-temp) show alloy wheels that are clearly 16”-diameter. There’s still no road-wheel choice in the options list, so it may be assumed that the 16” alloy wheels are what one now gets with any Rapido XLWB “Van”.

 

(I’m not sure this matters much in Roger’s case as the 15” wheels won’t fit over a Ducato X290 Maxi’s 300mm-diameter disks and calipers. So, as his Sun Living V65 SL has 15” wheels, it must have the smaller 280mm-diameter disks and must have been built on a ‘light’ chassis.)

 

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If I may add to the discussion, there are two final drive ratios available for the Fiat gearboxes, this is something you have to be aware of when rebuilding these boxes to ensure the output shaft pinion matches the differential. Thus the maxi chassis in all power options has a different ratio to the light chassis. Where the light chassis is ordered form Fiat with 16 inch wheels specified, Fiat could, if so inclined, fit the appropriate final drive ratio box.

 

Mike

1916935746_finaldriveratio.jpg.25de7a02ba248b3b23ff4c7d99dfc6bd.jpg

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mikefitz - 2020-06-22 12:10 AM

 

...Where the light chassis is ordered form Fiat with 16 inch wheels specified, Fiat could, if so inclined, fit the appropriate final drive ratio box.

 

Mike

 

Those were questions I put to the Fiat Professional technical rep at the NEC Show - whether, if 16”-diameter wheels were specified as a factory build-option for a Ducato X290 ‘light’ chassis, Fiat would fit the transmission used with the ‘heavy’ chassis, or whether there might be two transmissions for the ‘light’ chassis, one for vehicles built with 15” wheels and another for vehicles built with 16” wheels.

 

I’d asked the same rep about this at an earlier NEC Show, when he said he didn’t know but (now that I’d brought the matter up) he’d have to look into it. Anyway, at the later Show he told me that nothing mechanical was done transmission-wise at the Fiat factory to discriminate between ‘light’ chassis Ducatos with 15” wheels or ‘light’ chassis Ducatos with 16” wheels.

 

He added that the speedometer’s reading would be factory-adjusted according to which wheel/tyre-size had been specified, but that was just a software tweak.

 

He also asked which powerplant my 2015 Ducato had and, when i said it was the 2.3litre 150, told me this had a superior gearbox to that of the (then) 130 motor - and I think I recall you mentioning that here once.

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Just a question. :-)

 

Our 2017 X290 Ducato 130PS 2.3L LHD 6.0M 3.5 tonne MAM PVC is on the Maxi chassis with manual transmission and 16" wheels.

 

Our previous 2013 X250 Ducato 150PS 2.3L 6.75M 3.5 tonne MAM A Class coachbuilt (Hymer Exsis-I 578) van was on the "light" chassis with Comfortmatic transmission and 15" wheels.

 

My impression of the Maxi chassis is that, irrespective of the actual plated MAM, it is the superior base for motorhomes. Part of this is the enhanced braking and, oddly, the firmer suspension which, somehow, results in a less harsh ride. Nick Fisher described the Maxi ride to me as more "planted" on the road by comparison to the light chassis, which he described as driving like a shopping trolley, and I would describe as somewhat "skittish".

 

The advantages I notice with the Maxi are the controllability of the vehicle at low speeds - for example when pitching - especially on uneven ground, and its ability to drive away uphill without drama fully laden on wet or slippery roads. The obvious flaw in these observations is that I'm comparing a Comfortmatic with a manual but, nevertheless, I'm wondering whether that Maxi lower final drive ratio more than compensates for the higher overall gearing imposed by 16" wheels, leaving the effective overall ratios lower on the maxi than on the Light chassis. Does anyone know?

 

Although the Hymer had the 150PS engine and the present van has the standard 130PS (currently only on 9,000 miles) it feels at least as lively (in a motorhomey sort of way! :-)) as the Hymer. So I'm also wondering if another advantage of the Maxi chassis with its lower final drive might be to negate the need to increase engine power to compensate for the usually high weight of a motorhome. If this isn't an illusion, folk may wish to explore upgrading to the Maxi chassis in lieu of upgrading the engine power, as in most cases the chassis upgrade is cheaper - and brings the other advantages mentioned above.

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That's where me and Nick disagree, I had driven several x250's including a weeks hire of a WildAx on a LWB 35L chassis, but no XLWB 35H before buying our van, I was surprised as to how harsh the suspension is compared to the 35L.
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colin - 2020-06-22 12:19 PM

 

That's where me and Nick disagree, I had driven several x250's including a weeks hire of a WildAx on a LWB 35L chassis, but no XLWB 35H before buying our van, I was surprised as to how harsh the suspension is compared to the 35L.

 

What tyre pressures are you running at? Many times people blame suspension when lowering pressures is all that is needed.

 

Keith.

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Brian Kirby - 2020-06-22 11:55 AM

 

...I'm wondering whether that Maxi lower final drive ratio more than compensates for the higher overall gearing imposed by 16" wheels, leaving the effective overall ratios lower on the maxi than on the Light chassis. Does anyone know?....

 

Using the table Mikefitz provided, It should not be too hard to calculate a set of ‘combination’ intemediate-ratio/final-drive ratio data for comparative purposes, but there’s still the 15” (standard ‘light’ chassis wheel size) and 16” (standard ‘heavy’ chassis wheel size) to stir into the mix, never mind the manual/semi-auto transmission differences.

 

Not worth the effort in my view - I’m not going to do it. ;-)

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