Suspension - what have I got?! [Resolved]

[AeonMach]

I am not questioning whether your van should be class 4 or class 7.

The point is for a T32 Transporter it should have 103 minimum tyres.

Well yes and no: you were saying previously:
”…you need a 103 tyre minimum, otherwise it should be MOT fail. You can not put a tyre on with a load rating below the axle weight whether it is class 4 or 7.”

And I‘ve pointed out that that isn’t the case. The MoT - as the legal implementation of underlying safety regs (The Road Vehicles (Construction and Use) Regulations 1986) - says that it only applies to Class 7. Which was my point right from the beginning. It isn’t black and white as you are suggesting.

Now further “should” my van have 103 minimum tyres?
Well possibly! But I don’t think it’s legally necessary (unless as per above you’re strictly a T32 panel van which I’m not).
I think legally it’s fine as long as my loading doesn’t exceed my tyres’ load rating. (So the police would need to check that on a weigh bridge.)

…but - and here I’m kinda going to agree with you in the end anyway but for slightly different subtle reasons - practically I think you should because:
a/ insurance (they will use marked load rating as a simple minimum - I suspect)
b/ police - even if one is in the right legally, it’s a lot easier just to meet an obvious tyre load rating compliance than argue all that!! And potentially waste time having to argue against points or in front of a magistrate!
c/ common sense and safety margins - by complying with it you adhere to a safety system

But I would note that I suspect insurance expects all sorts of things to be ‘standard’ and many many of have changed our wheels and tyres from the OEM spec - how many of are running eg bog standard 215/60/17s??? Some van door stickers seems to give lots of options. Mine only lists 215/60/R17 despite being a performance 204PS 4Mo!?
And note most originals (except perhaps Sportline spec or some options) are going to be commercial van-rated tyres.
So I’m not quite sure why people are quite so obsessed with load rating compliance when also freely customising all sorts of other things? ;-)
I mean in my case I’m also on lowered suspension and really wide low profile tyres (275/35/R20s)…

Just for reference, I believe the numbers on the door are to do with the tyres that VW supply new on the van and the correct pressures for those tyres.

I just looked at the sticker on my van and there are pressures quoted for tyres of various sizes and weight ratings from 102 to 109. My van is a T30 and working from the axle weight need 101 rated tyres.

View attachment 225942

Yes, but it’s not just tyre pressures: it’s manufacturer’s recommended options (see also my point above about insurance expecting ’standard’), and which are all options that comply with the necessary load rating (necessary to meet axle weights). Note that all yours are indeed greater than 101.

So why my 102?
Maybe it‘s just stupidly ambiguous: this tyre perhaps happens to come in both 102 and 104 and it’s the up to you - if necessary (my argument above) - to use the 104 if (yet again, if) you need that load rating???

And because it gets weirder, having searched my original size there ARE 104/102 rated tyres!!
eg Kumho PorTran KC53. Only £ 81.62
WTF?

 

[AeonMach]

PS split load ratings:
I’ve worked out wtf they are!
eg my 215/60/R17 102/104 given on my door jamb!

It is specifying single and dual wheel (at each end that is) rear axle!! So 104 in this tyre size (which meets my T32 axle needs which suggest > 103). But 102 if there were dual wheels.

source (it’s a bit US centric but covering EU/metric oriented standards):

Deciphering the Sidewall - Tire Review Magazine

There is a lot you can tell about a tire just by looking at it. Federal regulations require most of that information to be branded on the sidewall, though

www.tirereview.com

 

[n10n]

So why my 102?
Maybe it‘s just stupidly ambiguous: this tyre perhaps happens to come in both 102 and 104 and it’s the up to you - if necessary (my argument above) - to use the 104 if (yet again, if) you need that load rating???

And because it gets weirder, having searched my original size there ARE 104/102 rated tyres!!
eg Kumho PorTran KC53. Only £ 81.62
WTF?

According to Pirelli, the dual rating in tyres is for when used as pair or as a single. Counterintuitively the lower rating is for dual tyre.

Tyre Load Index & Chart | Pirelli

What is tyre's load index? How do you find the load index on a tyre? Get expert advice from Pirelli.

www.pirelli.com

"The load index on light truck tyres is different from that of passenger cars: it usually has two ratings separated by a slash. This is because most light truck tyres are designed to be used in a dual back wheel system with two tyres side by side. The first number is the load rating when the tyre is used alone and the second is the rating when it is used as a dual tyre. The dual rating is usually lower to cover situations where one tyre in the pair fails and the other has to carry the full load."

The requirement in vehicle sticker is more confusing though. I have thought it would be similarly for dual rear tyres in flat bed pickups, however I've never seen even a picture of T6 flat bed with dual tyres on rear axle, not sure if such a thing exists.

 

[AeonMach]

Ill pop my 10 pennies worth in here .

…

Hope this helps

@CRS Performance yes that‘s incredibly helpful (Steve is it?)!

I might have to give you a bell to discuss that spring option…!

 

[AeonMach]

According to Pirelli, the dual rating in tyres is for when used as pair or as a single. Counterintuitively the lower rating is for dual tyre.

Tyre Load Index & Chart | Pirelli

What is tyre's load index? How do you find the load index on a tyre? Get expert advice from Pirelli.

www.pirelli.com

"The load index on light truck tyres is different from that of passenger cars: it usually has two ratings separated by a slash. This is because most light truck tyres are designed to be used in a dual back wheel system with two tyres side by side. The first number is the load rating when the tyre is used alone and the second is the rating when it is used as a dual tyre. The dual rating is usually lower to cover situations where one tyre in the pair fails and the other has to carry the full load."

The requirement in vehicle sticker is more confusing though. I have thought it would be similarly for dual rear tyres in flat bed pickups, however I've never seen even a picture of T6 flat bed with dual tyres on rear axle, not sure if such a thing exists.

lol, I just finally worked it out too and posts crossed! But thanks! Very useful to have this confirmed!

It‘s odd though isn’t it?
Given lack of T6 dual rear axles as you say why even print this confusing spec option???

 

[Gsixty]

Well yes and no: you were saying previously:
”…you need a 103 tyre minimum, otherwise it should be MOT fail. You can not put a tyre on with a load rating below the axle weight whether it is class 4 or 7.”

And I‘ve pointed out that that isn’t the case. The MoT - as the legal implementation of underlying safety regs (The Road Vehicles (Construction and Use) Regulations 1986) - says that it only applies to Class 7. Which was my point right from the beginning. It isn’t black and white as you are suggesting.

Now further “should” my van have 103 minimum tyres?
Well possibly! But I don’t think it’s legally necessary (unless as per above you’re strictly a T32 panel van which I’m not).
I think legally it’s fine as long as my loading doesn’t exceed my tyres’ load rating. (So the police would need to check that on a weigh bridge.)

…but - and here I’m kinda going to agree with you in the end anyway but for slightly different subtle reasons - practically I think you should because:
a/ insurance (they will use marked load rating as a simple minimum - I suspect)
b/ police - even if one is in the right legally, it’s a lot easier just to meet an obvious tyre load rating compliance than argue all that!! And potentially waste time having to argue against points or in front of a magistrate!
c/ common sense and safety margins - by complying with it you adhere to a safety system

But I would note that I suspect insurance expects all sorts of things to be ‘standard’ and many many of have changed our wheels and tyres from the OEM spec - how many of are running eg bog standard 215/60/17s??? Some van door stickers seems to give lots of options. Mine only lists 215/60/R17 despite being a performance 204PS 4Mo!?
And note most originals (except perhaps Sportline spec or some options) are going to be commercial van-rated tyres.
So I’m not quite sure why people are quite so obsessed with load rating compliance when also freely customising all sorts of other things? ;-)
I mean in my case I’m also on lowered suspension and really wide low profile tyres (275/35/R20s)…


Yes, but it’s not just tyre pressures: it’s manufacturer’s recommended options (see also my point above about insurance expecting ’standard’), and which are all options that comply with the necessary load rating (necessary to meet axle weights). Note that all yours are indeed greater than 101.

So why my 102?
Maybe it‘s just stupidly ambiguous: this tyre perhaps happens to come in both 102 and 104 and it’s the up to you - if necessary (my argument above) - to use the 104 if (yet again, if) you need that load rating???

And because it gets weirder, having searched my original size there ARE 104/102 rated tyres!!
eg Kumho PorTran KC53. Only £ 81.62
WTF?

I can see where you are coming from, however:

From MOT inspection manual: cars and passenger vehicles (note this is for cars and passenger vehicles, not for class 7) it clearly states (updated on 6th February 2023):

"Load rating​

Check the manufacturer’s plate to find the maximum laden weight of an axle. You must check that the tyres fitted have a load rating that can carry the laden weight of the axle."

As regarding insurance, as long as you have informed them of the changes then you are covered. The vans come with a range of sizes of wheells and tyres so you have that flexibility (note that VW offer a 20" wheel for vans T30 and below, but not T32). However all the tyres and wheels VW supply conform to the load rating (hence the T32 lack of 20" wheel option.

 

[n10n]

It‘s odd though isn’t it?
Given lack of T6 dual rear axles as you say why even print this confusing spec option???

It is confusing. Maybe it's just to match the tyre markings - if you fit a tyre with 104/102T rating it will be fine.

 

[AeonMach]

I can see where you are coming from, however:

From MOT inspection manual: cars and passenger vehicles (note this is for cars and passenger vehicles, not for class 7) it clearly states (updated on 6th February 2023):

"Load rating​

Check the manufacturer’s plate to find the maximum laden weight of an axle. You must check that the tyres fitted have a load rating that can carry the laden weight of the axle."

As regarding insurance, as long as you have informed them of the changes then you are covered. The vans come with a range of sizes of wheells and tyres so you have that flexibility (note that VW offer a 20" wheel for vans T30 and below, but not T32). However all the tyres and wheels VW supply conform to the load rating (hence the T32 lack of 20" wheel option.

Nope sorry it’s confusing but despite the headline saying it’s for cars and passenger vehicles it’s actually for cars, passenger and light commercial vehicles. (Click the contents link near top of the appendix section page in your link page.)



And then inside - section 5 on “5. Axles, wheels, tyres and suspension” - clearly ONLY points you (and the MoT inspector to that appendix and to check load ratings) if class 5 or 7.
¯\_(ツ)_/¯

 

[AeonMach]

It is confusing. Maybe it's just to match the tyre markings - if you fit a tyre with 104/102T rating it will be fine.

Yeah except I’m never going to do that because AFAIK they are only commercial, high profile wallowy tyres!

 

[n10n]

Yeah except I’m never going to do that because AFAIK they are only commercial, high profile wallowy tyres!

Most of the T6’s sold are also commercial and wallowy

 

[AeonMach]

Don’t try and make me commercial and wallowy again!!

 

[Gsixty]

Nope sorry it’s confusing but despite the headline saying it’s for cars and passenger vehicles it’s actually for cars, passenger and light commercial vehicles. (Click the contents link near top of the appendix section page in your link page.)

View attachment 225945

And then inside - section 5 on “5. Axles, wheels, tyres and suspension” - clearly ONLY points you (and the MoT inspector to that appendix and to check load ratings) if class 5 or 7.
¯\_(ツ)_/¯

It's a bit ambiguous to say the least. I'm still convinced it applies to class 4. If it didn't then legally you could put any tyre you wanted on and I find that difficult to believe.
It would be interesting if there are any MOT testers on here that really know and understand that could clarify this. I would love o have a definitive answer and explanation.

 

[CRS Performance]

Ah! Yes I think that lowering sounds right…
My understanding is that the SoLow shocks are 20mm less than standard Bilsteins and then normally combined with 45mm lowering springs; does that ’normally‘ give a lowering of 65mm? Which would approx match that figure. Does it work like that??
But do you not think that it really works?
Or is all that lowering from the spring???

I’m happy to get a bit more clearance…!

Shorter shocks are used for a few reasons one of which has been mentioned But ill try to explain technically the main reasons for them .

As an example a 30 mm shorter damper would probably have a shortened body by 10 mm and a shaft length of 20mm less totalling L Max ( max length) 30 mm shorter.

The easiest way to make comfort from a really low van is to shorten the body of the shock by what ever lowering range you have!! this would be a complete mechanical disaster. Its also the reason we dont lower cars / vans excessively

The body of the shock ( length ) is critical to the geometry of the suspension and steering and messing with this will cause the following problems because the shock body is what limits the travel of the suspension .
If the shock is too short the wheels and tyres will go into the wheel arch further than they were designed to and touch the inner liner and wing (instant TUV Failure in Europe ) MOT centres in UK are already failing vans for tyre marks on the inner wing liners. Also in cornering the wheel and tyre could simply smash against the wing causing lots of damage.
The drive shaft is designed to move up and down with in a specific range , a shorter shock will allow the Drive shaft to move to angles it simply wasn't designed to ( more than 7 Degrees ) This puts excessive strain on the CVs and stretches the drive shaft particularly during cornering. This will eventually see the drive shaft and CV s fail .

The good bits are that the shorter shock shaft will not bottom out so easily causing a shock failure and the additional travel does help comfort a little.
The last reason we use shortened shocks is to ensure that shorter , or very low springs when installed do not come loose when a car / van is lifted from the ground and the suspension is at full droop. This is a safety issue.

 

[AeonMach]

It's a bit ambiguous to say the least. I'm still convinced it applies to class 4.

I’m pretty convinced that it doesn’t! Or at least should not… The wording seems pretty clear to me.

If it didn't then legally you could put any tyre you wanted on and I find that difficult to believe.

Well no, because you’re still legally required to ensure your tyres are suitable for your load.
However the load rating (only) ensures that the tyres match the maximum load capability of the axles and overall system (eg brakes). You’ve still got to ensure you don’t exceed that load!!
That’s still the most important fundamental…

But I’m sympathetic to your point: it seems hard to believe this isn’t required (legally).
But then this is why I suspect most of the advice out there is simply to say you should comply with the stated load (and speed) rating.

But for most cars and light vans I suspect that most tyres load ratings easily outstrips likely loads?
Hence perhaps why it isn’t legally required???
We (Transporters) perhaps just happen to be right on the crux of where there is the possibility to carry sufficiently heavy loads? And fully loaded campers on eg light T28s certainly seem able to reeach and breach the load limit!

For many cars - certainly high performance ones - I guess the speed rating is perhaps even more important?

It would be interesting if there are any MOT testers on here that really know and understand that could clarify this. I would love o have a definitive answer and explanation.

Indeed.

 

[AeonMach]

Shorter shocks are used for a few reasons one of which has been mentioned But ill try to explain technically the main reasons for them .

As an example a 30 mm shorter damper would probably have a shortened body by 10 mm and a shaft length of 20mm less totalling L Max ( max length) 30 mm shorter.

The easiest way to make comfort from a really low van is to shorten the body of the shock by what ever lowering range you have!! this would be a complete mechanical disaster. Its also the reason we dont lower cars / vans excessively

The body of the shock ( length ) is critical to the geometry of the suspension and steering and messing with this will cause the following problems because the shock body is what limits the travel of the suspension .
If the shock is too short the wheels and tyres will go into the wheel arch further than they were designed to and touch the inner liner and wing (instant TUV Failure in Europe ) MOT centres in UK are already failing vans for tyre marks on the inner wing liners. Also in cornering the wheel and tyre could simply smash against the wing causing lots of damage.
The drive shaft is designed to move up and down with in a specific range , a shorter shock will allow the Drive shaft to move to angles it simply wasn't designed to ( more than 7 Degrees ) This puts excessive strain on the CVs and stretches the drive shaft particularly during cornering. This will eventually see the drive shaft and CV s fail .

The good bits are that the shorter shock shaft will not bottom out so easily causing a shock failure and the additional travel does help comfort a little.
The last reason we use shortened shocks is to ensure that shorter , or very low springs when installed do not come loose when a car / van is lifted from the ground and the suspension is at full droop. This is a safety issue.

Thanks @CRS Performance. I think I understood at least some of that. It certainly convinced me that this is not an area to dabble in without expert advice!

So in my case the SoLow shock I have is apparently 20mm shorter but that is overall length and perhaps not in the body of the shock at all? Or perhaps only a bit???
Assuming it’s not shorter in the body then all of my lowering will come from the spring it’s paired with, yes?
As stock mine is normally paired with a 45mm Eibach lowering spring (which THQ say is the optimal)…

…but (and I’ve tracked down the likely order from Leighton by the VW dealer) I think they‘ve replaced the springs (for whatever reason) with Cobra 40mm lowering springs.
Now that sounds to my inexpert eyes not dissimilar to the Eibach 45mm (less lowering in fact!)…
… but are they handling the weight of my 4Mo LWB (she’s not hugely laden - certainly not full camper)?

 

[CRS Performance]

Thanks @CRS Performance. I think I understood at least some of that. It certainly convinced me that this is not an area to dabble in without expert advice!

So in my case the SoLow shock I have is apparently 20mm shorter but that is overall length and perhaps not in the body of the shock at all? Or perhaps only a bit???
Assuming it’s not shorter in the body then all of my lowering will come from the spring it’s paired with, yes?
As stock mine is normally paired with a 45mm Eibach lowering spring (which THQ say is the optimal)…

…but (and I’ve tracked down the likely order from Leighton by the VW dealer) I think they‘ve replaced the springs (for whatever reason) with Cobra 40mm lowering springs.
Now that sounds to my inexpert eyes not dissimilar to the Eibach 45mm (less lowering in fact!)…
… but are they handling the weight of my 4Mo LWB (she’s not hugely laden - certainly not full camper)?

All after market springs are usually spec d at 40 mm in an empty van . the 4 motion already ads a ton of weight , you need to select the correct kit to cope with this .
More weight the lower the van goes , the standard shocks dont like this and the ride suffers badly
Really would recommend having a chat with us to get this right ,

Steve 07469785932