Decision made on wheels - Supermetal Trident 20's

[HowieDog]

Standard wheels 215/60R17 is 27.15". 275/35/R20 is 27.57".

Under 2% difference in diameter and over-read of speedo will mean GPS speed pretty much same as speedo reading.

 

[Abx]

I always use willtheyfit, plug in standard and new wheels and tyres and it will show you the speedo difference.

Standard wheels 215/60R17 is 27.15". 275/35/R20 is 27.57".

Under 2% difference in diameter and over-read of speedo will mean GPS speed pretty much same as speedo reading.

And good thing is you’ll be under the speed limit so no risk of speeding.

 

[HowieDog]

And good thing is you’ll be under the speed limit so no risk of speeding.

Works the other way unfortunately. As the speedo has a build in margin already this is effectively lost due to the larger circumference of the wheel.

 

[Abx]

Works the other way unfortunately. As the speedo has a build in margin already this is effectively lost due to the larger circumference of the wheel.

Of course, had just opened my eyes and was reading the table wrong.

 

[Lovebus]

Yo men.... ok so I found a site where I put original wheel size in and then current and gave me a 4.4mph difference?? But you are saying there is no difference, is that right?

 

[Lovebus]

The VW Trident wheels, what is the offset etc for these, as yes looking at willtheyfit it looks as though I am totally wrong and will be slower?

 

[Abx]

The offset won’t matter as that does not affect the circumference. 4.4 is quite a bit out and could catch you out speeding, I’d just make sure you get 35’s next time, or if you prefer the ride/look of 40’s then maybe have the speedo recalibrated, I know you can do this on the 6.1

 

[Lovebus]

I will for sure get the 35 next time, that was VW dealer getting the 40's..... and using that new site the speedo is actually reading slower, by 4.5 miles an hour.... so not much chance of speeding! When moving to the 35's, which I may do sooner rather than later, although would like all weather version the diff is even less.... this is very useful conversation and shows how little I know....

 

[Abx]

Just check the speedo difference again as that caught me out earlier, if the fitted tyres show a slower speed than standard tyres....then when you are doing the speed limit according to the speedo you’ll actually be going faster in reality, hope that makes sense.

 

[Lovebus]

No.... how is that? willtheyfit shows it goes slower, how is it actually faster? Sorry, v stupid here

 

[B J G]

Seems to be much confusion on speedo reading relating to tyres. using 235/55/17 as a reference.

normally speedo is approx. 2MPH over reading at 70 MPH. ie indicated 70 but 68 road speed.

275/35/20 would give 68.6MPH indicated with an actual road speed at 70MPH.

275/40/20 would give 69.5MPH - road speed 70MPH

Note tyre type, manufacturer and wear level all can vary those figures.

 

[Abx]

So I ‘think’ but hard without doing myself, it shows a slower speed this what high speedo is showing, so speedo shows 30 but you are doing 26, so then if

No.... how is that? willtheyfit shows it goes slower, how is it actually faster? Sorry, v stupid here worries and

No.... how is that? willtheyfit shows it goes slower, how is it actually faster? Sorry, v stupid here

No worries and I’m sure you are fine, just flagging as the numbers have caught me out in the past (and earlier) so always worth a double check, as depending what way they are out +/- the the speedo can over or under read, you’d not want to be in a position where speedo states 70 and you are all happy and you are actually going 75 and get a ticket.

Sorry about the above, phone throwing a wobbly, just read there last bit above.

This may help where I’m coming from, standard tyre left show 60 at 60, 275 40 on that right show 59.47 at 60, so if you were doing a speed on the 275’s that shows 60 you’d be going slight faster.

 

[B J G]

I find willtheyfit good but for a more visual wheel tyre comparison and speed I find tiresize.com adds to any understanding of what any change will have.

Tire Size Calculator

The best tire size calculator. Use our tire size calculator to find tire size specs and suggested tire sizes. Then check prices for all available tire sizes.

tiresize.com

This site also has an interesting tyre pressure guide which gives 275/40/20 pressure as 39psi against an original 235/55/17 44psi.

 

[HowieDog]

The VW Trident wheels, what is the offset etc for these, as yes looking at willtheyfit it looks as though I am totally wrong and will be slower?

Offset is 45 and they are 9 wide
Supermetal specs

 

[HowieDog]

Offset is 45 and they are 9 wide
Supermetal specs

Offset is 45 and they are 9 wide
Supermetal specs

There is 7mm clearance between the tyre and sliding door when opened fully.

 

[HectaTheSpecta]

Hi all,

Lots of good information in this post however what is the definition or calculation for "maximum laden weight of an axle" or where do I find it?

Load rating as per the GOV.UK website ( https://www.gov.uk/guidance/mot-ins...al-vehicles/appendix-b-tyre-load-index-tables ) states the following :

"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."

Which plate? If it is the Tyre rating plate then the attached is what my Cali states which is subjective. It does not specify the "maximum laden weight of an axle" but varying tyre load ratings so my question still stands please, how do I establish this please?

Thanks

 

[B J G]

Hi all,

Lots of good information in this post however what is the definition or calculation for "maximum laden weight of an axle" or where do I find it?

Load rating as per the GOV.UK website ( https://www.gov.uk/guidance/mot-ins...al-vehicles/appendix-b-tyre-load-index-tables ) states the following :

"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."

Which plate? If it is the Tyre rating plate then the attached is what my Cali states which is subjective. It does not specify the "maximum laden weight of an axle" but varying tyre load ratings so my question still stands please, how do I establish this please?

Thanks

View attachment 83245

No, it's the VIN Plate which on my T6 is seen in the engine bay on drivers side on left wheel arch.

The Front & rear axle weights are shown.
Take half of the highest axle figure for an absolute minimum wheel & tyre load capacity.
Some sources say that wheels should have a 25% extra safety margin.
Steel standard wheels are 960kgs load capacity per rim.

 

[Abx]

Meant to say minimum is 810.

 

[HectaTheSpecta]

This is the axel plate located under the bonnet of my 21 plate Ocean, the owners manual will explain which is axle one and two, dived axel number by two to get to the load rating of each wheel.

So for mine minimum load rating of wheels must be 787.5.

View attachment 83246

Thanks Abx!

After I posted I realised it could've been a different plate lol Mine is similar to yours barring the VIN. GOV also provide an explanation on how to read the please, also attached.

So if I take the max weight of an axle, and compare to the gov.uk recommendations on load ratings, I get the following :

1 - 1620 kg > 101 rated tyre
2 - 1575 kg > 100 rated tyre

Am I missing something?

Not a great deal in 1 and 2 but which axle is which?

 

[B J G]

1 is front, 2 - rear

3080 is gross max weight. Note not as muck as Axle 1 + Axle 2

5300 is Train weight max - van plus any trailer/caravan

 

[HectaTheSpecta]

1 is front, 2 - rear

3080 is gross max weight. Note not as muck as Axle 1 + Axle 2

5300 is Train weight max - van plus any trailer/caravan

so 101 and 100 respectively for minimum load ratings is sufficient or am I missing something as I noticed a number of comments with expectations of > 103

 

[HectaTheSpecta]

...Some sources say that wheels should have a 25% extra safety margin.

Thanks , my source is the law and does not stipulate any margins or tolerances which I would've expected have been built into the chartings and figures to begin with.

 

[B J G]

so 101 and 100 respectively for minimum load ratings is sufficient or am I missing something as I noticed a number of comments with expectations of > 103

I'd say 102 as a minimum but better to go higher as Cali's run at full or near full load all of the time.

potholes destroy tyre sidewalls so best to treat 103 as minimum (insurance implications if below that as not to insured spec) higher load capacity is a safety benefit.

As wheels increase in Diameter the rim width usually also increases. This makes them more prone to cracking through impact stress which would need a higher load rating to give a long life.
17" - 7"
18" - 8"
20" - 9"

 

[HectaTheSpecta]

I'd say 102 as a minimum but better to go higher as Cali's run at full or near full load all of the time.

potholes destroy tyre sidewalls so best to treat 103 as minimum (insurance implications if below that as not to insured spec) higher load capacity is a safety benefit.

As wheels increase in Diameter the rim width usually also increases. This makes them more prone to cracking through impact stress which would need a higher load rating to give a long life.
17" - 7"
18" - 8"
20" - 9"

Thanks and agreed, however 100 / 101 does comply with the law, MOTs and Insurance purposes.

 

[B J G]

Ref Insurance I'm just basing it on Cover being based on standard spec as delivered and any change would need to be notified. Going under spec isn't something that I would do or expect Insurance to accept.
Not talking about legal minimums

I'm running 1320kgs rims with 106 tyres. 102 spare.