john snoo · Mar 31, 2020

ha, yes i do have a mate who can fit em, but me being me, i end up bunging him more notes than i would probably have to give the apes at KwikFuk

Yes, re the widths of the wheel - I think I am right in saying 235/70/16 is the LR recommended standard for their 7J D2 wheels. So 245 would probably fit (as I know you can usually pinch 10mm) but not sure if that's naughty or not, if it needs insurance notification or not, and if it will gain/lose me anything over the 235s. I am probably just "chasing tread", a bit like people "chase megapixels" on security cameras, without realising that security tends to be more important at night, and higher megapixel CCTV cameras drastically reduce in night vision ability as the pixel count goes up! So there is a sweet spot of around 2mp to 3mp, but once you get to 5mp to 8mp (4k) you lose a load of night time clarity, just so you can have more detail in daytime when the thieving scum are tucked up in bed

. I fear I may be doing that wanting 245. Just seems quite a jump down from 255 to 235, but that jump could bring me as much benefit as losses. I would suck it an see, but at £150 a corner, I can't really do that

sierrafery · Mar 31, 2020

john snoo said:
Just seems quite a jump down from 255 to 235,

If you are so ''obsessed" about 255 then fit the std 255/65/16

john snoo · Mar 31, 2020

I'm not obsessed really, just curious what (if any) noticeable difference it will mean behind the wheel.

Am I right in thinking 235/70 will have bigger sidewall than 255/65?

sierrafery · Mar 31, 2020

Can't be too much difference cos the circumference is only 8mm bigger so 0.34% difference in side wall too... why dont you use a tyre size comparitor for such dillemas?

Stanleysteamer · Mar 31, 2020

john snoo said:
I'm not obsessed really, just curious what (if any) noticeable difference it will mean behind the wheel.

Am I right in thinking 235/70 will have bigger sidewall than 255/65?

Do we really have to give you a maths lesson?
do the following:
(235 x 70)/100 = x
(255 x 65)/100 =y
if x is bigger than y than you are right, if not you are wrong!

you are wrong!

Dippypud · Mar 31, 2020

john snoo said:
I'm not obsessed really, just curious what (if any) noticeable difference it will mean behind the wheel.

Am I right in thinking 235/70 will have bigger sidewall than 255/65?

And why would you care ?

What are you trying to achieve ?

john snoo · Mar 31, 2020

Stanleysteamer said:
Do we really have to give you a maths lesson?
do the following:
(235 x 70)/100 = x
(255 x 65)/100 =y
if x is bigger than y than you are right, if not you are wrong!
you are wrong!

Whilst it appears to be a rhetorical question, the answer is actually yes! (Well, no you didn't "have" to give me a maths lesson, but I clearly needed one!) I had no idea that was how to work that out! I know how stupid it must sound, but I have lived an entire lifetime believing (wrongly) that the second figure was the profile/height of side wall. That's a huge amount of programming and it's hard to shake. I would have bet my life on it that the 70 would have a bigger sidewall. Dumb as it sounds, that's quite a shock to learn different!

sierrafery said:
why dont you use a tyre size comparitor for such dillemas?

- Now I now such a thing exists, I will!

Dippypud said:
And why would you care ?

- I am new to this. I am nervous of finding out (after spending a lot of money) that going from 255/55/18 to 235/70/16 will make a BIG difference to road holding, handling, stopping, or a raft of other "unknown unknowns". That's what I am basically trying to "achieve" - knowledge of what to expect in differences on the road, from someone who has walked this walk (unlike me) and can say for instance "it will roll around like a boat" or "you wont notice any difference except on the ragged edge" or...... any other unknown unknown. The problem is I don't know what I am trying to find out, because I don't know what there is to find out, at least not until spending the best part of a grand, at which point I have to live with whatever it turns out like! That is the reason why I am not just pulling out the Amex and grabbing the first idea that comes to mind. I did that once already, once bitten.....

Andy J · Mar 31, 2020

john snoo said:
I'm not obsessed really, just curious what (if any) noticeable difference it will mean behind the wheel.

Am I right in thinking 235/70 will have bigger sidewall than 255/65?

Just throwing my bit in I have had a K reg 3.5 disco a R reg 3.9 and now a W reg TD5 all have had 255/70/16 with standard springs no ACE great ride only rubed the front arms on full lock.

sierrafery · Mar 31, 2020

john snoo said:
- Now I now such a thing exists, I will!

use this https://www.tyresave.co.uk/tyre-size-calculator/

sierrafery · Mar 31, 2020

Andy J said:
now a W reg TD5 all have had 255/70/16 with standard springs no ACE great ride only rubed the front arms on full lock.

And now a question which in most cases remained unanswered to me by those who fitted biggher than std tyres and were happy with the ride: How much is your EGT under heavy load ?

john snoo · Mar 31, 2020

sierrafery said:
use this https://www.tyresave.co.uk/tyre-size-calculator/

- Oh, in that case yes i have been using those. But they don't state the sidewall size. I was using one of those to keep as close to the 29" standard overall diameter as poss. I think I am seeing why my questions about sidewalls are causing a bit of frustration! I just did those calculations on other tyres, such as this one https://www.camskill.co.uk/m64b0s27...Eff_:_F_Wet_Grip:_B_NoiseClass:_2_Noise:_74dB and I see even that only changes the sidewall by a matter of 5-6mm, which is nothing compared to what I had the silly idea of thinking it would be!

So... sod the sidewall, that seems fairly consistent on the 16" wheels, so i just need to decide the tyre width. And that's kinda where I was a few posts ago, regarding how that extra 10mm or 20mm surface contact affects the ride on the road. Having said all that, I have organised a set of 16" wheels now and they have worn 235/70/16 tyres on, which I think means they will be 7J, so the 255 widths are out of the question I think anyway now. I could still consider that 245 though. More fuel used, more grip, thats about my best guess at this point. For same price, my Yorkshire heritage might be coming out, as it 'feels' like a better deal, more rubber

Andy J said:
Just throwing my bit in I have had a K reg 3.5 disco a R reg 3.9 and now a W reg TD5 all have had 255/70/16 with standard springs no ACE great ride only rubed the front arms on full lock.

Thanks - yes that was the kind of comments I was hoping for, just basically recommendations as I am running blind here. I have ACE, and I now have 7J wheels lined up so 255 is beyond my wheels anyway, but appreciate the input thanks (to everyone)

john snoo · Mar 31, 2020

sierrafery said:
And now a question which in most cases remained unanswered to me by those who fitted biggher than std tyres and were happy with the ride: How much is your EGT under heavy load ?

You have mentioned this a few times now. I am gonna read up on this even though it shouldn't affect me with standard sizes, curious to know what the effect of higher EGT is... great fun learning innit!

discool · Mar 31, 2020

john snoo said:
I'm not obsessed really, just curious what (if any) noticeable difference it will mean behind the wheel.

Am I right in thinking 235/70 will have bigger sidewall than 255/65?

It’s time to start thinking about the cons of the the larger tyre, such as its not standard factory fitment to the disco, therefor the rated speed and load is less, as shown in a tyre u linked, not being a factory fitment the insurance would like to know.
If there was a serious accident due tyre failure or any thing else after the ‘forensics’ the driver could be left without insurance and a pending prosecutions. As we have seen with tv/newspapers reported court cases.

Stanleysteamer · Mar 31, 2020

You Yorkshire too? There's a lot of us on here!

sierrafery · Mar 31, 2020

john snoo said:
i have been using those. But they don't state the sidewall size.

None of them gives you such data cos they give you the difference in diameter so with just a bit of logic you can figure out what's the side wall difference as it's the same as the difference in the diameter

Dippypud · Mar 31, 2020

john snoo said:
Whilst it appears to be a rhetorical question, the answer is actually yes! (Well, no you didn't "have" to give me a maths lesson, but I clearly needed one!) I had no idea that was how to work that out! I know how stupid it must sound, but I have lived an entire lifetime believing (wrongly) that the second figure was the profile/height of side wall. That's a huge amount of programming and it's hard to shake. I would have bet my life on it that the 70 would have a bigger sidewall. Dumb as it sounds, that's quite a shock to learn different!

- Now I now such a thing exists, I will!

- I am new to this. I am nervous of finding out (after spending a lot of money) that going from 255/55/18 to 235/70/16 will make a BIG difference to road holding, handling, stopping, or a raft of other "unknown unknowns". That's what I am basically trying to "achieve" - knowledge of what to expect in differences on the road, from someone who has walked this walk (unlike me) and can say for instance "it will roll around like a boat" or "you wont notice any difference except on the ragged edge" or...... any other unknown unknown. The problem is I don't know what I am trying to find out, because I don't know what there is to find out, at least not until spending the best part of a grand, at which point I have to live with whatever it turns out like! That is the reason why I am not just pulling out the Amex and grabbing the first idea that comes to mind. I did that once already, once bitten.....

That's because it a ratio and not a number as such ...

It's the ratio of the sidewall height to the width ...

Stanleysteamer · Mar 31, 2020

Dippypud said:
That's because it a ratio and not a number as such ...

It's the ratio of the sidewall height to the width ...

Wonder if Landies would look better if constructed following the Golden Ratio!

john snoo · Mar 31, 2020

discool said:
It’s time to start thinking about the cons of the the larger tyre....

Thanks. Yes that's a very good point and one I am pretty wary of (live and learn). Trouble is I am not 100% clear on which tyres you'd call "larger". I assume you're only talking about what people refer to as 'over size', i.e. bigger than LR specs? In which case I should be a legal beaver with 235/70/16 or various others mentioned so long as they are on the correct wheel width (7J or 8J). The funniest thing of all is my 04 Disco2 did (I am pretty sure) come with the 18" wheels as standard. But I wonder what the insurance database would say about that, or VOSA etc, as if you go on Camskill and enter my reg, it doesn't offer any 18" tyres cos it thinks my vehicle should have 16" tyres, hence 16" wheels. Interesting stuff, but yes, good advice thanks. I don't intend to give those slimey snakebelly insurance types a single friggin whisker to dodge a claim, I work for me, not them

Stanleysteamer said:
You Yorkshire too? There's a lot of us on here!

Ha, aye lad. Hornsea/Withernsea originally.

sierrafery said:
None of them gives you such data cos they give you the difference in diameter so with just a bit of logic you can figure out what's the side wall difference as it's the same as the difference in the diameter

There you go again making me look like a mucking foron. Leave that to me, I don't need any extra help

Stanleysteamer said:
Wonder if Landies would look better if constructed following the Golden Ratio!

Mine drives better if I drive it after a golden shower, if that's anything to go by.

Dippypud · Mar 31, 2020

Stanleysteamer said:
Wonder if Landies would look better if constructed following the Golden Ratio!

The Series by Fibonacci ...

john snoo · Mar 31, 2020

Wish I could turn this into a poll....

1. 235/70/16

2. 245/70/16 (IF that's not non-standard for insurance purposes, or i suppose i could just inform em)

3. 255/65/16

Votes? (for mainly road, wanting comfort and gentle ride with a bit of bumpy stuff now and then).

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