Hardware update gained 15% range

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Chewy
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Location: Forest of Dean. UK.

Re: Hardware update gained 15% range

Post by Chewy » Sun May 19, 2019 3:40 pm

TryLean wrote:
Sun May 19, 2019 1:55 pm
BillCB wrote:
Thu May 16, 2019 2:23 am
My earlier post saying skinny tyres have less RR is apparently wrong, according to Mr. Google. Still, Jaguar's own figures clearly show they are more energy efficient.

My comment was based a book I bought many years ago, "Chilton's More Miles to the Gallon", where he advised "hypermilers" to install the thinnest tyres possible and pump'em up as high as possible. This was during the oil crisis in the 1970s and I guess the technology has changed a bit since then!
Assuming that the 18 inch wheels are more efficient -has anyone experimented with tyre pressures? In all my other cars increasing the pressure to the top end of the manufacturers recommended pressures has resulted in better economy -is this true on the iPace?
I always run with around 2psi extra.


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anorak
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Location: Cambs. UK

Re: Hardware update gained 15% range

Post by anorak » Sun May 19, 2019 9:15 pm

Continental Tyres technical dept. state;

reduction in pressure by 0.3 bar (4 psi) - 6% increase in rolling resistance,
reduction in pressure by 1 bar (14.5 psi) - 30% increase in rolling resistance - several percent increase in fuel consumption.

So it will make a difference but not a huge one unless the tyres are inflated way above safe levels.

There are folk on here that over-inflate by a few psi but I don't know if you'd notice any difference in economy or range compared to the recommended pressures.

And a tyre's pressure will increase with temperature when it's driven (as well as with the outside air temperature). I've checked mine before and after a 20 minute run and found they went from 36 psi cold to 40 when warmer.
Last edited by anorak on Sun May 19, 2019 9:18 pm, edited 1 time in total.
I Pace EV400 S, Caesium blue, Oyster leather, 18" wheels
MY19, delivered 01/2019
IMC: S19B_19.40.4-436082 || Telematics: 17.2
Now on its 2nd front EPIC


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anorak
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Location: Cambs. UK

Re: Hardware update gained 15% range

Post by anorak » Sun May 19, 2019 9:16 pm

Haha. Once again beaten to the reply by Chewy.
I Pace EV400 S, Caesium blue, Oyster leather, 18" wheels
MY19, delivered 01/2019
IMC: S19B_19.40.4-436082 || Telematics: 17.2
Now on its 2nd front EPIC


Chewy
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Location: Forest of Dean. UK.

Re: Hardware update gained 15% range

Post by Chewy » Sun May 19, 2019 9:33 pm

anorak wrote:
Sun May 19, 2019 9:16 pm
Haha. Once again beaten to the reply by Chewy.
Making a habit of it :-)


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Thincat
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Re: Hardware update gained 15% range

Post by Thincat » Tue May 28, 2019 11:30 am

Hi FENorway; any news of your hardware range upgrade?

Also, I was watching a Youtube review of the I-Pace in which the Jaguar salesman said that the steering with 18in wheels is significantly lighter than 22in wheels. Has anyone observed that difference?
Cesium Blue HSE no sunroof, air suspension, HUD. Changed 20in wheels to 18in :D .


FENorway
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Location: Norge

Re: Hardware update gained 15% range

Post by FENorway » Tue May 28, 2019 3:29 pm

Thincat wrote:
Tue May 28, 2019 11:30 am
Hi FENorway; any news of your hardware range upgrade?

No. Have not done the upgrade yet.
Wont be the next 3 weeks either.
Will be away at work.

But I can confirm that the steering is much lighter with 245/55r19 compared to the 22". Also drove my sisters e-tron yesterday with 19". Its two different worlds when it comes to steering. Where the I-Pace is agile and responsive, the e-tron is more a magic carpet. But I understand why people buys the e-tron. Its German "Ordnung muß sein" no-nonsense, and with the 19 inch the e-tron seems to consume slightly less than the I-Pace with 22".
Not to mention the lack of noise. The e-tron is by far the most quiet car I've driven.
FE Corris grey light oyster/light oyster Performance 22" 5069 & 18" 1022 19B_19.40.4-436082 and 14.2


Chewy
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Location: Forest of Dean. UK.

Re: Hardware update gained 15% range

Post by Chewy » Tue May 28, 2019 3:37 pm

Thincat wrote:
Tue May 28, 2019 11:30 am
Hi FENorway; any news of your hardware range upgrade?

Also, I was watching a Youtube review of the I-Pace in which the Jaguar salesman said that the steering with 18in wheels is significantly lighter than 22in wheels. Has anyone observed that difference?
Nice find on the video :-)


Reddo
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Joined: Thu May 30, 2019 1:54 pm
Location: Norfolk / UK

Re: Hardware update gained 15% range

Post by Reddo » Thu May 30, 2019 2:25 pm

This is a very interesting thread, I am mystified by that the suggestion that of mass being at a further out radius of the wheel is significant. The rotational inertia of the wheel is surely insiignificant compared to the mass of the vehicle given that the wheels are not spinning and the vehicle is pretty heavy. Surely the biggest factor with larger wheels is likely to be that the 22s increase the ride height of the vehicle relative to the 20s (BTW 255x50R20) would be identical in radius) a higher ride height would massively increase drag at motorway speeds.

Given that iPace generates all of its torque from zero revs would larger radius wheels increase acceleration? I am not sure how the physics work in the real world here, has anyone done some accurate experimentation?


electricfelix
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Location: Amsterdam

Re: Hardware update gained 15% range

Post by electricfelix » Thu May 30, 2019 3:29 pm

I've driven around 20.000 km on 20" Goodyear, and then a ride to Switzerland (from NL) on 18". Especially driving around Swiss, where if you're not on the highway, there's 80km/h max I wasn't even trying to get to 160Wh/km stats all day long(!) - Yes I was taking it slow with a baby on board but never ever have I gotten close to those stats on 20" and then I did try! So I wouldn't be surprised if I repeat that route on 20" and it would get me 180Wh/km stats (but I haven't got the chance yet), it wasn't even good temperatures yet! Anyway, when weather is good range is good.
I think no one should think that the Jag will ever be an ECO monster (unless driven very carefully at low speeds) so why bother with these small tweaks. Just race & enjoy! But, if you want max range, then the decision is easy.


sciencegeek
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Re: Hardware update gained 15% range

Post by sciencegeek » Thu May 30, 2019 3:34 pm

Reddo wrote:
Thu May 30, 2019 2:25 pm
This is a very interesting thread, I am mystified by that the suggestion that of mass being at a further out radius of the wheel is significant.
It may not be the only factor but it contributes a lot (most), I'm sure. People who ride bicycles have figured this out long ago. That's why there are tubeless tires and carbon rims now. I can tell you I feel the difference (and so does anyone who does performance-oriented riding) on a 29er mountain bike between tubeless (virtually no increase in tire mass) vs with inner tube, and same with aluminum vs carbon rims. Huge difference.


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