[Manuuj]

I was thinking about my Fuel Efficiency figures today. I could not imagine why i wasn't getting atleast 10 kmpl within the city.
It then dawned on me that the LARGER DIAMETER tyres I have installed have affected my ODOMETER readings.

The odometer and speedometer are calibrated for the tire circumference (determined by its outside diameter) chosen by the manufacturer for their car model. There are often a few different sizes that could be substituted which have the same circumference and would therefore not affect the accuracy of the odometer and speedometer. If a tire having a larger or smaller outside diameter is substituted, the odometer and speedometer will no longer read accurately because the tire will rotate a different number of revolutions per mile than the tire chosen by the manufacturer.

Basically my Odometer is showing fewer kilometers run than ACTUAL kilometers run.
So basically for every 155 km I've actually travelled it only showing as 150 kilometers traveled. Therefore when i divide the Number of Kilometers travelled by Fuel Quantity used i am actually dividing by a lower number of kilometers than i have actually travelled. This in turn gives me a lower FE figure.

But the thing is the percentage difference in "Kilometers Recorded" VS "Actual Kilometers Traveled" isn't so much as to drastically improve the FE Figures by very much.







Also larger diameter wheels make the engine work harder as more Force is required to spin a larger diameter wheel/tyre than a smaller diameter one. That could also be a factor in my lower FE figures.

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[Trojan]

Originally Posted by Manuuj

I was thinking about my Fuel Efficiency figures today. I could not imagine why i wasn't getting atleast 10 kmpl within the city.
It then dawned on me that the LARGER DIAMETER tyres I have installed have affected my ODOMETER readings.

Also larger diameter wheels make the engine work harder as more Force is required to spin a larger diameter wheel/tyre than a smaller diameter one. That could also be a factor in my lower FE figures.

.

That is some absolutely crystal clear calculations there!! And you are absolutely right, though its common to state that wheels will have an impact on FE, no one really bothers to get into the Math of how!

But looks apart, how has been your experience with these tyres with respect to on-road and off-road performance: braking, traction etc.

I have been using the stock size Geolander AT and while they feel a bit undersized for the vehicle, the highway and off-road performance has been stellar.

[vigneshkumar31]

Originally Posted by Manuuj

I was thinking about the tire will rotate a different number of revolutions per mile than the tire chosen by the manufacturer.
. Therefore when i divide the Number of Kilometers travelled by Fuel Quantity used i am actually dividing by a lower number of kilometers than i have actually travelled. This in turn gives me a lower FE figure.
.

.

The first fact is absolutely correct. When we upsize or downsize because of the tyre dia difference , one has to recalibrate both speedo/ odo. That’s the fact, as you rightly pointed out.

But your upsize is off not way beyond 3 percent so roughly shouldn’t change the overall effect much.

Is it more to do with the tread pattern and running RT tires on the road primarily? Which is way more knobby and aggressive tread than normal HT or even AT. That would be a big factor because the contact patch is way different and hence friction and mileage.

[shan2129]

Hey Guys,

It could be the tread pattern, upsize/downsize, etc. However, FM is diligently saying that the FE will improve drastically after the first service.

I took the delivery on 30th December, completed 4k kms after that. On my recent trips I recorded an FE of 5.6. (Bangalore to Pondicherry took 2 tank full plus 2000 bucks of fuel) and I am not even counting the 15 litres that FM says is the reserve)

[Manuuj]

Originally Posted by Trojan

But looks apart, how has been your experience with these tyres with respect to on-road and off-road performance: braking, traction etc.
.

The tires have excellent wet and dry grip. They are not noisy like Mud Terrians. Plan to get these for my Endeavour also when i replace the Falkens. Earlier was planning on getting Highway Terrains for the Endeavour since all the offroad stuff will be with Aserix but now i feel I'd rather have the flexibility of having the option of taking the Endeavour offroad as well. I've only driven the Radars 1800 kms though so still early to give a definitive answer.

Originally Posted by vigneshkumar31

But your upsize is off not way beyond 3 percent so roughly shouldn’t change the overall effect much.
Is it more to do with the tread pattern and running RT tires on the road primarily? Which is way more knobby and aggressive tread than normal HT or even AT. That would be a big factor because the contact patch is way different and hence friction and mileage.

The tread pattern is like an aggressive All Terrain tyre. Same as BFG's KO2. I've read that the max allowed tyre upsize is upto 2%. Anything more starts having an impact. I was very careful not to go in for 265/70/R16 as these i knew would have a severe impact on mileage due to the increased width. The 245/75/R16 give the same diameter advantage as the 265/70/R16

I wasn't aware at the time that the 1 inch greater diameter would also impact fuel economy. That said i still would have gone for the 75 ratio and especially these Radar tyres for the 1 inch extra ground clearance as well as the beefy look they impart. They are also going to much superior offroad to the stock Ceats.

Originally Posted by shan2129

Hey Guys,
I took the delivery on 30th December, completed 4k kms after that. On my recent trips I recorded an ...5.6...

Big Gulp!! 5.6 kmpl!?! Yikes that is alarmingly low. Unless you were towing an Airbus i would be very concerned. Checked the Brakes i presume? Please do a full tank and check once again. Also try to upshift at lower RPM. Somewhere around 2000 rpm. Maybe that would help.

But still... 5.6 kmpl..

[amol4184]

Low FE might not be too much of a worry for 3 Door model but for 5 D model it will be a matter of concern for prospective owners in my opinion. The 5 D model can and will become the only car in a household unlike 3 D which is mostly a 2/3rd vehicle, and owners having other more general purpose vehicles.

Will be eagerly awaiting for FE figures from @Manuuj post the first service narrative that FM is pushing.

[msk_kapoor]

Originally Posted by Manuuj

Earlier was planning on getting Highway Terrains for the Endeavour since all the offroad stuff will be with Aserix but now i feel I'd rather have the flexibility of having the option of taking the Endeavour offroad as well.

Manuuj, is this because you still are not comfortable with Gurkha's to be fixed issues that you want to have Endeavour as stand by option or you are convinced that Endeavour is better that Gurkha for selected off-road conditions? Or you just want to enjoy the power and capabilities of Endeavour also along with Gurkha.

Personally i was thinking that Gurkha's USP is its off-road capability and already the multiple issues coming out of new owners are little alarming, hence have asked the above query. Do you feel somewhere that this version was a little off-road capability compromised by FM to accommodate the highway comforts?

[Bibendum90949]

Originally Posted by Manuuj

Big Gulp!! 5.6 kmpl!?! Yikes that is alarmingly low. Unless you were towing an Airbus i would be very concerned.

or the Boeing 747? Did he tow your "747"

[shan2129]

Originally Posted by Manuuj

Big Gulp!! 5.6 kmpl!?! Yikes that is alarmingly low. Unless you were towing an Airbus i would be very concerned. Checked the Brakes i presume? Please do a full tank and check once again. Also try to upshift at lower RPM. Somewhere around 2000 rpm. Maybe that would help.

But still... 5.6 kmpl..

I have checked all possible scenarios, cannot comprehend the 5.6. FM still says the figures are very possible and will improve after service.

Not the Airbus or Boeing, however I did tow a locomotive train between banaglore and pondicherry

Had a talk with FM support engineer, they are going to send an executive at my place to diagnose the issue tomorrow. Will update after that

[Poitive]

Originally Posted by Manuuj

I was thinking about my Fuel Efficiency figures today. I could not imagine why i wasn't getting atleast 10 kmpl within the city.
It then dawned on me that the LARGER DIAMETER tyres I have installed have affected my ODOMETER readings.

Manuuj bro, besides the circumference causing an odometer error, the bigger factor at play is likely to be the following. Please check and consider:
1. Increased weight of the alloys (?)
2. Increased weight of the tyre.
3. Tyre tread and compound.

Increased weight of the rim and tyre makes a significant difference to FE. It is not the same as carrying as much weight inside the cabin. The weight of the wheels is a direct load on the engine system, unlike the carried weight on something that is on wheels.

Tread and compounds have a lot of impact on rolling resistance; again something similar in effect to the direct weight mentioned above.I believe tyres also have a fuel efficiency rating based on that (IIRC EU labeling mandates that).

With the above two, I wouldn't be surprised with a 10-15% or even 20% drop in FE.

PS: Since you're on good terms with thr Force Motor guys, it might be worth checking what tyre pressure they recommended with your tyre setup.

[ThatBalenoGuy]

Hey @Manuj, You can totally see if you can source compatible Free-wheeling Hubs.
I believe they will take off a lot of wear and tear that goes to the moving parts connected to the front axle when in 2WD mode.

More importantly, it will give you a better FE. You can always step out, lock them and then do offroad business.

REF:

https://youtu.be/141TLb8arIw

[Shonith]

Originally Posted by //M

Looks like I spotted our

I have seen a lot of Gurkhas on the road. It's actually not that big. It has the height to its advantage. Lenght wise It's a small car. Looks like any mid sized suv. So in reality it doesn't dwarf a fortuner.

[Manuuj]

Originally Posted by msk_kapoor

Manuuj, is this because you still are not comfortable with Gurkha's to be fixed issues that you want to have Endeavour .....Do you feel somewhere that this version was a little off-road capability compromised by FM to accommodate the highway comforts?

No i basically want to keep the option of having the Endeavour do some offroad duty if required. None of the issues that have occurred so far in my Gurkha or even others are catastrophic in nature. The problem has been diagnosed and a solution implemented. I guess we early lot are the "Beta Testers".
Later Gurkha owners owe us a party!

This version has the same suspension setup of the earlier 2.6 liter verison. Only the 2.2 liter Extreme came with Solid Front Axles.
That though was great offroad wasn't good on road. The Suspension setup in the 2021 Gurkha is superb onroad and should be good offroad as well. I just wish they would have given more ground clearance.

Originally Posted by shan2129

Had a talk with FM support engineer, they are going to send an executive at my place to diagnose the issue tomorrow. Will update after that

Any update after the visit of the support engineer?

Originally Posted by Poitive

Manuuj bro, besides the circumference causing an odometer error, the bigger factor at play is likely to be the following. Please check and consider:
1. Increased weight of the alloys (?)
2. Increased weight of the tyre.
3. Tyre tread and compound..

The alloys weigh less than steel rims and should be the same as the stock Neo Alloys.The tyres weigh about 3 kgs more than the Ceats.

I don't know if that much really is enough to impact fuel economy so severely. In my Fortuner i only lost about 0.5 to 1 kmpl after i changed from 265/65/17 to 275/65/17. Here the height and width both had gone up in Obelix. With Asterix only the height has gone up 3.4% which isn't so much while the width is identical.

Another important point is that even the Gurkhas that are running completely stock alloys and tyres are facing the same FE issue as well, not just mine with the altered/upgraded setup. Something sure is amiss..

Originally Posted by ThatBalenoGuy

Hey @Manuj, You can totally see if you can source compatible Free-wheeling Hubs.
I believe they will take....

I would love to have Free Wheeling Hubs on Asterix. Any idea where i can source them? I had even asked Force about these during the buying process but they said it wasn't an option.

Originally Posted by Shonith

I have seen a lot... Lenght wise It's a small car. Looks like any mid sized suv. So in reality it doesn't dwarf a fortuner.

I beg to differ. The Gurkha cannot be compared to a mid sized SUV. I own an Endeavour and when parked next to Asterix it does look much smaller.




Even when one crosses a Fortuner Endeavour type of SUV on the road one feels seated much higher up, which as you agreed was a height advantage. But visually the Gurkha (even though its a 3 door) looks much larger than the 5 door Suv's like the Endeavour or Fortuner. Once the 5 door full sized Gurkha hits the road it will take care of the length disadvantage that th 3 door has vis a vis the Fortuner/Endeavour.

There was some issue also being raised about it being too high to fit into Mall parking basements. I have taken it into basements a number of times and not faced any problems as evident from these pics taken at Ambience Mall, Vasant Kunj, New Delhi.

[Poitive]

Originally Posted by Manuuj

The alloys weigh less than steel rims and should be the same as the stock Neo Alloys.The tyres weigh about 3 kgs more than the Ceats.

I don't know if that much really is enough to impact fuel economy so severely. In my Fortuner i only lost about 0.5 to 1 kmpl after i changed from 265/65/17 to 275/65/17. Here the height and width both had gone up in Obelix. With Asterix only the height has gone up 3.4% which isn't so much while the width is identical.

- Another point worth considering would be how the extra load would impact a high torque vehicle vs a relatively low torque vehicle. I imagine lesser impact on a vehicle with significantly higher torque.

- Further, though only probably a tiny amount, the impact of wind resistance too would be more in a less aerodynamic vehicle.

- It might not be enough to explain the drop though. What the right air pressure in this setup would be worth checking, given the big impact of air pressure on FE.

About the size issue:
The pic of your cars placed at roughly equal distance from the camera gives a lot more realistic comparison as compared to the earlier one from the road, where the Asterisk is a lot closer than the Fortuner.

[Shonith]

Here are dimension comparison of the Gurkha with some common SUVs. I am only focusing on L X W X H, not on accessories, not on roof racks. The below dimensions are all taken from the official website of the each car maker, Except for the Endeavour as Ford didn't have an E-brochure in their website.

1. Dimension of the Gurkha.
From the attachment the lenght and width fall in the ball park of most cars sold in the Indian market. There is nothing oddly special about these 2 figures. However the height of this offroader is very tall at 2075mm. I couldn't find any other car sold in the Indian market with height greater than this. So there is no doubt Gurkha is a tall boy. If you fellow BHPians know any other car which is taller than this kindly do share.

2. Dimensions of the Fortuner.

Fortuner is longer and wider than the Gurkha.

3. Dimensions of the Endaevour.

Endaevour is the longest among all the cars I took in this comparison at 5060mm. However it is smaller in width by just 24mm (2.4cm) and height compared to Gurkha. This might explain why the above endaevour owner felt his Gurkha was bigger.

4. Dimensions of Creta.

I had seen plenty Gurkhas on road. I always thought it was close to the Creta than the Endaevour or Fortuner. Dimension wise the Creta is considerably longer than the Gurkha. However the width and height is less. So in reality a car that's smaller in lenght and is marginally wider by 22mm (2.2cm) than a Creta, Cannot dwarf a Fortuner or an Endaevour. Unless you believe it does. If so, you might as well consider that a Creta might dwarf a Fortuner and Endaevour as well if you raise it, there is no harm in believing so.

5. Dimensions of New Thar

So a 3 door and a 3 door comparison. The Thar is wider than the Gurkha. Lenght wise the Thar is really short sub 4m actually.
From the above comparison the only aspect the Gurkha really feels big is the height. Width and lenght is still very close to the mid sized SUV sold in the Indian market the facts prove it irrespective of how the visual features make you feel.