Hankook pressures?

[Spireite]

I've just fitted Hankook tyres to my MH - Hankook RA18 109/107S - the weights are 1540 kg on the front axle and 1900 kg on the rear.

 

If you have fitted Hankooks could you give suggestions please for the pressures to give best safety and efficiency.

[Agaric]

That's strange my weights are exactly the same as yours on Hankook tyres, the maximum pressure fo the tyres is 65psi.

 

I'm using 52psi front and 63psi rear.

[JonMac46]

This is what Hankook told me in 2013. My van is 3200kg.

 

After doing some calculations we recommend that you run the front axle with a weight of 1690kg at 52 P.S.I.

 

And we recommend that you run the rear axle with a weight of 1750kg at 54 P.S.I.

[Brian Kirby]

Spireite - 2017-07-14 10:11 AM

 

I've just fitted Hankook tyres to my MH - Hankook RA18 109/107S - the weights are 1540 kg on the front axle and 1900 kg on the rear.

 

If you have fitted Hankooks could you give suggestions please for the pressures to give best safety and efficiency.

You don't say what van you have. We must assume your axle load figures are the result of a visit to a weighbridge. Since Hankook seem willing to give their recommended pressures for load, I'd suggest you contact their technical department, quoting the above details, and obtain their recommendation. One of the respondents above confirms similar axle loads but doesn't confirm the tyres are identical, the other quotes different loads for tyres of unknown size. The former may well be appropriate, the latter almost certainly will not. Why take the risk, when you could have a permanent record of your question and the manufacturer's reply?

[Derek Uzzell]

Spireite

 

As Brian has observed, you have provided in your enquiry no details of your motorhome (2013 Pilote Reference P716 ?) nor of the size of the Hankook tyres, but (based on educated guesswork ;-) ) I assume the tyres are 215/70 R15C as shown in the advert on the following link:

 

https://eco-tyres.com/shop/nt/21570r15-hankook-vantra-ra18-109107s-2/?gclid=CIKv36PRitUCFe8K0wodTwAGGA

 

Only a very few vehicles have a particular make and specification of tyre designed solely for that vehicle. Most vehicles have a size and specification of tyre that the vehicle-manufacturer has chosen as being appropriate, but the make of tyre can (and does) vary even when the tyres are original equipment fitted when the vehicle was built.

 

Consequently, all same-size tyres with a similar specification will have much the same inflation-pressure-to-load values. This means that, if one can obtain inflation-pressure-to-load data for, say, a 215/70 R15C tyre from, say, Avon or Michelin, those data will also apply (near enough for all practical purposes) to 215/70 R15C tyres made by Hankook, Continental, Pirelli, Dunlop or any other make.

 

The most readily available and comprehensive set of data that will include information on tyres likely to be fitted to motorhomes is currently Continental’s 2016/2017 Technical Databook Car>4x4>Van document that can be downloaded from here

 

http://blobs.continental-tires.com/www8/servlet/blob/476070/960c00deff28484e7fbdec87d1d00583/download-technical-databook-data.pdf

 

'Motorhome-suitable’ (Van) tyres are dealt with from Page 72 onwards and 215/70 R15C data occur towards the foot of Pages 78/79. For loadings of 1540kg (front axle) and 1900kg (rear axle) ‘safe’ inflation-pressures would be approximately 50psi and 60psi respectively (3.45bar and 4.15bar approx.)

 

To optimise fuel consumption, the higher the inflation-pressure the better, but using overly high inflation-pressures will impact on handling, braking, steering, tyre-wear and ride comfort. Having said that, it’s much better to err on the high side than the low, as under-pressuring tyres will result in increased fuel consumption, also impact on handling, braking and steering, and (if the under-pressuring is extreme) cause the tyre to overheat to the point that it fails.

 

I’d go for 4bar/58psi (front) and 4.5bar/65psi (rear). 4bar and 4.5bar are easily remembered figures and, although a mite high based on Continental’s data, are not excessively so.

[Agaric]

Just to confirm my tyres are Hankook RA18 215/70/15. The pressure I set them at was from the Continental suggested pressures, with a bit added for extra loading on each axle.

[Spireite]

Thanks for the replies and detailed information.

 

I had Continental tyres on previously and have replaced the front tyres with Hankook.

 

The previous front pressures were 51 psi (3.5 Bar) taken from Continental's guide and I see no real reason why the Hankook should not be a similar pressure but taking your comments into the equation I will increase the pressures to around 58 psi (4 Bar).

 

Does that sound sensible - or not?

[Derek Uzzell]

Michelin used to suggest that - for front tyres - using the ‘safe’ inflation-pressure taken from their pressure-to-load technical handbook and adding 10% provided potential advantages during braking and hard cornering when weight transferred to the vehicle's front wheels.

 

10% of 51 is 5 and 51 + 5 = 56, and 58 is near enough to 56.

 

Motorhomes are not F1 cars and, when you’ve factored ambient temperature and loading variations into the equation, plus weighbridge and tyre-gauge inaccuracy, two or three psi won’t be critical.

 

[Brian Kirby]

Agaric - 2017-07-15 10:54 AM

 

Just to confirm my tyres are Hankook RA18 215/70/15. The pressure I set them at was from the Continental suggested pressures, with a bit added for extra loading on each axle.

 

My bold above. You had earlier said: "That's strange my weights (1540 kg on the front axle and 1900 kg on the rear) are exactly the same as yours on Hankook tyres, the maximum pressure for the tyres is 65psi.

 

I'm using 52psi front and 63psi rear"

 

I'm just a bit puzzled. Converting your pressures to bar, they equate to 3.59 and 4.34.

 

As I read the Continental load for pressure table, the maximum front axle load at that pressure would be 1,615kg, so (assuming your "bit extra" remains below 1,615kg (but how would you know that? :-)) comfortably above your 1,540kg.

 

However, the rear load appears, from the Continental table (using the rear axle single fitment (RA S) line), to require a pressure of 5.0 bar (72/73 psi) - which exceeds the quoted maximum permissible set by Hankook for this tyre. I would suggest you check this with Hankook technical to be sure, as the Conti table appears to suggest these tyres may not be suitable for the actual load - and that you may presently be running them underinflated by 10psi//0.66bar.

 

Could there be a mistake somewhere (including in my reading of the Conti Databook :-))?

[Robinhood]

Brian Kirby - 2017-07-16 11:57 AM

 

However, the rear load appears, from the Continental table (using the rear axle single fitment (RA S) line), to require a pressure of 5.0 bar (72/73 psi) - which exceeds the quoted maximum permissible set by Hankook for this tyre. I would suggest you check this with Hankook technical to be sure, as the Conti table appears to suggest these tyres may not be suitable for the actual load - and that you may presently be running them underinflated by 10psi//0.66bar.

 

Could there be a mistake somewhere (including in my reading of the Conti Databook :-))?

 

I'm not sure where your "Hankook quoted" max pressure figure for these tyres came from, Brian, but the maximum load will be dictated by the load index.

 

I can find a number of Hankook tyres of this model/size with slightly different headline specs (and load indices), but assuming something like Derek's link above to 109/107 rated versions, the (single fitment) figure of 109 would be fine (at a max axle load of 2060kg).

 

From the Continental tables, the recommended pressures for similar tyres at the quoted rear axle weight would be somewhere just above 4 bar (maybe 60psi as Derek's initial 'stab').

 

I think you've made the mistake of using the Continental figures for CP (camping) tyres, which will habitually give you higher recommended pressures (esp. for rear-axle fitment).

[JonMac46]

Mea culpa! In my post above my intent was to show that one can contact Hankook and get recommendations for one's axle loading. Apparently I failed to communicate, even though I included my axle weights with the pressures.

BTW, my tyres are [2013] Vantra 215/70 R15. You can search for the full thread with excellent advice from Derek.

[Agaric]

Brian Kirby - 2017-07-16 11:57 AM

 

Agaric - 2017-07-15 10:54 AM

 

Just to confirm my tyres are Hankook RA18 215/70/15. The pressure I set them at was from the Continental suggested pressures, with a bit added for extra loading on each axle.

 

My bold above. You had earlier said: "That's strange my weights (1540 kg on the front axle and 1900 kg on the rear) are exactly the same as yours on Hankook tyres, the maximum pressure for the tyres is 65psi.

 

I'm using 52psi front and 63psi rear"

 

The max pressure which is written on the sidewall using Continentals figures would give 2060kg max. load.

52psi in the front using Continental figures gives max load of 1725kgs, plenty to cover the OH, who wasn't with me on the weighbridge and extra water in the tank etc.

 

63psi in the rear will give a max of 2010kgs which is close to max axle weight of 2000kg and 1725 for the front is close to the max axle weight of 1750kg.

 

I'm just a bit puzzled. Converting your pressures to bar, they equate to 3.59 and 4.34.

 

As I read the Continental load for pressure table, the maximum front axle load at that pressure would be 1,615kg, so (assuming your "bit extra" remains below 1,615kg (but how would you know that? :-)) comfortably above your 1,540kg.

 

However, the rear load appears, from the Continental table (using the rear axle single fitment (RA S) line), to require a pressure of 5.0 bar (72/73 psi) - which exceeds the quoted maximum permissible set by Hankook for this tyre. I would suggest you check this with Hankook technical to be sure, as the Conti table appears to suggest these tyres may not be suitable for the actual load - and that you may presently be running them underinflated by 10psi//0.66bar.

 

Could there be a mistake somewhere (including in my reading of the Conti Databook :-))?

 

 

The 65psi for the tyres is written on the sidewall which is 2060kg load.

 

My 52psi using Continentals figures gives a load of 1725kgs which is close to the max axle load of 1750kg

 

My 63psi gives a load of 2010kg which is close to the 2000kg max axle weight.

 

The extra which I added more for the front, one the OH was not with me at the weighbridge extra 51kg

extra water and diesel, all bases covered, took some weight off the back axle so I keep close to the 3500kg max weight, if I'm over the weight at times the tyres are OK and if I get officially stopped I rekon I'm still under 3675kg and water is easily dumped.