Rolling Radius for winter AT tyre

Nande2000

IT Fixer
T6 Pro
Hi,
Newbie question. I have a T30 DSG 150 2wd Kombi on order and it will come with 16' Claytons.

I'm looking at a set of All terrain tyres for the summer, I tow a caravan and just need a bit of extra traction for muddy campsites / Festivals.

Question is, what is the best rolling radius / tyre size from a performance point of view ? I don't want to fit spacers, but happy to go up a wheel size if it gives better traction with minimal impact on towing (Torque) performance. Also don't want to invalidate warranty in anyway.
 
The best will be the one you have now. Better traction will be gained with more aggressive tyres.
If you increase the Rolling radius you will reduce your braking power and change your gearing on the road.
Going to a wheel size of 17" or 18"( won't change the rolling radius with the normal size tyre) but may or may not change the number of all-terrain tyres available to you.
 
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Nande2000
Ask your self how often and what frequency am I going to use what ever type of tyre. Can I afford separate wheel and tyre packages. One for doing this and one for doing that. Am I looking for a do it all tyre that might perhaps be not quite as good as tyres that specialise in a more narrow narrow range of conditions.

Firstly we are entering a lock down. Its supposed to last for a month but they have already stated that it could be for longer. There may be additional restrictions placed upon us after the lock down.

As said by Loz your 16" rims are fine no need to change them You could even buy an additional set for off road or winter.. The more powerful T6 have bigger more powerful brakes that require larger wheels for clearance. For some 17" is as small as they can use other might have even bigger after market brakes or want bigger wheels for show and fashion. For you it is not necessary. Usually there is a bigger choice of tyres particularly off road tyres at 16"

If money is tight or its only very occasionally needed the just airing airing down to about 20 psi when on grass will help. I occasionally might go down to 8 psi but it is very risky a tyre could be forced from the rim so care has to be taken. For most people I would not recommend going much below 15 psi. We are just going into winter already frost has been on the ground even in the south. An investment in a good quality set of 4 or 5 All season tyres would not be a bad idea. They have specialise silicone rubber to stay grippy on icy and snow covered roads. The tread is more aggressive than pure summer tyres and they will provide more traction on mud, on wet grass. For a single set of tyres for all year use and a very occasional wet field they are the best investment that most people can make, if that is the use they are putting the tyres to. Look for the 3 peaks sign, these tyres are accepted throughout EU countries as being suitable for winter use.

Some might buy pure winter tyres have two set of rims with 4 or 5 winter tyres and a set of summer tyres much the same as above which actually are also winter tyre but the are more specialised will have 3 peaks pictogram impeded on them. Usually they are put on about now and taken off towards Easter, depending on where someone might live. They could be put on for camping and taken off again perhaps. They are meant for winter and they do not like to get too hot so best policy it not to rag them.

All terrain tyres are specialised tyres for frequent use off road, along tracks have a very much more aggressive tread than any of the above. They thrive on slushy muddy roads pulling up verges and so on. They are made of heavier construction are much tougher and will survive the sort of scuffing that would tear the sidewall of all the above. They can take the abuse that farmers might put them too. They are very suited to driving on wet grass, snow and so on. Like all the above they take to being aired down to improve off road traction. They are not as good usually as any of the above on the road. It is no problem if that is what you want to do but ordinary road tyres perform better on the road usually. Everything is a compromise. Perhaps as with winter tyres 2 set of rims is the ideal, just put your all terrain tyres on when you go away for muddy field use. Replace the with what ever road tyres you have when home. They could be used for winter use if they have 3 peaks pictogram Again, some manufacturers produce All Terrain tyres that have the 3 peak pictogram for legal use on winter roads throughout the EU. There is a fairly big difference between manufacturers product sporting different tread designs. Some are the sworn favourites of many Off Road and Landrover Drivers and have huge endorsements but other brands may be better for some. It all depends on the use they will be put too.

Look around here for what people use many of them will be doing the sort of camping that you will do. Unless you are travelling on very deeply rutted tracks used by tractors and off road vehicles, Then there is no need for bigger diameters to give the additional clearance that might be required. Going bigger might give a slight advantage in mud but we are limited to just how big because of mechanical restrictions. Bigger tyres might allow more clearance when airing down. I have noticed that the more narrow tyres 215 need to be inflated to much higher pressures than wider profiles. Look at the sticky on your door. Lower pressures, allows lower ground pressure reducing that sinking and depressing of the ground. It increase surface contact at extremisms it turns the tyre into a track, the tread bulges out and elongates. After you have done it is important to return to normal pressures for driving on the road, it is a legal requirement. It is dangerous to drive on road with underinflated tyres. It will damage the tyres through heat build up.

Read tyre reviews. Look at the labels, some tyres clear water better than others.



What ever you decide come back and we can all point you to what we each believe to be the best tyre of what ever Genre you decide on.
 
Thanks, the van is coming with All seasons fitted, which will be fine for general and maybe even winter use. I was thinking to buy some steel wheels for a second All terrain set for summer or for when i know we are off caravanning.

If I stick with the 16s then the options seem to be BFG K02s (215/65) or General AT3 - Though for both these the speed rating is under the top speed of the van by 1mph
OR Avon AX7s (same tread pattern as a cooper Discovery AT) of the same spec but H rated speed which is fine.

Are there any others I should consider ?
 
Michelin Lattitude Cross? (17" version shown here) not overly aggressive or noisy.
IMG_0545.jpeg
 
Just in case a different size of rim becomes available to you. I am running on 225/65 R17 which is a slightly larger radius. Most speedometers tend to over-read and our vehicles are no exception. With these tyres I have checked and the speedometer appears to be accurate throughout the range up to the legal UK limit, as far as I can tell. I have heard others say the same also. The BFG AT comes in this size if your mind is set on this particular tyre. For the use that you describe, its over the top, as it is well up to proper and hard off road use. With the speedometer reading spot on, I advise taking care and be very attentive and not to go over the marked speed for the limit at all, as there is no leeway.. Most people are careless with keeping to the marked speed and some parts of the country have zero tolerance. I do not find any disadvantage with being very slightly over size so far as acceleration or braking are concerned. My vehicle an Executive 4Motion is approximately 200 BHP and the small increase in size unnoticed.

BFG also do an AT 255/55 R18 which is bigger again and will make the speedometer under read. This can be corrected electronically. It may just be the case, that the rear wheel arch insert, might just tough slightly at one point to the rear of the arch, I am not sure, it is difficult to say. I am tempted because I often travel along tractor tracks that can become quite deep.

General Tyres AT3 appear to have a more comprehensive range of sizes. The tread is less aggressive . Like the BFG it has the 3 peaks pictogram for winter use From memory only, I recall that the label suggests they are not quite as good on wet roads you will need to look at that if considering.

To check sizes and errors etc Tire Size Comparison
 
Just in case a different size of rim becomes available to you. I am running on 225/65 R17 which is a slightly larger radius. Most speedometers tend to over-read and our vehicles are no exception. With these tyres I have checked and the speedometer appears to be accurate throughout the range up to the legal UK limit, as far as I can tell. I have heard others say the same also. The BFG AT comes in this size if your mind is set on this particular tyre. For the use that you describe, its over the top, as it is well up to proper and hard off road use. With the speedometer reading spot on, I advise taking care and be very attentive and not to go over the marked speed for the limit at all, as there is no leeway.. Most people are careless with keeping to the marked speed and some parts of the country have zero tolerance. I do not find any disadvantage with being very slightly over size so far as acceleration or braking are concerned. My vehicle an Executive 4Motion is approximately 200 BHP and the small increase in size unnoticed.

BFG also do an AT 255/55 R18 which is bigger again and will make the speedometer under read. This can be corrected electronically. It may just be the case, that the rear wheel arch insert, might just tough slightly at one point to the rear of the arch, I am not sure, it is difficult to say. I am tempted because I often travel along tractor tracks that can become quite deep.

General Tyres AT3 appear to have a more comprehensive range of sizes. The tread is less aggressive . Like the BFG it has the 3 peaks pictogram for winter use From memory only, I recall that the label suggests they are not quite as good on wet roads you will need to look at that if considering.

To check sizes and errors etc Tire Size Comparison

The BFGs do have the best tread pattern for mud. Problem is the speed rating is S and my variant requires a T
 
It is only a legal requirement for manufactures to supply tyres with the correct speed rating, construction and use regulations. It is perfectly legal to select tyres under that for the owner. For many years it was difficult to find winter tyres that had high speed ratings, now of course they are available. In the UK 70 mph is the legal max. Unless you travelling along the autobahns at warp factor speed then there is no need to worry. If yo lend your car out or you know that someone else my drive your car irresponsibly the, you can put a sticky on the sun shade or a warning on the speed settings. I believe that our cars electronics can easily (for every one but illiterates like me) from the dashboard instrument cluster via the stalks.
 
It is only a legal requirement for manufactures to supply tyres with the correct speed rating, construction and use regulations. It is perfectly legal to select tyres under that for the owner. For many years it was difficult to find winter tyres that had high speed ratings, now of course they are available. In the UK 70 mph is the legal max. Unless you travelling along the autobahns at warp factor speed then there is no need to worry. If yo lend your car out or you know that someone else my drive your car irresponsibly the, you can put a sticky on the sun shade or a warning on the speed settings. I believe that our cars electronics can easily (for every one but illiterates like me) from the dashboard instrument cluster via the stalks.

Yeah i get that. Problem is insurers take anything other than a 'recommended' manufacturer speed rating to be a modification
 
Yeah i get that. Problem is insurers take anything other than a 'recommended' manufacturer speed rating to be a modification

I have never heard of anyone asking insurers about suitability of tyres. I doubt that they would approve what I would like for breakfast, please do not inform them! I can not see why they would not be suitable but insurance companies are always looking for reasons to charge extra and the girl and boy Fridays in the offices can not answer anything that does not have a tick box. It is entirely up to you. You decide, if you are unsure, then stick to what you believe to be the correct thing to do or wait for someone far more eloquent than me to suggest otherwise and then you may to decide on that. If someone pt motorcycle or agricultural tyres on a super car then I am certain that would be likely to contravene something. i am not qualified to give a letter of compliance and I doubt that few on here are either.
 
Remember that winter tyres often have a lower speed rating and that is why we have a winter tyre speed waring in the MFD so the manufacturer expects there to be certain instances where the tyre may not be speed-rated, so the insurance companies will have to follow the manufacturer's recommendations in this case.
 
Nande2000 from what you have explained to us about your intended use, I can not see why you need tyres such as BFG AT or similar from other manufacturers. The tyres that you already have should suffice, unless you intend doing far more than you have explained. It will save you money and the stress of fitting something that you are unsure about. If you were that concerned about the ultimate traction, then perhaps a 4Motion equipped vehicle might have been or be the better choice. have said that.

Seikel, a German innovator and supplier of off-road equipment, including tyres for the T6 and many other vehicles can advise you. They have to satisfy the exceedingly strict TUV in order to sell and fit their equipment and tyres. The can supply a Letter of Compliance That may satisfy you and your insurers.


I am not sure if you need to purchase tyres from them to have this document or that you only need to purchase the Letter of Compliance.

I really hope that this helps you obtain what you want. There may be tyres categorised as AT that satisfy your requirements but you will need to research that, from the likes of BFG, General Tires, Goodyear, Dunlop, Continental, Toyo, Michelin and others. Good luck, let us now how you proceed.

Loz has experience with Seikel. He may have more to add about them, they are a respected company.
 
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Just another thought!:cautious::sneaky::unsure::D Some insurers are not very keen on any alteration, adaptation or modification of any kind. It may be that you need to look around for another insurer perhaps. An insurance broker may assist you or ask what others do on here when it comes to insurance and modifications.
 
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