Rally or gravel wheels and tires

[zlatan]

I have a 911 sc that I love driving on gravel and dirt roads. I also use it almost every day on the street. This winter I put studded Nokian Hakkapeliitta 9 and boy am I having a lot of fun. I am the only adult in my city wishing for more snow. So for the next summer I have been thinking of putting more aggressive off road tires and realized that truck tires would give me a good balance in between gravel performance and street durability. Currently I have 16" Fuchs but I think I need to go smaller diameter as truck tires are usually taller profile and may touch the oil lines under the front passenger fender. Also if I ever decide to go to the rally tire 15" rims seem to have more options.

Can you please please give me any suggestions on wheels and tires I should buy for mixed gravel pavement use.

Here is the photo of my toy in front of work on a -20 day.

[Canada Kev]

Are you in Edmonton?

Before you make up your mind on wheel size, perhaps you should decide exactly which tires you want. There are a limited number of off-roadish tires available in smaller sizes. For example, BFG A/T's are available in 215/75-15 at about 27.5" diameter while they are also available in 215/65-16 at 27" diameter. So if you got 15 inch wheels and decided on that tire, you would be stuck with a choice that was half inch larger in outside diameter at the smallest size.

You could also lift your car a couple inches to make some room and give yourself some more ground clearance.

[356911930]

Zlatan,

Here are some widened steel wheels 7 x 15 you may be interested in.


FS 7x15 Widened Steel Wheels


Rahl

[rbogh901]

I don't know how well a 27 or 28" tire would fit but I know it's been done.

[chris_seven]

You will not really find a tyre that is a decent compromise between Asphalt and Gravel.

If you use a Gravel Tyre aggressively on Asphalt you will suffer as the blocks will deform and they tend to lose grip quite suddenly. You will also wear the corners of the tread blocks very quickly and this will then severely compromise the tyre's gravel performance.

In my experience a typical M+S Gravel Tyre would be useless after 25 competitive miles of Asphalt.

Gravel tyres also tend to be much harder and have stiffer sidewalls as they rely much more on mechanical grip. They tend to be designed to spin more and cut through the loose gravel so that they find a hard surface. Tread patterns tend to be open so they don't clog.

Asphalt tyres generally have softer sidewalls so that the extra flexibility helps them grip by 'sticking' to the road surface. Tread patterns are minimised so that the maximum rubber contacts the road and they work best when they don't spin.

A very good Asphalt tyre such as a TB15 is very poor on Gravel and at speed would be prone to puncture and frankly dangerous.

Good Gravel Tyres on a 911 tend to have a useful or 'competitive' life of around 50-60 miles depending on ambient temperature.

On gravel we currently use DMack DMG2 tyres on our Rally Car - 195 on the front and 205 on the rear.

Gravel Tyres

On Asphalt we use Kumho V70 Ecsta Tyres in Medium or Soft Compound in the wet and soft compound ECSTA C03 in dry conditions

Motorsport - Kumho Tyre UK

We use Cookie Cutters on Gravel as the forged Fuchs tend to bend and we use Magnesium Minilites on Asphalt.

The 'Hakka' is really a Snow tyre and not too good on Gravel.

[Esa911sc]

I'm using 205/55R16 Hankook euro winter tyres on gravel in my Regularity Rally SC. I have now driven with them maybe 5kmiles and now it looks like rear tyres only have 5mm pattern left.
These tyres are sold in mid Europe (Germany etc) and they have harder compound than nordic non studded winter tyres.
In winter I'm using Hakka 7 studded 195/65R15 on cookies.

[Cevan]

Can I just say bravo for driving your car in the winter. I'm too afraid with all the salt they put on the roads here in New England.

[Jp-oh]

I can attest that studded hakkas and aircooled 911s are a special kind of hilarious fun. Later in the winter get it on a frozen lake.

[3literpwr]

I’ve generally only run Michelin or Pirelli mediums in the states on actual stages. Most of the tires I have run seem like they wouldn’t last a summer but I’ve never tried. Back in the mid 2000’s. We raced against the head of tech for Rally America who, at the time, was running a 500hp mustang. If memory serves me, he ran BFG all terrains as even hard compound gravel tires got destroyed by the wheel spin. BFG’s are prone to flats, but that might not be an issue here as it’s not a competition car.

[zlatan]

Thank you for great suggestions guys.
Canada Kev I live in Regina, Saskatchewan. Your diameter answers are super useful. I didn't consider that before.

Cevan as far as the salt on the road goes we are lucky that they don't salt the roads in Saskatchewan. They just put sand for traction so it is a lot easier on the cars. I am a bit worried driving it in the winter but fun out ways the worry and what's the point of owning the car if I can't have fun in it.

I am not planning to drive it aggressively on the pavement with the gravel tires. I just want to have an opinion to go to work with the car without swapping the tires. For tarmac racing I will use different set of wheels. I am not planning to race often at all I just love driving on the country roads and that is the main purpose for the gravel tires.

I can't wait for the lakes to freeze a bit more to take Hakkas on the ice.

[Canada Kev]

[QUOTE=zlatan;9822167]Cevan as far as the salt on the road goes we are lucky that they don't salt the roads in Saskatchewan. They just put sand for traction so it is a lot easier on the cars. I am a bit worried driving it in the winter but fun out ways the worry and what's the point of owning the car if I can't have fun in it. /QUOTE]

Sorry to be the bearer of bad news: they put salt in the sand/gravel mix to keep the moisture in it from freezing the grit into big chunks and jamming up the spreading equipment. It's no where near as much as they use in Ontario, but it's still there. Just wash the car lots.

[rbogh901]

Originally Posted by Canada Kev

, BFG A/T's are available in 215/75-15 at about 27.5" diameter while they are also available in 215/65-16 at 27" diameter. So if you got 15 inch wheels and decided on that tire, you would be stuck with a choice that was half inch larger in outside diameter at the smallest size.

You could also lift your car a couple inches to make some room and give yourself some more ground clearance.

How easily can you expect to fit a 27.5 inch diameter Tire? Is this realistic?

[zlatan]

Originally Posted by rbogh901

How easily can you expect to fit a 27.5 inch diameter Tire? Is this realistic?

I tried to put 225 60 16 (26.6" diameter) on the front and regardless of how much I lifted it it rubbed the oil tube under the passanger fender when turning the wheel fully to the left. It was very slightly and I didn't want to mess with it so I went to a smaller winter tire. I am pretty sure that moving the tubes would allow for at least an inch or to larger tire.

I am also interested in seeing how others have solved this challenge.

[Canada Kev]

A 225 wide tire is too much at that diameter.

Lee Keen seems to be able to manage it on his "Safari" cars. The ones like this one and his red car have BFG A/Ts, so it can be done. You an see on the second picture that the bumper ends have been trimmed slightly. Maybe also check up on the Luftgekult car and see what they might have done.

[Canada Kev]

The tires that Leh Keen use on his personal car are BFG AT KM2 in 215/65-16. Here's a picture off a video and a blow up that shows the tire size.