Rally tires 101 – How to pick the right rally tire for your rally car

We just started selling Federal rally tires which made me realize I should write a post on rally tires! In the US market there are also Maxxis rally tires, Pirelli rally tires, Hoosier rally tires, Dmack rally tires, Black Rocket rally tires, IndySport rally tires, BFG rally tires, Michelin rally tires, MRF rally tires, Dunlop rally tires, Yokohama rally tires and probably a few others I’m forgetting. And these are just the rally tires we have seen in Rally.Build in the past six months!!! So how does one go about choosing which rally tire is best? I am not going to answer that question, I am going to share the things I think about and contemplate when it comes time to buy a new set of rally tires. This is mostly from a stage rally perspective for those competing in American Rally Association, Rally-America, CARS, and NASA Rallysport but many of the concepts can easily apply to SCCA rallycross.
Since everyone likes acronyms let’s call it the SWAPP.
Size
Wear
Availability
Performance
Price

Size – What is the car and how much power. It is silly to use a 215 width Dmack WRC tire on a 100 hp Open Light Impreza just as it is silly to try to run a 175/60R15 on an Evo. Gearing can also be affected by size and running a shorter tire can improve gearing. Wheel well fitment depending on offset of the wheel is also important, more so in recent years with more wheels and users aiming for that stanced look. My general rule of thumb is Group 2 or Open Light is best suited to a 185 or 195 width tire where higher HP Group 5 and Open class machinery can use a 195, 205, or 215. These aren’t rules but more a starting point. If you happen to run a 13 or 14″ tire you are lucky as there are only about two brands even making those tires so you really just find a balance of availability and performance.

Wear – What compounds are available and what compound do you need? Most rally tires sell their tires as soft, medium, and hard compound but the only ones that the compound REALLY means anything is Pirelli, BFG/Michelin, and Dmack. These are the companies testing and developing specialty rubber formulations for rallying. The rest likely take an existing compound from their line up and knowledge from off road, snow, moto, etc. and use it with very minimal testing. If you are using Pirelli or BFG/Michelin it is fairly easy as their compounds are based upon ambient temperature. The rest is out the door. I am of the belief that many of the companies use compounds closer to off road moto tires and that the surface is more important than the temperature. Harder packed surfaces require the soft compound and looser surfaces prefer the harder compounds. We have seen this in real world applications with the soft Maxxis outperforming a medium at a rally like 100AW and the soft Federal showing good wear and excellent grip with the hard Maxxis wearing excessively at the Lands End Hill Climb which is very hard packed and typically 80-90+ degree ambient temps. A medium compound is often a great solution to balance grip, longevity, and multiple events/surfaces.

Availability – We live in a global economy and anything can be found if you are willing to sacrifice time and money. The BFG/Michelin is still considered the best tire available but you now have to order them from Europe and they could easily get into the 4-500 per tire range! Other tires can easily take 3-6 weeks to source or longer. There are two formats supported in the USA. Privateer imported tires such as Dmack, Federal, Dunlop, Black Rocket and MRF that are brought in by small rallyist owned shops in container quantities are usually easy to source though they have a limited supply of tires. Manufacturer imported tires, such as Maxxis, tend more towards a direct to consumer format.

Performance – This is hands down my favorite topic. Let’s start with the most obvious. The tires developed for WRC, that being the top end BFG/Michelin, Pirelli and the Dmack DMG+2 (the fancy 215 width Dmack, not the standard ones) are the best tires for performance. There is no doubt about that, they were developed for the highest level of competition and are priced accordingly. For the other brands, who’s opinion do you trust? Theoretically you could have Driver A, a top level driver tells you that his brand is the best rally tire he’s ever used but half the space on his car is of decals for that brand, another brand was tested and developed in conjunction with Driver B with great results yet Driver C claims that this other brand of tire has the best lateral grip of any tire he’s driven on. Driver A is likely sponsored by the manufacturer so his report is biased. Driver B might have been a top driver in the US with by far the highest budget but does that make him any good at tire development? Driver C makes heavy claims for someone consistently finishing in the bottom half of the pack. I am no more qualified to make any claims about tires or recommendations either yet I constantly am discussing tires with customers. I am constantly collecting anecdotal evidence of my customer experiences and individual performances combined with my prior career in medical research as a biostatistician helps me identify trends. These are about all that we have to go on and usually it guides us more towards what is worse or does not work than anything. We have cut open most major brands to assess construction difference and compare sidewall thickness but even this leads only to hypothetical conclusions, “perhaps the thinner sidewall in this one area is why people have seemed to experience more punctures?” At the end of the day, most brands out there work great for most drivers. The cheapest tires will understandably leave some time on the table but the midrange tires are mostly within 95% of the performance of the best tires.

Price – There are three factors to price. Tire, shipping, and mounting. If you have a local shop like Rally.Build that offers free mounting and saves you on shipping costs then you may just be saving money over that alternative tire. Having an experienced person mounting your tires will save you in the long term. I have seen new rally tires permanently leak at the bead and new rally wheels damaged from inexperienced mounting. The $5 special may be just that. Your local company also supports your local events and having local rally companies is conducive to having more rally events so it is always best to shop local.

Conclusion – What should you buy? You should buy the tire that is going to work best for you based upon your goals. Go volunteer at some events that you are hoping to run in the future and start asking the privateer drivers about tires? What sizes and compounds. Call your local rally shop and find out what they sell and recommend for the events you are doing. I am always available by email and love to talk rally stuff!