When you buy a new motorcycle, the tyres it comes on ex-factory might have the same pattern name and design as the ones you could buy from a motorcycle tyre retailer. But when you take a closer look you might notice in some cases that there is an extra letter in the pattern name (eg. S22F E). This additional letter indicates that it is what we call a “spec tyre”. This means that this specific version of our tyre has been slightly tuned to fit the specific needs or character of the motorcycle its mounted on, at the request of the motorcycle manufacturer. This could be to better deal with the weight of this motorcycle model, high speed stability, chassis construction, … It’s important to note that this spec tyre will only have the desired effect on the motorcycle model it has been tuned to. So if your motorcycle is equipped with a spec tyre, you can replace them with the same spec tyres or with the standard replacement tyre (in this case: S22F – “F” stands for “Front”) when the tyres are worn out. The choice is yours, but know that the priorities for a motorcycle manufacturer can differ from those of the rider, so the tyres might behave differently than you expect. Bridgestone’s standard replacement tyres are always developed to meet the rider’s needs on an overall performance level. However, don’t use a spec tyre designed/tuned for Bike A on another bike. In that case, or whenever in doubt, use the standard replacement tyre which was developed for a wide range of usages and bikes. Your local tyre dealer can assist you in making the correct choice, and can also advise you on possible local legislations regarding the usage of certain tyres on your bike.