“Although happy with la-sportiva mutants i found with doing trail/road at 70/30 had an impact on mileage use hence opted for Challengers due to reviews on them declaring to be perfect for on/of road..i have covered around 50mls and so far so good..very little to no wear on studs as yet..i have noted in respect of speed training traction can be an issue but then these shoes are not for that purpose so should you be out on a race day a sole purpose race trail shoe change would be advised..you can comfotably/rely on Challengers to take you the way 8.5min mls..deffo my go to shoe for mixed terrain decent jogs..”