by JimDirt » Thu Jun 22, 2017 9:34 pm
I have not had experience with that exact tire , but in general the 90/100 is going to absorb hits better like rocks , etc , it will stay on top in sand more , but has a tendency to get sketchy in ruts as it tends to grab the sides/edges of ruts more than the narrower 80/100 , the 80 will work in ruts better but does not do as well as the 90 on hard pack and the 90 works better on heavier bikes , so basically get the tire that performs the best for the conditions you "mainly" ride , a narrow tire for rutted hard pack , or a wider tire for rocks ,roots and sand , otherwise its a compromise to get good single features , but mediocre everywhere else , on a related note i run a 80/100 on my 450X , but as mentioned its a compromise , i ride a lot of single track , but encounter a lot of ruts ,hard pack and rocks , so the 80 works OK in those situations , not great , but OK , the 90 for me is too cumbersome in the ruts , which in the Idaho mountains , is common along with Lava and River rock , so again , its a compromise , as it seems to dig in , in sand , which sucks on a heavy X , i have decided that getting another front wheel so i can have a desert tire and a woods tire would be the best solution , i have 3 rear wheels for my 450R for different track or trail conditions
Anyway , not a direct answer to your question , but hopefully it gave you a idea of what each would work best for...
Side Note: , i use a Pirelli M403 on my X and a Pirelli MX Xtra X (80/100)on my 450R , but will be switching to a Pirelli MX32 for the R front (80/100) (switching to a MX 32 Pro on the rear from a Dunlop MX52 with a Tubliss) , and i use a Kenda Equilibrium for the rear of the X with a Tubliss
2020 CRF450R
2006 CRF450X

Weiser , Idaho