The differences between the SunRace CSM-990 and the SunRace CSM-980 - 9 spd cassettes

[Kim H.]

I would like to know the differences between the SunRace CSM-990 and the SunRace CSM-980 - 9 spd cassettes besides the same gear cog counts as being 11-13-15-18-21-24-28-34-40T.

Is the the material ?

Which one is better made ? ..or would last longer ?

Thank-you,

Kim Hetzel.

[Joe Bernard]

My cursory search reveals that the 980 has a steel spider and and lockring vs. aluminum on the 990 and weighs 75 grams more. 

This was a difference I discovered when choosing an 11-50 11-speed a few years ago, in that case the fancier one also used an aluminum big ring. I believe all the cogs on the 9-speeds are steel. *

* SunRace has too many versions of the same cassette. It's confusing. 

Joe Bernard