Wtb ci31 carbon tcs mtb rimthis ci31 carbon tcs mtb rim has been in testing and development for two years raced hard in the enduro world series finale ligure and through the harsh rocky mountain region at big mountain enduro this rim has been pushed to the limit the ci31 carbon tcs mtb rim survived and its now ready for whatever challenge you want to throw at it complete carbona sleek and understated design gives a timeless finish to this rim masking the incredible strength of the carbon