So finally today I changed my rear tyre and installed service 100/90-18. Got it for Rs.2500 from tyre house on Murree road.
- tyre rubber is harder than Panther and other good imported tyres.
- very poor road grip when applied hard breaks @ 70-80 km/h speed.
- it also skids even when riding with 2 persons (total passenger weight was +200 kg)
- did not felt any difference in initial pick or top speed.
My little brother also has a GS with MRF 100/90-18 zapper-y installed. His bike jams on the road when applied hard breaks and never skids. The tyre rubber is very soft. The tyre cost was Rs.4300/-
Uptil now I would say service 100/90 is just an average tyre. I have found panther 90/90 having more grip than service 100/90.