Concatenate and pass as parameter, bash

Need some help with removing default gateway. For example, there is an IP 192.168.4.15 with default gateway 192.168.4.14. I connect to WLAN with gw 10.0.0.1 and after that I would like do remove previous gw.

  IFS='.' read -ra IPARR <<< "$IP"
  Gateway="${IPARR[0]}.${IPARR[1]}.${IPARR[2]}.14"
  ssh blah@$IP '/sbin/route -v del default gw $Gateway;'
  #ssh blah@$IP '/sbin/ip route delete $Gateway dev rndis0;'
  #ssh blah@$IP '/sbin/route -n'

Both ways don't work. However, it is possible to remove it if I ssh into machine. My guess is that something wrong with passing $Gateway variable. Any suggestions?