To check read speed you can use the following command
hdparm -Tt /dev/sda1 /dev/sda1: Timing cached reads: 25292 MB in 2.00 seconds = 12664.26 MB/sec Timing buffered disk reads: 432 MB in 3.01 seconds = 143.56 MB/sec
Here 12664.26 MB/sec & 143.56 MB/sec are the read speeds.
DD command will give the write speed of hard drives
dd if=/dev/zero of=/tmp/output bs=1024 count=4096k conv=fdatasync; rm -f /tmp/output 4194304+0 records in 4194304+0 records out 4294967296 bytes (4.3 GB) copied, 165.193 s, 26.0 MB/s
Here 26.0 MB/s is the write speed.
Hope this helps!