You may be able to get it working by making a custom config.
Start by opening notepad copy & paste the below.
ik_enablesmoothing 0
seta vt_maxlockedpages "256"
seta com_videoRam "1718"
seta com_maxfps "60"
fs_cachepath "C:\Users\TheWolf\AppData\Local\id software\rage"
jobs_numThreads 4
vt_splitTranscodeJobs 0
vt_maxPPF 8
seta vt_pageimagesizeuniquediffuseonly2 "4096"
seta vt_pageimagesizeuniquediffuseonly "4096"
seta vt_pageimagesizeunique "4096"
seta vt_pageimagesizevmtr "4096"
vt_restart
Edit lines with your correct info such as video ram on your video card.
Edit the cachepath line with the correct info, usually your login.
Looking around there are lot of threads here about Rageconfig.cfg
Save the file to your rage base folder. Mine looks like this: D:\Stream\SteamApps\common\rage\base
but save it as Rageconfig.cfg not .txt.
When you launch Rage it will auto load the Rageconfig.cfg
Edit: Come to think of it there is another way.
Open Steam, right click on Rage on the left side of the screen.
A popup will come up, go to properties click it, then click Set Launch Options.
copy and paste this: +set com_skipIntroVideo 1 +r_swapInterval 1 +vt_maxPPF 8 +vt_pageImageSizeUnique 4096 +vt_pageImageSizeUniqueDiffuseOnly 4096 +vt_pageImageSizeUniqueDiffuseOnly2 4096 +fc_maxcachememoryMB 4096 +ik_enablesmoothing 0 +fs_cachepath "C:\Users\TheWolf\AppData\Local\id software\rage"
You will still need to fix the cachepath with the correct name.
Click Start in w7 and the name should be at top right side of that menu.