I'm in the process of re-doing a Ruckstell that had 3:1 gearing in it. I wanted to go back to standard with a 40 and an 11 tooth. Here's my question/dilemma... Can I run this as a 3.54:1 ?
The 39 tooth ring gear that came out of this rear looks absolutely perfect and has "Mark USA" stamped on it. I think this rear was done in 1963 and has very little time on it. I don't have a 40 in anywhere near the condition of the 39. I have a perfect 11 that I got at Hershey a while back.
Guys have told me how they like doing 3.25:1 in the Rux. My car is a '26 Touring and we use it a lot.. I've been running a stock rear with 3.65 in this car for the past 5 years and maybe 10,000 miles. Will I be in for any unusual challenges setting up the backlash with this combo?
That MARK Auto Parts 39 tooth gear is just for a 3-1 set - I don't believe you can run an 11 tooth pinion against that ring gear.
Steve is correct that ring will not mesh correctly with an 11 tooth pinion. Notice I said
Good to know. Maybe someone out there wants to trade the 3:1 set for a standard set?
Dave, somewhat off track, but Chaffins sell a 12 tooth pinion which will work with the 39 tooth ring gear, to give you a ratio of 3.25 This sits nicely between the 3:1 and standard. My roadster loves it.
Allan from down under.
Thanks Allan. I've decided to stick with standard 40/11. Now I just need to trade someone my 39/13 set.
Dan, could you give us a little education on gear meshing as you eluded to it above.
Why can we have a 10 tooth & 11 tooth pinion work with a 40 tooth ring gear?
Ford designed and "specially" cut the 10 tooth pinion to "roll over" the teeth on the 40 tooth ring gear. There is information written up about it in the Ford Service Bulletins.