I broke another ring gear so now I have my axle apart for a total rebuild. I always knew the standard ratio was 3.63 but never gave any thought to how many teeth were on my gears. I picked up a nice ring and pinion set at the Richmond swap and while working on my car, I noticed the pinion looked larger and different. It had 11 teeth and I looked it up and it is for the standard ratio. I was surprised to find that my old pinion was a 10 tooth gear and was even more shocked to find the gear is Ford marked. I don't know the history of my axle assembly but, it looked untouched, still had babbitt everything. What would be the story behind the 10 tooth factory pinion? In each of the pics below, my old 10 tooth is on the left. Thanks.
I think(dangerous) that the 10 tooth pinion was installed in coupes and sedans for sale in certain parts of the country that were hilly.The experts will probably post more information.
Other than the broken ring gear issues, how did you like how the car ran with the 10 tooth pinion?
It's pretty hilly where I live and I've pondered installing the 4:1 gear if the rear axle ever had to come apart.
The 10 tooth pinion gear was indeed made by Ford and was an option for hilly areas. I have one in my Town Car and it seems to loose very little in top end performance, acceleration is certainly better and I use low band very little.
As I remember from the literature, it was considered an engineering marvel as it would mate with the 40 tooth ring gear which was designed for the 11 tooth pinion.
They are still being made: http://www.modeltford.com/item/2597B-10.aspx (a bit pricey, though)
Don't throw your pinion away - it may still be useable? Usually the ring gears takes more beating like getting worn out before the pinion.. but do you have any idea why your ring gear broke?
The 10 tooth can be nice in flat country or on speedsters where there is an auxiliary transmission. The overdrive on a Warford or similar can seem a bit steep with standard gears but when matched to a 10 tooth pinion you get good power/acceleration in direct and a nice cruising gear in overdrive. I love the combination in my speedster with a Chicago aux transmission.
Well that's really interesting. Thanks guys. This is the first I've heard of this option. As for how it ran, I've always thought it was ridiculous how the car jumped hard off the line, revved up fast and had to be shifted only half way through an intersection. Cruising rpm always seemed a bit high with too much noise and vibration and the car would not exceed 40 mph. In other words, it reminded me of the regrets I had years ago when I put 4.10s in my 5.0 Mustang. Two positive things I noticed were that other T owners would comment about how my car pulled well up mountain accesses in high gear and I now know why I always say that the stock T brakes are fine, my car has tremendous engine braking and I hardly use the brakes at all. It all makes sense now. I have only once driven another T for a few blocks. I notice how pleasant it was to drive and wondered why my car was so harsh like a drag car. I can't wait to try the 3.63 ratio in mine. As for how I broke the ring gears, it was poor engagement. I replaced the babbitt thrust washers the first time and that seemed fine for a year. This time I'm installing the Fun Projects pinion bearing kit. I'm also replacing both axles, bearings, sleeves and the driveshaft bushing.
As I understand it, the 10 tooth (4 to 1) ratio was available as an option in any part of the country. The 26 fordor I had from the San Francisco area of California had a Ruxtell with 4 to 1 gearing. On the other hand, I have heard that Ford also installed them in vehicles sold in areas with very poor (muddy) roads. My grandfather's 27 coupe that came from the Lake Charles, Louisiana area had them, also.
I can see that the 4.10 ratio would be of great benefit on the worst of the early roads. Obviously the 3.63 will be much better overall on modern roads. I'm really looking forward to what is sure to be a better T driving experience.
4.10 is something like 37/9, not 40/10, which is 4.00:1 . It would be aftermarket modification in a T.
R. D., I think Dave really meant 4:1 gears, not 4:10 gears. After all he did say it was a 10 tooth gear and I have never heard of a ring gear that would produce a 4.10:1 ratio. Even if you could use a 10 tooth pinion with a 39 tooth ring, you'd end up with a 3.90:1 ratio.
Dave -- Walt touched on this above, but in my opinion, the best of both worlds is a 4:1 rear gear with a KC Warford transmission. That combo gives you great hill-climbing power and a great top end. And you'll have 6 really useable forward gears!
I read somewhere 4.10 but anyway, no Warford for me. Gotta stay as original as reasonably possible.
In that case, Dave, I'd go with 3.63 gears regardless of whether you have a Ruxtell or not; and 4.00 gears if you drive in really hilly or mountainous areas. If all your driving is done in level areas, 3.00 gears work fine except in maybe tudor or fordor sedans. My Dad and I had them in my Grandfather's 27 coupe with a stock engine and had no trouble, at all.
According to the profile, you live in Hamilton. I was only there once, but it is not anywhere as hilly as it is here in southern California. Here I have 3 Model T's. One has 3.00 gears. It runs great downhill and on level. And since it is a roadster, when I am driving alone, it will pull hills OK in Ruckstell. However, it is quite hard on the low band when driving in traffic in the high Ruckstell range. If there is any small grade I must use Low Low to start out from a stop.
The other two T's have standard 3.63 gears and they pull the hills much easier. Also on level I can start out in Ford low just fine. Only great difference I notice is when going very fast (over 35) the 3.00 sounds better as the engine goes slower.
I don't think you need 4.10 gears unless you have a very heavy car such as a fordoor, centerdoor fully loaded, or town car. And then only if you have a lot of steep hills. A Ruckstell or other auxiliary transmission works just fine for pulling hills.
Here in Hamilton it's quite level except for several mountain accesses only two of which I will use with the T and I will still be able to use high gear. Tonight I finished assembling the axle and it went perfectly. Just waiting for the driveshaft parts to arrive. So the 10 tooth makes it a 4.00, not a 4.10, is that right?
The stock ring gear has 40 teeth, so with a 10-tooth pinion gear it would be a 40:10 ratio, which is 4:1.
With the stock 11-tooth pinion, it's 40:11, which is 3.636:1.