New member 31 Roadster rear end question

[46Chris]

Hi,
New to the forum and about to (hopefully) get my first '31 Roadster. It is advertised as a '55 mph' car, and I asked what rear end is in it. I was told that it has the 'roadster rear end', which allowed steady 55 mph cruising. My understanding is that there was just one rear end ratio offered at the time, the 3.70. The engine was rebuilt, and my concern is that just rebuilding the engine would not prepare the car for touring speeds. I'm about to plunk down money, but I have this nagging concern and would like to ask you fellows who know a heck of a lot more than I do.
Thanks, 46Chris

[Charlie Stephens]

My guess would be that it has a 3.54 rear end (from the description) but I have never heard of "a roadster rear end". Sounds like something made up by someone trying to sell a car. Count the number of turns of the engine required to push the car ahead one tire revolution. Is the speedometer correct? Have you driven it at 55 mph (and a chase car with a known speedometer)?

Charlie Stephens

[BILL WILLIAMSON]

Even with 3.78 gears, a good Model A will easily run 55 all day long. If I were you, I would rebuild the engine & drive it. Roadsters are lighter too! Bill W.

[Patrick L.]

A '31 roadster ?? Standard or Deluxe ?? Regardless,, if its a good car,, buy it !! It'll probably have the standard 3.78 rear gear and may not like '55' mph,, but,, thats all part of owning a Model A.. There are a lot of claims floating around about these old monsters,, but,, most of us don't run them that fast..

[zzlegend]

Originally Posted by BILL WILLIAMSON

Even with 3.78 gears, a good Model A will easily run 55 all day long. If I were you, I would rebuild the engine & drive it. Roadsters are lighter too! Bill W.

Bill, i think he already stated that the motor was rebuilt. My guess is a 3:78 rearend. Just a thought.

[Bruce,Upstate NY]

Sponsored Links (Register now to hide all advertisements)

A friend has a 3.26 or similar in his roadster, which is about the same as a Mitchell in overdrive. Fine if no hills.

[1930artdeco]

Hi Chris and welcome. My Townsedan will do 55 easy on flat roads and I outweigh you by a couple of hundred pounds. I normally run her at 50 and I have a 'high compression head'. But even if you have a stock engine and it was rebuilt correctly, she should do 55 with the 3.78 rear end.

Mike

[glenn in camino]

If you want to keep it for a while, I wouldn't take it over 50.

[Marco Tahtaras]

Originally Posted by glenn in camino

If you want to keep it for a while, I wouldn't take it over 50.

That's a surprise coming from someone in the hobby as long as you've been in it! I've done tens of thousands of miles at 55 mph MINIMUM. Maybe it's because I chose it as an everyday car and club tours were just a fun fill-in event.

[BILL WILLIAMSON]

Originally Posted by zzlegend

Bill, i think he already stated that the motor was rebuilt. My guess is a 3:78 rearend. Just a thought.

ZZ,
The Dog was reading for me, and I don't think he had his glasses on?? bILL w.

[columbiA]

While some may cruise at 55+,I have never gone over 45 in high gear with 4.11 ratio or 60 in overdrive with 2.94 ratio.

[wi0v]

I think the question is how fast to you run these engines. I would like to find a portable tack to check the rpm at 50mph. Mine seems to be turning plenty of rpm's at 45. So, has anyone of you 55mph guys every tacked yours at that speed.

[[email protected]]

I have often seen old car test equipment like Tach / Dwell meters at garage sales and EBay for a few dollars. Just use the alligator clips to attach to Positive ground and the passenger side coil terminal.

Also a GPS will give you an accurate MPH to plot out your RPM to MPH ratios. Most Model A speedos are not 100 % at all speeds so they will not give you good results. The Apple IPhones and IPads also have a free speedometer app that can be downloaded that work good just like the GPS's.

[c125bob]

My speedo was way off above 30 mph. At 30 and below it's right on the money. Never could figure out how guys were getting 50-55 out of thier cars. Mine sounded like it was really wound out 45 mph.

After a GPS check I found out that when I was showing 35 on the speedo I was going 44 ! Struggled to make it to 45 and was running 57 ! I'm glad I didn't push it to try and make 50 before I checked with the GPS. The faster I go the more error (slow read) in the speedo. Check yours, it may be running faster than you think !!

[antiquepa]

I have a 31 delux roadster, i;ve put 46,000 miles on her since i bought her in 2002, i run at the most top speed 45 mph. This to me is a good speed, never pushed it any futher, after 46k the car still runs good. To each his own, you still got to stop and i feel you got good control between 40-45 mph. Just my 2cents!!