Just looking for any thoughts on wheel sizes from the learned out there. My son and I are currently rebuilding a 1929 Hope bodied Austin (photo attached) in Australia with the intention of taking her on some endurance runs. The first trip will have us going over a fair amount of gravel roads with some softish sand underfoot in some locations, it’s about endurance not speed. We have six wheels all in varying states of disrepair and the intention is to have new rims pressed and of course new spokes fitted. The current crownwheel / pinion is a 8/42 and the available gear box is a 4 speed (not got in to the guts of that yet).
I understand A7’s had 16”, 17”, 18” and 19”wheels and I was planning on going larger with the idea being that a larger wheel is more rubber on the road, and better for cruising but maybe that will make the slow speed stuff more difficult?
Any thoughts on the size of rim we should go for?
Thanks in advance
Steve and Tate
Steve & Tate Davidson
Perpetual Amateur Austineers
Steve why do you say 29, I thought the consensus was about 32. I am following with interest your progress on this car and I'm sure it will be a beauty. regards Russell
I would go for 19" wheels with 3.50 section tyres. The car will look correct, 19" tyres are readily available and cheap, and they will cope well with any difficult ground. The 5.25 axle ratio will be okay, especially with a 4-speed gearbox. Looks like a good project and I am sure it will give you lots of fun on your planned adventures.
(10-09-2018, 10:03 AM)squeak Wrote: Steve why do you say 29, I thought the consensus was about 32. I am following with interest your progress on this car and I'm sure it will be a beauty. regards Russell
my mistake, I was trying to do two things at once, the final figure that Doug came up with was 2nd of June, 1930
10-09-2018, 06:41 PM (This post was last modified: 10-09-2018, 06:47 PM by Dennis Nicholas.)
With my Nippy I use 19 inch for the trials ....3.50 front and larger rear. Has had much success, but for road use at any speed the handling is a bit scarey. 16 inch (an Austin export size) I found very good for normal road use but tyres in that size became nearly impossible to get so had 15 inch built using Citrone 2CV rims on front (2CV tyres easy to get) and (I think) Peugot rims for rears (for extra but not too wide). Both had extra strong spokes.......these were built by a motorcycle wheel man who punched the rim holes properly. I still use the 15s after many years and they are still as strong. So look for a motorcycle wheel man........my man was so much cheaper than car wheel firms.
10-09-2018, 08:34 PM (This post was last modified: 10-09-2018, 08:38 PM by Ian Williams.)
Hmmm Dennis, I think you probably need to look at your suspension, steering and maybe tyre choice, In my experience a Nippy with 19" wheels and appropriate tyre is quite stable at any speed.
PS Shinko E240 Classic fit 16" wheels, they look quite good, handle well and are readily available for a decent price.
As you will have seen a massive rebuild has been underway for some time. Much wear and tare has been found. The extra front weight and power from the larger BMC A probably has not helped in the extreme balance of the car but on the 19" it is no where near as stable as on the 15s. The Big7 front axle adds help with the slightly wider track and one end of front shock absorber is direct onto axle with no shackle. My previous Nippy had the Bowden IFS and that was a transformation from the standard front suspension.
Incidentally I live not too far from Ottery St Mary and once visited the little workshop where the Bowden stuff was made and spoke to the engineer. He very kindly gave me photos of the IFS drawings (sort of drawings) which I must get down to photocopying and sending to the A7CA for the archives.
(10-09-2018, 10:26 PM)Ian Williams Wrote: Ahh I see Dennis, yes your car is heavily modified so perhaps not a great comparison of the purpose of suggested wheel size on a standard car.
A few questions if I may- are you sure your car is a 1930 as Squeak has questioned? Are you sure your diff ratio is 5.25? What is the wheelbase?
1930 models used 4.19 ratio, had a 6'3" wheelbase, and the fact also that you have a 4-speed g/box makes one wonder if your car isn't later with w/base 6'9" as Squeak has queried. Cheers, Bill in Oz
