tell me about BMC axles

cool, so a midget 3.9 axle.... anyone got one? and how wide are they? I'm hoping for a few more inchs than the reliant one so i don't have to use spacers....

Well, my A35 handbook says the rear track is 3' 8 3/4" (1.14m if you insist ) and as far as I know this is identical to the spridgets.

They are also a bit fragile - killed one halfshaft before my engine rebuild, and 2, and a diff, after (not particularly torquey 105bhp). A mate also knackered a shaft/diff with the std 65-odd bhp...

They only use one outer bearing, so halfshaft relly gets some hammer apparently - wide wheels with spacers would make that worse? Tougher halfshafts and double bearing kits are available (as well as disc brake conversions) but are eye-wateringly expensive.

I think a comany makes/made a 3.5 diff?

What about one of the little vans (bedford rascal etc) - narrow enough and a bit tougher? I think one was used in a Frogeye kit car?

I've got a Datsun 1200 axle you could use. 114.3pcd though you may be able to re-drill it to 4". The ratio is 3.9:1. I think the track is about 1240mm on them but I can measure the width hub to hub if you want. I may also have a spare Datsun 1000 axle which is a bit narrower.

-Ed

ratdat, how hard are they to drill to 4"?and will the brakes be small enough?

i have heard of people running 100hp through a bmc axle no problem, and wondering what all the fuss is, but at the same time people don't rate them much more over 60hp.

i am planning on running between 100-140hp at the fly wheel, in a car that weighs 500kg, the car doesnt need to be my daily, so the odd wheel bearing now and then is not a problem - unless you think they will only last a realy realy short time? as for half shafts, i can ge tthem at about £200 a pair for uprated ones, so not tooo bad, and should take the grunt.

the problem is in finding a 3.9:1 ratio axle, with other ratios available for experimenting, with 4" pcd and a near as dammit track, and drums that fit under 10" wheels, that are basasically the same as the stock kitten ones!

i think a midget axle will have to be done and tested. see how long bits last! in theory 500kg car and no race clutch should help ease the load on it.

Nick

I couldn't tell you but I'll have a look and see and get back to you.



I used to have lots of A35's and saw the demise of numerous halfshafts. I broke on in a bog standard A35 van! If you run a 3.7 diff then it reduces the likelyhood of breaking a half shaft but does put more load on the gearbox. My 1275 powered A40 Farina went through ten gearboxes in two years like this. Those components just aren't up to power or hard driving.

you shoudl be ok with the midget casing and the weight of your car. I have broke 1 but My midget puts out more power than it was designed too so don't worry.

Expect to pay about 50notes upward for the casing, if second hand check the rebound mounts. (you may not need them anyhow) As they tend to rot away leaving a arpature for water to Rot the main half shaft casing, (Happend twice to me), this will then cause them to break or leak.

so the midget axle is the strongest...

bgt, how much power does your midget have?

thanks for all the advice

Nick

Last Dyno run was about 4 Years ago, I have nearly the same Spec as Filmidget and it was ran just over 108BHP so not bad, I reckon it would take a bit more. I know Frontline do kits for the rear end, if you have a bit of wolla, then bosh one of theirs on. Their Kits will take more power and use the standard casing.

My current Project involves the Midget with alot more power than that for sure.