Axle Tramp

Post by **grahamt7** » Fri Oct 14, 2005 2:10 pm

Can someone define 'axle tramp' for me please?

Thankjs,

Graham

Post by **Alec** » Fri Oct 14, 2005 5:01 pm

Hello Graham,

it is where the (usually) inner rear wheel bounces up and down under acceleration caused by the engine torque trying to turn the rear axle casing which in turn twists the spring towards an 'S' shape. This causes the wheel to dance with a loss of grip.

Alec

Post by **rayofleamington** » Fri Oct 14, 2005 5:51 pm

yes that's pretty much it, although it is not too hard to get it without turning a corner and to me it seems even easier to get in reverse.

If you don't have the engine top steady you could soon break stuff if you are lead footed and don't avoid axle tramp. Even with the engine top steady it will eventually do some damage.

Post by **bigginger** » Fri Oct 14, 2005 5:55 pm

The worst time for it, I've found, is pulling out from a side road at right angles to a main road, ie with the front wheels turned and the need to accelerate briskly for safety's sake (traffic approaching stupidly fast...). It can be VERY hard to avoid

Post by **grahamt7** » Fri Oct 14, 2005 7:00 pm

Cheers for the replies chaps

Post by **bmcecosse** » Fri Oct 14, 2005 7:26 pm

It also breaks half-shafts as i discovered 40 years ago !

Post by **Cam** » Fri Oct 14, 2005 8:15 pm

... and weak leaf springs as I discovered 3 or 4 years ago!

Post by **dunketh** » Sun Oct 23, 2005 11:42 am

Is there a cure?

(simple and cheap preferrably, like fitting wide wheels or something?)

Post by **Alec** » Sun Oct 23, 2005 12:04 pm

Hello Dunketh,

the usual cure is to fit radius rods (anti tramp bars), these are (usually) tubular rods which hinges on the same plane as the front of the spring and bolt to the axle tube. This locates the axle's vertical movement and prevents it rotating.
There are a few different configurations and are sometimes angled so as to restrict sideways movement of the axle during cornering.
I would suggest that if your engineering knowledge is not strong that you buy a ready made kit.
Wider wheels would probably agravate axle tramp as the unsprung weight is being increased. Better damping would also, to some extent, help.
I have seen, I think it was a Chevrolet Suburban, that had the dampers located with one in front and the other behind the axle line to reduce the effect of torque reaction on the axle. I'm not so sure that is an effective remedy however.

Alec

Post by **Peetee** » Sun Oct 23, 2005 4:39 pm

I'm running a Minor with 1300 Ital engine and uprated oil in the shocks (SAE 20). No axle tramp so far.