I have noticed a slight resonance through the chassis when travelling at around 20 to 30 mph and was curious what the propshaft was doing at this point. I popped the tunnel cover off and video what happened...

http://www.youtube.com/watch?v=XLuUsPJzl3s

There is a misalignment through the centre bearing as shown here...


Prop alignment 1


Prop alignment 2

Could this be a route cause or is it an imbalance in the prop, too squidgy centre bearnig rubber, etc...?

Any ideas would be greatly appreciated as it does cause a slight knocking when travelling at these speeds. Above and below 20 to 30 mph it's absolutely fine.

Cheers,

Chris.

I had a similar problem at 80 mph when i come off the gas and the propshaft man said it was squidgy prop bearing rubber ....

unforgeable the car got sold before i fixed it

Can't help thinking that you would be best to remount the centre bearing in a 'neutral' position to avoid putting it under constant strain.

Anyone else got any input? Maybe?

Ta in advance.

Bailey Morris say it's supposed to have pressure on the rubber bearing mointo

What did BM say Mango?

It needs pressure on the centre bearing? i.e. not central?

Thanks,

Chris.

Sorry for the late bump!

Any other input from anyone?

Currently pulling the car apart to upgrade/fix some choice bits...

Thanks,

Chris.

If you have a telescopic joint at one end take a pic of that plz I suspect the prop might be slightly to long wich is forcing the prop to bend ???

If there was free play at one end then surely you would by unable to make the prop force it's self to one side of the bearing as it would just try and centre itself ??? Pics plz

There is a telescopic joint at the sprocket end of the prop which is nominally centered across its length of travel, allowing the maximum extension and compression in either direction.

I'm pretty sure the prop can't be bent as this is a wobble that only seems to resonate at certain frequencies (i.e. at certain road speeds). If it was a bend, the relationship between road speed and 'wobble' would get linearly worse with speed (excluding any constructive 'wobble', i.e. resonance).

Having pulled it all apart now, it seems like the centre bearing will always droop slightly due to the mass of the prop itself and the fact that it's rigidly mounted at either end (i.e. sprocket adapter and diff input).

Does anyone else see this droop? Or is my centre bearing too soft?!

I'll grab a piccie in a min.


Do you have a picture of your centre bearing by any chance big_l?

Thanks again,

Chris.

P.S. Great build by the way big_l!

Cheers dude . Must just be a soggy bearing then mines not exactly hard rubber !!