Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Rear Wheel, Hub and Sprocket Change.

Great Job Calum, excellent...I downloaded the pdf for Tyre or Sprocket change in the future...beer deserved

very well documented! good job, calum. you are right, it's not rocket science, but it needs some guts to do it your self. and with this little "helper" of yours, some of the TMs will hopefully try it out :-)

Super job Calum !

Thanks for sharing with us. Wish we had such information for all jobs nessecary on our M3W's.

Small question: is the front sprocket on the bevel box still OK and did you only changed the rear sprocket ?

Front sprocket seemed absolutely fine so It's staying on. From the look of it, changing the front sprocket would be a bevel box out job and would need a very large socket.

Brilliant job, something I will need to do in the near future, could you advise the cost of the parts and how long you had to wait to get them.
Looking at the aluminium flange arrangement, would it be possible to make a spacer to reposition the wheel and use the original spacer?

Also are you still running on the original frame on the car, any signs of fracture?

Thanks....Mike

It would be more along the lines of machining metal off of the mating face of the old hub to move the wheel towards the drum which would leave a bit of a thin flange. Don't think I'd want to chance it.

My chassis cracked after about 10 months and something like 7000 miles and was replaced with a late 2013 chassis so presumably has the marginally thicker walled but tougher material tubes and the welded in gusset plates rather than the 2014 chassis with the triangulated welded in tubes.

On the cost and waiting time, let's just say it's a lot and I had a half hour wait at the service department counter and a coffee while I waited.

Is the front sprocket made of steel or is it also made of aluminum ?
And if the last is correct why only the rear sprocket give problems ?

Front sprocket is steel as far as I can tell - I didn't try a magnet on it! All I did was look at it and have a feel for wear but it seemed fine.

Sounds like an excuse for a new socket

I have done just over 5k miles in my car and have always kept the belt tensioned to 15mm deflection and the belt set to run on the edge of the sprocket, giving about 3mm clearance between belt and tyre. The belt would however rub on the tyre now and again when accelerating and the sprocket is also wearing away but not to the point that it can be replaced under warrantee.

Inspired by Calum's post I decided to see if I could modify the hub to align the sprocket better, and avoid the drive belt overhanging the sprocket or it rubbing on the tyre. Also since new I have had an annoying scraping noise from the drum brake which was quiet loud when moving slowly which I needed to investigate.

Checking out the position of the wheel, sprocket and belt, the hub required 5mm off of its wheel flange, to move the wheel away from the drive sprocket and create a couple of mm clearance between the belt and the tire when the belt was running against the thin flange on the sprocket.

The wheel's flange on the hub is 20mm thick, 5mm was turned off by a local firm for £30. The reduce thickness looks ok to me and should easily cope with the stresses imposed on this part. (A seasoned engineers opinion that is)

The grinding noise was found to be one of the return springs of the brake shoes, catching the cap head screws within the brake drum, this was bent out of the way.

The belt now sits in the center of the sprocket’s face and if it moves across this face is kept off of the tyre by the sprocket’s flange.

I have done over 200 miles since the mod and it has made a significant difference, no more scraping between belt and tyre and no more grinding when going slow. It is better than new, Brilliant. All I need now is a steel sprocket to replace the worn aluminium one which I hope I can negotiate a good price for when the chassis kit is fitted to strengthen the front end.

Here are some photos, can't get them to show in this post...
[img:center]http://i448.photobucket.com/albums/qq205...p;1438705952371[/img] [img:center]http://i448.photobucket.com/albums/qq205...p;1438705952371[/img] [img:center]http://i448.photobucket.com/albums/qq205/talkmorgan/IMG_3764_zpsr6klrqhf.jpg?t=1438620488[/img]