Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Drivebelt alignment

My very early M3W is still running on the original Alum sprocket and also the original (alum) hub.
I have noticed that the drivebelt has started to rub against the tyre wall.
Is there any adjustment on this alignment?
The belt does run squarely on the drive sprocket, without any overhang.
Any pointers are appreciated.

Thanks
Andrew

Andrew
With the original hub, the belt should actually overhang the open side of the sprocket by a few millimetres. It sounds wrong but that is how it was arranged.
If you have the rear on stands with the tyre clear of the floor you can spin it backwards and forwards by hand while watching the belt. When the alignment is incorrect the belt will walk to one side of the sprocket or the other when you spin the wheel one way and the reverse when you spin it in the other direction. When it's correct the belt will stay in pretty much the same position on the sprocket.
Hope this helps.

ajs, the best REAL repair is to install the latest hub. I had the same problem as you and had a fearful amount of belt rubbing on the tire. Tne new and expensive hub solved the problem. Good Luck

Thanks Calum - I will jack it up & see how it goes. The belt has never overhung the edge of the sprocket, as shown in your excellent write up - in my experience anyway.
Hbats - thanks for your advice, do you remember the cost of the new hub?

Thanks
Andrew

it is about €1500 incl VAT and 4 manhours installation (2013 prices)

Hello again,

Taken the time to have a good look at my rear wheel drive arrangement tonight.
It looks as though the belt has been slightly rubbing against the side of the tyre for some time - maybe even since new.
Car has done just over 3000 miles .
I've checked everything is tight & the the belt runs evenly on the sprocket - all seems fine.
Just had an idea - can I run a slightly less wide tyre - 165/65 r15 instead of the current 175/65 r15?
This should give me 5mm extra clearance on the drive belt side?
I understand that there will be a slightly smaller contact patch on the road & possibly a little less grip, but surely not that significant.
What are your thoughts?

Thanks
Andrew

I think a little less grip on the back would be good. If it created less understeer on the front. Not sure it would though

Anyone on here experimented with tyre pressures to reduce under steer etc.?

If you search back there has been quite a bit of tyre pressure discussion.

The consensus is to run the (Avon) front around 28psi with the rear at round 25.

The Avons have a soft sidewall so the higher pressure helps stabilise the tyre.

I've now switched to Bockley's and also run these at 28psi which gives a good balance.

A LOT of discussion on tire pressures and tires. The Avons are sidecar tires and, as such, were never designed for the forces they get as steering tires. See the associated videos of them looking like they'll fold off the rims like noodles...

Blockleys in front with 27-28psi and 25psi in the rear. You can still light the rear end off with a passenger but is much easier solo. It's just money going up in smoke anyway...