Talk Morgan Forums Morgan Sports Cars Morgan Plus Four, Supersport & Plus Six (CX & CXV Generation Vehicles) Plus four has a ‘clonk’

not familiar with the new plus four. One thing I didn't see mentioned, check the drive shaft universal joints. I know on the corvette they clunk like heck when (1) going bad or (2) under greased.

My +8 had something very similar, much more annoying then it sounds on paper, as you spend all your time trying to drive around the noise. It ended up being shipped back to the factory, after trying a lot of things and having the car for a couple of months, they checked the wheels "two were just on spec and one was outside spec". Unfortunately I was never able to find out what "spec" was.

The MMC changed all 5 wheels from the "Indian" Chrome Wire Wheels to the then newly introduced SS ones, which I was impressed with.

The problem has never reappeared.

Brian - you were blessed - great service which is not universally dispensed!!!!

The earlier post from Nick (vincentvg) echoed my exact experience back in 2012 when my car was one year old, and I have followed the same procedure ever since.
As a matter of interest, does anyone ever rotate their wheels front to back etc to prolong tyre wear? I am thinking that it’s not a good idea with splined hubs, but interested to hear thoughts of others.
Another reason for asking is that if it were permissible, moving wheels around may solve the clonking issue if one wheel fitted a particular hub a bit better?

I believe the answer to your Clonk is movement in the hub conversion for Wires.
I have Alloys - no Clunk, my brother has Wires - Clunk and Oakmere have arrived at a cure.

which is??

Thanks for all the replies. Not been able to respond as I was locked out some how.

Thanks to ‘capta2’, your experience and your brothers really confirm my experience and what Oakwood explained to myself about what was causing the issue. Oakwood have been good and took the car back to fix the issue but while it was much better in that it was not as loud, it did not completely cure the issue so the car has now gone back to MMC to be fixed.

The issue, as I understand from Oakmere, is the wire wheels require an adapter plate that is bolted on to the hub but the holes in the adapter plate are larger than the studs on which they are located. The ‘clonk’ originates as the slack between the adapter plate and studs is taken up when changing gear.

The cure, as I understood from Oakmere, involved inserting a sleeve around the threaded studs to reduce the slack between the studs and adapter plate.

‘Capta2’: does this explanation sound correct to you?

Roger

2021 Plus Four in blue

If I understand correctly, the Plus Four is only made with one type of hubs, for bolt on wheels. And if you want to mount a central locking wheel you have to mount an additional adapter plate like in this picture below? And MMC was not able to buy adapters that have no play or the correct bolt diameter?
So if only hubs for aluminium bolt on wheels are used in production, then it has the disadvantage that for centre lock wheels additional unsprung weight is the price unlike "real" centre lock hubs on the traditional Morgan which are even lighter than the bolt on hubs for trad. Morgans. (I know this because my workshop had both types of hubs on the weight scale when I had problems with the Minilite wheels on my Plus4 Super Sport 10 years ago). But it has the advantage that the whole thing can be simply unscrewed if you prefer to ride aluminium wheels later without having to change the hub?



Sorry if I got a bit excited earlier, but if I were in the market I would definitely buy the Plus Four with bolt on alloy wheels under these circumstances. It used to be form follows function, now it seems form follows fashion. And if the spoked wheel look is not so dramatically important, I would ask MMC to take the wheels back and fit aluminium wheels...and have the surcharge refunded. BTW I personally like the new alloy wheels very much but that is of course not important to this thread with the exception that also the clonk is easily cured.

The use of an adapter plate for fitment of wire wheels, kind of leaves me stunned and what I would expect from an after market solution rather than from the original manufacturer. Add to that not a close fitting adapter plate leaves me speechless! Surely it can't be that hard to fit different types of wheel hubs during the design, and build stages.