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Hi, having bought a SIL 47T crownwheel, which is machined so that the friction plates can sit lower, and a Readspeed 5 plate clutch (which seems to be the same overall height as a standard clutch) I am struggling to see how it can work together correctly. I tried assembling initially without springs and found that the tags on the lowest plain plate sit below the level of the clutch spider (standard Innocenti S2 item) and do not engage. My guess is that it is unlikely that the clutch will be compressed this far in normal use, and/or the springs will be coil bound before it gets that far. That said if it is compressed far enough it would result in the bottom plates being stuck under the clutch spider and a clutch which wouldnt engage. This wouldnt happen on a standard crownwheel which doesnt have the slots machined deeper into the basket, as the plates would sit higher.
Presumably I need a different spider which extends the support for the lower plates nearer to the clutch sprocket. There seem to be several options, Casa, ReadSpeed and MB, the only one that is obviously deeper is the MB one.
Another option would be to buy crownwheel without the slots machined.
Do I need a new clutch spider/crownwheel or am I overthinking this ?

I am not familiar with the Readspeed five plate clutch. Is it the Supergrip 5 plate for £43 that you refer to?

Is this it? https://www.readspeedscooters.com/readspeed-supergrip-lambretta-5-plate-clutch-kit-6192-p.asp

The Supergrip appears to be a combination of five corks and thin steels (1.2mm) that fits into the same space as four traditional corks and 1.5mm steels? Readspeed’s website says it should all fit into a standard sprocket, spider and pressure plate, which begs the question, why are you having problems?

I've had the very same crownwheel & reedsppeed plates setup for years now with no problems bud

This is a photo with the clutch bell, bottom friction plate and plain plate installed (no springs). As you can see the tabs on the plain plate dont engage with the spider. I have tried the same with springs installed and compressed the springs until coil bound and have the same problem. The same thing happens, but to a lesser extent, with a standard clutch plate and plain plate.

It may be that I am overthinking this.

No, you are not overthinking it, and well done for picking up on the issue, which would otherwise have caused you issues. What you have is a conflicting set of components from different sources.

In the same way that multi-plate (5 / 6) often require the tangs of the top cork to be bent downwards, so they don't override the top of the sprocket and effectively machine it down (write it off), it is not uncommon to have to bend the tangs of the bottom steel upwards so that it doesn't ride under the basket as yours is. Some of these upgraded clutches used to supply 1 x steel with longer tangs so that they 'reach' the basket when bent up.

However, most clutches have resolved this be introducing a billet machined basket that is right-angled at the bottom, not radiated like the standard 'bent' construction, thereby removing the problem. Unfortunately , your combo of deep crownwheel and standard basket, with standard bottom steel is the issue... and something needs to be swapped out.

Cambridge Lambretta certainly used to sell steels with longer tangs, however, like others, changing to billet centres means that they may no longer be available. Swapping baskets is an ideal, but not so affordable, option.

The standard Readspeed 5-plate assembly was intended to be used with a standard sprocket, not allowing the bottom steel to go so deep (ride under).

Ok cheers, thanks for confirming. Would something like the Casa spider solve the problem ?

Theoretically, yes. However, having tried the mix and match approach before, many times and coming a cropper many times, you can find that the machining of centres and crownwheels are not always compatible. I have previously found that a) machining depths stop centre from protruding beyond crownwheel/bush/bearing face, and b) the diameter machining of centre bottom recess can catch the outer edge of raised crow centre.

Whilst the above may not be the reality, and may just come across as 'doom and gloom' on my part, it is a reality of 'mix and match from different suppliers.. if you opt to mix and match then there is a very high chance that you'll be getting your Dremel out or surface plate reducing parts to make them fit.

Yes, that 'should' resolve the issue... but don't be surprised to find that something needs fettling.

Good luck with it.

Adam_Winstone wrote:Theoretically, yes. However, having tried the mix and match approach before, many times and coming a cropper many times, you can find that the machining of centres and crownwheels are not always compatible. I have previously found that a) machining depths stop centre from protruding beyond crownwheel/bush/bearing face, and b) the diameter machining of centre bottom recess can catch the outer edge of raised crow centre.

Whilst the above may not be the reality, and may just come across as 'doom and gloom' on my part, it is a reality of 'mix and match from different suppliers.. if you opt to mix and match then there is a very high chance that you'll be getting your Dremel out or surface plate reducing parts to make them fit.

Yes, that 'should' resolve the issue... but don't be surprised to find that something needs fettling.

Good luck with it.

forgot to say bud that I have Foxhat Spider which theoretically is the same as what the Casa spider is trying to achieve

^... yep, there are plenty of baskets on the market that have adopted this right-angled bottom design to resolve the bottom steel under-riding; Casa, Tino, Readspeed, MB, ScootRS, Foxhat, etc.

As mentioned already not all fit in a mix and match scenario, unless you're prepared to fettle. However, once you've got a combo that work together (which is why buying a complete clutch from a single source can be a better idea) they normally work very well.. provided that you don't opt for uprated springs that become coil-bound before compressing far enough to use your new found travel depth.

Thanks for the help, have ordered a Casa Spider.

hullygully wrote:I've had the very same crownwheel & reedsppeed plates setup for years now with no problems bud

I’ve had this clutch for a few years now it’s been faultless tbh. Real good VFM.