LCGB Forums

Hi..
I've got a problem with the rear hub on my series 2. Its an innocent hub which I fitted a year or so ago. I do not seem to be able to get rid of a very small amount of 'shift' on the hub though....
Having fitted it and torqued it up to 120 lbs/ft - If I put both hands on the tyre opposite one another at a particular point on the wheel then I can feel the movement (tiny knocking) on the shaft. If I leave the wheel where it is and move my hands around the tyre but still opposite one another - no movement. it seems to taper off away from a given spot.

I checked the shaft and can't sense any movement at all within the bearing. There is also no sign of wear on the oil seal and no sign of damage to the splines on the shaft. And no obvious signs of damage to the cone on the inside or outside surfaces.

To try and resolve the problem I bought a tin of grinding paste and spent literally about 40 minutes on and off to get a good fit in the hub.....but I've done this by hand so could I have caused it to get worse?

This is going to sound a stupid and ignorant question - but surely this isn't right is it? Are the hubs and cones matched as pairs, have they been 'bedded' in already? - they were bought as a complete set. Would this be an MOT fail if it had one still or is a tiny bit of shift acceptable?

Any advice is really appreciated.

Martin

There are three tapers & IMHO they are 'designated/named' incorrectly. If you compare all three cones though, the differences are obvious & selection of the correct type for any particular hub is possible, but so much easier if @ least two of the types are available: S 2/early S3 & later S3.

It's good practice to seat the cones into the hub with grinding paste

Now, to your particular problem, which I can relate to. Having been involved with tuning & hard riding, for racing, there was little option than to utilise the strong Serveta hubs whilst I was riding the tracks. The later GP types would fail, but 'fail safe' by imploding inwards toward the gearbox. Still brown trousers time though....

The problem was, & still is, not necessarily procuring a good used Serveta hub, but a good enough cone. The new ones that are sold by SR are a good fit (though should still be lapped in) but my suspicion is that they are not hard enough. I don't have a Rockwell tester, but my the 'file' method would confirm my thoughts. Freshly ground in, fitted, torqued up, the hub would exhibit no discernible rock before being ridden. Tried again, after a race meeting, play would be there. Stripped down, the bore of the cone would exhibit marks in the bore from the layshaft splines.

In 47 years of continuous Lambretta ownership, that is the only issue that I have experienced.

If I were you, I would suspect the cone manufacture. If it's not the Serveta type, you might quite easily remedy it by use of a good, secondhand matching cone.

Let us know, eh?

Thanks Warkton....this sounds encouraging. I honestly started to think I was going mad!!!

To the naked eye - the cone slots beautifully into the hub - and looks like an even fit all the way round. But when I slide the code onto the shaft on its own theres a gap. It can be 'rocked'.

My gut instinct is that the 'rock' I get when its sitting free on the shaft is the same movement I'm getting when its torqued. In my ignorance I was assuming this was correct and that once the hub is fitted onto the shaft and torqued that it would squeeze the cone which would then fit neatly on the splines (no?).

I've been over some old threads on here and seen hubs and cones re a bit of a pain. So do I use the serial numbers on the inside of the hub and give them to a supplier and ask for a good quality cone for that hub? is it that simple??

thank agin

Martin

I've just whipped the hub off...its an innocenti 19045070......


any thoughts on where I'd get a replacement cone? Scooter restorations do not appear to have one for that serial number hub.

Thanks

Martin

Right - I've just had a closer look at the hub. On closer examination it looks like the seat or 'bore' the cone fits into on the hub could be out of alignment.... quite significantly actually. I'm wondering if this is the main problem - because I was getting problems getting the wheel to run perfectly true.

Can you also tell me if the cone should fit snug with no 'rock' onto the splines...?

thanks

Martin

The cone should be a snug fit on the layshaft and the gap should always be placed over a spline. The cone needs space to be compressed into the hub as you tighten the nut - if it bottoms out in the hub it's not going to do its job properly.

Reading through your responses, it occurred to me that the taper bore of the hub may be a problem.

I once bought a S2/early S3 on eBay that looked reasonable but would need the taper lapping to a cone. Although it got a better surface, the problem was that the hub taper had a small split & was opening up when tightened. That's probably why it was for sale, but by the time I got around to looking @ it, there was no means of redress.

Thanks both for your replies...I'm pretty confident the cone seat in the hub is out of alignment.....its going back to the supplier to see.

Cheers

Martin

The knocking noise could very well be to do with a worn layshaft caged roller bearing in the endplate and not the hub at all?

Sorry I've been off here for a few days - and thanks yes, although I don't want it to be the bearing I'm realistic it could be the cause of the slight 'knocking' sensation I get when I really pull the back wheel around in situ. To be honest albeit it important its less puzzling that the 'simple' problem I'm struggling with below. But I'd appreciate your thoughts still if you don't mind having a look....

It turns out the last hub was slightly skewed .......the 'bore' in the hub (not sure what else to call it) that fits over the cone was very slightly off. However - I now have another scootopia replacement and cone. Why though, does my wheel just not want to fit square on the shaft. There are no signs of damage or trauma to the splines, theres not obvious movement in the shaft and the oil seal is in tact. But I just simply cannot get the bloody hub (and wheel) on straight. I'm tightening it to 120 ft/llbs etc but it drifts when I rotate the wheel and is dragging on the brake shoe.

I've held a long alan key across the rear near side running board so that it brushes against the rear rim and when I rotate the wheel....as a bit of a make shit gague to see how out of line the wheel is. On rotation it goes from brushing the surface of the rim to about a 2mm gap the other side. I'm literally dumfounded with his and its stopping me from enjoying the bloody weather whilst it lasts.

What on earth am I doing wrong here!!!??? I went through a bit of a palaver with the last hub and grinding paste because there was a suggestion the cone wasn't fitting neatly into the hub. But these are new and bought as a matching set again (as per the last ones). I will add that the last one was a replacement because I had the locking ring drama that so many other posters have described on here that meant I need a new hub.

Lapping in(?)...I haven't done this for the new hub/cone because it only arrived yesterday and looked spot on. But I'm assuming this may be the next suggestion. So am doing this right? has anyone got a suggestion for holding the cone square so I can apply gentle/even pressure whilst rotating it. Should it actually be done in a lathe or something?

The wheel simply refuses to sit square on the shaft. It looks great when I locate it over the splines and spins nicely. Do the bloody think up tight and it goes t*ts up.
I'm not an engineer - but I have managed to replace the piston and ignition system on my TV a couple of years ago without incident. But this is befuddling me now.

Someone!! please!!! - I've taken to watching bloody coronation street with the missus now to getting my mind off it. Bloody summer will be over next!!!

sorry to rant...

Martin

greenfingers wrote:
as a bit of a make shit gague

I do love a Freudian slip

Is it possible that you could borrow a trusted hub & cone with wheel? That will prove one way or another that your hub, cone & wheel are the problem, or not.

If you bought a brand new hub & received a replacement, could be that it came from the same batch.

That aside, it really is worth grinding paste into any hub & cone. For one thing, it proves the angles are a match. I've seen them mismatched, despite my tender years You could @ least apply some Engineer's Blue, or even Tippex to prove the angles are the same.

Just bear with it. Not worth taking any risk & letting the Missus have the insurance pay out, though if you do throw caution to the wind & be quick & we're still in lockdown, I suppose the funeral wake won't cost her a fortune......

Ha...yes she'd have the insurance spent in minutes. And it was a shit gauge to be fair....

Its a scootopia hub and cone...I was working on the principle that it would be unlikely to have another hub that was wonky. I've seen very favourable comments about them before.

I have thought about boot polish as an alternative to engineers blue so see if its fitting all the way down the face - might give the a go this afternoon. How can something so simple be such a pain in the arse!!!! Perhaps it is the bloody cone.

thanks anyway...I'll keep trying

Martin

Right.....

should the cone be a snug fit on the lay shaft? Mine has a fair bit of play which I've always assumed disappears as the nut is tightened to secure the hub.....is this right?

I've attached an image to show as best I can - there is a fair bit of a gap between the outer shoulders of the lay shaft spindles and the inner surface of the cone.

..looks like coronation st again tonight....

Martin

Hmmmm. (Again)

Just as an aside, I dug out a Serveta hub & all of the cones that I have. Although with all of the cones to hand, it is obvious that that only three of the cones could 'match' it is easy to understand that an incorrect cone could feasibly be fitted. Sorry to over-stress the importance of a match, but that's me, I'm afraid

(i think the Scootopia hub is based upon the Serveta design, though could be wrong)

The cone itself should be a spring fit. Not as in 'summer' but it should require that a screwdriver, say, be pushed in the cone slot to ease it open (Oooer ) & allow it to be positioned, with the slot central to a spline rib.

You could squeeze the spline up to close the gap as I have done in the past, but should you do so with a brand new component? The jury is out on that. I guess you could 'phone the supplier & ask.

This scenario is a worry, though. I am aware that the hubs are renowned for quality, as is Scootopia in general. The new taps came in for a bit of a verbal bashing not long back, but mine have been fine, but I am a bit anal & always strip down any such thing to check assembly & in any case, usually deburr any holes/passages (Oooer again ) from new, invariably endeavouring to attain what I believe to be a reasonable reserve @ the same time.

I think you could do worse than 'phone Scootopia & have them check out another hub & cone on a fitted layshaft prior to sending yet another replacement. It's got to be better than watching soaps with the Missus, & I'd bet she'd prefer her bit of solitude watching such a real life documentary as that....Yawn....

I’m fitting a scootopia hub onto a new casa layshaft and have the same issue as in the cone is loose on the shaft, and when I tighten the hub nut although not fully torqued up But tight I can pull the hub off the shaft although the cone stays locked in the hub. Second issue even with a thicker washer I think the hub nut may be bottoming out.