TFS speedo drive (again!)

[Ian]

I'm starting a new thread for this as it's a slightly different question to a previous thread on the subject.

I want to fit a speedo to my TFS, driven off the BHC hub. At present the hole on the backplate where the drive would mount is blanked-off. I have several speedos available, but am looking to fit a 'D' shape Smiths one. However I see there are variations - I have one that is marked up to 55mph, but another up to 70mph. Obviously my TFS isn't going up to this kind of speed, but does the internal gearing (i.e. rotations per minute of the drive cable to speed on the display) vary between these two variations?

And then there's what to fit to the hub...

IanCordes mentioned elsewhere: "The TFS drive is the same Greeves part number as that of the TES; M/WBB105. It has the 44 tooth drive ring and 14t tooth pinion, so the gearing is all the same."

I am guessing that the pair of gears aren't inside the hub - I can buy these from Villiers Services. But what about the actual drive that sits on the outside? Are these still available or do I need to source one secondhand? And then of course some maths is in order to work out how it should be geared, but that depends on the speedo. I'm not fussed about being dead accurate, but I want the speedo to be more or less right.

Any help appreciated!

[IanCordes]

Hi Ian. The calibration of the speedo head is what differentiates between the 55mph & 70mph D shaped speedo. You can have the faces changed, and the unit re-calibrated to suit the new face.

They would both have the 44/14 tooth arrangement at the back wheel. The speedo drives fitted to Greeves right through appear to be the 1.5:1 ratio, model BG2504/01 right-angle drive.

The D shaped Smiths chronometric speedo was last used to my knowledge on the TES, the 70mph version.

.I think the TFS had the 60mm round magnetic speedo, mounted in the cast alloy binnacle with the small hole (obviously!) The export TFS Trail had the large grey-faced Smiths magnetic unit in the large-hole binnacle,

You may be lucky and find the 44T bevel drive gear still in the hub, which will save a bob or two, provided it is sound. If you need to change it, remember it has a left-hand thread. Also,there is a right and a wrong way round, although it will of course go on both ways.

The 14 tooth one is attached to the right-angle drive unit with a split pin.

You will have to source the right-angle drive unit second-hand.They do come up, but fetch brave money, often £120+.

Cheers

Ian C.

[Greevesnut]

Ians (both)
Take a look at page 13 Leading Link No.199 dated Feb 2018. There you will find a list of all the Smiths speedo heads fitted to Greeves trials bikes from 1954 -1966.
This data was extracted from original Smiths information leaflets collated by Brian Thopmson and kindly donated to the GRA a few years back.
Hope this helps
Peter.

[John Wakefield]

East Restorations used to make the angled speedo drives, but I think they have stopped making them, other than that as Ian C says second hand ones come up on 'fleabay' at inflated prices from time to time.
contact:
East Restorations. The Meeting House,
63 High Street,
Navenby,
Lincoln LN5 0EF

Tel. 01522 810029 email: eastrestorations@tinyworl.co.uk

Much better and much cheaper to forget a mechanical set up and fit one of the wired cycle speedos which give much more info, ie re setable trip mileage, total mileage, time and of course very accurate speed indication. Smiths speedo set up on trials bikes was always a disaster, they quickly succumbed to mud and water

[shelly]

There are two types of right angle drive short projection for tin hub and longer for alloy hub they don’t always say on the ad.

[IanCordes]

Ians (both)
Take a look at page 13 Leading Link No.199 dated Feb 2018. There you will find a list of all the Smiths speedo heads fitted to Greeves trials bikes from 1954 -1966.
This data was extracted from original Smiths information leaflets collated by Brian Thopmson and kindly donated to the GRA a few years back.
Hope this helps
Peter.

Yes, that bears out what I said.
Ian C.

[Ian]

Ok that's all really useful info, thanks. My TFS isn't standard and doesn't have the binnacle (it has Ceriani forks) and I think the D shape speedometer will suit it best.

So I'm looking for the 44/14 tooth arrangement in the hub, and the 1.5:1 on the drive. That's good to know. Tomorrow I will have the back wheel off for a look, on the off-chance it has the big one in there.

Who'd have thought rigging up a speedo could be so expensive!! On the TES my dad bolted on a speedo and we tucked the cable under the engine somewhere to get it past the MOT. Given the bike is MOT exempt I could get away with similar, but I'd like it to actually work.

[Mike Norris]

Hello Ian. is it possible to take a drive from the gearbox as per my Anglian. Villiers Services have the parts, they supplied me with all the parts.

[John Wakefield]

Hello Ian. is it possible to take a drive from the gearbox as per my Anglian. Villiers Services have the parts, they supplied me with all the parts.

Only if the gearbox is machined to take the drive, many are not

[350biker]

Having gone through this saga with my '62 model TD just a couple of points. If the thread in the backplate is either not present or damaged dont forget it is a completely wierd thread size. See various comments and threads about this. The rear wheel angled gearbox comes in all maner of specifications and could be the wrong gearing and even the wrong direction of rotation. East Restorations sorted mine out for me a year or so back. Also the accuracy of the speedos leaves a lot to be desired but surely the gearbox mounted version can suffer from the wide variation of gearing generated by different gearbox and rear wheel sprocket sizes. Clearly a rear wheel mounted version does not have this problem. I have the D shaped speedos and use my 70 mph version on the Greeves, the 55mph version is now on my 1949 BSA Bantam!. 70 mph was a bit optimistic for my rigid D1 Bantam.

[IanCordes]

It is pretty straightforward really. The speedo drive for TCS, TDS, TES & TFS is BG.2504/01, as confirmed by the parts list for all these models. They all have the 44 tooth drive ring and 14 tooth driven gear.The number is stamped on one of the end caps; see attached. It is a short reach, irrespective of tin or alloy f/w hubs, clockwise rotation. Greeves part # M/WBB105 in all cases. The tin hubs have the nut inside the brakeplate, the f/w hubs have the nut on the outside. All but the TFS had the 'D'shaped chronometric speedo head, which I believe was actually an 80mph unit, not 70 as I said earlier. The TFS had the magnetic speedo; specials excepted.

Ian C.

[PeterJGreig]

I have two of the brakeplate drive units, one with about 30mm of thread to fit thro' the b/plate and one with 15mm, the longer one needs a good clean & grease, tother needs the skills of a decent lathe operator, I would tackle it myself if I were going to use it but anyone reasonably competent could do the job. No sensible offer refused. I also have eight! of the gearboxes which fit on the wheel spindle in various states, let me know if any interest. Did we find a source of parts for the CEV (I think) front wheel drive units? Mine was pulled apart by a too short cable. Peter.

[trialrider17]

Ian ,a couple of the speedo angle gearboxes on Ebay at the moment .
Simon

[Ian]

Good info Ian, thanks.

The threads appear to be intact on the hub itself and the backplate, unfortunately the 44 tooth gear is absent. Perhaps some minor work with a needle file is needed to tidy the threads up. The one on the backplate had a rubber bung in it which I carefully replaced for now.

Peter - I can find out which length of thread I need. Are they both the correct ratio/direction as above? Also do you have pictures or a description of what lathe work is needed. I am fairly competent so I may be able to take care of it.

I will need to buy the 44/14 gears anyway - am I best contacting Villiers Services for this?

Thanks.

[John Wakefield]

East Restorations did do the gears (see) https://www.greeves-riders.org.uk/fo...st-restoration