Alloy wheels for Javelin/Jupiter, possibly others

[Chris Spencer]

Here you go again Jack only informing our dedicated loyal members and readers of half the story - pray why have you not also informed them of the 'Moon Dream Scale' - you know the one where you loan Keiths glasses after coating the lenses librally in 'Ribenia' (blackcurrent juice) and wonder aimless around the workshop !

Not be outdone of course by the well known Moon scale of 'It looks like I can strip this thread if I just give it a little turn more' Opps !

And there is always the classic Moon scale of 'This is what I am actually going to do but then again I might just change my mind and do several other things instead' !

[Jack]

Quick update on this, as we have now got the wheel and hub to Compomotive who have looked at things.

The PCD on the Jowett wheel is 180mm, vs the Saab 175mm. Not a big difference, you might think, but enough of a difference that the blank Saab wheel can't be drilled in a slightly larger PCD - there isn't enough material outside the bolt holes for them to be comfortable doing this.

They are researching alternatives for us, as they manufacture in house there may be potential to manufacture something with a slightly larger PCD and match the offset of the existing wheels. They are researching this for me and will give me an idea of costs before we go ahead with anything.

Nothing is standard, nothing is simple...

[juliancrossley]

Hi Jack
Did you manage to get a set of wheels in the end from Compomotive to suit the Javelin PCD? I 'm looking for a set to suit my Javelin race car project. Do you know if the offsets are the same as the Saab?
Julian

[Forumadmin]

Jack and Amy are in Harry Potter World in Florida, so I will answer. Jack did not have success, although they did have one of my wheel for weeks measuring it. I think the conclusion was they did not have a stock wheel. Not sure where we go from here, as I doubt if we can get a concensus on what diameter and width are desired. The most important to some is the look, so we either need a Javelin or Jupiter looking wheel, rather than a later Minilite or even more modern spoke.

Do we change the hub so we find a more common PCD? Perhaps go for an Alufin or similar?
Do you change the rear axle to sort half the problem and then worry about the front?
Clearly the most popular would be a plug compatible Javelin or Jupiter wheel, but I doubt if alloy would be strong enough unless considerably thickened. It is worth considering as wheels and tyres may get scarcer and more expensive.

I used a SAAB 15" wheel and redrilled 5 new holes on Jowett PCD to go racing on, used spacers on Land Rover studs to get correct steering geometry and anti-fouling. To accomodate the slight lack of metal some weld was added. But these were steel, but could be done with alloys.

[Srenner]

Well, it's time to re-visit wheels and things!

Even after building up material in weak spots and stress relieving the wheels through freezing, I got a couple of cracks in new places running 758 in two race weekends. Very discouraging.

In no particular order of preference:
1)Fabricate a thin plate for the inside of the wheel, welded to the wheel center with arms radiating out to the rim and welding them at that point as well. Sort of a double panel wheel. Will require a jig, truing, longer wheel studs and ?

2)Meet with some metal spinners here to have the centers remade, but I think JCC or JOAC tried this without success.

3)Make new hubs (f & r) to switch to a different bolt pattern. I'm thinking Jaguar due to the 16" XK120 wheels period looks. Just having the centers would allow selecting a rim width if one wanted to stick with stock tire sizes. Not sure if the tangs for locating the hubcaps are the same circle. Datsun (Nissan) 240z, et al rear drums are 9" alloy, but getting scarce. I have one to play with and things could be promising.

4)Adaptors per the photo Moises posted earlier in this thread showing a Jowett ft hub capable of using VW wide 5 pattern. Not sure if my race organizers would approve of that. (How does one post the previous stuff inside the new post?!?)

5) Datsun (Nissan) 240z,260z and early 280z rear drums are 9" alloy, but getting scarce. The Datsun club is planning a run. I have one to play with and things could be promising.

Open to any and all ideas on this issue. Willing to negotiate, compromise and grovel, if needed. MMmm, sounds a bit too much like my dating life.
Cheers,
Scott

[Jack]

Hi Scott (and everyone else)

Now back from visiting Harry Potter, managed to get through the entire experience without Amy spending money we don't have on wands, cloaks, scarves or anything else in the huge number of shops. Great fun, but very hard work walking all day. We also managed to spend an entire week in the US without visiting IHOP once as discussed last year. I did try Denney's eat as much as you like pancakes though, managed about 4 before giving up - I feel I have let myself down.

So back to wheels. The outcome of all of the discussion with Compomotive was that they could do it, and would do it, however we'd need to have a reasonable quantity in order for them to produce a modified design similar to the one they have produced for the Saabs linked above. We lent them a wheel to measure with a view to modifying the Saab wheel, however they weren't comfortable with the reduced material outside the holes on a Jowett wheel, so wouldn't supply them drilled for us. For racing or even road use it sounded dubious, so a replacement wheel is what is probably required.

To my simple mind, it seems easier to get a wheel made to the correct PCD for the drums and other fittings we already have. Replacement wheels can't be that difficult to produce in steel, and with alloy wheels becoming more and more affordable for even custom jobs it seems like the simple solution instead of trying to get drums from other manufacturers to fit and then facing a number of other issues with the axle, offset, suspension etc.

I can reopen discussions with Compomotive if there is significant interest, but there would need to be a reasonable demand for a single type in order to get the designs sorted.

The other interesting development on the Works Experimental car were drums from what we think was another car, as yet unconfirmed which, which have a smaller PCD. That may enable use of the Saab alloy wheels, or indeed provide a source of steel wheels for us. It is on my "to do" list to get the PCD accurately measured from those wheels in order to try and establish what car they came from - from the two different drums we have (with the same PCD) it seems that there is definitely something else out there that fits, and the taper etc on the axle is the same as far as we know. Keith may be able to provide a bit more insight into this as he removed the drums a few months ago for the rally and is more familiar with the originals than I am. This could be our low cost solution - take parts from other more common cars or from other clubs which may have had parts remanufactured.

Jack.

[Moises Jr.]

I am not an expert on the subject, my dad knows a lot more than this, but it has an adapter to use WV beetle wheels, but on issues of competition better look porsche wheels 356A.



There are a number of adaptations of Fuch or targa type tires that are not valid to be closed in the center.



Regards

[Keith Clements]

Jack and I are continuing discussions with Julian Crossley about manufacture of aluminium finned hubs to fit both Jowett PCD (stud pitch circle diameter) wheels and an off-the-shelf wheel (probably SAAB PCD). The advantages of this hub will be it will be about 40% lighter and thus reduce unsprung weight, have less inertia for acceleration and provide considerably improved cooling thus saving on brake material and bearings. We are aiming for a cost of about £300 per hub designed and manufactured by a reputable manufacturer.

There is a lot of design and prototype testing to be done but we would like to hear from anyone who may be interested now so that we can include their ideas and bring down costs.

We hope to offer a package that has been race and rally tested. So watch this space for the revival of the Jowett Team Sport. The hubs can be further improved with ducted cooling as used by some of Jowett Team Sport previously. We may be able to offer different brake lining materials for competition work.

Hopefully the wheels will look similar to the Jupiter wheel and should be able to offer a selection of tyre sizes and tread patterns for daily and competition use within various homologation regulations.

[Srenner]

I'm in.

[Drummond Black]

Looking at the possibility of fitting other wheels takes me back nearly 40 years when I converted the Javelin to use VW 5 1/2 J wheels but still retained the Jowett hubs. I looked and measured numerous wheels around at that time and I remember that Saab and Jag were considered. I still have the jig I had jig bored to modify the hub for the different PCD . I know that a 1/4 inch adaptor ring was fitted to the front hubs and I think that was required to allow clearance for the track rod end.
I then fitted 1/2" Dia high tensile studs. The VW wheels were 15 inch dia which could take a wide selection of tyres.
My recollections of driving improvements were positive and the overdrive on the Javelin compensated for the slightly smaller wheel circumference. That Javelin also had a Jupiter axle fitted.
Takes me back !!

[John Dolphin]

I would be interested in a set of Alfin Drums and hubs.

I had a chat with Typecast at Silverstone a couple of years ago and mentioned that the Jowett drums were integral with the hubs. They suggested making a separate hub and having replacement finned drums. I think that this is what the works race cars used as you can see a second row of six studs inside the wheels studs.

I have also see photos of the works car alfin drums and the fins are stepped to clear the inside of the wheels.

I asked about how the braking surface was keyed to the aluminium drum and it sounded like the outside of the cast iron braking surface had projections on it to key into the aluminium. I remember reading that the works rally cars had problems with the cast iron brake surfaces detaching from the drum after long alpine descents.

[Forumadmin]

Ok so I will fit them to Peter's car whilst they are here and test them when I take it back to Switzerland!!!! Hopefully manufacturing techniques have improved in the last 60 years.

[PJGD]

Since we are in an updating mode, can we also:

a) Design the hub to accept taper roller bearings from the word go? That would improve the life and reliability of the inner hub bearing which has always been a problem, particularly on the heavier Javelin but by no means unknown on the Jupiter.
b) Is it worth protecting the design to make adaption to front disc brakes a possibility? Of course, discs need to be used with a brake booster which both probably need to be Girling (not AP Lockheed) to keep the materials compatible with the original master cylinder and rear brake cylinder seals.

Philip

[Keith Clements]

Thanks Philip, I will put the preliminary design in the Gallery which should be before the end of the month. We did discuss tapered rollers but I am now using sealed for life bearings which are less than £14 per axle, so it may not be worth the trouble to redesign. I do agree they used to go frequently but found using Bentone based grease seemed to cure the problem. Can someone find the tapered roller mod drawings that I think John Blaze did and post in the Gallery, please?
Ben Shaw fitted a brake booster to my Javelin in the 1960's. Brilliant mod but whether it would work on discs is another matter. Homologation too may be an issue. Would it not be better to simply have a separate design for discs?

This is from Jullian yesterday.

I have spoken with Typecast and asked them to produce a design along the lines we discussed on Wednesday. They will look at 3 PCD options standard Jowett, 170 Compomotive HSP1550 and 165 which is available as a 15”dia steel racing wheel from Weller. I need to contact Weller who are just around the corner from us to make sure they can do a width of 5” instead of the 7”which is currently listed on their website. I have also asked them to ensure the drum face stays on the same relative position as standard.

I have also spoken with James at Compomotive who is sending me a drawing over of the HSP1550 wheel detailing the offset dimensions etc. With this it should bepossible to confirm any foul condition and spacer requirements if this vehiclewere used.

Budgetcosts for these wheels are around £160 each but the price can be reduced if we were to order say 4 or 5 sets. The Weller are much cheaper around £70 but of course don’t offer the same rotational mass advantage.

As my car is stripped at the moment I can’t check the wheel clearances so if I send the drawing to you would you be able to check them or find a man who can?

Typecast are working on the first cut design to the timescale we discussed in time for the rally so with a bit of luck we should have a meaningful design and costs by then.

[PJGD]

I have posted John's bearing modification drawing to the gallery here: https://jowettnet/forum/download/file.p ... &mode=view