javelin Radial tyres- again Sorry Folks!

[paul wilks]

For those of you who have been following this thread and have not simply got bored (and I wouldn't blame you!) the latest in the saga.. (I have also been in regular email correspondence with David Morris, Alf Heseltine and Drummond Black and thank them for their patience!- Thanks chaps)

I duly bought five 'Nexen' 175/75 R16 101/99N 8P.R radial tyres and had them fitted to my 'new' JCS commissioned wheels (bought about twenty odd years ago and never used). To cut to the chase, they wouldn't fit under the rear near-side wheel arch.

I have measured the tyres and they are exactly the same spec (apart from make) as fitted to Alf Heseltine's superb Javelin. But Alf's are about 6" wide and mine are 6.25". I have also measured the clearance between my Avon HM Tourist cross plies fitted and the inner wheel arch and this is 0.75" at the nearside (metal) wing and 1.25" at the offside (fibre-glass) wing. Both were obtained from Ken Braddock (Roy's brother) over 40 years ago. Perhaps they are narrower than the original wings? It certainly looks that way. It's obvious that even Alf's slightly narrower tyres wouldn't fit under the nearside wing.
I have been in touch with Longstone tyres and they were very keen on my fitting 550 x 16 Michelin X rather than 175x 16 but at 170mm wide as compared to the 144mm of the cross plies these will be no better than my radials and still won't fit. They did however assure me that the cross plies will fit on the wider replacement JCS wheels. I am indebted to Drummond for info on the size- the original wheels were 4 1/8" wide at the rim the JCS wheels are 4 3/4".

So it looks like I might have to throw in the towel re radials for the Yellow Peril.

My next question is aimed at members who are still running Javelins on cross plies. Out of the variety of makes is there any real difference? Dunlop, Avon, Waymaster? I know there are still Javelins on cross plies so I would really appreciate your help in (finally) replacing my tyres. This should ensure I won't have to bother all of you with this question ever again! But of course it doesn't mean I won't be bothering you with other questions- as I have in the past!!

Thanks for your patience
Paul

[robert lintott]

For Paul,

Some saga re radial tyres . I have followed this because as we discussed I am interested in changing to radials . I would suggest looking at several points .
First you have two different wings , there is always scope for variation in pressings especially if they are fibreglass or fitted from other cars. Maybe the edge flanges are different and could be modified? Are they the same distance from the inner wing each side?

Have you checked that the rear axle is centered , for example are the brake drums equidistant from the chassis side members . With the Javelin suspension this location is fixed by the cross tie rod, which is adjustable .

Also are you sure that with the JCS wheels --which are wider-- the outer edge of the rim is the same distance from the inner plane of the centre disc ( ie from the outer face of the brake drum when the wheel is fitted ) as it is for the standard wheel. It could be that the extra wheel width results in an overall wider track which is causing the tyre to foul the wing .

As I understand it others--Steve Waldenberg for example see the August Jowetter--have fitted this size of radial successfully, so either the tyre width you have is larger or the car measurements are different or is it the JCS wheels ? Have you tried fitting the radials to your standard wheels?

I hope you succeed, it would be disappointing to have got this far for no result

With best wishes Bob PS will be in touch about the fuel filter etc

[robert lintott]

Paul, I just went out to my garage to take some measurements on my Javelin which may be of interest. It has 5.50 x 16 Excelsiors which have poor grip in all directions! It has been restored so the rear wings have been off though I expect they are original .The wheels are standard 4" rims .

I had not noticed before but the two wings are of a different shape . where the tyre passes the inner flange at the rear on each side the gap is 2 inches on the N/S and 0.5 inches on the offside. At the front intersection the gaps are 1.5" and 1.1". The O/S wing is in line with the cill at the bottom of the doors but the N/S is well outside . I think this is entirely caused by the wing shape since the wheels are central on the chassis. I measured the distance from the outer face of the front yoke on the trailing arm and the tyre on each side, each is 2.25".

Application of pressure on the N/S wing --my knee--- can push it inwards to about the same as the O/S, and the O/S can be pulled out about 1" quite easily . I will consider fitting a brace , tension on one and compression on the other--if I go to radials

On the standard wheel, the outer rim is in line with the inner wheel pressing where the hub cap fits on , perhaps the JCS wheels with a wider rim are outside the line? . The rim edge is approx. 1" outside the face of the brake drum on standard .

It may be that you can push the wing (s) out enough to get clearance, though the clearance may be poor when cornering , on the front as well? Perhaps an antiroll bar would help? , Alternatively fit the radials on the standard wheels?

I hope you will be successfull and report regards Bob

[ChrisCole]

I bought two 175R16 radial tyres for the rear axle - they fit fine, they are 19 mm (3/4") wider that the cross ply Avons. There is clearance to the rear wings. For a trial I then fitted them to the front axle and raised the front on two jacks on the lower wishbones so they were 'as on the road' but I could turn from lock to loack. On right lock the tyre hit the chassis and on left lock the exhaust. Also they were both just about to hit the top steering knuckle (old style suspension). I then went for a drive - it was very bad, the car had a sway action all the time and my son felt sick. This was admittenly with cross plys on the rear!! So another problem is chassi foul on the fornt and does anyone think the ride would be better if all radials were fitted?

[M S G Benning]

According to my information, it should be Xply to front & radial to rear.

[Keith Clements]

Where did you get your information? I would think that mixing radials and crossplies is not a good idea, but I cannot think of a technical argument to back that up. I would have thought that you would get more understeer with crossplies on the front and more oversteer with radials at the front, based on the relative wall stiffness. You would also get less front wheel braking with crossplies on the front so, unless you have a brake bias adjuster fitted to control that, I would have all four tyres the same.
This is all assuming you have the steering geometry set up for the specific tyre you are using. If you have not changed it then your offset, castor and camber may well be incorrect and you will either have light or heavy steering as well as perhaps dangerous self centering.

It is also assuming the tread and rubber hardness are similar which will affect how the tyres perform in dry or wet conditions.

[M S G Benning]

It would be better if all xplys are used or all radials, but if you are going to fit 2 of each, the radials need to be fitted to the rear & xplys to the front otherwise it is an MOT failure & has been for a VERY long time.

[M S G Benning]

this is why they should not do away with the mot,s

[Forumadmin]

Why is it an MOT failure? apart from the obvious 'it is dangerous'. I guess oversteer is more dangerous than understeer if my hypothesis is correct. I may well have known the answer to this in the early 70's but do not remeber now!

[Jack]

I would have been surprised if it failed an MOT, I was only aware that the tyres on each axle must be of the same type and size. But in the manual it says that a cross-ply tyre or bias-belted tyre fitted on rear axle and radial-ply tyre is fitted on front axle, or a cross-ply tyre fitted on rear axle and a bias-belted tyre fitted on front axle is a fail, so an observant MOT tester should fail it.

Jack.

[garthwright]

Just to repeat the gist of an e-mail I sent Paul way back, I took the luxury of fitting my Javelin with 4 off 165(80)HR16 Avon Turbosteel some 3 years ago. They are pricey - I recall about £160 each by the time I had done a deal. But the transformation of the steering, roadholding and feel of the Javelin is just amazing. Had always used Avon Crossplys before - however these cost ~£100 and wear out or perish relatively quickly.
The 165HR16 also looks good on the standard Javelin rims. The supplier couldn't balance them but they haven't needed it yet. Wouldn't have another crossply anywhere near the Javelin after experiencing the difference - it feels now as a modern car - precise steering and none of that cat's eye wander. Couldn't afford a spare but then haven't needed one in 22 years and any tyre would do in an emergency!
Anyway I can only but report that my driving experience of the Javelin since fitting these has gone up several fold!

I have 175/75r16 -6 ply tyres on the wider JCS wheels on my Jupiter - hardly worn after many years but awful on balance/weight. Am saving for 550r16 Michelin X's which are lighter (11kg) - experience seems to be very positive with these (on the wider JCS wheels?), any detailed comments would be welcome on this.

[jowettgeoff]

Firstly, I can confirm that when radials were starting to become common, 'official' recommendation was that if mixed with crossplies, the Radials go on the Rear (R & R, geddit?). this is because perceived wisdom is that 'ordinary' drivers should only be allowed to have cars that understeer - a mantra that persists today, which is one reason why modern cars usually have stiffer anti-roll bars at the front than at the rear.
Ref the JCS wheels, I was involved in setting the parameters for these. The conventially-designated rim size is 4"J, as opposed to the original Jowett's 3"J .The lettter J relates to the rim type. To the best of my recollection, (not always reliable!), I asked for the rims to be mounted to give 1/2" extra both inside and outside, thus retaining the original contact point centre, and not interfering with the cars' original geometry. This also compensated for the fact that the front inner rims can be very close to the track rod ends. Additionally, they are a slightly heavier gauge than the originals. Regarding the rear wing clearance, it seems fairly common for Javelins to have an unequal clearance left to right. I suppose this could be adjusted by means of the Panhard rod - though this seems a bit brutal. Even more brutal is to grind down the lip of the wing on the offending side, which is precisely what I've done . Concours owners will shudder - but if you decide to do this, be careful that the heat from the grinder wheel doesn't blister the paintwork.
I recently posted about the Austone 175x16" Taxi tyres I've had fitted to the Jup. I can report that they are bedding-in nicely, and have a nice 'drifty' cornering feel, though there is a slight balancing issue around 60. I reckon driving at 70 is the answer, but my dear wind-swept wife prefers 50 .

[Forumadmin]

This I found useful http://www.longstonetyres.co.uk/page/help
I am about to replace my Henley 5.00/5.25x16 tyres so am contemplating what to do. Keep with the crossply look and feel or go for radials and be able to stop and corner. Never has there been a more difficult choice.

Crossplies http://www.longstonetyres.co.uk/search? ... 1&x=34&y=6
or http://www.classictyres.com/item/534/50 ... d--premium
500/525x16 Waymaster Premium 685d 146w £74.50 Max Speed: 75 mph Max Load: 400 kg Weight: 6.7 kg
500/525x16 Dunlop C18 678d 144w £109.50 Max Speed: 95 mph Max Load: 381 kg Weight: 9 kg
500/525x16 Excelsior 660d 105w £74.50
500/525x16 Avon Tourist 678d 144w £112.50 Max Speed: 75 mph Max Load: 400 kg Weight: 7 kg
500/525/16 FIRESTONE 57MM WHITE WALL Diameter: 673 mm Section Width: 134 mm Max Load: 485 kg Weight: 8 kg £199.20 inc. VAT

Now if you are prepared to fit a wider 5.50" or 165mm tyre to the rim http://www.longstonetyres.co.uk/search? ... 6&x=35&y=6

Radials
550HR16 Michelin X 690d 170w £159.50
165HR16 Avon Turbosteel 674d 165w £162.00 Max Speed: 130 mph Max Load: 531 kg Weight: 9 kg
Race but road legal
550x16 R5 Dunlop 688d 178w £199.50 Weight: 7 kg

Prices add VAT! and do not forget some tubes.

Note the 175R16 AUSTONE CAR TYRE: ROAD: TAXI: TL Type: RADIAL Diameter: 685 mm Section Width: 185 mm Max Speed: 87 mph Max Load: 750 kg Weight: 10.5 kg

is really too wide to fit on a standard Javelin Rim. Indeed it may be illegal and invalidate insurance but it is only £82 inc VAT!. As someone said on the MG YA forum, fitting wider rims and new tyres is actually cheaper than just getting new tyres.

[jowettgeoff]

My Austones are CSR81. Speed rating Q. =99mph max.
Phew - you had me worried there for a moment Keith
I think what you say about 175/16 Taxis on 3" rims is absolutely right. But certain Jowetteers have raced and rallied with Kingpin Taxis, haven't we
Then again, we Jowetteers like a bit of danger eh?
G McA

[Forumadmin]

Yes we have Geoff, but were we not all on widened rims in the end?

You need to have them at 40 psi to stop the tyres rotating on the rims when you brake hard when on such narrow rims! I would not recommend fitting them to standard rims.

By the way, when do you go above 87mph? You naughty boy!