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Navigator Tyre choice

Submitted by nicholas_clarke on Thu, 17/01/2019
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Having been given a 'birthday present' of a new front rim, spokes and tyre for my 1946 Navigator by my long suffering and generous wife I realise that my non standard and hideous 3.50 x 18 rear tyre needs replacing - particularly because its modern 'rounded' cross section rubs against the narrow part at the front of the rear mudguard.    My notoriously fickle memory and browse of photos suggests that the 3.00 x 19 Avon Speedmaster Mk 2 I have on the front is the original equipment, handles well and looks the part.   Happily these are readily available.    No where in all my original Norton manuals can I find the rear tyre spec but I assumed it would be either 3.25 x 18 or 3.50 x 18 and probably Dunlop K70 or the Avon equivalent.   Despite much searching the K70 in those sizes is only available for a 19" rim - the alternative being the slightly more modern and 'rounded' (and therefore potentially wider) K82.   Frustratingly the K82 does not come in the right size to fit front and rear so I cant fit a matched set.  Two questions - has anyone experience of mixing the Speedmaster and K82 front and back on a Navigator and if so do they complement each other in road holding.   Secondly which is a better choice for the rear, does the 3.50 tend to foul the rear mudguard or do I need to fit the 3.25?    Needless to say I don't want to fit modern or foreign tyres which just don't look right in my eyes!    I hope that all makes sense and look forward to your wisdom!

Nick              

Submitted by dan_field on Thu, 17/01/2019

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1947 eh, that’s an early one! ;-)

I’ve got Mitas on my Jubilee, they look fine and seem to handle well enough.

But I have the same decision to make on my Navi which needs a new set of tyres. I never liked the square section tyres, and am also looking at the K82s

Dan

Submitted by nicholas_clarke on Thu, 17/01/2019

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Thanks for that Dan, I have measured the rear tyre which is rubbing against the mudguard on the near side where it narrows for the chain guard.    That tyre is 100 mm wide where as the K82 350 x 18 is only 93mm and the K82 325 x 18 is only 89mm.   I wish I could track down the correct data for the original tyre to know whether to go for the 350 or 325!

Nick 

Submitted by gary_painter on Thu, 17/01/2019

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Whatever tyres you choose, don't bother getting them from feked.com.

They hold very old stock and charge full price for them, with postage on top

It's very unwise to use tyres after they are 5 years old, as they deteriorate and performance drops off dramatically.

The date stamp tells you when the tyre was made, it's a moulded in, 4 digit number in a little "box" with rounded ends.

First two digits represent the week number, second two digits represent the year. Hence 0319 is the third week in 2019.

Submitted by patrick_mullen on Fri, 18/01/2019

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I am pretty sure that the original tyre size on a 1959 Jubilee was 3.25 front and rear. The later Jubilee models MIGHT have gone down to 3.00 on the front but kept 3.25 on the rear.  The standard Navigator probably was 3.00 front and 3.25 rear.

What sort of use do you have in mind?  For ordinary every day road  use I doubt if there's much difference between brands so I use Mitas on the rear.  If you are seriously into competition performance where every hundredth of a second is critical that might be a different proposition but the difference between soft, super soft, ultra soft  gets seriously expensive for very marginal returns.  Jubilees/Navigators never were high performance - pleasant tourers is a fair description.

Patrick     

  

Submitted by nicholas_clarke on Fri, 18/01/2019

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Thanks for all of that Patrick, very helpful - I have spent a lot of time trawling the internet to find accurate information about Lightweight tyre sizes but with no success.   3.00 seems to be correct - mine has a very old Avon Speedmaster Mk2 on it and it looks right, fits the mudguard perfectly and handles well so I will go with that.   3.25 would certainly fit the rear mudguard but at only 4mm wider I wonder if 3.50 is a better choice - it is what it has on at the moment but it is a very 'curved' profile and 7mm wider than the 3.50 K82.   As for make of tyre, you are absolutely right, given the Navigator's performance I don't need a high spec tyre but being a bluff old cove I would prefer Dunlop or Avon!   A little more research required me thinks!

Nick        

Submitted by dan_field on Fri, 18/01/2019

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I’m sure Andy would know if you drop him an email, or if I remember I’ll ask him at the Bristol show in a couple of weeks! Might get my tyres there too.  I have the same dilemma for my M50, same sort of performance but 19” wheels.

Dan

Submitted by dan_field on Sat, 19/01/2019

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Just been out to the garage, my very usable rear wheel has a Dunlop K81 on it 4.10 by 18 so that makes my mind up for me. Disappointingly the ackront from rim I was intending use to match the rear turns out to be WM1. 

Rear wheel

Submitted by robert_tuck on Sat, 19/01/2019

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The wm1 Borrani Record rim on our Atlas happily carried a 3.00x 19 tyre and was orriginally fitted to an Inter or early Manx, I think its currently carrying a 90x90 tyre.  

Submitted by nicholas_clarke on Tue, 22/01/2019

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Hi Gary, thanks for the info ref feked.com and age of tyres, fear not I will be sourcing them from a reputable dealer!   I will update when I hear back from Andy

Nick

Submitted by nicholas_clarke on Sat, 26/01/2019

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Hi all, 

I've not heard back from Andy S yet but enquiries through a very helpful Dave at Vintage tyres in Lymington (01590 612261) confirm the original equipment front tyre for the Navigator was 3.00 x 19 and the rear was 3.25 x 18.   In the absence of a period matched pair think I will be going with the Avon Speedmaster Mk2 front and a Dunlop K82 on the rear.   I took the Navigator out for a very enjoyable long run yesterday and was again really impressed with how the Pazon electronic ignition has transformed the engine's power delivery.    All I have to do now is find time to replace the weeping timing side oil seal.....    Deep joy!  

 



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