Land Rover Lightweight

23-KB-26
 Rims, Valves,Tyres and Speedometers
 The majority of Lightweights were issued with 5.00 F x 16  standard rims.

Rims
5.00" F x 16 FV607330 231601 riveted STC 3402 welded
6.50 x 16 tyres were standard on 5.00" F rims
5.50" F x 16 LWB  rim  569690 (riveted) NRC 7578 (riveted)  ANR4636   (welded)
569690 - 1 5/16" off-set (33mm)
5.50" F x 16 FV2000727 NRC 7578 ANR 4636
5.50" F x 16 x 33 This means the face of the centre of the wheel where it sits agains the hub face is 33mm outwards (positive offset) from a vertical centreline through the wheel
5.50" F x 16 LWB  rim 272309 (riveted) was an earlier rim with a
1 13/16in offset  (46mm)
The latest rim that has been fitted to the Defender 2005 on, is the RRC503600 a  5.1/2" J x 16 it looks very similar to the conventional well base but has the bead hump (safety bead) and is marked on the periphery "TUBELESS".
It is a modern rim that you would have to take a close look at to see the bead edge with a tyre fitted.  It maintains the Series looks but uses the best modern rim section for a tubeless tyre
For Details of the Rims look HERE


Valves

The original hole for a valve stem on a Land Rover rim  was 5/8" (15.8mm)  When the tubeless rim with bead hump appeared that had a 7/16" (11.5mm) hole for the valve stem. It is best to fit tubes with the larger rubber inflation stem on Series rims. You can fit tubes with the smaller diameter stems but you should install a plastic valve grommet in the rim hole.

  Common Tyre sizes  
       
  6.50 x 16   
     
7.50 x 16 7.50R16 205R16 205/80/R x 16
Most tyre makers specified a minimum of 5.50" rims for 205R16,  7.50"x16 or 7.50R16 sizes
 
  My Tyres  
     
6.50 x 16 C  GOODYEAR  HI-MILER (CUSTOM) XTRA GRIP
6 Ply Rating - 28.5in Diameter
       
Kelly Safari SJR M+S 7.50R16LT  112/107Q - 32in Diameter
       
As can be seen from my two sets of tyres, there is a 12.5% diference in circumference. Hence the difference in speedometer readings. My Speedometer reads most correctly on the 6.50 tyres.

Which make? What tread? Can I fit 'bigger' ones? etc.
This is a minefield that at the moment I am avoiding!

Which speedometer have I got?


The identifying mark on the face: SNT 6209/22 1504

The calculations

Series Land Rover have a 4.7 : 1 reduction differential and a   2.2 : 1 speedometer drive gear reduction from propshaft to speedometer. 4.7 divided by 2.2 = 2.136 which means a 1 : 2.136 step up from rear wheels to speedometer. For every revolution described by the wheels we get 2.136 revolutions in the speedometer. This is a constant relationship (K) that can be use in every speedometer calculation.

Here are the calculations for my Imperial speedometer marked 1504 turns per mile.
 turns per mile divided by K gives the number of  turns of the wheels per mile

 1504 divided by 2.136 =  704

 My Lightweight will do 704 turns of the wheels for every mile clocked up on the speedometer.

 A mile is, 5280 feet, divide this by 704 wheel turns gives 7.5 feet of travel per wheel turn

 that is a wheel circumference of 7.5 feet or 90 inches.

Dividing this by 3.14 (close enough to Pi) gives the diameter of wheel.

 90 inches divided by 3.14 = 28.6 inches.

Hence, it is calibrated for 6.50 x 16 Tyres.


Thanks to 'FULLTILT' for his help in preparing this page