Tyres for the Citroen H, HY, HZ van
The tyres available for the Citroen H van were 17r400 and the taller 19r400. The later tyre gave the effect of raising the gearing with more relaxed cruising/higher top speed. The 17r400 tyres are still available from specialist outlets, Vredestein recently ran off a small number, but they are over £330 a tyre. See here for a supplier of 17r400 : https://www.classictyres.com/item/647/17r400-vredestein-transport-classic--commercial-tyre--road--citroen-h-van We have not been able to find a supplier of 19r400.
The overall diameter of a 19r400 is about 28.4 inches and the 17r400 around 27.3. Width in each case, side wall to side wall is around 190-195mm. The diameter across the opening of the tyre is 400mm, the diameter across the opening of a modern 16" tyre is about 406mm. In theory this might mean that a 16" tyre is slightly too big for the H van wheel.
While I have seen warnings against using a modern radial on a H van rim, many people seem to use them without issue.
This page is about exploring the possibility of finding a modern heavy duty tyre to substitute the expensive metric tyres and get more relaxed cruising into the bargain.
A 195/75 x 16, which seems to be about 22mm/1 inch lower when placed next to a 19r400 has an overall diameter of 27.5inches, so seemingly more the size of a 17r400 tyre.
Someone with an Arca Motorhome (based on a Peugeot J7 chassis from the 1970's? ) wrote :
"On my Arca tyres are Michelin XCA75 19R400, a metric size and now almost unobtainable. Other owners have fitted 16" size tyres with no apparent problems. My own Michelin Agilis 205/75-16 are a very close match".
A 205/75 x 16 with a diameter of 28.1, is slightly smaller than a 19r400, so probably not going to give us the cruising improvement we are after but a lot better than a 17r400 or the 195/75 x 16 that is a common fitment.
A 205/80 x 16 has a diameter of 28.8 which might be perfect on an H van to raise the gearing slightly to give more relaxed cruising?
The Load rating is important, especially in a HY Catering conversion or Camper van which can weigh 3,000Kg+.
Contrary to myth you do not need 7ply tyres or C rated tyres or Commercial Tyres on your Van.
The Law on a tyres load and speed capability are covered by Regulation 25
The Regulation requires that the tyres fitted to the vehicle are not only capable of supporting the maximum permitted load on each axle but of doing so at the vehicle's maximum speed. To keep within the law you must always fit tyres that have a speed capability and load index at least equal to or higher than those originally specified by the vehicle manufacturer.
So in our case with a 2,995Kg all up weight each tyre should be capable of handling 3,000Kg / 4 = 750Kg at the vehicles rated speed.
This is one of the better explanations of Tyre Load Index and Speed Rating.
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=35
Using this guide my load rating should be greater than 100 but remember that modern load ratings are based on a high maximum speed. For example a 205/80R16 104T has a maximum load capability of 900kg at 118MPH, the slower the vehicle the higher the load the tyre can safely take at that lower speed.
For example a 104T rated tyre at the Citroen H vans top speed of 60MPH will be nearer 1,250 Kg, so the four tyres would safely support 1,250 Kg x 4 = well over 5,000Kg and a huge safety margin.
What you should avoid are retreads/remoulds as these have a much lower Load Index rating AND Speed Rating, possibly invalidating your Insurance and be illegal.
The the new Vredestein 17r400 tyres have a max load of 850Kg and the Speed Rating at 81MPH, equivalent to a 102M. A much lower load capability than a modern 205/80r16 104T.
While the taller 205/80r16 tyre might alter the speedo reading by recording a slightly lower figure it should be remembered that most speedos are optimistic by about 10%, but something you need to think about.
UPDATED 12/09/13 : Someone has tried a 205/80/16 with great results.
ERIC PORTER put 205/80-16 on his Citroen H and writes :
UPDATED 21/10/13 : Someone has tried a 205/75 x16.
"Hi, this is to tell you that I have just fitted 205/75 x16 tyres on a OEM Citroen hy wheel with perfect fitment, no problems whatsoever. Of course, an inner tube was used for added safety. Regards, Petros Gkanoutas".
Please note that there several variations of this Continental Contact tyre with similar letters, but only the 110S TL has the high load ratings. The 104T XL, for example, is an old now obsolete tyre that is still available at some suppliers.
For a budget alternative try the Avon RANGER A-T 104T 205/80/16 R16 it is a more chunky tread so probably a good Winter tyre. Available here at around £64 : http://www.camskill.co.uk/m64b0s233p108162/Avon_Tyres_SUV_4x4_Avon_Ranger_AT_-_205_80_R16_104T_XL_TL_Fuel_Eff_%3A_G_Wet_Grip%3A_C_NoiseClass%3A_3_Noise%3A_72dB
National Tyres also stock both tyres. We have seen other tyres, like Hankook, for a few pound less than these two, but the Load, Noise, MPG and grip is not so good overall.
We can not recommend any one adopts modern Radial tyres, but it has been suggested to me that if you go down this route, while a modern radial does not require an inner tube for sealing in the air, you should still use an inner tube as it helps with the tyre seating on the rim and compensates for the switch from Metric Tyres so is essential from a safety viewpoint. Atlantic Motorhome sell the correct inner tube for the above tyre sizes. Please note that the valves are different dependent on year.
Engine/Gearbox conversions and the part played by the Wheels/Tyres
Related to the above and the way the tyres affect the gearing is Engine and gearbox conversions. There has been much talk about, and some actual conversions, to the Audi turbo diesel engine and box. We have looked at this in detail (using similar Passat engine/box) and there are a number of issues directly related to the drivability of a converted van because of the gearing differences between the H van and an Audi car, primarily because of the wheel/Tyre size.
The Audi gearing is set up to drive a light weight, aerodynamic car at up to 130mph with the engine turning at 4,300rpm. It has small wheels compared to the H vans. If you put Hvan sized wheels on a Audi it would raise the gearing by up to 25%.
The H van is anything but light or aerodynamic, especially a Hi-Top. Throw in a 25% increase in gearing that would drop the revs at the H vans 60mph top speed down so low the top 3 gears are unusable. Also the bottom 3 would be so high that it can go almost as fast in 1st with the Audi engine as it does in the original vans 3rd gear.
Which is great, except that try to imagine what it would be like to pull a fully laden catering van away from the lights up a slight incline in a 1st gear that is now as high as the original Citroens 3rd!!
If you still think it would be ok, consider a Volkswagen T5 1.9tdi pd from 2006 (same sort of era used for the similar but slightly more powerful Audi engine/boxes) with a gross weight of around 2,800kg, dependent on model.
The H van is usually heavier at 2,950kg and less aerodynamic by a factor of at least 3!! yet the T5 gearing is set to reach max revs in top about 79mph, not the 128mph of the Audi. The T5 has a 1st gear that maxes out at about 14mph. There is a very good reason it is not 45mph!!!
The Audi is a light nimble car, so pulls away from a standstill with no drama. But the same gearing in a heavy truck just doesn't work. Increase it by 25% because of the huge wheel/tyre combination in the H van and you are really stretching things. If you do go down this route, may we suggest you either fit 10inch wheels with 50 series rubber or keep a fire extinguiser in the cab ready to spray onto that burning clutch?
We have thrown out the idea of the Audi/VW engine/box option, not just because of the above, but because the Electronics and wiring required are hideously complex and almost unmaintainable by an ordinary Garage who would have no manual or documentation. Simple faults could mean weeks off the road while the mechanic works it out.
Our preferred route is to fit a more powerful (90bhp as opposed to a 1951 H vans 39bhp), modern Ford engine to the existing gearbox, without any complex Fuel Injection or Electronic Control Unit.
Apart from improved drivability, relibility, cheap parts, longer service Intervals, lower running costs, etc the most significant benefit is almost the opposite of the problems above. The new engine revs to 6,200rpm, 2,000rpm more than the standard engines 4,200rpm, giving 30% more speed in EACH gear without any change in gear ratios. So you still have a low first gear but the Ford engine gives you the option of higher speed before you have to change up.
This reduces the gap between the gears, Top speed also rises by 30% making cruising at 60mph a comfortable option. The shorter stroke Ford engine is more refined and quieter than the Citroen 1,911cc unit. It is also more efficient so uses less fuel for the same power produced.
Compare the following costs:
Item Citroen Ford
Electronic Distributor 250 79
Alternator 190 69
Starter 190 120
Clutch Cover 152 47
Exhaust 400 120 (twice the Silencing)
Rebuild 2,000+ 990
By changing the Engine you also overcome the primary limitation of the original Citroen Gearbox.
Our Ford conversion kit is ready now.