Horizons Unlimited - The HUBB

Horizons Unlimited - The HUBB (https://www.horizonsunlimited.com/hubb/)
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-   -   Michelin XZY 7.50 R16's (https://www.horizonsunlimited.com/hubb/equipping-the-overland-vehicle/michelin-xzy-7-50-r16s-23383)

roamingyak 3 Oct 2006 21:00

Cheers - does using tubes make a difference?

There is a big difference between 60psi that you state and Andrews 48psi!

I'm on a 110 with tubes on standard landy rims etc

moggy 1968 4 Oct 2006 01:04

Quote:

Originally Posted by diesel jim
Taken from one of my military handbooks:

"normal road pressures:

TUL (which is truck, Utility Light = 300Tdi wolf 90)
front 28psi (2bar) rear 42psi (3bar)

TUM (truck utility medium = 300Tdi 110 wolf)
front 32psi (2.2bar) rear 60psi (4.1bar)

battlefield ambulance (300tdi 130" big body!)
front 40psi (2.8bar) rear 65psi (4.6bar)!!!"

then:

"Emergency soft, emergency soft pressures should only be used in extreme conditions where extra floatation is required. max speed 25mph (40kph). return to road pressures ASAP"

unladen:
front 16psi (1.1 bar)
(don't know what rear should be, there is a misprint in my paperwork!)

laden:
front 16psi (1.1 bar)
rear 28psi (1.9 bar)

Is that for the XZY though, as the ambies run G90s

Andrew Baker 4 Oct 2006 17:15

Clarification - based on experience 80,000 miles XZY.

XZY's with tubes, 500 kg load, high temps 38 Deg +

Tarmac road / good or rough piste - FR28 RR42 (1.8 / 2.2 BAR)

Desert sand / general desert conditions (not generally soft) 1.5 / 1.8 BAR

Soft Sand 1.0 / 1.2 * Keep speed to 40 MPH max, avoid sharp turns.

Soft sand combined with dune ascents 0.8 / 1.0 BAR * MAX 40MPH, avoid sharp turns.

The XZY is a super rugged tyre, originally designed for building site use , I have never had a problem in 4 trips and daily UK use, but tubes (I use Michelin Airstop - the correct type for the tyre) are vulnerable to high temps generated by low pressures/friction combined with high ambients.

Military handbook pressures probably refer to temperate Europe.

Always check pressures in the heat of the day in the desert, the opposite of what you should do in the UK. The tyres heat up as they do in the UK but more so due to the higher ambients, heavy loads and the friction from sand, and what starts out as 1 BAR at dawn can be 1.4 BAR half an hour later.

XZY's are rugged but being skinny, not the best tyre for soft sand, particularly with a big load, so minimize weight. Wider BFG A/T's are definitely better in sand, but no so durable in the long term. I wish Michelin made a wider XZY, would probably be too heavy, even the 7.50's are very heavy tyres. When worn XZY's can be 'interesting' on wet roads, particularly if it hasn't rained for a while with a lot of rubbery/grease deposits on the road. You get used to them though.

Hope this helps,

Andrew.

moggy 1968 5 Oct 2006 03:35

you won't get the same elongated footprint with the BFG though, and thats what really matters. skinny is also a lot better in mud if you are going near any. it also puts less strain on your steering and bearings than big wide tyres that the vehicle wasn't designed for. 7.50s are also available more or less anywhere, or a close metric equivalent.

I would always also advocate 2 spares. I had 3 when I went to russia and ended up coming home with no useable spare (not michelins that time!) and in africa recently both me and my mate ripped a sidewall each, so we were glad of the security of an extra spare.

that time I used continental sand tyres from Vass (£40 each) which were excelent in the sand.
I am paying them a visit in a week or 2 to get XZYs as using them in the army has persuaded me that for variable use they are the best, and I have used BFG MT and AT michelin XCL and various others as well, both wide and slim.

diesel jim 5 Oct 2006 22:59

Quote:

Originally Posted by moggy 1968
Is that for the XZY though, as the ambies run G90s


Sorry.... all those pressures were for G90's (for the wolf 90/110 and 130)...

not sure how they compare to XCL/XZL's.... i've got the figures somewhere, i'll dig them out.

moggy 1968 9 Oct 2006 20:06

ok, straight from the side of a miltary 110! rears 48, fronts 28. the difference to allow for the fact presumably that military 110s are frequently heavilly loaded.

The G90 is basically a truck tyre, hence the higher pressures (esp with the weight of the ambie)

Andrew Baker 9 Oct 2006 20:52

Presumably you may need 60 psi in an ambulance body or heavily loaded 110, preferably in a tubeless format. The sidewall of the XZY states that max load is 1.5 ton or something at 65 psi (per tyre). Personally I wouldn't want to use tubes at those pressures in high temps, your experience might be otherwise.

The latest version of the XZY is called an XZY* and can be run tubed or tubeless (say so on the sidewall). Apparently Vass has some of the older type, possibly ordinary XZY. Don't know what they've got for sure, I'm off to Bedford this saturday to see.

Andrew.

Andrew Baker 9 Oct 2006 21:02

If anyone wants my old XZY's (4 @ 80,000 miles and 2 unevenly worn but deep treaded spares - neglected to rotate the tyres) they are available in Crowborough East Sussex in about 10 days with 5.5 rims and tubes - £5 each. May be useful as spares if nothing else.

CornishDaddy 9 Oct 2006 22:06

Mine!
 
Hi Andrew,

I could take those off your hands .......

Cheers

Ollie

ChrisC 11 Oct 2006 00:57

Hi Andrew

if Cornish Deity does not want, or whatever for any reason then let me know and I will take them

Cornish Deity: if you don't want/need all I will take whatever you don't want/need

Thanks

Chris

CornishDaddy 11 Oct 2006 08:13

Nope - I'm up for them.
 
Hi There Andrew,

I tried replying to your mail, but it got bounced back with the domain eurobell.co.uk retired.

I'm up for them, and can pick them up one weekend.

Chris,

Might be a couple of spares, let me chat to Andrew and I'll post here.

Andrew Baker 11 Oct 2006 17:49

Sorry, forgot my email was not updated which it now is.

Andrew.

CornishDaddy 11 Oct 2006 18:01

Sent a PM
 
Hi Andrew - have sent you a PM as you have private emails turned off. My email address and phone nr are there so we can continue ..... :)

Andrew Baker 16 Oct 2006 18:27

Went to Vass today and bought 5 brand new XZY's on tubeless rims (70 +VAT)which happear to be 130 HCPU rims unless I'm mistaken. Part number is ANR 1534. From my researches I did not know that 6.5 plain steel rims were available as tubeless. The only 6.5 rim I can find ANR 1534PM is a 1 ton tube type. Can anyone throw any light on 6.5 rims ???

Also apparently it has a band around the rim to stop punctured or low pressured tyres coming off the rim. Don't know if it works in the desert at 1 bar, or should it be binned - any ideas?

Andrew.

Andrew Baker 24 Oct 2006 20:02

Found out that the tubeless rim (see previous reply) has a band inside to keep the tyre on called a ...tyron. Apparently it's a genuine LR part no RRC 100000. Anyone know anything about these? I'm told you can drive at low pressure with them...?

Andrew.


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