How wide is a tyre???

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01 Nov 2012 13:47 - 01 Nov 2012 13:48 #1 by dandjcr
dandjcr created the topic: How wide is a tyre???
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Paul Scherek
Member
Posts: 136
Hi all,
I am making a compartment for a second spare tyre which I hope to make a snug fit. Down the track I plan to obtain rims suitable for tubeless tyres and fit B F Goodrich LT285/75R16 A/T tyres.
Can anyone tell me please the overall width when inflated of LT285/75R16 tyres, not just the tread width but the total width of the walls so that I can make the compartment just right?
Thanks,
Paul
August 30, 2012 at 6:23 PM Flag Quote & Reply

wessa #400
Member
Posts: 67
Hi Paul,
I have LT285/75R16 BF Mud Terrains on my Landcruiser. Now measuring them on the vehicle in the dark by running a straight edge along the inside and measuring to the outside they are 280mm wide overall. Hope this is of some assistance.
Cheers
Wessa #400
August 30, 2012 at 6:50 PM Flag Quote & Reply

Paul Scherek
Member
Posts: 136
Thanks Wessa,
That is exactly what I needed. I am sure the AT will be similar width to the MT.
Cheers,
Paul
August 30, 2012 at 7:18 PM Flag Quote & Reply

outyonda.com
Member
Posts: 58
width of rims determins the tyre width.
August 30, 2012 at 7:55 PM Flag Quote & Reply

chris @ shirley james
Member
Posts: 18
paul,for any tyre,the tyre size such as you speak of, the first number is the width of the tyre from outside of sidewall to outside of sidewall when mounted om the correct rim for for that tyre. Chris
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August 31, 2012 at 10:03 AM Flag Quote & Reply

Paul Scherek
Member
Posts: 136
Thanks Outyonda, thanks Chris.
I had assumed that the width spec was the tread width, not the wall to wall width. Knowing it is wall to wall makes it much easier.
It seems though that I can't use the 285/75 Goodriches anyway - in America, that tyre is rated to 1700 kgs but only 1500 kgs in Australia. Pity, I have had a good run with those tyres on other vehicles.
Cheers,
Paul
August 31, 2012 at 1:06 PM Flag Quote & Reply

Peter_n_Margaret
Member
Posts: 198
Too small for an OKA.
--
Cheers Peter, OKA196 Motorhome. www.oka4wd.com/xt196.htm



August 31, 2012 at 9:29 PM Flag Quote & Reply

Paul Scherek
Member
Posts: 136
I know tyres have been done to death on this site, but there is always more to think about. Peter, when you say too small, do you mean in terms of load rating or footprint? The gearing on mine with the original split rims and 8.25/16 tyres is just right - I certainly wouldn't want to pull a taller top gear. Also, I would very much like less unsprung weight on my single shocker XT.
I see that the Michelin LTX-AT tyres in 285/75/16 are rated at 1700 kgs and have a rolling diameter of 834mm, only a fraction more than the notional 825mm of the 8.25/16's. Do you have any thoughts on this as a selection?
Grateful for any thoughts.
Cheers,
Paul
September 1, 2012 at 6:45 AM Flag Quote & Reply

Peter_n_Margaret
Member
Posts: 198
Footprint too small I reckon.
Bigger diameter is better for every condition.
The vehicle was designed for 9.00 x 16 (936mm) with 11.00 x 16 (984mm) as an option for the millitary.
I have no problem with gearing using a tyre that is 928mm and would hapily go a bit larger. I also prefer lots of spare capacity in the load rating. The only time I have ever had continuing tyre issuse is when they have been loaded close to their capacity, so the 285s fail on both criteria, for my money.
--
Cheers Peter, OKA196 Motorhome. www.oka4wd.com/xt196.htm



September 1, 2012 at 10:01 AM Flag Quote & Reply

okadoc
Member
Posts: 98
Hi all, speaking to Mick Burke recently who purchased some 325/85/16 XML Michelins from us a few months back, he mentioned that he drove approx 50kms on one flat tyre and felt no difference and suffered no damage, he is on the forum here and I'm sure would welcome anyone confirmation as to these tales and I can only say that with their run flat ability, 5300lb load carrying capacity @ 65 psi, 85% aspect ratio (air bag in themselves), 40 mil thick wall and supreme travel comfort and their caterpiller track like soft going attributes and the huge bonus plan of being regroovable , Yep we love em, and ya can't wear em out. That should just about do It.

Enjoyable safe travels to all, Doc and Lyn Davey

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September 1, 2012 at 1:21 PM Flag Quote & Reply

Chalkie
Member
Posts: 21
Sounds great. What rims are they on?
September 1, 2012 at 4:08 PM Flag Quote & Reply

outyonda.com
Member
Posts: 58
Paul the 60 series Dyna diff fitted to OKA is designed for 825x16 tyres. I have five OKAs, the first new from the factory in '93, the curse of the OKA is uni joints & tyres. I tried all shapes & sizes & failures, because nothing suitable is available, I designed, engineered, certified & built my own tubeless rims. I have 18 on my OKAs & there is a couple of sets on other OKAs . While making the rims, this is what i found. Axis point & 825x16 match. I found a split rim with a spacer to match 900x16 axis point. If you went to 1100 a bigger spacer. It is all to do with backspace. 7" & 8" rims fit inside vehicle dimensions, 10" protrude.

I use 285/75x16 Goodyear Duratrack tyres 1700kg, over 100K km done. 285/75x16 is similar diameter to 825x16 but has same tread width as900x16.

7" rim fits 285/75x16, 825x16, 900x16, 255/100x16 tubeless.

8" rim fits 285/75x16, 325/85x16

10"rims fit 325/85x16 + +

The 285/75x16 axis/camber/caster meet. As for other sizes, you may need adjustment. My OKA with 19.5 rims I will fit with 900x16 tubeless. A 285 Goodyear on 8" rim is 13" wide; on a 7" rim is 12.5" wide. That is my spin on wheels, if you want to know more, just ask. cheers Brett
September 1, 2012 at 4:31 PM Flag Quote & Reply

Paul Scherek
Member
Posts: 136
Peter, my Oka really feels like it wouldn't pull a higher gear. It cruises happily and economically at 100KPH but I frequently come close to needing a change down. I think with a 10% increase in tyre size, I would probably seldom use 5th gear.
Brett, thanks for that comprehensive bunch of suggestions. I was planning to get 8 inch rims, probably the Eagle Alloys. How does one determine if the axis point for these rims is the same as for the 8.25/16's? Are you still making rims for sale, and if so, can you tell me how much they weigh compared with the split rims? Did you like the Goodyear Duratracks? I am not worried about wear, but I hate punctures and I hate noisy tyres.
OkaDoc, those big Michies sound great, but I am sure my Oka wouldn't pull that gearing.
Thanks everyone, and apologies for bringing up this old topic again.
Cheers, Paul
September 1, 2012 at 6:19 PM Flag Quote & Reply

outyonda.com
Member
Posts: 58
Paul small tyre versus tall tyre. I find the XT performed & handled better with 825 sized tyres. 80psi on road, 60 on dirt, 40 on rock, 20 on sand. The LT likes 900 tyres. When I hook all three together, the LT doesn't like it. Five years ago I started with Goodyear Silent Armor 1500kg but air would leak around the bead or bubble sidewalls. When pulled apart, the inside had the old fashioned fracture. Goodyear changed compounds, tested all kinds but no good. Next they give me Duratracks 1700kg & I am still using that first set. Road noise, if you stick your head out the window, you can barely hear them. I had a mate who tried muddys, you need ear muffs & they toe & heel. I will weigh a couple off rims next week when i get home. I tried alloys, broke two out of five, one on a rock, one on blow out, in the bush you can't repair them (they were 12" wide), a pig on road but great in sand. Yes I am still making rims, 0429 831 040 for details. Brett
September 1, 2012 at 7:02 PM Flag Quote & Reply

okadoc
Member
Posts: 98
Hi Chalkie, the rims I run are the 10 inch Eagle (058) purchased from Summit Racing for USA $131 dollars stateside and steel 10 inch rims from Custom Wheels in California which have a 4500 lb load rating and pass our requirements for ADR in oz. These cost US$180 stateside. They have a 4.5 inch back spacing and fit the Oka great and as far as the 38.5" in 325/85/16 XMLs being a problem with the gearing or noise it's not an issue. We also run the 1100/16 mitchies on 8 inch rims and they are an all round super choice of tyres as well, very comfortable and quiet and strong as. Everyone that we have conversed with on these combinations have said they would never change back to the dark old days of running on tyres that simply dont have the load capacity and footprint , alll the best and safe travels Lyn and Doc Davey
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September 2, 2012 at 12:20 PM Flag Quote & Reply

outyonda.com
Member
Posts: 58
I went through the rims from USA . 2 are in the scrap heap, buckled. next genuine F 250 pressed rims. 3 pulled the nuts through the centres. moral of the story, you get what you pay for.
September 4, 2012 at 2:22 PM Flag Quote & Reply

Paul Scherek
Member
Posts: 136
Ouch! That's the sort of thing we don't need. As you say, you only get what you pay for. Look forward to learning the weight of your wheels.
September 4, 2012 at 6:52 PM Flag Quote & Reply

okadoc
Member
Posts: 98
Hi all, hey outyonda these rims you had problems with, who made them, were they Eagle 058's by any chance and any steel rims makers and details if you would'nt mind to help us avid followers avoid falling for the same crap, Thanks, Doc and Lyn Davey
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September 4, 2012 at 9:33 PM Flag Quote & Reply

outyonda.com
Member
Posts: 58
RIM WEIGHTS. 900x16 on split rim 75 kg 285/75x16 on xtra tuff rim 45 kg . . . split rim 225 kg xtra rim 16.7 kg scrap heap rim 13.8 kg . . . . the rims in the scrap heap are those sunrasia/speedy things you see on landcrusers. i got them through buearepairs via USA $ 170 ea might be ok for F 250 but not OKAs, the ones that thnuts pull through are genuine ford,ex USA. . the alloys were a mates brand unknown. he had a jacked up F truck. made the OKA look like a monster truck, wide & tall, too tall, could only use 5th gear downhill. Great on beach but;,. I'll try anything once. this was about 10 years ago. . .. ALLOY RIMS speedway if you lent on something, throw away , on trucks as a steerer 3 to 5 years your tyres chop out at 20k. I find alloy can't handle extreme load & pressure over time, after all an OKA is a small truck pushed to the max most of its life. I may be wrong but that is what i have found. Cheers Brett
September 5, 2012 at 2:51 PM Flag Quote & Reply

outyonda.com
Member
Posts: 58
sp;it rim 25 kg
September 5, 2012 at 3:07 PM


Paul Scherek
Member
Posts: 136
Thanks Brett, do you mean that a split rim complete weighs only 25kg, and the xtra tuff rim weighs 16.7kg? My wheels (split rims with 8.25/16 Hankooks) weigh over 60kgs each - I had thought most of that would have been the rim, not the tyre. I was hoping to reduce the weight as much as possible.
Cheers, Paul
September 7, 2012 at 8:55 AM Flag Quote & Reply

Peter_n_Margaret
Member
Posts: 198
My 19.5 x 8 1/4" tubeless rims weigh 30kg each and the 305 XDE 2s weigh 50kg each!
--
Cheers Peter, OKA196 Motorhome. www.oka4wd.com/xt196.htm



September 7, 2012 at 10:39 AM Flag Quote & Reply

Chris J
Member
Posts: 56
Paul,
Like Brett I have Dura-tracks 285/75/16 mounted to Eagle 085 alloy rims. Since fitting these rims and tyres Oka 166 is a different vehicle, the Oka pulls up most hills in 4th and 5th unlike the 825/16, I was changing to 3rd and 4th. I lost a bit of speed but I sit comfortably on 90 Ks / hr along the black top. I can lift the spares onto the tray by myself and I haven’t had any flats so that’s an added bonus. Since the upgrade I have travelled twice to Cape York via the OTL, and have just completed two week trip along the coast track from Cape Melville to Cooktown. The vehicle drives like a mini on steroids.
The only downside in the smaller tires is the ground clearance. If I were to go to a larger tire diameter to increase my ground clearance then I would change my Diff ratios from 4.11:1 to a lower ratio to allow the standard Perkins OKA setup some leg room
My rig is a dual cab and has light commercial registrationin QLD with a 4,495 KG GVM. OKA-166 weighs in at 4040KG fuelled and ready to go. add two passengers and your away.
All round I’m very happy with the outcome.
Regards, Chris.

--
Chris and Janice Jones - OKA 166





September 7, 2012 at 12:19 PM Flag Quote & Reply

Hal Harvey
Site Owner
Posts: 510
Chris, standard OKA diff ratio is 4.88, so you probably don't have 4.11s. It doesn't matter unless you ever want to change of course - but if you do ever want a lower ratio (higher numerically), you'll probably be looking for 5.86s.
--
Hal

September 7, 2012 at 1:41 PM Flag Quote & Reply

Chris J
Member
Posts: 56
Thanks Hall,
That's what I meant, 4.88:1
Regards, chris.
--
Chris and Janice Jones - OKA 166





September 7, 2012 at 2:04 PM Flag Quote & Reply

outyonda.com
Member
Posts: 58
Paul, most of the weight is in the tyre.. i will take the bath scales up the tyre shed. Does anyone have a weight of an Eagle alloy ?
September 7, 2012 at 7:04 PM Flag Quote & Reply

Chris J
Member
Posts: 56
Brett,
My Eagle 085 8" rim weighs in at 25 lbs or 27.5 lb boxed up with center insert.
regards, Chris
--
Chris and Janice Jones - OKA 166





September 8, 2012 at 11:26 AM Flag Quote & Reply

Moose2367
Member
Posts: 110
I weighed my rims a few weeks ago, as seen in my 6.7 conversion thread.

Thought i'd do a comparison on the steel 16inch split rims and the new alloys today.
I weighed the steel wheels fitted with 8.25 x 16 tyres first - 66kg each (they're for sale now too)
Then i weighed the 37 x 12.5 x 17 wheels fitted to the alloys - 52kg


It is surprising when you see the physical size difference.
September 8, 2012 at 1:53 PM Flag Quote & Reply

Ewart & Vivian Halford
Member
Posts: 117
I found a post I put up a year ago. I weighed a rim and tyre on a set of bathroom scales.

Original split rim weighed 28 kg. A 255/100/16 xzl tyre with rust band and tube weighed 44 kg. Total weight was 72 kgs.
September 8, 2012 at 3:33 PM Flag Quote & Reply

Paul Scherek
Member
Posts: 136
Thanks everyone for the great replies. I see now that I am not going to gain much on the weight side, so I will probably go for steel. My main reason for change was so that I could run tubeless tyres, and get a decent choice of treads. I have made room for the 285 width, but can change it later if I go wider. I will try out the Duratracks on steels and see how it goes.
Thanks again, Paul
September 8, 2012 at 7:07 PM Flag Quote & Reply

Alister McBride
Member
Posts: 97
Gday all, great debate once again!
Doc, just wondering if you can post a contact for the steel wheels you got for $180 from 'Custom Wheels'? I did a search for them but the one i found only had hotrod alloys... Also, what was the wheel centre thickness? The standard split rims are 10mm from memory! I suppose if they're rated at 4500lb it doesn't matter anyway, but still interested... Are they tubeless? Do they have an 8" option?

Cheers,
Alister
September 8, 2012 at 8:37 PM Flag Quote & Reply

outyonda.com
Member
Posts: 58
i have 2 sets of rims in the scrap heap rated at 4500lb. . the important things are 10mm centre,s dished centre,s & 3mm outer rims.
September 8, 2012 at 10:45 PM Flag Quote & Reply

okadoc
Member
Posts: 98
Hi all,we got our steel 4500lb rims from Custom and Commercial wheel, 17866 Valley Boulevard, Bloomington,CA 92316 Owners name is Ray , cheers Doc and lyn Davey
September 14, 2012 at 8:13 AM Flag Quote & Reply

okadoc
Member
Posts: 98
Sorry Alister, yes we have the 8inch rims from custom and they are dished and tubeless, cheers Doc
September 14, 2012 at 8:17 AM Flag Quote & Reply

okadoc
Member
Posts: 98
hi all,the 1100x16 and 325/85r16 mithchies tread depth new have just read on my digital micrometer 18.4 mil in the centre of tyre and 21 mil on the shoulder, the steel rims from custom and commercial wheels in Californica have 8.5 mil dished centres and 4.5 mil rims, the 325's require a 9 inch rim but sit very comfortable on the 10 inch wheels and dont loose the bead when sand .deflated under power.We run 10 inch eagle alloys as well . No problems to report on any of the above as yet but this summer wet season in the gibson and little sandy deserts will supply best anecdotale evidence as to their longevity under extreme conditions and the torque multiplication from the P400 V8 through the 4L80E onto the 325/85R16's via 35 spline 4340 chrome moly ,front and rear axles and ARB Air Lockers.The outer uni joints up the front are greased hard face to hard face,no needle rollers,much stronger all round just got to give em asquirt of grease daily when in that drive mode,the free wheeling hubs are new warns with all the good gear and crown wheel and pinions were supplied by locktup 4x4 in Freo and rated as strongest quality avaiable.

September 14, 2012 at 8:06 PM Flag Quote & Reply

okadoc
Member
Posts: 98
September 14, 2012 at 8:15 PM Flag Quote & Reply

okadoc
Member
Posts: 98
September 14, 2012 at 8:15 PM Flag Quote & Reply

Alister McBride
Member
Posts: 97
Thanks Doc! Paul K also runs the 325/85R16 Michies on 8" rims and finds them better for many reasons... All food for thought.
September 14, 2012 at 10:22 PM

David and Janet Ribbans - Oka 148
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Last Edit: 01 Nov 2012 13:48 by dandjcr.

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