What size wheels and tyres for C18 Mark 3

Luka
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What size wheels and tyres for C18 Mark 3

Postby Luka » Wed Mar 30, 2016 8:41 pm

I had a blowout on the weekend and my 9 inch rim cracked.
So I'm looking at getting a set of bigger rims and tyres.
What do people recommend 13 or 14 inch?
And what about width, they range from 165 to 195 with increased load capacitor as the width increases.
Would a wider tyre make it more difficult to manouver the boat by hand on the jockey wheel?
Luka
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paul trotter
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Re: What size wheels and tyres for C18 Mark 3

Postby paul trotter » Wed Mar 30, 2016 10:39 pm

That was sad Luka,

I just got heavy duty truck tyres for my nine inch wheels.

Did the tyres go first then the rim cracked with the rough hit on the asphalt?

Pray tell more!
Paul Trotter
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maxm
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Re: What size wheels and tyres for C18 Mark 3

Postby maxm » Thu Mar 31, 2016 7:55 am

Give Vern a call Luka, I'm pretty sure he's done a few trailer conversions to larger wheels.

There have been a few conversations here about converting from 9 in to larger wheels and it sounds like the main hassle is that you may need to reposition the mud guards to provide clearance. If you do then you may also need to raise the boat to clear the guards. You should also check how easy it is to get light truck tyres in 13 and 14 inch. According to this thread some had problems getting light truck tyres in 13 inch but found 14 inch readily available. I know I run 14 inch LT tyres on my trailer and had no problems getting those.
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don47
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Re: What size wheels and tyres for C18 Mark 3

Postby don47 » Fri Apr 01, 2016 8:42 am

Luka, every trailer that I've renovated/rebuilt (half a doz or more now) I've gone for the 13".
Contrary to talk about LT tyres being harder to obtain I've not had any probs in ordering so far.
Reasons why I like 13" (175R13) for an 18 trailer include keeping the boat lower on the trailer itself thus lower to the road & at the ramp.
You don't need to adjust usually the guards from the 10" situation to greatly for that height either, just spread their shape wider to suit new wheel size & some height clearance if they are metal pressed type. Brackets will probably need to be repositioned on trailer, can you weld or are your brackets bolt on (not many are) ?
The bigger wheels will travel the road better & I find handling is probably a bit easier.
Your 5 stud 10" are probably a HT Holden pattern which you can have easily checked.
Don't forget gal is better than steel & you can easily obtain in sunraiser style if desired.
If you do particularly want HT pattern new gal 14" (sunraiser style) with new rubber fitted (no Ks on them) well I do have a pair sitting here in shed.
Don.

Luka
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Re: What size wheels and tyres for C18 Mark 3

Postby Luka » Fri Apr 01, 2016 7:49 pm

Paul,

It would appear that the rim failed.
I had new rubber fitted towards the end of last season so they are less than a year old but the rims are original alloys, so far as I know.
I inspected the rubber as did the local tyre service technician and we could not see any evidence of tyre failure, only the side wall damage from the rim running on the flat tyre.
The rim cracked away for about 20% of the circumference on the inside face only.
Last year when I replaced the tyres, I asked them to fit the highest load carrying tyre they could find which turned out to be 625kg at 85 psi.
I can only inflate to 60 psi as that's as high as my gauge goes. More telling, upon inspecting the wrecked rim, under the dirt on the inner side I saw an inscription rating the rim at 1120 lbs, ie 508kg, so less than the rubber.
I've always been told to allow at least 1200kg for the weight of a Mark 3 and trailer so these rims would not be sufficient.
When you say you fitted heavy duty truck tyres to your 9 inch rims, I don't know what that means in terms of load rating, but as I said above, I was told at the time that what they fitted to mine was the max rating I could get.

I'm now convinced I need to upgrade and am leaning towards 185R14 light truck, which is what Carlos has. 13 inch wheels will only give me 670kg per tyre and I'd like a bit more margin
The light trucks seem to be readily available as others have attested and the 185R14 is load rated to 850kg so no troubles there, I presume the rims will also exceed that rating although looking at Carlos' there is no load rating designation on the rim.
I borrowed Carlos' wheels tonight and tried to fit them but unfortunately they are Ford stud pattern and don't fit mine.
None the less, I jacked the boat to the corresponding height of the tyres and took some measurements. It looks like I'll clear the garage door but tomorrow I'll move the boat under the door and jack it up again to the corresponding height to confirm. It's a slightly pointless exercise as I think changing the rims is a must do and if I can't get the clearance I'll just need to offset the mast to the side to get in which is a hassle but doable.



Also, looks like I may be very close to not having to raise the boat on the trailer, or maybe by only an inch.
Luka
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paul trotter
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Re: What size wheels and tyres for C18 Mark 3

Postby paul trotter » Sat Apr 02, 2016 8:33 pm

Thats a real bugger Luka.

Thats bad news!

For me that means new roters and new wheels before I have a failure.

I got the same tyres as you and had to get them up to 80psi or so!

Its only money!9
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Re: What size wheels and tyres for C18 Mark 3

Postby don47 » Sun Apr 03, 2016 7:14 am

Trotts, bet ya one of Dave's 13" multi fits, bolt straight on so long as guard not prohibiting.
Don.

Luka
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Re: What size wheels and tyres for C18 Mark 3

Postby Luka » Sun Apr 03, 2016 8:14 am

Yes, only money, and some hassle.
I took Max's advice and spoke to Verne who could not recall if the hubs needed replacing also and suggested I speak to Trailer City down here.
They said yes, hubs would need to be replaced. I have the day off on Friday so will take the boat in for a quote. They can also raise the boat rollers if required and supply the galvanised "Sunrayser" wheels.

ps What's a roter? Is it the hub?
Luka
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Re: What size wheels and tyres for C18 Mark 3

Postby MichaelC » Sun Apr 03, 2016 8:03 pm

Luka
You need to add your ballweight to the maximum tyres rating. So if your tyres total 1340kg and you have 100kg ballweight, that gives you 1440kg you can tow. More margin than you might think. The wider 13inch LT tyres have a higher rating too.

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paul trotter
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Re: What size wheels and tyres for C18 Mark 3

Postby paul trotter » Mon Apr 04, 2016 10:31 pm

I think Luka Rotter = hub eg the round thing the bolts reside in and the brake pads attach to!
Paul Trotter
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don47
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Re: What size wheels and tyres for C18 Mark 3

Postby don47 » Tue Apr 05, 2016 6:05 am

Rotor is the brake disc.
Btw, of course there are cheaper import types of rims in our market place these days regardless of whether 13" or 14" & the same can be said for tyres.
I've always made sure that rims fitted have been of a quality brand & are 6" & not some of the cheaper which are usually lesser in width & which can also hinder clearances to some differing types of brake units. Actually, if memory serves me right I did fit because of availability & hub type 14" to one particular trailer.
Don.

sail417
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Re: What size wheels and tyres for C18 Mark 3

Postby sail417 » Tue Apr 05, 2016 10:51 am

On the Jawar trailer, the 13" with Holden hubs (with brake rotor all one unit) work well and the clearance to the guards and boat did not have to be altered. Having said that, when I got my boat back in 1989 the springs were set into the lower part of the bracket as it had the small wheels on it (a Jawar detail) to give more ground clearance. As soon as I got the boat I discarded the small alloy wheels and never regretted it.

On another note about tyres, I was at a Tech Talk about tyres at one of Sydney's top indepentant tyre dealers and the subject got onto the life of tyres in regard to the 5 year rule. It was said that with car tyres in normal domestic use, it is recommended to replace them every five years but if they are kept mostly in a garage then stretching to seven years could be OK if they still have a lot of tread remaining and general good conditiopn.

The talk was mostly about track tyres and tyres suitable for car trailers and therefore, boats as well. I asked the question "Due to the short life that racing tyres are exposed to UV rays and the same for light commercial truck tyres due to the expected high number of km in a short period of time, are they manufactured with less UV resistance"????

The answer was "YES"................so for us, the FIVE year rule should be carefully monitored, and since my ownership since 1989, that seems to have been proven, by me and others.

BTW Don, bumped into one of your motor trade buddies at the Tech Talk.............no damage done.

Sorry Luka, back on topic again, if you have a Jawar Trailer I can scrounge through some storage devices and send some pic's to you.

GU
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don47
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Re: What size wheels and tyres for C18 Mark 3

Postby don47 » Tue Apr 05, 2016 7:33 pm

Pheewww,,, could have been one of a number & they all talk, so glad about that Greg ! Ha, ha !
Interesting yours words about UV.
Don.

Luka
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Re: What size wheels and tyres for C18 Mark 3

Postby Luka » Tue Apr 05, 2016 7:45 pm

Thanks Gerg,
Although my trailer is a Tracer.

I did some research on 13" tyres.
Seems there's not as much choice out there and the rubber carrying capacity (670kg) is not a great deal more than the small 9'' wheel's rubber (625kg)
In 14" there was more suppliers and choice in width with load carrying up to 950kg per tyre for the 195R14 (Bridgestone R623 light truck)
Luka
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sail417
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Re: What size wheels and tyres for C18 Mark 3

Postby sail417 » Tue Apr 05, 2016 8:25 pm

Yes Luka, it doesn't surprise me now after many years that there is less choice in tyre sizes for the 13".

As you have to bite the bullet and make a decision, I would say that with the weight of the MkIII you will never regret going for 14" rims (can't advise on width) with Ford bearings and that is going to mean a larger axle. Also heavier springs and hydraulic over-ride disc brakes..............love the hydraulics, you can never have too much stopping power, no matter what you tow with.

Good luck with the project and hope it's a happy ending.

GU
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