Tyres.

I need new tyres and want to replace the 700 x 20's with 750 x 20's. There is only about an inch and a quarter, or 30 mm between the widest part of the duals. The wheels appear to be 5 and a half inches wide. Has anyone done this successfully with these tyre sizes?

The truck will only be a hobby truck and will probably never be loaded but will tow a trailer with my Tandem Drive Morris Commercial on it. Not practical to drive the Tandem interstate as it has a cruising speed of 41. 6 kilometres per hour .

Were can I get roadworthy used, or new, tyres in Victoria, at a reasonable price? I need six, or maybe seven.

Try here Morris...

www.antiquetyres.com.au/tyre-brands/vintage-truck?page=1

Morrie m80
Az U say 30mm gap
the 30mm gap BTween the duels would be fine
just check th@ the tyres dun rub on the chassis or the combin under on the tray
Or the steer n on full lock against the chassis or springs etc
cya

Morris, finding decent used tyres of that size is like rocking horse dooda. Plenty of paddock trucks about with rotten tyres so you will have to buy new, so either Chinese or American. At one time 20-30 yrs ago) the 7.00 were hard to get while every tyre shop had 7.50 so everyone went that way just for the convenience. In theory you will be left with a 3/4" gap.

Even tyres start getting a bit close you could put a piece of plate with appropriate holes in it between the wheels

Used to be a able to buy plates like this once

Paul

Thank You everyone who replied. I looked at the workshop manual again and it appears that the truck originally had 650 x 20 tyres and a previous owner has put 700's on it. The wheels are five and a half inches wide. Do you think they will take 750's without any trouble?

Morris

The Australian Tyre and Rim Association handbook (the ADR reference) says those rims are OK for 7.50

Lang

Lang,
Where can a bloke get a look at that wheel/tyre book you refer to?
I have similar sort of query, the publihed rim sizes are 4,50E-16 semi drop centre
Rim width between flanges given as 4,5 inchs
Recommended tyres are 6.00-16 Nylon.
I have a full set of 7.50-16 tyres including a spare, 5 of them brand new but haven't got around to doing anything with them as yet.
Do have a set of 6.00 -16 rims but have to have the centres machined out to suit a Karrier.
Dave_64

From my days of working with the forklifts and their wheels the 20" rims came on ly in 5.50, 6.00 and 6.50 wide. SO going back to the smaller 600 x 20 tyre size there just may have been a 5.00 x 20 rim but I dont think so.
If 6.00 x 20 were original and now stepping up to possible 7.50 x 20 you will change the ratios on the drive, if that is an issue.

Dave

It comes out annually and anything to do with wheels and tyres the ADR people just say "Refer to Australian Tyre and Rim Association latest information"

Unfortunately my 2010 manual is packed up with the flood clean up. The reason for such an old book is each year they upgrade to the latest sizes and they slowly drop out the older sizes. The latest ones have very limited information on bias construction tyres (except for earthmoving and specialist sizes). The last year that your information is included still the authority so if you have to go back to find your size it is still the legal reference.

If you want the latest manual it is available here.

tyreandrim.org.au/

If you want an older manual with heritage type tyre sizes they sometimes come up on Gumtree and Marketplace.

Just an aside, I am always surprised how narrow rims can be to be legal in older tyres. The widest is also quite a step up. Old tube types were much more forgiving than tubeless.

Lang