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HC GLS wheels

PostPosted: Thu Sep 21, 2017 12:23 am
by wyke
Rims on my 78 1256 are in. Bad way and looking to buy new / refurbished rostyles ....

First , I have read a number of threads about wheels ...wider tread...wider wheel arches ...-7 offset , lowering , raising, chopping valences ..... etc etc ...not understanding any of it !

What is the standard wheel rim size and tyre ? Can I get hold of any ?

What wheels do people think look best ...without any need for modification .

The ones I have are so badly rusted from inside ..probably not safe!!!

Any simple info , pics , ideas ...greatfully received.

Re: HC GLS wheels

PostPosted: Thu Sep 21, 2017 9:17 am
by 1972nail
The standard Rostyle wheel is 5" wide and fitted with 155 80x13 on the 1300 GLS and 175 70x13 on the 1800 or 2300 GLS.

You can be certain of getting away with 5 1/2" wheels and 175 70 x13 tyres without modification. Some people have been able to fit 6" wheels with wider tyres without modification but others haven't, it depends on manufacturing tolerances, wheel offset, tyre size, castor settings etc...

The Droop Snoot Firenza had 6" wheels with 185 70x13 tyres as standard, but it has no metal front panel to catch on the wider wheel/tyre combination and the castor angle was set at the upper limit of the 2-4 degrees to avoid contact with the foot well.

Re: HC GLS wheels

PostPosted: Thu Sep 21, 2017 11:19 am
by wyke
Many thanks ..that certainly helps ....can wheels still be sourced ? If so what style is best other than Rostyle ?
Thanks again

Re: HC GLS wheels

PostPosted: Sun Sep 24, 2017 12:15 pm
by Fred Dukes

Re: HC GLS wheels

PostPosted: Tue Sep 26, 2017 4:11 pm
by wyke
Thanks Fred....can you still get new Rostyle?

What is difference between 175 / 70 and 175 / 80 rather than 155 /13 ?

Think that's what the post said !

Thanks again

Re: HC GLS wheels

PostPosted: Tue Sep 26, 2017 4:14 pm
by wyke
Sorry 155/80 as opposed to 175/70
:shock:

Re: HC GLS wheels

PostPosted: Tue Sep 26, 2017 4:56 pm
by 1972nail
The 155 80 and 175 70 have the same or very very similar 'rolling radius' that means that the speedo will read the same for both tyres. The 175 is a wider 'section width' than the 155 tyre.

Re: HC GLS wheels

PostPosted: Tue Sep 26, 2017 7:00 pm
by Colin
The '80' number and '70' number relate to the sidewall (profile) height as a percentage of the tread width. So a 155 / 80 x 13" tyre has a 155mm tread width with a sidewall profile height that is 80% of 155mm = a 124mm sidewall height (quite tall by modern standards).

A slightly wider tyre with a slightly lower sidewall profile, like the 185 / 70 x 13", has a proportionately lower side wall to tread width ratio - In this case 70% of 185mm = 129.5mm sidewall height

So the 185 / 70 x 13" tyre is 30mm wider but only has a 5.5mm greater sidewall profile than the 155 / 80 tyre. This means the 185 / 70 x 13" tyre will have an 11mm larger overall circumference than the 155 x 80 tyre. This will give very slightly higher gearing - but probably not enough to be noticeable.

Modern tyres are obviously much larger and wider with much lower sidewall profiles eg, 235 /55 x 18" on my Astra GTC.

These HP Firenza Avons are currently for sale on fleabay -
http://www.ebay.co.uk/itm/Vauxhall-fire ... Swa51Za8p~

Re: HC GLS wheels

PostPosted: Wed Sep 27, 2017 3:27 pm
by wyke
Many thanks ...much clearer now !

Is it possible to still get new Rostyle Wheels?

Thanks

Re: HC GLS wheels

PostPosted: Wed Sep 27, 2017 3:49 pm
by wyke
Thanks for link from eBay but I think the previous post suggested that 175 /70 would be my limit on a GLS, the 185 would be too wide ?
Thanks