Section : Wheels and Tyres

Tyre size on 4.5Jx13 Dunlop bolt on wires?

Posted By : Stephen Williams, 25-Oct-2006, 09:23pm

Hi, I have a set of 4.5Jx13 Dunlop bolt on wires for my Mk. 2 GT6 and have been reading all the posts about tyre sizes. I know that everyone seems to agree that 175x70x13 are the favoured size, but this seems a little wide on 4.5" rims. On my old steel wheels 175 look a bit balloony and I have had coments from the MOT guy about them being borderline fail as extending outside the front wing. I'm not even sure but I think this is 4.5" but they could be 5" rims!

I have also been reading much on how wider tyres do NOT necessarily give you a larger contact area and more grip. ( take a peek at http://www.carbibles.com/tyre_bible.html ).

What is everyone elses opinion? Also can you get rim tapes to cover the spoke ends or is lots of insulating tape acceptable, I can't find any info.

PS. I bought the wires without tyres - Used and complete with centre badges and nuts.

Followups :

Tyre size on 4.5Jx13 Dunlop bolt on wires?

Posted By : Michael Charlton, 26-Oct-2006, 09:09am

After months of experiments and the use of Minty Lambs website for wheel and tyre calcs I found on my 4.5 wires that 175 x 70 x 13 is correct.
I had been using 155 x 70 and they made the car sit too low. One of the lads in the club runs on 175 and they are perfect.
My chrome wires are now packed away for winter but will be re fitted with 175 s in spring.
In the mean time for winter i now have some Minilites, and they are fitted with 175 x 60 x 14 on 6" rims and they fit perfect in side the arch.
Dont forget that the hub adaptor throws your wheel out some 1/2 to 3/4" over and above normal rims and that is why you will have to keep the tyre narrow or if wider your wall has to drop in height therefore lowering the car.( and ripping ones silencer system off on lumpy roads) Try Minty Lambs page to satisfy your curiosity

Mike
- Tyre size on 4.5Jx13 Dunlop bolt on wires?
  
  Posted By : Michael Charlton, 26-Oct-2006, 09:17am
  
  Sorry mis read. . . . . . .bolt ons!
  Then 175 s is definitely correct on 4.5 s as there still is a throw out because of the hub attachment
  
  Mike
Tyre size on 4.5Jx13 Dunlop bolt on wires?

Posted By : George Ralph, 26-Oct-2006, 12:34pm

Personally, I would think that 175 section tyres are too wide for 4.5in rims. They will balloon over the rim as you suggest and could cause instability due to the tyre "rolling" on the rim, could cause uneven tyre wear also. The standard size for a 4.5 rim is a 155/80 you could go to a 165 but 165/80 would be too tall and 165/70 to short. Unless the car is modified for much increased performance, standard size good quality tyres would be your best bet IMHO
- Tyre size on 4.5Jx13 Dunlop bolt on wires?
  
  Posted By : Van Hamlin, 26-Oct-2006, 08:31pm
  
  I'm prepared to be proved wrong but as far as I know no car manufacturer has fitted 175/70x13 to 4.5x13 rims.
  
  There's probably a reason for this - they're too wide.
  
  Van
  - Tyre size on 4.5Jx13 Dunlop bolt on wires?
    
    Posted By : Stephen Williams, 27-Oct-2006, 08:43pm
    
    I suppose that I could go for the middle ground and fit 165x70x13. But I have to consider that this is a tuned car and is putting a far bit of power down through the wheels. I like the look of wires and after reading many stories of stripped splines, went for the bolt on's instead. Looking at my current steel wheels (Dunlop options I am reliably informed) they must be 5" rims and even they look a bit balloonie on 175x70x13's.
    
    Again looking at http://www.carbibles.com/tyre_bible.html (the bit near the bottom with tyres with red squares)- this guy seems to know what he's talking about and puts forward a strong argument that wider tyres don't give more grip. At the moment I am thinking that I would be better with a narrower tyre and a stickier compound, they might not last as long but give a more predicable handling.