fitting midget rostyle wheels

Post by **picky** » Sun Mar 26, 2006 5:40 pm

Im just cleaning up some rostyle wheels from an MG midget to fit to my minor, and I am wondering can I use the same wheel nuts as the original minor wheels?? Also what tyre width would give the best grip?? As I have read about as the tyres get wider they dont squat down so much and the contact area gets less... but I think that is only if you fit tyres that are much too wide. The rostyle rims seem wider than the minor ones.
help much appreciated,
Tim

Post by **jonathon** » Sun Mar 26, 2006 6:03 pm

Check the angle of the taper on both sets of wheel nuts, if they are the same then you should be able to use the minor ones, although a capped nut would look better as the nuts are now in clear view. I'd go for 165/175/60 section tyres.

Post by **bmcecosse** » Sun Mar 26, 2006 7:14 pm

Offer the Minor nut up to the wheel and look at it very carefully - but since they are from the same era I think they should be ok. I think Minors look slightly odd with 13" wheels - the wheel arches are too big and open. Using 60 section tyres will be too small - the rolling radius will be well down and the gap around the tyre in the arch will be even more obvious. I would go for 175/70 x 13.

Post by **picky** » Mon Apr 17, 2006 11:05 am

so would 175/70R13 tyres be more or less the same rolling radius as the 14" wheels with crossplies?? As I would like to be able to keep the standard spare wheel in the boot and be able to use it.

Post by **bigginger** » Mon Apr 17, 2006 12:59 pm

If the others are radials, I don't think you'd be advised to use a crossply as a spare - not to mention the fact that it's illegal

Post by **minor_hickup** » Mon Apr 17, 2006 1:18 pm

Yes and scary to drive like that in the wet

Post by **picky** » Mon Apr 17, 2006 2:22 pm

Ok good point, so the crossply is out, and finding a fifth rostyle 13" wheel is no good because it wouldnt fit in the slot in the boot due to larger width. What size radial would I need to get for the 14" spare? has anybody else who uses non standard wheels come up with a good solution to the problem of not having a spare wheel?? or do you just do without one? I did find a rolling radius calculator thing on the internet somewhere but I cant find it now...

many thanks for everybody's input so far,
Tim

Post by **rayofleamington** » Mon Apr 17, 2006 2:26 pm

picky,
let me know your email adress by PM and I can send you a simple excell file that'll let you calculate tyre sizes by yourself.
The calculation isn't difficult but laying it out on excell is a nicer way to compare a load of different options all together.

Post by **picky** » Mon Apr 17, 2006 2:29 pm

rayofleamington,
PM sent...
Tim

Post by **rayofleamington** » Mon Apr 17, 2006 2:45 pm

file is on its way

Post by **wanderinstar** » Mon Apr 17, 2006 4:19 pm

Tim,
This may be the tire calculator you mean.

http://www.miata.net/garage/tirecalc.html

Its certainly very useful.
Ian.

Post by **bmcecosse** » Mon Apr 17, 2006 8:02 pm

Just run a tape measure round each tyre and compare the result. A 145x14 radial fits in the spare well ok - in fact - so does a 155x14! I reckon 175x70 will still be slightly smaller rolling radius - but reasonably near.
Ian - what size 13" tyres did you use ? And what does a tape read round the inflated tyre ?

Post by **picky** » Mon Apr 17, 2006 8:26 pm

many thanks for the link and rayofleamingtons excel gadget, the diameter of the 14" 145 standard tyre is 587mm and the diameter of a 13" wheel with a 175/75 tyre is 592mm which according to the tyre calculator website makes the speedo 0.9% too slow... I dont think I will notice the difference in speed somehow! and I think that If I do need the spare it will drive ok if I buy a new 145 radial tyre for my spare wheel?? hopefully will be more comfortable and less shakey than the 10 year old crossplies...

Tim

Post by **minor_hickup** » Mon Apr 17, 2006 9:09 pm

Erm you're running on 10 year old crossplies? You're pictures suggest you're running a tuned motor as well?!

Post by **picky** » Tue Apr 18, 2006 9:39 am

I know... and im getting sick of practically stopping before going round a corner just to stop it sliding all over the place. Yes the motor has all the tuning parts fitted and it does run but it needs a rolling road as its much slower than it should be.

Post by **bmcecosse** » Tue Apr 18, 2006 1:16 pm

So the 13" wheel with 175/70 tyre (you say 75 - is that a typo because I don't think there is sucha profile ??) is actually slightly larger diameter than the 14" with 145/80 radial ??

Post by **picky** » Tue Apr 18, 2006 1:49 pm

well the tyre size calculator link has a drop down list an 75 is on it, whether you can buy tyres like this I dont know! if you put in 175/70 then it says that the speedo will be 2% fast... so there is not much in it really. however a 185/70 tyre on the 13" is almost exactly the same as the 145 14" wheel.. only 2mm difference in diameter.

Post by **Onne** » Tue Apr 18, 2006 6:18 pm

Some commercial vehicles and 4x4 use 75 hight. Normal cars don't.
No offence to the LCV drivers though

Post by **wanderinstar** » Tue Apr 18, 2006 6:41 pm

What exactly have you done to engine?
Ian.

Post by **rayofleamington** » Tue Apr 18, 2006 7:07 pm

That isn't a 'common' tyre size but they do exist if yuou loom around vey hard e.g. : Simex 175/75-13 85H
185/70 is much more common, but obviously you'll have to check lots of other things as well as overall diameter, whichever tyre you choose.