135's or 145's

[Chris W]

Well there are Michelin 145's on there now and I like the look with my 205/70 truck tires  . I don't plan on cutting on my mag gasburners anytime soon. 

[Zach Gomulka]

Where did you get that "formula"?

If you want a base line of where to start, look at what the car makers put on cars.  VW installed 155s on 4" and 4½" wheels.  Same wheels got 165s too.  The rare stock 5½" VW wheels got 175s.  If you research a 2CV, you will find it's wheels are probably 3" or 3½" wide to use 135s.  According to the car makers, a 4" wheel is too wide for a 135 tire.

Mexican Beetles had 4½" wheels.  Never a 5½.

It's not a formula, just my "rule of thumb". A 4 1/2" wheel is actually 5 1/2" when measured from lip to lip, therefore I believe you should have a tire on there that is at least 5 1/2" wide (5 1/2"=139.7mm, round up to 145).

When I lay my 145's on my 4 1/2" wheels flat on the ground, the tire touches first, not the rim (but just bearly). That's the way a tire should fit, IMO.

[Jesse/DVK]

I have 135s on my Flat 4 BRM, 5,5 inch? And I think it looks good .

[Zach Gomulka]

FF BRM's are 5", like the originals.
FF also has them in 6 1/2"

MWS offers them in 4 1/2", and 5 1/2" (correct me on this if I'm wrong)

[qubek]

You're not wrong Zach

I believe Mexi Bugs came stock with 155's on a 5 1/2", and the tire fits just about flush with the rim. You at least want a tire that is about 20mm larger than the width of the rim- so 4.5" wheel = 114.3mm + 20mm = 134.3, or a 135 tire.

Where did you get that "formula"?

If you want a base line of where to start, look at what the car makers put on cars.  VW installed 155s on 4" and 4½" wheels.  Same wheels got 165s too.  The rare stock 5½" VW wheels got 175s.  If you research a 2CV, you will find it's wheels are probably 3" or 3½" wide to use 135s.  According to the car makers, a 4" wheel is too wide for a 135 tire.

Mexican Beetles had 4½" wheels.  Never a 5½.

Chris, send your wheels out and get them chopped down to 4½"!  That solves everything.

Mexican Beetles indeed had 4,5 not 5,5 rims. That doesn't change the fact that 155s work much better on a 5,5 than on 4,5. Indeed VW did use very narrow rims, with the following results: <a href="http://video.google.co.uk/googleplayer.swf?docId=640695539059738855" target="_blank">http://video.google.co.uk/googleplayer.swf?docId=640695539059738855</a>

I remember times when i played with little Fiats and a popular, tried combo was a 135/70-13 tire and a 5,5 inch wide rim. We wanted to have a good handling without using wide tires - the engine was week.

I'm talking about handling not the looks - the latter is subjective.

BTW - those Fiats had 135-12 tire and a 4x12 rim from factory, so I don't think car makers consider 4" wheel is too wide for a 135 tire.