James,
The question of tyres and wheels on the Elan is a complicated subject. The Elan was produced for almost a decade, and the tyre and wheel choice reflect what was acceptable for the period. Thus tyre size started out as 5.2-13 with 13X4.5 wheels, moving to 145-13 and 155-13 tyres. The narrow 4.5 width wheel was considered acceptable for the 5.2 tyre in those days, although wider wheels are considered more desirable today.
The +2 used 165-13 tyres with 13X5.5 wheels.
Stock steel wheels, whether bolt-on or knock-off are NLA. The original wheels are very light weight, and, at 40+ years old, are often suspect unless well maintained and/or refurbished. Much heavier replacements were manufactured at one time.
After market aluminum (and magnesium) wheels have been produced during the years. Minilite still make 13" and 14" aluminum wheels in both bolt-on and knock-off for the Elan and +2, although the weights have crept up during the years. There are posts from users and their adventures with these wheels.
If you have knock-off wheels, that is about the market. Bolt-on wheels have many more options, since wheel manufacturers often cater to any reasonable bolt circle, wheel size, rim width, and offset. Some have a Minilite or 26R lookalike wheel in aluminum in various weights and sometimes in magnesium. Superlite has aluminum wheels in three weight ranges (with commensurate pricing) plus 26R look alike magnesium wheels in 13, 14, and 15 sizes.
Tyres are another problem area. The standard 155-13 and 165-13 tyres are no longer used on high performance production cars. The replacement market is generally oriented to inexpensive, low performance sedan replacements (meant for 3000 lb sedans, not 1600 lb Elans) with the exception of the Michelin XAS which is often considered too pricy.
It should be noted that Lotus specified S rated tyres, while the XAS is H rated and a well modified Elan with a 5-speed probably should be shod with V rated tyres. However, given wide wheels (5.5 or 6) and high tyre pressures (30+ psi rear or 2.1 bar) a H rated tyre should be safe enough.
Replacement tyres probably should be close in diameter to the original tyres. The 155-13 tyre has a rev/mile figure of 912, the 165-13 is 887. Other tyre sizes close in diameter to the 155-13 are 185/55-15, 175/65-14, 185/60-14, 175/70-13, and 175/55-15. Tyre sizes close in diameter to the 165-13 are 175/70-14, 185/65-14, 195/55-15, 175/60-15, 185/70-13, and 195/60-14. A size intermediate in value is 165/70-14.
There is a down loadable spreadsheet 20080411zGearRatios.xls that is available at
viewtopic.php?p=82911 at the bottom. It has a sheet TiresS that has tyre sizes sorted by rev/mile so that you can see all combinations close to a particular size. The tyre size has a clickable link to TireRack (it used to work years ago, anyway) so that you can see different manufacturers for each size, at least for US customers.
There is another down loadable spreadsheet at
elan-f15/updated-spreadsheets-t18445.html that offers different views of tyre/diff/rpm etc. It also has tyre rev/mile data.
Every body will have their opinions on this, but this gives you the raw information with which to do your research.
David
1968 36/7988