QuestionHello,
I have a two-part question about correct wheel width size and tire width size. One concerns wheels/tires already on the car, the other concerns new wheels and still to buy (winter) tires.
Car in question: 1993 Skoda Favorit Hatch.
Original tire/rim width: 165/70R13 4.5x13
The idea was to keep the total diameter of the wheel as close to the original as possible to maintain correct speedometer readings and performance. I also wanted slightly wider tires than the original 165s and settled on 195s because even though the engine runs really well, it's only 40KW after all. With 195/40 I could fit a 16" alloy very nicely so I settled on Falken ZIEX ZE-912 195/40. However, finding a 16" rim for ET4x100 on a budget isn't easy and the only ones I could find that fitted the car, both technically and esthetically, had a width of 7.5! Nominal tire width for such a rim is 245, I believe? Still, I bought them and had the 195/40 tires fitted. Amazingly, the rims fit the car very well and don't even come close to touching the wheel arches. However, the rear rims come very close to the suspension coil and under certain conditions - load, sharp bend (< 90 degrees) the rims touch very lightly, though only enough to thinly scrape the paint off that part of the coil. Also, it only touches intermittently because, surprise surprise, 3 out of 4 rims are warped. And although it's been balanced out, it's far from the ideal solution. It isn't even a real solution. All in all, not a good buy. :( Live and learn.
Now, I know I should probably get rid of these rims or have them re-alligned (sorry, don't know the proper term in English!) which is expensive. As it is now, they looks great, the grip and cornering is fantastic, very stable, but all in all these rims are no doubt hell on almost every suspension component you can think of (coil-scraping + vibration at 80-100km/h. Steady at 120+). What should I do?
1. Do I sent the rims to be repaired (warp taken out)? Or is that relatively expensive and would I be better off looking for smaller 16" rims in the 6.0x16 area?
2. For this car I don't want to go any wider on the tires than 195, but was the fact that I mounted these tires on 7.5 rims even a good (safe) idea in the first place? (Regardless of whether I have the rims repaired or not.)
3. In general, what are the nominal (best suited) tire widths and the minimum and maximum tire widths for every rim ranging in width from 4.5 to 7.5?
I also ask this because I am about to buy four original 5x13 rims for this model car (will be careful this time and check if they're warped!) and want to use them either to mount winter tires or - if I get rid of the 7.5x16 rims - to mount summer tires
Long story, but would really appreciate your insight and advice.
Many thanks in advance,
Dave
AnswerDave,
The allowable rim width range for a 195/40R16 is 6 1/2" to 7 1/2". You want to be within that range, so it is not a good idea to use 6" rims with this tire size.
The first step in this process ought to be getting enough load carrying capacity. I have a book that summarizes the vehicle tire placard information for vehicles sold in the US. Needless to say the Skoda isn't in it. I am going to assume the 165/70R13 is the proper tire size for this vehicle.
A 165/70R13 has a load index of 79, and an overall diameter of 562mm and fits on a 4 to 5 1/2" rim.
You asked about rim width vs section width and the issue is too complicated to discuss in this format. However, if you use:
http://www.1010tires.com/TireSizeCalculator.asp
You can get the allowable rim width as well as a comparison of the diameters.
You can play around with the tire sizing and compare the results with what is available - both tires and rims.
And lastly, be sure you get a tire with at least a Load Index of 79 (shouldn't be too hard!). If that tire happens to be an Extra Load (XL), also known as "Reinforced", then you may need to adjust inflation pressure.
Check back with me when you've had a chance to go through all that and I'll review what you've come up with.
