Need sage advice re: rubber - Page 3 - PeachParts Mercedes-Benz Forum

TurboRedkneck · #31 12-17-2018, 05:36 PM

Anyone else ever used the newer 185/r14 van/light truck tires? I’ve been using them on my rear for my ‘83 300, but have been a little hesitant to put them up front because they are slightly larger diameter than a 195/70/r14. I’m thinking of giving them a try next time all around though. They have done rather well with extra weight from towing because they are 6 or 8 ply rated (depending on brand) but do seem to add a little extra unsprung weight. (I’m aware not rotating isn’t ideal, but for a while I was driving a lot of curvy roads and really chewing up front tires, so I was just getting them from the junkyard and mount balance myself.)

97 SL320 · #32 12-17-2018, 07:49 PM

Quote:

Originally Posted by Shern

That’s a great call. I mean the lack of consensus here is astonishing: 175 Sr 14????? 220/8 (1971)

After a peep on tire rack, I’ve learned the aspect free original tires had a diameter of 25”. 175/70 are around 23.8, 195/70 are 24.8 which is about as close as I could get to the original.

195/70/14 is somewhat an odd size. I'd go with the more common 195/75/14 . This is only slightly taller ( 25.5 ) and as the tire wears , it will be closer to your original tire.

ROLLGUY · #33 12-17-2018, 07:58 PM

Quote:

Originally Posted by 97 SL320

195/70/14 is somewhat an odd size. I'd go with the more common 195/75/14 . This is only slightly taller ( 25.5 ) and as the tire wears , it will be closer to your original tire.

Odd size??? 195/70/14 seems to be the most popular size for a W123 that I have seen.

97 SL320 · #34 12-17-2018, 09:34 PM

Quote:

Originally Posted by ROLLGUY

Odd size??? 195/70/14 seems to be the most popular size for a W123 that I have seen.

I just did some checking on Tire Rack, the once mighty 195 / 75 / 14 shows 4 tires and the 195 / 70 / 14 shows 17. Given this new info the, 70 offers more choices. I'd still go with a 75 for a bit more side wall height and a tire that wears to the cars original size Vs a 70 starts out small and gets smaller.

97 SL320 · #35 12-18-2018, 07:20 PM

Quote:

Originally Posted by 97 SL320

Have a look at these tire repair resources, I'm betting the repair is beyond safe limits.

https://www.tireindustry.org/tire-maintenance/tire-repair

http://us.coopertire.com/CooperTiresConsumer2013/media/Documents/Service_Bulletin_108_0914.pdf

I've just followed my own tire repair standards and rejected a tire. Found a nail that was 3/4 of the distance away from the outer most tread groove. The nail was angled towards the side wall so the inner liner hole was part way down the sidewall. Tire had sub 1,000 miles.

A few things come into play.

The tire is on the rear of a front drive car so it sees light load. ( + to fix ).

Tire is China ( - to fix ) ( I would not put a China on the front. )

I get tires for free from my local scrap yard and have a supply ( - )

The car needs to be standing ready at all times, it is my spare and Mom and Dad will get it when their car finally rusts away ( - )

If this was my spare car and I still worked 4 miles @ 35 MPH from home, I'd patch and tube but that job is long gone ( - )

robertb1958 · #36 12-19-2018, 09:02 AM

I think it was mentioned in one of the replies, but the original aspect ratio was (from memory) 78 or 80.

So, a 175x.8=140 sidewall height. For about the same height (and overall dia), a 195/70 comes pretty close, as would a 185/75 (not many choices)

I am not sure what rim width is on a 240D, but one of the problems with running wider lower aspect ratio tires is that the rims are often too narrow for the wider lower aspect tires. Tire rack has a chart for each tire that lists recommended rim width range. Also, I was surprised to find a new 175 original size choice that confirms the math above, sidewall height is 139.7mm calculated from the stated 25" dia.

I am getting tires for my W124 today. The small original size results in mostly inexpensive tire choices these days. I will probably go with General RT43s, they have been good on Nancy's Mazda 3 and have good reviews on Tire Rack, or maybe the Firestone Firehawks. Wish higher performance tires were still available, but sadly not much good choices available, IMO. What were those good Michelins back in the 1980's?

My thinking is that decent tires cost $300-400, and last 3-4 years. Worth $100/year for better handling, ride, and safety, for sure!

robertb1958 · #37 12-19-2018, 09:30 AM

Sorry, double post deleted

300TD1982 · #38 12-19-2018, 06:07 PM

When I bought my used W123 300TD, it came with 205/70/R14 so that's what I still use.

ROLLGUY · #39 12-19-2018, 07:54 PM

Quote:

Originally Posted by 300TD1982

When I bought my used W123 300TD, it came with 205/70/R14 so that's what I still use.

I like to run 205's on the heavier cars as well, especially a TD. The 240's work best with aluminum disc wheels and no larger than 195's (my opinion).