Which wheels should I use? - PeachParts Mercedes-Benz Forum

junqueyardjim · #1 04-23-2016, 10:53 AM

I bought a set of 4 15" wheels which I can use on the W123. Tire availability is said to be shrinking on the 14" rims, though the tire people I deal with tell me I can still get them in Michelin. Will the 15" give me a better handling and driving car? Will the ride be inferior? What 15" tire would you recommend?

Clemson88 · #2 04-23-2016, 11:37 AM

Michelin is the only tire to use, imo. I went to a 15" wheel on my 84 SD but I still have to order tires.

Honestly, having gone from old worn tires on the 14" wheels to new Michelin's on the 15s and it's an unfair comparison.

As far as the supply of Michelin 14s being exhausted, I consider how many of these wheels are still being used. I can't imagine how long it will be until there are no more Michelin 14" tires for these cars.

Never-the-less, if the wheels are nice/chrome or easy to care for then I can understand you're wanting to change. I think the engineers here have comments which might address the fuel economy and mileage change from 14s to 15s but other than that it's a personal choice.

I'd like to have a set of 8 hole chrome 15s for my car so that washing wouldn't be such a pain in the rump/

junqueyardjim · #3 04-23-2016, 12:09 PM

Thanks for the feedback. I did by the 8 hole in factory finish, nice but not cherry, Each wheel has a spot or two of rash. I think they will look great on my car,

t walgamuth · #4 04-23-2016, 01:19 PM

How much do the 15" rims weigh? Lower profile will give slightly quicker response to turn in input, ride a little harsher....none of that very noticeable if wheel/tire weight is not changed much.

Diesel911 · #5 04-23-2016, 02:07 PM

If the diameter of the installed Tires are different turning will be slightly harder but going over rough roads will be slightly easier.

Heavier Tires and Rims increase the un-sprung weight and that can have a negative effect when you hit a bump.

Increasing the Tire Diameter changes your alignment slightly.

However, the steering and alignment issue may never be noticed.

Dan Stokes · #6 04-23-2016, 03:07 PM

Remember that changing dire diameter effectively changes gear ratio so you'll want to keep that in mind. A taller tire lowers the numeric ratio - I have a 3:08 gear in Mutt and 2 sets of tires, 28" tall and about 22" tall. I forget what the calculated ratio change is but it's significant. Going from a 14" rim to a 15" rim probably won't be that drastic but still, it's there. The shorter tires will accelerate more quickly but require more RPM at cruising speed. It will, therefore, throw your speedo off so you'll want to remember to correct for that (I've seen a little chart posted on the speedo with the correct numbers, 50=54 or whatever). There are online correction formulas to help generate the chart.

Dan

junqueyardjim · #7 04-23-2016, 06:44 PM

Well the one tire I got with the set, which I think is a 185/65 R15, inflated is very close to the same height as my current tire which is a 195/70 R14. Both tires had about the same tread remaining. My memory is slippery right now as I have been on a pain pill for about 10 days. Off of it now, but memory is shabby, so to speak. But as I remember from yesterday the R15 was about 1/4 inch or less taller then the R14. Not much difference. Actually very close. It also seems to me, that the 8 hole Benz wheel is lighter than the 14" Bundt

junqueyardjim · #8 04-23-2016, 07:29 PM

Yes, ultimate gear ratio is very important. I am using the standard RA Ratio from my 85 300D which is a 2.88. Did I luck out with that junhkyard engine! Well I guess. My Son in Law Steve called me to say his Buddy Ben had this diesel engine which he said was in good shape, (how does the junkyard guy know) anyway, they would pull it if I wanted it for $400.00, but it had to be picked up "today". Well, it was a hot day in August in 2011 I think, and I went down to look at it. It was an 80 or so SD, and it was a total mess. I don't know how long it was there, but I know it was there for more then 4 months. Well I jumped the battery on it, jumped those two screws on the fender and had the kid that was with me hold the engine fuel stop in the run position. It fired right up, with no glow plugs. It didn't run very long, but long enough that I could like the sound of it and we took the beast home. And by putting it in this beautiful 240D solved my very worrisome problem of having a very tight pilot bearing installed. However, after 4 or 5 years use, the pilot bearing didn't fail and my mechanic said it pulled out like as normal pilot bearing.
Well anyway, Don from Chicago wanted and was waiting for that engine. It had compression on 4 cylinders of about 410, only one, number one hole was at 385 psi. Why does it seem like number one cylinder on the Mercedes Diesel is lower then the rest.
Anyway, at my age and not feeling well, or at least my wife not feeling well, but I am too old and too tired to swap out any engines or transmissions. I just can't do it any more. Shop labor cost me $1400.00, but included swapping the oil filter, changing the motor mount arms, install new water pump, new vacuum pump, adjust valves and renew the turbo and more. Parts and machining of flywheel and all new clutch parts and few other parts mentioned cost me $500.00. He is not a diesel mechanic though he has serviced my car for years. I had taken the engine down to the point of pulling it out when I shipped it to him and that makes re-assembley much more difficult. But he did it all just perfect. He couldn't get the air cleaner to hook up at the "U" tube because I gave him the lower filter "box" from the SD and the length of the intake and outlet on that filter is turned around from the filter in my 300D. Wow, he was hot that he couldn't get the connection right. He did laugh though when I showed him why he couldn't make it fit. Anyway, that engine is about as fine a running engine as I have seen in a 300D. It pulls so well, I think it is amazing. I did check all the glo plugs, but it does start like one is not doing the job, but in 15 to 30 seconds all is well. I have just under a 1000 miles on it, it doesn't smoke, it doesn't leak and all around I think it is just great. It is very quick to 90 mph. And it is such an easy car for a big old guy like me to get into. I am 83, can't get my weight down or the scale is just stuck on 260. Anyway, that is a lot of beef to (maybe bull crap) to get in and out of the car. But in the 240D/300D it is very easy. I took the AC out or off from it because I just don't need it. Windows all work like new as does the sun roof. If you need air conditioning on a 300D W123, I think one should look at a total new unit. The old ones just don't do it. I drove to Lafayette, IN the other day and on the I65, a guy in a new Lexus with dealer plate really gave the car the once over. He couldn't stop looking at it. I thought that was pretty good.

Junkman · #9 04-23-2016, 08:32 PM

Stock 15" is very close to stock 14" tire. Run whatever wheel you like best. Do something different if you want or when you can't get another set of 14s or whatever you have on there at the time.

I just bought a set of Michlin Defenders. They are supposed to last for 90,000 mi. That's more than 6 years because I have too many vehicles. The car will be broken in at ~300,000 mi when the tires need to be replaced. The good thing about tires is they don't have to be adjusted. Simply get them balanced & rotated and no issues until they are worn out. I wish all of the other systems were like that.