How flexible can I get with offset +25? - PeachParts Mercedes-Benz Forum

Mervyn · #1 06-06-2002, 02:08 AM

Sorry guys I'd to start a new post cos I couldnt find my last post......

I just fitted a 18X8.5J (offset +17) rim on my 1983 W126, and it sits perfectly fine even though the W126 uses offset +25. In fact, my new rim still sits rather recessed from the fender edge, about 1 and 1/2 inches inwards.

My question is, does that mean I can disregard the offset as along as the rim sits clear of the fender edge? In other words, can I use a similar rim but with lower offset (say +5) just so that it sits out a bit more?

I asked because all along I was under the impression that offsets must be strictly adhered to when changing rims, but in my case, it seems that it is not critical. Pls advise, thanks so much!

Cheers

#2 06-07-2002, 12:23 PM

The farther outward you go (smaller ET number in the German system), the more stress you are putting on the outer wheel bearing, even though in older cars with traditional double Timken-type tapered roller bearings, the inner, larger bearing is the one which is intended to carry more weight. Even _Hot Rod_ magazine folks used to urge people to proceed with caution anytime they wanted to go beyond an additonal 1/4" of outward offset (reducing the ET number by more than 6mm in the German system). In my opinion, the closer you can stay to stock offset without having clearance problems on the inside, the better you can trust your wheel bearings.

Mervyn · #3 06-07-2002, 11:12 PM

Thanks for the advice.

I've read from an article on track widening (intentionally pushing the rims out towards the fender edge) and it says:

"You can improve your vehicles handling by simply widening the track of your vehicle. Widening the track
will give you a more stable ride & improves your vehicle center of gravity. By spacing your wheels out to
the maximum allowed by fender width, you will also improve the cars appearance (more aggressive). "

This is the reason why I asked the earlier question, as I'd intended to get as much width as possible without rubbing against the fender by varying the offset.

Do you have any idea what kind of bearing systems my W126 is using? Many thanks!

#4 06-08-2002, 04:23 PM

They are promising things which won't happen, since lowering the roll center is primarily a matter of changing the suspension geometry, and they aren't warning you about all the extra kick-back in the steering that would be caused by such extreme changes in offset, not to mention the real possibility of busting a wheel bearing the first time you hit a serious chuckhole.

I've not actually looked closely at a W126's front wheel bearings, since all my experience is W123 or older, but I'm likely to get some W126 experience soon, since a friend just inherited one with about 175,000 miles and I had to do a quick steering play adjustment so that he wouldn't be afraid to drive it. I am pretty sure, though that any M-B with standard wheel offsets of ET30 or less has tapered Timken type serviceable bearings -- later models have wheels with larger offsets -- at least ET35 and usually more -- because of the different hub design required for the newer low rolling resistance all-sealed-and-swedged-together-into-an-unserviceable-unit type of bearings, but I've only dealt with them on BMWs and Audis.

Mervyn · #5 06-09-2002, 02:14 AM

Ahhh, I am grateful for the enlightening.

I am pretty much satisfied with the current setup, only that I was too enthusiastic about getting the wide wheeled look. Will heed your advice, thanks again for the time.

Regards

#6 06-09-2002, 09:31 AM

out closer to the fender lip, and are willing to risk a little extra stress on the wheel bearings, the way to do it would still be to get wider wheels rather than use the same wheels with spacers. The wider wheels will then give more support to the tire sidewalls for better handling -- in effect it converts your tires to a lower aspect ratio. You would need to find wheels with the same "backspacing" as what you've got; "backspacing" is a term popular with the _Hot Rod_ crowd which means the distance from the mounting face inside the rim to the extreme edge of the _inside_ bead flange of the rim (although some seem to mean to the inner sidewall of the tire). That guarantees that you've still got the same clearance inside.