20” Unimog rims on a Mercedes 814 DA

[Tiktaalik]

I’m trying to confirm if a 20” Unimog rim will fit a Mercedes 814DA. It currently has 19.5” rims on it made by GABO and I have heard they will fit but would like to confirm that the specs match.

Can any of the Unimog experts on here confirm if there is any Unimog rims available with the same bolt pattern, center bore and offset as the stock 814DA rim (see info below)?

814 DA
Stock Rim: 6Jx16 ET 120
6Jx16 ET 129
Stock Tire: 215/75 R16
Bolt Pattern (PCD): 6x205
Center Bore: 161mm
Lug Nuts: M18 x 1.5mm

 

[part time nomad]

Sorry i can`t help you, but i shall watch the posts with interest!
What is the reason for you wanting to change? is it because the tyres are easier to find! or going to singles on the rear,

I got new 19.5s from Germany, delivered here to the UK.

 

[Tiktaalik]

Very limited tire options for 19.5" and they are all delivery truck tires (At least in the US). No AT/MT tires exist in that size. The 19.5" I have are dual in the back so you can't air down. I'd also like to go singles in the rear to simplify the process of changing tires by the side of the road.

 

[part time nomad]

My Fulda 19.5 are all terain!

There was a thread on here by (Ianc - pre birth of a camper) I think, from what I remember he put 20" on and handling problems.

maybe worth a look!

Got any pics of your truck?

 

[Tiktaalik]

Fulda? Where are you located?

What kind of handling problems did they have? I will search.

Since I started this thread I've learned that although Unimog rims will fit, the offset is different and that may cause problems so perhaps Unimog rims isn't the answer.

I am now looking at having GABO make me a set of 20" rims specifically for this truck. Here is a a custom 20" set they made for another 814DA with the correct offset. The 20" rim size allows for Continental MPT81 (as seen here) and many other options.

 

[Tiktaalik]

Here's a photo of the big fella I bought. It is as an an unfinished restoration so it needed some work to get it running. It's in a shop in The Netherlands now, getting ready for RORO.

 

[part time nomad]

I am located in Bedfordshire UK . Those tyres look fairly meaty! mine are more all terain. as probably 90% of the time that will be ok.

Mine is a box body truck, I will try to put a pic up from the phone.

 

[part time nomad]

View attachment 635301View attachment 635301View attachment 635301

 

[Gretar]

Several threads have discussed the choice of tyres for the Vario. I use Michelin XZL 275/80R20 on 9x20 Unimog wheels and very happy.

 

[part time nomad]

Do you run singles or twins on the rear?

 

[Spaceman spiff]

Several threads have discussed the choice of tyres for the Vario. I use Michelin XZL 275/80R20 on 9x20 Unimog wheels and very happyView attachment 636905View attachment 636905View attachment 636907.

Did you have to use a spacer in the rear to make them the same width?

 

[charlieaarons]

Yes Unimog wheels of the 6x205mm bolt pattern have been used. The narrower 9” wide ones. I don’t think spacers are needed since the midline of the rear duals and front singles appear to be in the same line.
Obviously I would want to use only the smallest tires 275/80R20, which don’t have the greatest load capacity.
335s can be obtained with a very high load index of 150 but are ~48mm greater radius. And would absolutely require a gearing change which might be hard to find since the axles are MB proprietary.

 

[Tiktaalik]

Here are the custom GABO rims with the +125ET offset. No spacers.

 

[charlieaarons]

Load capacity for the MPT81s in the picture is 4240kg/axle which is enough. By flipping the rim in the rear there’s going to be pretty major wheel bearing stress increase however.
You would essentially going from ET 0 (the sum of offsets of duals, one being flipped) to -(125mm + thickness of flat mounting part of rim ~10mm).
What year is the 814DA? Does it have the OM364 or 904LA? If the 904, it might be possible to gain 41hp relatively easily through ECU reprogramming or replacement. Although I don’t have any idea on whether the turbos and injector nozzles (not too expensive) or actual unit injector pumps (expensive!!) are the same. The pumps are controlled by the ECU.
And you’d want to have an EGT gauge and observe it for weeks or months in hilly terrain to get a baseline before changing anything.

 

[Tiktaalik]

Stock offset is ET120 and the GABOs are ET125. I believe those Unimog rims have ET137.

My 814DA is a 1992 and I have the OM364LA engine. I plan to install an EGT eventually.

Load capacity for the MPT81s in the picture is 4240kg/axle which is enough. By flipping the rim in the rear there’s going to be pretty major wheel bearing stress increase however.
You would essentially going from ET 0 (the sum of offsets of duals, one being flipped) to -(125mm + thickness of flat mounting part of rim ~10mm).
What year is the 814DA? Does it have the OM364 or 904LA? If the 904, it might be possible to gain 41hp relatively easily through ECU reprogramming or replacement. Although I don’t have any idea on whether the turbos and injector nozzles (not too expensive) or actual unit injector pumps (expensive!!) are the same. The pumps are controlled by the ECU.
And you’d want to have an EGT gauge and observe it for weeks or months in hilly terrain to get a baseline before changing anything.