JDLindy

Hello all, Is there any concerns with replacing 18" wheels with 20" and adding low profile tires?

I have a 2007 ML320, CDI with 18" wheels, and was given a full new set of OEM 20" (wheels only, no rubber) from a 2010 GL450, and am considering buying low profile tires so diameter is same.
I need new tires for the 18" and now have an option.

Is there any concerns I should consider, is this feasible, or is it ill-advised?
The only reason I am considering is cosmetic as I have to buy new tires regardless. I don't have a financial investment for the 20". Before I spend $1,400 on tires, I thought I would ask the group if this is ill-advised.

- Current Vehicle: 2007 ML320: OEM 255/55r18.
- New Wheels: 2010 GL450: OEM 275/50r20.
Changing to,
- New Tires & Rims: 2007 ML320: 275/45r20.

1) The overall diameter is within 1%, so he braking, speedometer, shouldn't be much of an issue.
2) The bolt pattern 5 x 112, is identical.
3) Width is 20mm wider, but is this an issue ??

Is there an alignment issue, or any other consideration I should be aware of ?

Thanks
Joe

OUZO Power

On my summer setup I'm running 275/45r20 on 9.5 wide rims and they look perfect. No issues.

I also have 20" GL rims for the winter and I'm running 265/45r20. What sucks is the rim is 8.5" wide. So I'm stuck with this tire size. Limited and expensive options. I've always wanted to put 275/45 on them as there are more and cheaper options but from what I have found is you need a 9" wide rim to pull a 275 off.

What is the rim width of you GL rims?

JDLindy

Thanks for your reply Ouzo

The width of the GL450 wheels measure 9 1/2". Internet search suggests the tires should be: 275/50r20. So I believe 275 should be fine.

That said, I just ordered 275/45r20. I need the lower profile to keep the total diameter close to the ML320 OEM 255/55r18.

I am still apprehensive whether the 2010 GL450 wheels will work on my 2007 ML320.

Joe

OUZO Power

9.5" then your good to go with 275/45.

What's the offset?

BTW those also came standard in the post 09 ML I believe.

You have nothing to worry about.

JDLindy

Offset? different width between front and rear?
If this is the question, they are identical width.

I think this might be my main concern, the front's might be too wide and may brush against the struts? I did try the wheels on (without the tires), and they are fine, but the tires will make a difference.

Thanks again Ouzo

OUZO Power

Look at the back of the rim. It will have a number ET??. All 4 will be the same they are not staggered.

Whats that number and I'll tell you if your good or not. But since it came off a GL 99.9% chance your good and the number will be between 45-60.

JDLindy

Ouzo, you are good ! Here are the numbers...
- ET56 DOT
- D8.5J x 20H2

OUZO Power

Rim is good to go. You won't have any rubbing.

It's the exact same spec as my GL rims I use in the winter.

But we confirmed they are 8.5 wide and not 9.5.

I'll look to see if it works with a 275 tire when I get back to the office.

On the GL it might have used a 275 tire but it had a bigger profile.

OUZO Power

OK confirmed. And this opened up a whole new realm of possibilities which is fantastic.

275/45R20 Tires work on SUV's and the minimum required width is 8.5".

http://www.lvvta.org.nz/documents/in...lity_Guide.pdf

Scroll down to Page 7.

Or you can use this calculator.

http://www.tyresizecalculator.com/ty...ize-calculator

Good luck and post pics after you are done.

JDLindy

Thanks again Ouzo. Above and beyond, and I appreciate the help. I will post a couple of before and after pictures next week when I get the tires on the wheels, and on the ML

Cheers
Joe

paulg

I understand the need to change for cosmetic reasons, but make sure you are prepared for a MUCH harder ride. Especially over potholes and ridges.

Don't forget, the W164 ML was first released on 17" rims, and the engineers at the time presumably judged the ride/handling compromise to be about right for the type of vehicle.

Move on a few years and we see 22" wheels on MLs. I feel sorry for anyone who has to drive thise on English roads. Maybe your roads are in better condition, but they would need to be almost perfect to ride acceptibly on 20" wheels.

I guess I'm getting old and find a car with a bad ride offensive these days. Though I also want it to have good handling, turn-in, low roll etc... The tradeoff will always be there, especially in a vehicle like ours that's got such a high C of G.

I went from 19" (standard-fit) AMG wheels to 18" and the the transformation in ride was dramatic. If you go the other way (or further) the difference will also be dramatic.

Thought I should mention this in case ride quality is important to you.

JDLindy

Thanks Paulg, good comments for sure

We live in the suburbs 30 minutes east of Vancouver, Canada, and I doubt our roads are any better (or worse) than English roads, but there is one drive I look forward to... the "Sea to Sky Highway" from Vancouver to Whistler Mountain, a 2 hour drive with twists, turns, hills, bailey bridges, switch backs, and incredibly scenic too. A 'must do' if you make if over here. (You will recall Whistler Mtn hosted the Olympics in 2010)

I did anticipate a rougher ride, but until I get to drive it myself i won't know the extent. That said, I do appreciate your comments, and am bracing myself. I needed new rubber on the 18" anyways, and i got the 20" rims for a steal, so thought I would give it a try. I will keep the old rims just in case the ride is unbearable, although i doubt it.

I have always enjoyed getting fresh new tires, and i'm sure the new rubber (275/45r29), will offset new rougher ride. (for a while anyways)

I will post my experience, and 'before and after' pictures in a week or two, after I get a chance to drive it.

Thanks again Paulg. I appreciate your comments.
Ouzo was extremely helpful too, and helped me make my decision.

OUZO Power

You'll be fine with that tire size. If you have Airmatic and set it to comfort you'll be good to go.