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fernweh
Date registered: Apr 2006
Location: Calabasas, CA - Centenario, BCS - Luebeck, Germany
Vehicle(s): Few Mercedes-Benz, a Toyota Amphibious and a Vespa
| RE: rims/tires...again
Hello Piotr,
I'm not familiar with your 280GE transmission set up.
All our G's were engineered from the factory to their specs. (engine size, horsepower, drivetrain usw)
If you change this equation - installing larger tires - things might not work so perfect any longer. Your engine has to work much harder and doesn't have enough power to move the G like before. The automatic transmission will provide the best power band, depending on speed, engine speed, throttle position, intake vacuum to your wheels on the ground. With the changed equation, the transmission will shift much more often trying to compensate for the now greater workload - turning those large tires. you might even have manually shift the box in order to get some better performance out of your engine.
If you use the little gear-change calculator, it will tell you exactly which gear set you need to use - having changed the diff gear ratio correctly, you "fool" the engine/transmission into believing everything is back to 'factory specs'.
Any increase of workload will have effects on the transmission, like higher oil temps and so on. Can a 'good' transmission handle the increased load, I do believe so, but others might want to install a larger trans oil cooler. All auto trans seem to like the correct fill level.......
I'm not sure but your 'electronic box' might handle only the kick-down mode, when activated to shift down immediately, all other shift points are the results of correct set-up between engine and transmission to factory specs. Again, changing factory specs.........
Karl
Edited by fernweh 5/30/2007 10:16 AM
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4x4abc
Date registered: Apr 2006
Location: La Paz, Baja California, Mexico
Vehicle(s): 02 G500
| RE: rims/tires...again
Nicky,
I like that paint job very much. Its #2 on my options list to paint my black G500 - #1 is the matte military green. I wash my car only 3 times a year and one of those use oriented paints would not show immediately that I don't care about washing. |
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4x4abc
Date registered: Apr 2006
Location: La Paz, Baja California, Mexico
Vehicle(s): 02 G500
| RE: rims/tires...again
Piotr,
we have been over ths many times - but you don't listen well (selective hearing/reading?)
your original tire size was 28" - you changed that to 33"
you lose 3.5% of torque with every inch - so, you lost 5x3.5% = 17.5%
your original diff set up is 4.9:1 - to make up for the loss, you will have to increase that number by 17.5%
4.9 + 0.86 = 5.76
So, 5.76:1 would be the perfect match for your tires
But Mercedes does not offer any gears in that range (they have: 4.11, 4.375, 4.857, 5.286, 6.167)
So, 6.167:1 is your best choice - actually you will gain 7% of torque (not bad)
your rpm will be higher by that same amount (the amount is so small, it can be neglected)
instead of 3000 rpm at a certain speed, you would now run 3210 rpm
on the transmission side - you might be better off buying a good used transmission rather than having all kinds of "experts" sticking their fingers into your sick tranny |
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jcaine
Date registered: Dec 1899
Location:
Vehicle(s):
| RE: rims/tires...again
tomorrow I'm finally picking up my 17" porsche ceyanne wheels... I tried one on last week to make sure the spacers were right and the overall wheel/tire diameter looked slightly smaller than my stock set up... I beleive these will also be at least a few pounds lighter than stock... in theory if this is the case (smaller diameter and less unsprung weight) I should have a performance increase...
We'll see...  |
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nugat
Elite Veteran
Date registered: Jan 2007
Location: Warsaw, Poland
Vehicle(s): 280GE, 290GD, c303
Posts: 876
| RE: rims/tires...again
Karl, Harald-thank you for your input.
My sick transmission was cured today, I hope . It turned out that the control box was not sending clear signals to the gearbox due to bad connections (those are really not too well protected and had the right to go bad after 20 years). After cleaning, cutting wires etc the auto box works very nice-in S/SA (high) position of TC. In GA (low) the changes are more felt than before ( I think). Is that normal?
The reason I am not jumping at the diff gears change idea is the cost. Here MB quoted 4,000US (four thousand) for parts alone. How much is it in the USA? For that money perhaps it is better to exchange the 280GE /150HP engine for a nice used 2.7 turbodiesel? What do you think?
Piotr
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4x4abc
Date registered: Apr 2006
Location: La Paz, Baja California, Mexico
Vehicle(s): 02 G500
| RE: rims/tires...again
Piotr,
a stronger engine will not help you.
Listen : "Its the gears!" - repeat after me: "Its the gears!"
Harsh shifting in low range is normal. I just hope you did not do this on pavement.
17" wheels (= less rubber) will make the ride of a 460 rougher. Off-road performance stinks. On-road handling will improve, but it will be rougher.
G parts are coming from Germany and Austria - so, lower prices in the US are not likely.
Each gear set (you need 2 - 1 front and 1 rear) is about €650. New bearing and seals in each diff will cost you another €100 per diff. The work itself is easy and straight forward.
I'll bet you pay more for a 270CDI conversion. |
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nugat
Elite Veteran
Date registered: Jan 2007
Location: Warsaw, Poland
Vehicle(s): 280GE, 290GD, c303
Posts: 876
| RE: rims/tires...again
4x4abc - 5/29/2007 10:38 PM
Piotr,
a stronger engine will not help you.
Listen : "Its the gears!" - repeat after me: "Its the gears!"
Harsh shifting in low range is normal. I just hope you did not do this on pavement.
17" wheels (= less rubber) will make the ride of a 460 rougher. Off-road performance stinks. On-road handling will improve, but it will be rougher.
G parts are coming from Germany and Austria - so, lower prices in the US are not likely.
Each gear set (you need 2 - 1 front and 1 rear) is about €650. New bearing and seals in each diff will cost you another €100 per diff. The work itself is easy and straight forward.
I'll bet you pay more for a 270CDI conversion.
17" wheels--that's not me...
"It's the gears".
So the parts' prices are the same. When you add what you suggest on your page-brake boosters etc, will come to a lot more.
You don't write there about bearings/seals. Any chance to get part numbers for those (w460), maybe update on your page?
Turbodiesel conversion has the nice side that savings start right afterwards. Given differences in mileage and fuel prices , the cost of conversion has the chance to be recouped in 20-30,000 km.
Piotr
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4x4abc
Date registered: Apr 2006
Location: La Paz, Baja California, Mexico
Vehicle(s): 02 G500
| RE: rims/tires...again
Piotr,
all the numbers you want have been on my pages for some time. Helps to look.
Gear order numbers are up, wheel bearing numbers are up, the needed tools are up and diff bearing numbers are up as well:
gears
bearings
tools
pinion
I am here to help whenever I can (remember "Pay it forward"?
Edited by 4x4abc 5/30/2007 6:05 PM
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nugat
Elite Veteran
Date registered: Jan 2007
Location: Warsaw, Poland
Vehicle(s): 280GE, 290GD, c303
Posts: 876
| RE: rims/tires...again
Thanks,
Indeed I haven't visited your page for a while and it's been updated.
The "tools" link has some problem though.
P. |
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nugat
Elite Veteran
Date registered: Jan 2007
Location: Warsaw, Poland
Vehicle(s): 280GE, 290GD, c303
Posts: 876
| RE: rims/tires...again
you fixed the link, quick! |
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jcaine
Date registered: Dec 1899
Location:
Vehicle(s):
| RE: rims/tires...again
ok... finally got the 17 inch porsche cayenne rims on... had to have a custom set of spacers made but that's another story. The good news is they look pretty decent and I beleive they are giving me better acceleration... the diameter is slightly shorter than the 16 inch set up I had and they are significantly lighter... I didn't have a chance to weigh them but I would suspect 7-8 lbs less per wheel at least. Feels like it's just a bit qucker through the gears and I can start in second gear from a rolling stop where I couldn't before...
I have only been on the highway briefly but it felt it may have been reving a little higher at highway speeds as compared to before, which would make sense if the diameter is smaller it would wind out quicker... I need a tach to really tell...
I'm going to drive on these a little bit and then try the 18 inch G500 rims I have... those are slightly taller than stock and about 5lbs heavier... I suspect they will give me the opposite effect... slightly worse acceleration and taller highway gearing... I like the way the 18's look a little more than the 17's but if they make a negative difference in performance, I'll stick with the 17's...
The ride on the 17's is also at least as good , if not better than the stock 16's with the 225/85's...
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hus55
Expert
Date registered: Apr 2006
Location: north cyprus,lapta.
Vehicle(s): 300GDS, G300 LONG,300GDT CLK55 AMG CAB.
Posts: 2230
| RE: rims/tires...again
interesting to hear. so i guess theory doesnt always equate i practice,any pics of the new wheels on your G? lighter wheels certainly improve ride comfort(carlsson super lights) are one of the lightest wheels available for saloon mercedes giving a far superior ride to any other alloy wheel on the market,its been tested in 20" form on an sl55 and they ride awesomely quiet and smooth.But are your alloys able to carry the G's weight?
enjoy  |
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