# Gearing for Hymer 660



## lovejoy (Mar 2, 2009)

Good morning, As I'm a bit of a newbie and my ears are still unfamiliar with the revs on my 1989 Hymer S 660 /Merc 410 D, could anyone please give me the gearing i.e 1 st=5mph.
2nd =10 mph.... etc
When I drove it back from London down to Cornwall it felt like I was revving the guts out of it and then almost stalling it in 5th !

P.S. Has any anyone any info on the ceiling mounted air conditioner for the Hymer.

Thank you 
Love, Lovejoy


----------



## gm6vxb (Nov 3, 2007)

Three ways of working out gear ratios.
One is to have a GPS with speed display, then run at known revs for a mile or so in each gear (quiet roads obviously). Not easy but it can be done and you can get fairly accurate figures after a few tries.
Second is to try at your local Merc dealership. If they are friendly it may be possible to either get brochures or (computer) other information on ratios.
Last way is not easy with a diesel. Put the vehicle in each gear in turn, then rotating the engine look for one complete revolution or the wheel. Number of revolutions or the engine for one revolution of the wheel will give you ratios in each gear.

Alternatively I am sure there is someone on here who has the original handbook which may have gear ratios. 
Martin


----------



## Proff (Jul 22, 2005)

Our 660 had the same feel about it, Rev the nuts in 3rd, and it would almost stall in 4th, 5th was a flat road gear only...
So last Aug I spent £2300 and had it Turboed, now it pulls from 35 in 5th and I no longer dread hills  plus get around 1.5 mpg more 

I just need a higher ratio diff now as it still sounds like your killing it at anything above 58 mph...

BUT 55/57 mph is a nice cruising speed, you keep the lorries company, and they seem to get where they are going


----------



## funkyronster (May 1, 2005)

Aug I spent £2300 and had it Turboed,

By who? Interested

Ron


----------



## Proff (Jul 22, 2005)

I was one of the last to be Turbo intercooled by TB Turbos of Lancaster.
The mechanic/ workshop foreman who did mine now does them at his own place
cmautoservices
he's on this site and will be glad to quote you....
I'm still over the moon with the way ours just pulls like a freight train, even with 1.5 tonne trailer behind


----------

