Roller drop gears or normal straigth cut drop gears?
Turbo Mini Forums

Hi all

Just wondering what the difference is between Roller drop gears and the normal stright cut drop gears?

they are all the same except the idler gear

which there is one called a timkin roller
where the gear has been machined to accept a timkin roller, expensive around 170 pounds for this item

its supposed to be the ultimate ... it is but....

its not needed as long as you fit new needle roller bearings in the idler & gearbox case and the clearances have been set correctly

peeps on here are placing 200BHP through the needle roller bearings without any or little trouble!

suppose if you have the money though

however....

after sitting in benross's car the joy of not having the idler chattering away was most welcome

In a few years when i have money again i shall be fitting a roller jobbie

thanks nic

as you say the noise reduction is a lot better may be 80+ % better

How does the idler bearing arrangement affect noise then chaps????

Dave i have listened to many gearboxes with SC drops in

and have found that the ones with the idler timkin set up is “considerably! Quieter”

this must stem from having no needle rollers in application
with the timkin setup
the timkin idler also reduces the running clearance some what

and the timkin idler virtually eliminates the side loading on full load

mine are timkin and still bloody clatter!

Team Racing

mine are Timkin and are louder than a friends normal straight cut drops.

i must be deaf then.....lol

In my experience there are different types of drop gear clatter,

the first is a loud dull slapping clatter from the idler flapping from side to side against the alloy casings (on helical setups)

the second is a more metalic sound than above caused by large clearences on the primary gear (also on helical sets)

both these types should be eliminated with SC drops as there is no side ways movement, (i've not expirienced it anyway)

This leaves the actual gear backlash noise, this does change from anufacturer to manufacturer, minispares gears allegedly have the best tolerances.

Also one thing worth noting is some people just run sealant between the engine and box this will affect the noise, (as will different thickness gaskets from cheap suppliers)