Ive been using the double lip Viton on Driveside for many many years and Ive never had a seal go on me.
As for the large Mag side yes I use them there as well again with no problems.
I just gave full set numbers so people can choose what they want to do.
See here for Typical Viton spec http://www.cellulardevelopments.co.uk/r ... on-fpm.asp
Which can run alot hotter then the typical rubbers used for seals see below
NBR - Nitrile rubber
The most widely used elastomer in most current applications. It is particularly recommended in case of contact with:
- Paraffin-based (aliphatic) oils
- Mineral oils and fats (oils for engines, gearboxes, differentials, etc.)
- Hydraulic oils
- Water and aqueous solutions (lyes).
The temperature range varies from -30°C to + 120°C.
ACM - Polyacrylic rubber
This elastomer is recommend for use with:
- engine oils even if containing additives and sulfur
- transmission oils
- hydraulic oils.
The temperature range varies from -25°C to + 150°C.
MVQ - Siliconic rubber
Due to its chemical composition (high molecular weight chains of appropriately modified polysiloxanes), this series is particularly resistant toward atmospheric agents, light and ozone. It also exhibits an excellent high- and low-temperature resistance, so that its field of application covers a broad range. Despite its less than fully satisfactory tear and abrasion strength, its low friction coefficient amply compensates for the relative effect. It is recommended for:
- resistance to atmospheric agents, ozone, etc.
- mineral oils
- glycol-based fluids.
Never use with petrols.
The temperature range varies from -55°C to + 180°C.
FPM - Fluorinated rubber
This elastomer has exceptional heat and chemical resistance. Its properties remain indefinitely stable up to about 200°C. It offers excellent performances in contact with:
- aliphatic hydrocarbons
- aromatic hydrocarbons (toluene, benzene, xylene)
- vegetable and mineral oils and fats, even if containing additives
- chlorinated solvents
- ozone
- light and atmospheric agents.
The temperature range is from -30°C to + 200°C.
HNBR - Hydrogenated nitrile rubber
The chemical structure of this elastomer (obtained by hydrogenating an appropriate type of NBR nitrile rubber) allows achieving, especially if vulcanized with a peroxide system, an average heat resistance 30°C above that of nitrile rubber, and an excellent abrasion resistance.
Its resistance to oils and solvents is on average slightly superior to that of nitrile rubber, except for special cases. It is therefore recommended for:
- heat resistance
- ozone resistance
- abrasion resistance.
The temperature range is from -40°C to + 150°C.
EPDM - Ethylene-propylene rubber
This rubber is based on ethylene-propylene plus a third (diene) monomer which allows its reticulation with sulphur. Due to its chemical structure, it has a peculiar resistance to fluids such as water and steam and environments such as ozone, which recommends its use for:
- water, up to boiling point
- steam
- particular hydraulic systems, such as braking systems
- ozone
- atmospheric agents
- bases
- polar solvents at ambient temperature.
The temperature range is from -50°C to + 150°C.
If I remember rightly I think it was ROLF that brought out the double lip first, then everybody else followed suite.
IMHO I believe that the Viton seals do last longer as they are formulated to withstand the latest unleaded fuel, with all there additives which break down the standard seals.
The double lip does add an addition seal however small for you crankcase
Another tip I also never use the Drive side bearings with the inbuilt seal ie 6305 C3 RS
As when you check data sheets on them the RPM rate for them are dramatically reduced ie 7.5K rpm where as standard ones have limited speed of 16000 rpm
But hey the choose is yours Im just giving my opinion and some facts plus a lot of usage.
Smiffy
