Radical SR3 & Cold winter evenings

[gaxor]

Amazing as it may seem, we have decided for the first time to keep the same Radical for 2 seasons running - shocking I know!!

Seriously though we are carrying out a pretty comprehensive inspection/overhaul before this years racing, and are seeking some advice relating to the wishbones. Would it be recommended to have them inspected for cracks, and if so can anyone recommend a suitable establishment in the SE (Crawley/Redhill) area. We will as a matter of course be re-plating (Zinc Passivating?) all of the wishbones/nik-link bars etc.

Any other advice gratefully received

Gary

[Simon T]

How old are they?

[gaxor]

5 years old now.

[Laurence7]

Gary

I'm currently going through the same process myself with a bunch of Clubsport wishbones. I’ve had them vapour blasted and they’re now awaiting inspection prior to getting them zinc plated and passivated (provided there's no evidenc of cracks! ).

Dye Penetrant Inspection is well within the capabilities of the intelligent amateur. There are two basic types - one uses a (red) dye that is drawn into any crack by capillary action and is visible to the naked eye, the other type uses a dye that fluoresces under ultra violet light. For this method, you need a UV lamp producing “black light” in an otherwise unlit room.

These websites explain the process and provide contact details for one of the leading brands in the UK.

http://www.mig-welding.co.uk/forum/showthread.php?...

http://www.twi.co.uk/content/ksijm001.html

http://www.henkenind.com/dye_penetrant_inspection....

http://www.magnaflux.com/Default.aspx?alias=www.ma...

I would look at the weld areas and anywhere where your judgement tells you there’s a bending load.

For Clubsport/Prosport lower front wishbones the place to look is the underside of the forward main tube – this is under tension loading (due to drag load under braking) and bending (due to spring compression caused by braking and cornering). In addition, at this position there will be some degree of stress concentration due to the way the mounting bracket is welded to the tubes.

The SR3 lower front wishbone is probably a better design in this respect, as it is effectively ‘upside-down’ as far as the welded bracket is concerned with the bracket being welded to the upper (compressive bending) surface, so the there is no stress concentration on the lower surface at the position of maximum bending load. Nevertheless, that forward tube is still subject to tension and bending loads, so that's where I'd look in particular.

I'd look at the other wishbones as well of course, but to my mind, its the front lowers that take the hammering, due to heavy braking and kerbing.

In all this, I’m not meaning to imply that there is any deficiency in the design of Radical suspension components, but given the punishment that can be meted out to wishbones under racing conditions (who hasn’t winced as they’ve taken a kerb a bit harder than intended!), it makes sense to inspect for cracks. And I suppose it ought to be said - If in doubt, replace!

[Laurence7]

Update on Dye Penetrant Inspection:-

A suitable product is Rocal's Flawfinder Kit, product reference 63181, info here
http://www.rocol.com/corp/index.php?option=com_con...

It can be purchased for £51.03 + VAT, from here
http://www.lawson-his.co.uk/
or contact Rocol direct for a local distributor