Puzzling smell

[mudguard]

(No, nothing to do with sprouts or beans for dinner)

Out for a blat today, noticed a strange smell only at 40Mph and above. A burning smell, perhaps burning rubber or oil. Definitely went away at low speeds. Definitely me - no-one else around - supposedly busiest day of the year? Certainly not in west Kent where I was enjoying the sunshine and the empty roads.

No unusual noises. All gauges fine. Engine running fine. Brakes fine - not dragging. Steering smooth and unobstructed. Handbrake not applied . Pulled over (immediately to be distracted by a passing local who wanted to tell me all about I was driving his dream car, yeah I get it, mine too, but right now I really want to check that it's safe rather than have a chat, sorry). Exhaust gases clear. Lifted bonnet, nothing leaking, nothing smoking, coolant/oil levels fine. Examined 4 wheels - nothing making contact.

Set off again, and immediately I hit 40 the smell returned. Then I immediately realised what it was and didn't even need to stop the car to confirm. I also knew I could safely drive the car back home, provided I did not exceed 40. 

Puzzle: what was it?

[Jonathan Kay]

Private Message sent.

Jonathan

[SM25T]

The Christmas enigma of 2018

[paul richards]

Something caught on exhaust?

[David Belding]

Slightly seized caliper? One dragging pad won't be felt with the wheels on the ground but will make one disc very hot at speed. Happened on my Volvo last week, offed the disc etc.

[mudguard]

Adhesive failure between front cycle wing and upper wingstay arm - but not lower wingstay arm. 

Hence, at rest, it sits by gravity and all appears normal. At around 40Mph, it acts like a sail, lifting up and waving around and pushing the lowest part of the wing into the tyre. 

Aware of the various discussions re: bigheads, choice of adhesives etc etc. Have a long-term plan, but for now it's firmly fixed on with a cable tie.

[SM25T]

Good detective work.

[SM25T]

If it is anything like mine was ... the Sikaflex was firmly adhered to the powder coating ... but the PC wasn't attached to the wingstay. Cleaned off all loose coating and brush painted with black Smoothrite ... then refixed wing with Sikaflex ... big fillets either side of stay ... then several longways strips at 90 degrees to the stay. Clean inside of wing with acetone (nail varnish remover) before starting ... but keep it away from the painted side.

[mudguard]

Thanks Ian - mine failed differently. The break was between the adhesive and the fibreglass, adhesive still very firmly attached to wingstay.

(edited as I initially misread your comment)

[SM25T]

Ok .... so clean fibreglass with acetone to get a good bond.