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You are here: Home / Tech / The damage and repair of Imogen Smith’s Norco

June 20, 2016 By Mike Blewitt Leave a Comment

The damage and repair of Imogen Smith’s Norco

MarathonMTB La Clusaz Roc des Alpes Norco MTB

Being able to repair a bike on the road, or on the trail, takes some luck, preparation and hopefully some calm thinking. A couple of weeks ago, I posted about the spare parts and tools that Imogen Smith and I would be taking to Europe for three races across France and Switzerland. The selection was made on reasoned judgement, availability of parts on location, and obviously keeping an eye on baggage restrictions.

Packing spares europe MTB

True – a spare swing arm in here would have helped!

And while bike building and maintenance had so far been a breeze, disaster struck on Saturday at the Roc des Alpes UCI XCM Series marathon, when Imogen was leading the women’s race in atrocious conditions. After meeting her on the second pass through the Col de Aravis, I descended back to our hotel in La Clusaz to get in the car and drive to Le Grand Bornand for a final feed zone before the last climb.

MarathonMTB La Clusaz Roc des Alpes Norco MTB

Waiting in the chilly air on Aravis for Imogen’s first feed, 37km in.

The mud on the course was ridiculous. The course had been changed a little to avoid the worst – but it was still almost axle deep in places, and also with freshly cut grass adding to the mix, creating a fibrous mud that stuck to everything. On the descent I passed one guy with his bike upside down and rear mech torn from his bike. Then I caught another descending with his rear mech dragging on the ground by the chain – his hanger torn from his bike. The mud was creating carnage.

Riding down to La Clusaz - this blokes drivetrain is dragging along the ground.

Riding down to La Clusaz – this blokes drivetrain is dragging along the ground.

A quick change and bag pack with some sports drink, extra gels and tools and I set off, finding the course in La Grand Bornand, and setting up a mini tech zone with jackets, food, tools and spares. I spotted some of the men who has been in front of Imogen on Aravis, so was grateful I was there on time.

MarathonMTB La Clusaz Roc des Alpes Norco MTB

The custom feed/tech zone.

MarathonMTB La Clusaz Roc des Alpes Norco MTB

Everything you could need, all from a musette.

And then my phone beeped – a message from Imogen. She was at the hotel with her frame fatally broken. My heart dropped. Winning a UCI marathon race would have been a Big Deal. Points. Self-confidence. Respect. And so much more.

Driving back I found a wife in despair – but what this post is about is getting Imogen’s team bike going again.

So, what happened?

Far from the frame ‘just breaking’, the truth could only be known once the bike was clean. It was filthy. Mud was jammed up around the fork, I even pulled a rock as big as the end of my thumb out from above a seal. Similar claggy mud was jammed around the chainring, swing arms and brakes. The down tube had an inch of mud along it. We hosed it first at the hotel, and got the big bits off.

MarathonMTB La Clusaz Roc des Alpes Norco MTB

Mud – yes Europe has many varieties.

Then, we packed it up and drive towards St Jean de Sixt to an Auto Lavage for some hot soapy pressure washing. You cannot avoid pressure washing after such conditions. You still need to be smart about it.

At this point I could see the problems. Yes, the frame was broken. The derailleur hanger had twisted clockwise and pushed into the frame. The derailleur had broken at the top pivot, and bent. But the real problem was the chain jamming between the jockey wheel and outer plate. The mud, with cut grass, had built up so much in the jockey wheels it derailed the chain. With it jammed, barely half a pedal stroke would have pulled it around and caused the damage.

MarathonMTB La Clusaz Roc des Alpes Norco MTB

Well that’s a problem.

Repairing the bike

With a spare rear derailleur on hand, and Norco Revolver swing arms being the same size across all models (the Gravity Tune size specific geometry is managed via BB shell placement in the main frame) the solution was pretty simple. I’d strip the seat stay assembly off my bike, aim to not drop any bolts or spacers, do the same with Imogen’s, and get her bike running again. I even had a spare blue cable crimp.

MarathonMTB La Clusaz Roc des Alpes Norco MTB

One organ donor hanging around.

MarathonMTB La Clusaz Roc des Alpes Norco MTB

Laid out awaiting a rebuild.

I tested on her bike whether I could move the hanger back into place and have it held by the clamping force of the through axle. It worked. Would it work under shifting load? Time would tell.

I pulled down Imogen’s bike, and cleaned the parts, not quite with surgical precision as it was about 5 degrees outside our tiny chalet. I then did the same with mine, using one of our flattened bike boxes on the grass to help in case I dropped anything.

MarathonMTB La Clusaz Roc des Alpes Norco MTB

The perfect workshop above Col de la Croix Fry.

I gave her chain a good clean, and looked over the spare rear mech. It’s actually off Richie Tyler’s Whyte, so has been through Mongolia. I lubed the clutch mechanism to make sure it was working.

Shimano moved the position of the clutch on the XTR rear derailleur for M9000. Photo: Richie Tyler

The spare, in a previous life. Photo: Richie Tyler

Rebuilding was easy enough – some Ride Mechanic Bike Butter on the bolts and spacers, and it all went together well enough. Wheels in, mech on, and then adjusting the limits.

I gave the chain a good inspection. Nothing was bent or damaged, so I tried it on there. We have a SRAM GX cassette on Imogen’s bike for extra range. At first I was concerned some teeth on the larger sprockets were bent – but it was just some fine tuning on the road to get the shifting optimised.

MarathonMTB La Clusaz Roc des Alpes Norco MTB

Ready to roll and race again. That’s our little chalet in the hills behind Imogen.

And my turn

So that was the important one done. Now could I use some bush mechanics to use the damaged swing arm on my own bike? I’d had some great offers for loaner bikes – but they all involved friends or colleagues going out of their way – so my best option was to get my bike up and running.

MarathonMTB La Clusaz Roc des Alpes Norco MTB

With a coffee, anything can be possible.

Putting the frame back together was easy, as was rigging up the Di2 again. That is far faster than setting up mechanical shifting again. The chain was fine obviously, but it was a case of holding the hanger in place and fitting the wheel. The Norco’s hanger bolt head had been sheared off, and I couldn’t budge the base of it from the alloy insert in the frame, not even with the end of a sharpened spoke.

MarathonMTB La Clusaz Roc des Alpes Norco MTB

Hmmm. Some Araldite from Mr Bricolage is in order.

But, I built the Norco back up, soft pedalled it through the gears while balancing the seat on my neck, then gingerly took it on the road. All good.

Trail testing our the Norco Revolver

So we rode! We drove to La Clusaz and rode up to Les Confins on the road. In part as a recovery ride for Imogen, and also to test the bikes under gentle load up a road climb. All was going well, the sky was clear, and we carried on along an old gravel road until we were high above another valley. I had a strict ‘no mud’ policy so sticking to the rocky old roads and trails was perfect.

Smurf ride. #VTT #nofilter #smurf #marathonmtb

A photo posted by Mike Blewitt (@mike.blewitt) on Jun 19, 2016 at 6:34am PDT

Filed Under: Tech Tagged With: MarathonMTB, Norco, Repair, roc des alpes

About Mike Blewitt

Mike loves all things bike, but marathons definitely hold a special place in his heart. He's the co-founder of MarathonMTB.com. He's raced extensively throughout Europe, North America and Australia and has represented Australia twice at the UCI Marathon World Championships.

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