Firstly there are a few things we need to clear up:
Carbon is not abrasive friendly. Bags and cardboard are not abrasive friendly. Simply covering tubes with lagging foam does virtually NOTHING to stop external blunt force from distorting and cracking the frame.
The general rule to safely transport a bike in a soft bag/ cardboard requires 2 things:
1- Create a ‘soft’ frame around the bike to avoid contact with the frame itself.
2 – Covering the surfaces with non-abrasive padding to avoid abrasion and additional impacts
Here we go:
1 – Wheels/ seat post/ pedals/ rear mech/ bars from stem cap off.
2 – Unscrew the hanger from the dropout instead of only removing the rear mech. Why? This is exposed to a corner impact and can damage to carbon dropout. The hanger itself does the damage.
3 – Cut lagging (shown in grey) to your frame tube size and ducktape the surface leaving the slit open. Label each one for easy re- fitting.
4 – Fit a dropout protector where required (shown in red). We repair 90% of chain/ seat stays as a result of not having a protector in place.
5 – Unscrew the stem cap and gently roll the bars around the fork until they fit nicely around the headtube and fork blade. Keep trying and eventually you will see how easily they can fit in this position. Don’t over bend the cables. The bars also act a a protection for the fork.
6 – Wrap the rear mech in foam and place the chainring on a sturdy foam base as you lock the frame in. Bottom impacts often bend the teeth. The base must withstand this. Replace after impact has damaged this base.
7 – Once you have stuffed as much of your kit/ helmet etc into spaces, it is time to fit the outer frame (shown in blue). I use ducktape covered polystyrene sections squeezed into the front/ back and top covering from the seat post hole to the stem. If your wheels fit either side of the frame then you do not need to pad the sides.
8 – Lastly DO NOT deflate the tyres completely. If you do the rims get a pounding from impacts. Semi deflated the tyres can also help absorb impacts and act as further padding.
It takes about 20 min to pack and 5 min + to unpack.
CARBON BIKE INSPECTION SERVICE
/in carbon, tech /by Rob GranvilleIf you have a scratch or a mark on your carbon bike which you would like a qualified carbon bike inspector to look at then drop us an email or a message and we will inform you of the next steps. There is no reason why you need to worry before riding out this summer. Prices start around £80. Contact us with your inquiry and inspection options. We scan the bike from top to bottom. We can include your groupset condition inspection. If we find any issues you have 2 choices:
1 – Get in touch with your insurer if you want to pass on the claim. You will be required to provide them with our inspection report to qualify the claim.
2 – Get it fixed yourself and know that the bike is in good order. Remember composite bikes are complex machines. Don’t risk it if in doubt.
ARE GRAPHINE BIKES NECESSARY?
/in Graphene, tech, Uncategorized /by Rob GranvilleLike all things new in the bike world, graphene is the shiny new toy. Everyone is talking about it but is graphene really necessary? I would venture to say no. To clarify – We repair any composite construct and we have a keen interest in graphene as we learn new repair solutions.
Yes, it is a wonderful material and yes it can conduct electricity (so does carbon by the way). Lightness and stiffness might be another motivation and repair is most likely possible but why am I not as enthused by graphene as I should be?
Carbon has taken bikes to the limit where any further weight shedding may not be in the best interests of all riders. Let me explain – Cycling terrain generally undulates creating benefits and drawbacks depending on the rider and the bike. Inertia is also a benefit so light is not always the ONLY goal.
Carbon bikes are already safely at the tipping point of weight versus stiffness. By loosing several more grams on the frame and adding more stiffness by using graphene will work well in certain circumstances but is only one element in one bikes advantage over another. Carbon is fit for purpose as GRP, Glass-reinforced plastic is for high performance boats.
Graphene is still too expensive and challenging to process. Stocks in graphene, according to Nanalyze, is not yet an invetment opportunity and as a result the prices will not drop anytime soon. However we see an increase in the use of graphene oxide powder which is used to strengthen resin. I would be intrigued to understand how robust a full graphene bike will be to surface impacts and how abrasive resistant it will be in the future. This is where Carbon is not great.
I will let this one play out.
CREAKING COMING FROM MY DOWNTUBE
/in carbon, tech /by Rob GranvilleI was asked to look at what might be delamination in the down tube area during an inspection procedure. At first we could not solve where a creaking sound was coming from because the scanner could not find anything and it sounded similar to de-lamination so we had to find it.
I won’t mention the brand but when we inserted the endoscope we came across some expanding foam in the middle of the downtube cavity which impeded our exploration further. I asked for the downtube to be squeezed while we had the endoscope in position. We discovered that the expansion foam had slightly come away from the carbon wall causing the part to creak when he road it.
It seems some manufacturers have found a temporary solution to rattling internal cables. I say temporary because mid downtube sections are susceptible to flexing during riding which in turn can cause this rather minor de-bond over time. As small as this is it simply drives the rider nuts with irritation and concern. Hope this helps someone!
REPAIRING A CARBON RECUMBENT
/in carbon, paint /by Rob GranvilleWe don’t often get asked to repair recumbents but this one is a super light disabled version which is clearly an expensive and hard to find bike. The structural damage affected the chasis and the safety nose cone. I am glad to say we were able to complete this as well as hide the repair in the weave.
Glad we could help out on this one.
HOW TO PACK YOUR CARBON BIKE FOR TRAVEL – PART 2.
/in carbon, paint, tech /by Rob GranvilleFirstly there are a few things we need to clear up: Carbon is not abrasive friendly. Bags and cardboard are not abrasive friendly. Simply covering tubes with lagging foam does virtually NOTHING to stop external blunt force from distorting and cracking the frame. The general rule to safely transport a bike in a soft bag/ cardboard requires 2 things:
1- Create a ‘soft’ frame around the bike to avoid contact with the frame itself.
2 – Covering the surfaces with non-abrasive padding to avoid abrasion and additional impacts
Here we go:
1 – Wheels/ seat post/ pedals/ rear mech/ bars from stem cap off.
2 – Unscrew the hanger from the dropout instead of only removing the rear mech. Why? This is exposed to a corner impact and can damage to carbon dropout. The hanger itself does the damage.
3 – Cut lagging (shown in grey) to your frame tube size and ducktape the surface leaving the slit open. Label each one for easy re- fitting.
4 – Fit a dropout protector where required (shown in red). We repair 90% of chain/ seat stays as a result of not having a protector in place.
5 – Unscrew the stem cap and gently roll the bars around the fork until they fit nicely around the headtube and fork blade. Keep trying and eventually you will see how easily they can fit in this position. Don’t over bend the cables. The bars also act a a protection for the fork.
6 – Wrap the rear mech in foam and place the chainring on a sturdy foam base as you lock the frame in. Bottom impacts often bend the teeth. The base must withstand this. Replace after impact has damaged this base.
7 – Once you have stuffed as much of your kit/ helmet etc into spaces, it is time to fit the outer frame (shown in blue). I use ducktape covered polystyrene sections squeezed into the front/ back and top covering from the seat post hole to the stem. If your wheels fit either side of the frame then you do not need to pad the sides.
8 – Lastly DO NOT deflate the tyres completely. If you do the rims get a pounding from impacts. Semi deflated the tyres can also help absorb impacts and act as further padding.
It takes about 20 min to pack and 5 min + to unpack.
HOW TO PACK YOUR CARBON BIKE FOR TRAVEL – PART 1.
/in carbon, tech /by Rob GranvilleSoft or hard boxes? The debate rolls on. I always thought hard boxes were the safest until a cyclist friend, who actually worked as a bag packer at Gatwick, suggested that soft bags/ cardboard were generally treated more carefully while the hard cases often were found at the very bottom of a pile of holiday cases due to their size and handled with a little less care then the softer more vulnerable bags. Don’t test my theory until you read part 2.
Dutch manufacturer Vanmoof for example printed an image of a TV on the box which reduced bike damage by 70-80% so there must be something in it. Unfortunately for some soft bag design there are glowing design errors which I will attempt to help mitigate in part 2.
MOUNTAIN BIKE PAINT
/in paint /by Rob GranvilleHow have the manufacturers responded to the elements that can affect paint on a typical carbon mountain bike?
You have 2 options it seems:
1 – Powder coat the frame if it is alloy. The limitations are in the colour choice and the designs limitations but it is as hard as nails.
2 – The other option is to apply many more layers of paint and lacquer to absorb the shock of chips. Usually a typical road bike will receive about 2-3 layers of lacquer. In this example, this Trek MTB has about 8 layers which is clearly an indication that they want to protect the exposed surfaces from abrasion and chip damage as much as possible. There are other brands which apply std 2 pak bike spray in this many layers. Others opt for weight saving but it depends on what the bikes primary use will be.
That said there is no particular right or wrong way to paint a MTB other than the point that std bike paint can take a hammering on loose terrain compared with road bikes and therefore the manufacturers apply different solutions to MTB spray jobs.
The best overall solution, if you want to keep your bike is good aesthetic condition, is to apply Invisiframe which is a thin clear adhesive tape cut to your bikes profile. Works a treat.
CAN A CARBON REPAIR BE TOO STRONG?
/in carbon /by Rob GranvilleYes. This mountain bike came in for an inspection requested by a concerned customer after it was repaired by another carbon repairer. The large ‘block’ of carbon (pic left) now present on the BB/ downtube is much thicker then the original tube wall. As a result if this area were knocked during riding it will simply shere the surrounding original carbon punching a hole into the frame.
It is so important to know what you are doing when repairing composite bicycles. This is one example we see on occasion but it answers a more important, common question – ‘Can you make the repair stronger then the original section?’ The answer is usually no. We repair (pic right) to the specification of the frame for very good reason!
WE STAND BY OUR WARRANTY
/in paint /by Rob GranvilleThis customer had a custom respray last year. Over time it developed paint flaws which were consistant with an error in the paint process. We inspected under microscope and discovered shrinking and adhesion issue which was not down to user error:
BIKE SHOP SUPPORT
/in Uncategorized /by Rob GranvilleWe make sure, as with all our bike shops, Sigma Sport are always satisfied with our service:
‘Hi guys,
The frame arrived today and, as usual, the finish is excellent. Just wanted to say a massive thank you for getting this turned around so quickly.
It is very much appreciated.’