• Guide to put your Brompton on a Diet

    by  • January 8, 2017 • Cycling • 0 Comments

    Recently I have joined the countless people around the world who have invested in a Brompton Bicycle. It is an incredible bicycle; the most fun I’ve had on a bicycle for a long time! and already is helping me get around, however at the back of my mind is always the engineer who asks; “can we make it lighter?”

    Check out my current progress on saving weight on my Brompton 2017 M6L

    Straight away I am amazed (and saddened) that there is not a Carbon Fibre Brompton, but then again Brompton is a small company with only around a 30mil turnover who doesn’t have the resources or experience with Carbon Fibre technologies, and so they stick to what they know.

    This guide mainly covers those that have already bought a Brompton bicycle and are looking to shave some weight from it. If you are on the look out for a Brompton however and have yet to invest in one then there is a different set of questions you should be asking?-

    Do you need all those gears? – The gearing system adds weight, and weight is the bane of a folding (and carrying bicycle) I bought myself a 6 speed, which is effectively a 3 speed hub and a 2 speed cassette and derailleur, added together makes the 6 sequential gears. If you don’t need all these gears, or a strong enough cyclist to only rely on higher gearing there is no point on the 6 speed. Save yourself some weight and cash and just invest in the 3 speed. Originally I was only myself going to go for the 3 speed however I got the upgrade for free so I thought why not.

    Which metal? – If you can afford it, a titanium version is going to straight away give you massive weight savings (1kg+) but like everything comes at a cost.

    Functionality – Think carefully around the handlebar choice, whether you need a rack or mudguards. The difference between the classic ‘M’ handlebar and the straight ‘S’ handlebar is nearly 100g

    For reference I have a standard construction 2017 M6L Brompton in Tempest Blue – not that the colour makes any difference, I just think it looks lovely. For the rest of this post I talk through some of the ways you can shave weight from this type of Brompton (steel / alloy construction) sorted by which will give you the best bang for your buck. Some of the tips and changes will still help those that already have a Brompton higher up the food chain.

    Puncture Protection
    If you are not carrying around a puncture repair kit or invested in the Brompton toolkit which although very well built and designed is rather expensive, then what is the point carrying the bicycle pump that Brompton includes on the bicycle. It is 92g of weight that is useless unless you carry the other tools. Another option is just carrying the pump in your bag rather than on the bike.

    Cost: Free
    Weight Saving: 92g

    Seat Post Stop
    If you don’t replace the seatpost with a lighter titanium or carbon version, a complete overkill weight saving can be removing the seat post stop. Recently Brompton did replace the old version with a 34g lighter version, so it is especially good if you have an older Brompton. The only issue is not wanting your Brompton to scrap the floor or damage the post.

    Cost: Free
    Weight Saving: ..g

    Tyres
    Puncture resistance is the compromise here, if you are after high resistance most swap out the standard Brompton Kevlars for Schwalbe Marathon or Marathon Plus versions (like I have on my main touring bike) – these are almost bulletproof but can be extremely heavy (my touring bike ones clock in at nearly 1kg each).

    Going the other way, the Schwalbe Kojak folding tyres are by far the fastest rolling and lightest tyres for your Brompton. Buying a pair of these can save you nearly 500g over the standard Brompton setup.

    Schwable Kojak Tyre

    Cost: £30 (each – Evans Cycles)
    Weight Saving: 232g (each)
    Link: (Evans Cycles

    Inner Tubes
    Its always good to keep a spare inner tube, thus it may as well make sense and swap out the standard issue inner tubes with higher quality and lighter versions. Schwalbe make tubes for this size which Brompton rebrands as their superlight versions. Sometimes its just cheaper getting them direct.

    Product: Schwalbe Lightweight Inner Tubes
    Cost: £5.60 (each)
    Weight Saving: 20g (each)
    Link: (brilliant bikes)

    Wheelsets
    The front wheel is the next easiest port of call for an easy to replace meaningful weight saving on your Brompton.

    Brompton have their own ‘superlight’ version which has a different front hub configuration and different walling on the rims to reduce weight. On the market however there are plenty of 3rd party rims and hubs that are prebuild such as the SJS wheels saving 70g, or you can build yourself to save weight.

    I haven’t mentioned the rear wheel as that is more difficult (due to the inclusion of the hub gearing), but if you are brave you can still replace the rim itself for a (small) weight saving.

    Product: SJS Front Wheel
    Cost: £65
    Weight Saving: 70g

    So by this stage we have only scratched the surface by replacing wheels but managed to save a potential 0.71kg off of the bikes weight at a cost of £161.20. Luckily the existing tubes/tyres could be used as backups and spares, and then there is always eBay to sell any unneeded components.

    Saddle
    The standard saddle that Brompton provides has the advantage that it includes a handle to assist carrying the bike when folded, however this adds weight. Saddles in general are a trade off between weight and comfort. I would always suggest a Brooks saddle as they are incredibly comfortable and I use one on my touring bike. But on a Brompton it would add almost 200g of weight. Brooks has the answer with their Cambium C13 Carbon versions, which switch out the steel rails for Carbon Fibre, saving just over 80g.

    Brooks Cambium Saddle C13

    If Brooks aren’t your thing, then there is always a variety of different race or performance oriented saddles which could save around 100-150g. The only trade off (apart from comfort) is that you would have to hold the Brompton by the frame and not the saddle when carrying it. An extreme example is something like the ‘Selle Italia Flite Tekno Flow Saddle with Carbon Rails’ which only weighs 125g vs the standard Brompton saddle weight of 323g!

    selle-italia-flite-tekno-flow-side

    Product: Brooks C13
    Cost: £149
    Weight Saving: 82g

    Pedals
    The standard pedals have the advantage that one of them is folding, reducing the width of the packed bike and allowing it to remain flat when stored on its side e.g. in a cars boot.

    This comes at the price of weight, overall the folding pedal weighs 289g for the pedal, bolts etc. and the other side weighs 119g totalling 408g.

    The Brompton pedals are a respectable weight in the folding pedal category, however if you only pack it on its side occasionally then maybe removable pedals are the way forward. For the best decrease in weight however you may just need to live with pedals that don’t fold.

    I use SPD and SPD-SL cleats on my other bikes, so for the best savings we can turn to Shimano’s latest pedal technology, which is the ‘Dura Ace 9000 SPD-SL Carbon Pedals’ which weigh in at 248g

    Product: Dura Ace 9000 SPD-SL Carbon Pedals
    Cost: £136
    Weight Saving: 160g

    Seat Post and Pentaclip
    This is another big area with a large room for improvement. The standard Brompton seatpost and Pentaclip comes in at 503g. For a period Brompton produced a rather expensive titanium version, however there are now a selection of Chinese Carbon Fibre alternatives which are even lighter and even cheaper.

    My choice is the Hylix carbon seatpost which sells on eBay for around £60 + possible import duties. This carbon fibre seatpost comes with a carbon seat clamp and titanium bolts which totalled up weigh only 266g

    Product: Hylix Carbon Seatpost
    Cost: £60
    Weight Saving: 237g

    Handlebars
    Just like the seatpost, the standard steel/alloy handlebars can be replaced with Carbon Fibre alternatives. I have the M Handlebars, however these were modified in my 2017 version to have a lower overall rise. On eBay you can get Carbon Fibre versions of the S and M handlebars, but not currently of the new style.

    Hylix again do a carbon fibre M handlebar (old style) which reduces the weight down to 151g from the original Brompton 282g

    Product: HYLIX Carbon M-TYPE Riser Handle Bar
    Cost: £60
    Weight Saving: 131g

    So how much do I save overall, and how much is it going to cost?
    Lets go through the shopping list on this Blog Post and see just how much I can shave off my starting 11.78kg weight.

    Remove Pump – Free – 92g
    Kojak Tyres – £60 – 464g
    Schwalbe Inner Tubes – £11.20 – 40g
    SJS Front Wheel – £60 – 70g
    Brooks C13 Saddle – £149 – 82g
    Dura Ace 9000 SPD-SL Carbon Pedals – £136 – 160g
    Hylix Carbon Seatpost – £60 – 237g
    Hylix Carbon M-Type Handlebar – £60 – 131g

    Total Cost: £536.20
    Total Weight Saving: 1,276g

    New Bike Weight: 10.5kg

    The biggest bang for your buck definitely is the tyres, followed by the seatpost, and if you don’t carry a puncture repair kit then there is no point carrying the pump. Some of the items I’ve mentioned may be a little over the top (Brooks saddle, Dura Ace Pedals) which drive up the cost significantly so there is room to search around what is listed here. If I had switched to an S type handlebar or only choosen 3 gears more weight could be shaved, not to mention if I could find carbon fibre mudguards or retrospectively buy a titanium rear triangle and forks…

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