Purchasing a Thorn bike
It takes approximately 10 days from the very start of the build process to completion of a bike and for it to be ready for delivery. However, each order is placed in a queue and the overall delay between placing an order and the bike being ready for delivery or collection, is currently 35 days.
If you need your bike more quickly than that, for a non-refundable fee of £100 (£150 for tandems), we will build your bike in overtime with a turnaround of within 2 weeks from the point of order (although we often manage to build them more quickly than that).
There are now 4 options to place an order:
- In person: Many of our customers prefer to make an appointment to discuss their order with one of our specialised sales team here in Bridgwater. Just call 01278441505 to arrange one.
- By telephone: Call us on 01278441505 and speak to one of our dedicated sales team who will guide you through placing your order.
- By email: Print off pages. 61 – 80. Fill in using black ink the options you require and then scan and email it back to us at email@example.com .
- By post: Print off pages 61 – 80. Fill in by hand the options you require and then post it back to us at: Thorn Cycles Bike Department, 91 – 93 St John Street, Bridgwater, Somerset. TA6 5HX
With all of the above options we will produce you a quote (valid for 7 days), detailing your personal specifications. All you need to do then is to agree the specification and pay a deposit of £100 and we will activate your order.
Yes, absolutely! Many of our customers prefer to make an appointment to come and meet us here in Bridgwater to see for themselves the range of bikes that we sell and to place their order here in the showroom. This gives the opportunity to spend usually one to two hours discussing the options available with one of our specialist sales team.
First of all, we will discuss with you the type of riding you are planning on doing on your new bike to help you decide on the model of bike you wish to purchase.
Then we will measure you to assess the size of frame you require and determine which riding position you prefer.
Using these measurements, we will calculate the exact set up to achieve your preferred riding position on your new bike.
During the appointment, you will be able to ask as many questions as you like and will be guided personally through every aspect of your bike build, ensuring that you will end up with the perfect bike. You should allow 2 hours for this.
If you are purchasing a Rohloff equipped bike you may want to go for a test ride. Some people like to go for a short test ride which can be fitted into the allotted 2 hours, but others like to go for a longer ride and if you plan to go on a longer test ride, please inform us at the time of making your appointment.
The short answer is; no!
The reason why we have test ride bikes is so that cyclists unfamiliar with the Rohloff 14 internal gear speed hub can understand what it is like to ride a Rohloff equipped bike, as it is still a relatively uncommon gearing system.
Our derailleur models do not go out of the showroom as everyone knows what it is like to ride a derailleur equipped bike, and, from the gear changing point of view, although our derailleur bikes are superb machines, they are no different in this respect, to any other similarly equipped bicycle.
If you do buy a Thorn derailleur equipped bike and you are not totally delighted with your new bike we offer a 14 day money back guarantee, which effectively means that you get to test ride your own bike, made to your exact size and specification, for a whole 2 weeks! If you decide you don’t like it, you can simply return it to us (see FAQ “What if I don’t like my bike?”) and we will refund you the purchase price of the bike, no questions asked!
Some of our Rohloff equipped bikes share the same (or similar) geometry as our derailleur models, and so by test riding one of these, you can get to know your size and the feel of the bike.
Below is a list of the models and sizes available to test ride:
Thorn Mercury: 520L, 550L, 550S, 580L, 610L
Thorn Nomad: 510L, 565L, 540L
Thorn Nomad S+S: 540L, 590L, 620L
Thorn Raven: 500L, 530l, 530s, 565l, 600l
Thorn Raven Step Through: 420
Thorn Raven Discovery 8A
- The Thorn Sherpa shares exactly the same geometry as the Thorn Raven and so by test riding a Raven you would know how a Sherpa feels. Similarly, the Mercury shares the same seat height and stand over height as the Club Tour, and so by riding a Mercury, you would know which size Club Tour you would require.
In the UK, you can only buy a new Thorn bike or Thorn frame directly from us
We do not have any UK dealerships.
Occasionally, you will find a Thorn bike being sold privately on eBay or through a
private second hand sale.
We often sell bikes on our customers’ behalves through our St John Street
Many people use the Thorn Cycles Forum to sell their bike so this is a good
place to look if you know what you want.
We have sold hundreds of bikes from here in the UK and delivered them to
customers all over the world so it is not necessary to be here in person.
Upon the receipt of a small deposit (which is fully refundable) we activate your order.
Paying a deposit holds the current price for you, irrespective of whatever price increases may have occurred between placing the deposit and paying the balance. We operate a queuing system and when your order arrives at the top of the queue we start to build your bike.
We accept payment by debit card; all major credit cards (except American Express); wire transfer (BACS transfer), SJSC gift vouchers.
We accept cycle to work vouchers (see cycle to work FAQs). We do NOT accept cheques. You can pay for your bike in full upon collection. If you are having your bike delivered we require payment in full before we dispatch it. We expect full payment within 28 days of the predicted completion date printed on your invoice.
As soon as your bike is complete we will contact you to either arrange a collection appointment, or ask you to make your final payment and arrange a convenient delivery date.
If you live in the EU, yes, you do have to pay our VAT unless you are VAT registered in your own country – see the FAQ "Can I live in an EU member state and not pay UK VAT?”.
If you live outside the EU, customers do not pay VAT you will not not be charged VAT unless youchoose to collect yourbike from us here in the UK – see the FAQ "Can overseas visitors collect from the UK and not pay VAT?"
Yes, customers living in the EU may purchase from us without paying our VAT if they hold a valid VAT number for their business.
All you have to do is provide your VAT number and once verified, we will be able to sell to you excluding VAT.
Because of Government rules we will only deliver to a customer; they may not collect from us unless they pay VAT first and then claim it back.
The link below may be useful.
The cycle to work scheme involves a lease agreement between an employer and their employee. Employees agree to deductions from their salary each month which repay their employer for their initial outlay.
The monthly payments cover the employer’s lease agreement with the employee over a period of time, and amount to the cost of a bicycle for which the employee intends to use to travel to work. The bicycle remains the property of the employer until the completion of the lease agreement period.
Most employers use an agent to administer the scheme and all cycle to work agents take an administration fee – usually 10%, although some take more. There is no price limit for bike purchases and most employers limit their employees to a voucher of a maximum value of £1,000 because to enter into a lease agreement for amounts of over £1,000, the employer needs to have a credit licence. Unless your employer has a credit licence, you will be unable to buy a bike from us here at Thorn Cycles using a voucher only unless you are prepared to top up your voucher yourself, since our bikes are far more expensive than that!
Several cycle to work schemes exist, they are offered from chain shops and agents which have come about as a result of the government’s Green Transport Plan and as mentioned before, they charge an administration fee. We do not absorb this cost. The prices of our bicycles are never negotiable and we pass the administration charge on to the buyer. Passing on the administration charge is the only viable way for us to participate in the scheme. We are not unique in this matter; see quote from Cycle Scheme’s website below;
“Some bike shops may add an administration fee to quotes for custom bikes, because the profit margins are lower than those available on standard, massproduced models.”
Technically, at the end of the lease agreement the bicycle does not automatically belong to the employee - the bicycle belongs to the employer until the end of the lease agreement period. At this point, the employer has the right to keep the bike or to offer it for sale to the employee for a fee. You will need to discuss this with your employer.
It is also important to consider the length of your employment contract prior to entering into an agreement. If employment ceases prior to completion of the lease agreement it is probable that appropriate deductions for the cycle will be made from your final pay, and in this instance, there will be tax deductions. HOWEVER, if your employer has a credit licence (you must obviously ascertain this for yourself) and you will be able to cover the WHOLE cost of the bike using a voucher. You will have to fund the administration fee levied by the agent of your choice (be it Cycle Scheme or Cycle Plus or Bike to Work etc.) yourself, which of course also varies from agent to agent, but usually, it is10% - 15%. You would be able to treat this as a deposit to get the build in progress whilst awaiting the voucher. Your employer will need to be registered and to have been briefed by a cycle to work agent, or they may administer the scheme themselves. You may need to talk to your employer’s accounts department to guide you through obtaining your voucher.
There are now two types of voucher: paper or electronic.
We need the paper voucher physically here at our shop before we can apply for it to be redeemed by the agent running the scheme for your employer. This MUST be signed by the customer. We do accept scanned, emailed or photocopied signed vouchers via email if accompanied with similarly presented proof of ID such as a driving licence or passport. Similarly if you wish to post us the voucher you may do so.
Customers can now request an E voucher which can be downloaded to a phone. This can be brought into the shop to be redeemed.
Why do some of your upgrade prices seem expensive when I can buy the same item cheaper on the internet?
The prices of our standard specification cycles are artificially reduced to allow many more people to access these cycles and importantly get bums on saddles!
The items used to build these bikes are bought in quantity, generally directly from the manufacturers themselves. This allows us to bulk purchase and help to keep our prices down.
Upgrade items are generally bought from the accreddited importers and are not bought in quantity due to the large range of upgrades we offer. The cost price to us of upgrade items is therefore greater as there is not an economy of scale, this is reflected in the upgrade prices we charge.
But I can buy the same item from another supplier and I will save money!
If you are able to buy an item cheaper from another supplier please consider warranty issues. With our complete cycles* you will receive either a 14 or 100 day 'money back if not delighted guarantee', in which all upgrade items are fully covered. Additionally, we will deal with subsequent warranty issues swiftly and without quibble. This may not be the case with another supplier.
* Available on selected models of complete cycles.
I'm not worried about warranty issues?
Please then buy the upgrade items from an alternative supplier, you can then fit them to the cycle yourself.
Deliveries and collection of Thorn bikes
How will my bike be delivered? (UK deliveries)
If your bike is being delivered we will arrange a convenient date for delivery.
We use Parcelforce 48 large courier service. Parcels sent via Parcelforce 48 are trackable and you will be expected to be available to sign for your bike when it arrives. You will need to stay in all day as they cannot give a delivery time.
Please note: Occasionally Parcelforce are unable to deliver within the stated time frame. This is important if you have to take time off work to receive your bike as you may be disappointed.
If it is difficult for you to guarantee to be in to sign for your bike, it is possible to arrange with us in advance to have your bike delivered to another address as long as there will be someone in to sign for it. A contact number for the address is always required by the courier. This means you can ask for your bike to be delivered to a friendly neighbour, your place of work, a local shop or pub, or your granny’s house!
If none of these options are available to you, we can ask for your bike to be delivered to your local Parcelforce depot and then you can collect it from there.
If your bike is being delivered abroad we cannot give you a precise date for delivery.
We use various courier services who in turn use their own sister courier companies abroad.
It will be dependent upon the country you are having the bike delivered to as to how long it takes for your bike to arrive.
Your bike will be delivered in a box or boxes, and will require mechanical adjustments when it arrives. The least you will have to do is to straighten and tighten the stem. Comprehensive instructions for this are included in the Owner’s Guide that accompanies your new bike. For some deliveries though, there will be a considerable amount of reassembly required (perhaps up to 4 hours of labour), and a certain level of mechanical competency therefore expected. In these circumstances some customers prefer to take their bike to a local bike shop to have it reassembled for them.
You can collect your bike from us here but your invoice will include the 20% VAT element. You can claim this VAT back under the VAT Retail Export Scheme by filling out a VAT refund document here when you collect your bike.
You must provide us with a valid passport, identity card or a driving licence as proof that your home is outside of the EU. You then need to produce this document together with your invoice to customs as you exit the UK or any other EU country for a final destination outside the EU. This must be done by the last day of the third month following that in which the goods were purchased. You then need to post the form back to us. We advise that you photocopy the form and keep a copy for yourself and DO NOT leave the form with customs as sometimes they go missing and then you would not be able to claim back the VAT. Only upon our receipt of your stamped form, are we then able to refund you the VAT.
Yes, in fact we prefer you to come and collect your bike so that you can be set up optimally on it before you leave.
When you come to collect your new bike we like to allow plenty of time for you to spend with one of our mechanics. This allows them to make any final adjustments to your bike and to explain any technical questions you may have. Sometimes, these appointments can take between 1 and 2 hours - depending on the type of bike. On the other hand, you may wish to simply collect your bike and leave straight away and this is, of course, an option!
We never like to disappoint our customers and we try our utmost to meet important deadlines but some things are outside of our control.
Whilst we appreciate that customers will need to make plans that revolve around their bike build and the collection or delivery of their new bike, we try not to make definite dates for such arrangements prior to the completion of the bike. There are several reasons for this:
- Components may become unexpectedly unavailable or out of stock and we may have to wait for them to come back in.
- Staff may become unexpectedly ill
- We are all human and we sometimes make mistakes
- With the current global warming situation we may get struck by a tsunami/snowed in/descended upon by a plague of locusts – who knows what might happen – nobody expected the Titanic to sink!
Once we have completed your build we will contact you to arrange delivery/collection and make these final arrangements. Even then outside factors may influence how soon you are able to get on your bike and ride – courier failure, damage in transit, delay at customs; the list is endless! So to be on the safe side, if you need your bike by a definite date, make sure you order your bike in plenty of time so there is some leeway to counteract any of the above potential problems.
Visiting Thorn Cycles
Exit the M5 at J23.
Take A39 Bridgwater A38 Glastonbury/Wells. Take 3rd exit A38 toward Minehead/Highbridge/Bristol. At roundabout take 1st exit onto Bristol Rd/A38. Continue to follow A38. Go through 2 roundabouts. Turn left into St John Street/A372.
We are on the left.
We are a 4 minute walk from Bridgwater Train Station. Leave the station and proceed South towards the town centre along Wellington Road. Go straight ahead into St John street.
You will find us on the right hand side of St John Street.
We are a 6 minute walk from Bridgwater bus station. Head west out of station towards New Road. Turn left onto New Road. Turn left onto Eastover. Cross at pedestrian crossing and proceed along St John Street. Thorn Cycles will be on your left.
In the town
5 Taunton Road,
Bridgwater TA6 3LW
Tel: 01278 458 580 firstname.lastname@example.org
Close to M5 - outskirts of town
The Premier Inn
Bridgwater TA6 4RR
Tel: 0870 242 3344 - www.premierinn.com
The Cottage Inn
68 Wembdon Hill
Bridgwater TA6 7PZ
Tel: 01278 423259 thecottage-inn.co.uk
Bridgwater TA5 2DP
Tel: 01278 671611 www.tyntearms.co.uk
Local Village accommodation:
Huntstile Organic Farm
Near Bridgwater TA5 2DQ
Tel: 01278 662358 /07725 278280 www.huntstileorganicfarm.co.uk
Local Village accommodation
Near Bridgwater TA5 1HA
Tel: 01278 733237/ 07928 368836 email@example.com
10 mile ride in
The Rose and Crown
Stoke St Gregory
Taunton TA3 6EW
Tel: 01823 490296 firstname.lastname@example.org
Rohloff equipped bikes
If you have bought a Thorn Rohloff equipped bike and you are not totally delighted we offer a 100 day money back guarantee. This means that, if you ride your bike for 100 days and decide you don’t like it, you can return it to us either in person or safely packaged in a Thorn bike box and we will refund you the purchase price of the bike including any or all of the items from our bike build menu.
This offer does not include pedals or accessories. This offer applies to complete bike builds and to EU customers ONLY.
Derailleur equipped bikes
If you have bought a Thorn derailleur equipped bike and you are not totally delighted we offer a 14 day money back guarantee. This means that, if you ride your bike for 14 days and decide you don’t like it, you can return it to us either in person or safely packaged in a Thorn bike box and we will refund you the purchase price of the bike including any or all of the items from our bike build menu.
This offer does not include pedals or accessories. This offer applies to complete bikes and to EU customers ONLY.
If when you receive your bike there is a problem, we do our very best to sort it out for you. This can involve anything from us replacing parts to sometimes rebuilding the whole bike. What we want is for you to be 100% delighted with your bike and we will do everything we can to ensure you are.
We are proud of our bikes and our name is now well deservedly famous across the world of cycle touring, and indeed, the world itself. We pride ourselves over our after sales customer service and we will gladly answer any questions you might have about any aspect of your bike, technical or otherwise.
Through our sister company St John Street Cycles, we are able to deliver spare parts all over the world. We are quick to answer our email enquiries; you can expect a reply usually within 12 hours of emailing us during a normal working week (Monday to Friday 8.30 – 17.00).
We are always willing to speak on the phone. We do our utmost to help you with any problems you might have including faulty equipment and technical advice. JUST ASK!!!
Loosen the stem bolt(s) that secure the handlebar stem to the steering column. Wiggle the stem from side to side to see that it is loose. Align the stem and the handlebars with the front wheel, and gently secure the top bolt. Stop when you feel the cap first contact the stem (or spacers). Secure the stem bolts. Check for play by pulling back and forth on the fork. A knocking sensation is called play. Turn the handlebars in different directions while checking for play. There may be play at this early setting…if there is, loosen the stem bolts. Turn the adjusting bolt in the centre cap 1/8th of a turn clockwise. Secure the stem bolts, check for play again. Repeat until play disappears. Remember to loosen the stem bolts before turning the adjusting bolt. Do not over tighten stem or handlebar bolts. There is usually a manufacturer’s torque setting on the stem.
NOTE: IF ANY HEADSET IS OVERTIGHTENED THE BEARINGS WILL BE PERMANENTLY DAMAGED. The degree of damage is directly proportional to the amount over tightened. If you are still unsure then watch this short video to see a qualified mechanic adjusting a headset.
Generally speaking, you can get your bike serviced at your local bike shop but many people decide to let us do the service because of our own specialist knowledge of our own bikes.
You will need to ring us and make an appointment to drop off your bike to us. Sorry, we cannot collect your bike from you (see FAQ “Can I have my bike collected/delivered for servicing or repairs?”).
Your bike should be clean otherwise we will charge you a cleaning fee of up to £35 depending on how long it takes us.
Our charges for servicing are £35/hour plus parts at full retail price. Typically, a one hour service is sufficient for a lightly used bike. This includes a full systems check, including adjustment of gears and brakes. If there is a need for the replacement of essential worn parts it generally takes 2 hours.
We will discuss with you what work you wish to be done on your bike and when you would need/want to collect it.
We must have a contact number so that we can contact you if we discover any issues with your bike that require us to do more work than discussed with you at the point of drop off. We usually agree a maximum spending limit with you beforehand so that we can judge the amount of work to be done.
Before the bike leaves our workshop we will assess the bike for all aspects of safety, and we will advise you of any work that is likely to be necessary by the time for the next service – rather like you get at an MOT.
Sometimes, the work we have been asked to do on a bike is insufficient in our opinion, to make the bike safe to ride. If this is the case, we will contact you to see whether you wish us to undertake this work. Should you choose not to, when you collect your bike you will be asked to sign a disclaimer saying that you understand the bike has some safety issues and that you are happy to take the risk.
Unfortunately we are unable to do this.
We do not have insurance as it is prohibitively expensive and would inevitably serve to make our charges higher. We do not wish to make our costs (or yours) any higher than they already are. If your bike were to be lost or damaged during transit it would need to be replaced or repaired and we would feel duty bound to do so. This of course would result in at least reducing any profit we might have made, and possibly cause us a loss of a considerable amount more (if we were required to replace a whole bike when all it came in for was an oil change, for example) and that is a risk we are not prepared to take.
Often our customers’ bikes are their most cherished possession and are ‘one offs’. To replace such a bike would be impossible. Packaging the bike takes an appreciable amount of time and effort which will also adds to the cost, making it even more expensive for the customer. There may be exceptions where there is absolutely no alternative, and in these situations there would have to be an agreement made in advance by the customer and Thorn Cycles whereby the customer would need to declare in writing, their OWN liability for loss or damage during transit. There will also be heavy surcharges for such transactions.
We recommend that for best function the oil in the Rohloff hub should be changed every 12 months or every 5,000km whichever occurs first. To get expert guidance on changing the oil yourself watch the video.
You will need a complete oil change kit available from our sister company St John Street Cycles. - part number 12171
Alternatively, you can bring your bike to us here at Thorn Cycles and ask us to do the oil change for you; simply ring us to book your bike in for an oil change and leave it to us.
Here at Thorn Cycles we provide a lifetime warranty on our frames that are bought as part of a complete bike build. We do not fit kick stands to our bikes as a part of any build. If you insist that we fit a kick stand for you, or if you choose to fit one to your bike post build, we will not entertain any claims for damage arising from the use of or fitment of a prop/kickstand.
Damage can result in several ways:
- Where the stand fits to the bike the clamp will inevitably damage the paint finish, this allows water to track under the finish and cause corrosion.
- Where the stand fits to the bike on some models the thin gauge tubing used will be crushed, this may cause a stress fracture of the tube or weld area.
- When on the stand you or a passer by may lean on the bicycle and your/their weight may cause the stand to break and the bicycle to fall or worse the tube where the stand fixes to be crushed or damaged.
- The load most of our bikes are able to carry combined with the weight of the bicycle exceeds the max load of most commercially available stands, which may cause the stand to break or bend
Instead, we recommend that a Click Stand is used, details of which can be found at www.click-stand.com. These are essentially a prop that your bike leans on, which does not become a part of your bike but rather a small, lightweight accessory carried as part of your luggage. Alternatively, you can adapt a fishing rod prop (available from your local fishing shop) to achieve the same result. Of course, you could find a convenient tree, fence or wall to prop your bike against (using your saddle), or even simply, gently lay your bike down on the ground!
For internal gear mech Thorn Rohloff equipped cycles
Rohloff shifter gear cable replacement video - click to play
This video is for guidance only; always refer to the Rohloff owners manual.
Brake squeal is phenomenally irritating... I loathe it too!
There are several causes of brake squeal, many of which can be dismissed as inapplicable in your case.
This leaves us with 3 possibilities:
- New rims and blocks often squeal until they have had their surface imperfections worn smooth and the brake blocks have worn to be flat... the problem is greater when both rims and blocks are new… the "problem" will go away with a little use... I'd suggest going down a long hill with the brakes on and give each brake a real squeeze whenever you have sufficient momentum.
- Dirty rims/blocks can sometimes squeal for a short time... if the problem does not go away, or if there is petroleum-based contamination, I'd consider giving them a good scrub with some detergent... ironically this may make the squealing worse for a moment. I usually clean my rims by rubbing them with a clean dry rag.
- The brakes blocks have not been set up with a small toe in.
We are usually very careful to do this but the mechanic may have got it wrong. With the bosses in front of the fork, if there is any degree of toe out the brakes will continue to squeal indefinitely. But if you have bosses on the back of the fork, the brakes will automatically toe themselves in with wear... if you can see any significant toe out (that is the rear of the block making first contact with the rim) then the mechanic has not done their job properly and you will need to toe the brakes in… the time taken to do this varies from a few seconds to considerably longer.
The method I use is to loosen one shoe off and insert a very thin bit of card at the very back of the block… then I squeeze the lever really hard and tighten the shoe up. I repeat the process on the other side.
The things to watch for are:
- That the card does not drop out… if it does you will have perfected a method for reliably toeing out the brakes!
- That the card is only at the very back of the block… ditto above.
- That the shoes do not drop down in their slot… otherwise you will miss the braking surface.
- That you don’t push the shoes up in their slot… otherwise you’ll wear the side wall of the tyre.
- That the shoes follow the curve of the rim.
- That you always check everything you have done before you ride the bike.
I hope that this helps… I‘d try  first…unless  and  seem more applicable!
It is best if you rehearse all the operations in your head, before "going for it!"
The first thing to realise is that, if you have ever used a cassette remover and chain whip to remove a cassette, you will be tightening up the sprocket on the Rohloff hub, if you attempt to use the chain whip in the same direction as you would with a cassette hub you do this you will screw the sprocket very tightly, onto the hub
The reversal of the sprocket should be planned, in advance of needing to do it... given the massive service life of the sprocket, the need to reverse it, shouldn't be a thing that takes you by surprise. I say this because you will require access to a large vice, which is mounted securely to a workbench.
Remove the QR skewer, locate the sprocket removal tool's lugs into the slots on the hub and replace the QR skewer... this is important to maintain secure location. Tighten the QR fully…the skewer can remain in position until the sprocket is removed… the tool’s design allows for the sprocket to pass over it.
Now locate the flats of the tool in the jaws of the vice and clamp the tool securely.
Take the chain whip and wrap it carefully around the sprocket and use its leverage to turn the sprocket ANTI CLOCKWISE. (When viewed from the sprocket towards the hub). This may take considerable force.
NOTE THAT BECAUSE THE HUB IS INVERTED (SPROCKET SIDE DOWN) THIS WILL MEAN LEVERING THE CHAIN WHIP CLOCKWISE, AS YOU SEE IT, WHEN LOOKING FROM ABOVE.
I hope that this is clear... if it is not, please re-read what I've written and if it still does not make sense... please contact Thorn or Rohloff direct.
Please note the 13t Rohloff sprocket is non-reversible.
Because our alloy eccentric is anodised and because the inside of the shell is treated with rust inhibitor (as well as being greased prior to assembly) a seized–in eccentric is a very unlikely occurrence. However, if the bottom bracket is allowed to become submerged and active steps are not taken to drain the water out, it is possible that some oxidation will eventually occur… the longer this process is allowed to continue, before any chain adjustment is attempted, the more possible it becomes that seizure may occur.
The design of our eccentric is deliberately crude and simple but well engineered… this makes seizure unlikely in the first place and enables simple, easily sourced, “tools” to be used upon it if necessary.
If the eccentric will not turn, using the tools provided, the following procedures should be implemented.
- Remove the eccentric bolts from (the underside of) the shell… they are stainless into stainless, so they would need to have long exposure to a strong corrosive agent (sea water) to become seized.
- A light tap with a soft mallet (or lump of wood) onto the centre of the left hand crank, may be enough to free the eccentric, otherwise place a drift (wooden dowel or section of pole/branch or whatever) against the alloy eccentric and attempt to drive the eccentric through the shell by striking it firmly with a mallet (hammer, stone, brick or lump of wood)… the bond (caused by the oxidation of the shell/eccentric) should be broken and the eccentric can then be adjusted. Proceed to step . If this does not work, as it may not, because you will be unable to get a direct blow to the centre of the eccentric, proceed to step  If this procedure has been successful, it is wise to carry out steps , , ,  and , as soon as practicable, afterwards.
- Remove the eccentric bolts from (the underside of) the shell.
- Remove the left hand crank. (You will need the appropriate tool, if you don’t have self-extracting cranks).
- Push the eccentric out or the shell and proceed to steps  and  If the eccentric is seized you will need to follow steps  through to .
- Remove the bottom bracket assembly. (This will involve removing the right hand crank and you will need the appropriate bottom bracket tool).
- Place the largest drift obtainable (as long as it is slightly smaller than the dia of the eccentric, because it will be going through the shell too!) against the eccentric and strike the drift heavily with a weighty object… the eccentric will move… but, if really tight, you may have to prevent the frame from moving during the process (Beware of frame damage). If the eccentric moves but becomes stuck again, strike it (and drift it out from) from the other side (I know from all the development work, when I was determining necessary tolerances, that a tight eccentric has a preference over which side it will most easily drift free from).
- When removed thoroughly clean and re-grease the eccentric, the shell and the threads for the screws. Now is a good time to consider a re-application of a product like “Wax Oyl” to the insides of the frame tubes…don’t forget to remove the seat post too.
- Re-grease threads on screws, then adjust the throw of the eccentric and tighten the screws.(8 – 10 Newton metres).
THORN tubing is made from a billet of 4130 Cr-Mo steel which is then pierced (this is what makes the tubes seamless).
The billet is repeatedly cold drawn, until it becomes a tube. It is then pulled through a mandrel, which makes it double butted (a double butted tube is one that is thicker at the ends where it is joined to other tubes, but thinner in the middle). The tubes are then heat treated which vastly increases the ultimate tensile strength (UTS) of the steel, making them highly resistant to denting.
Reynolds use the same techniques to manufacture their highest quality tubing. As we all know Reynolds use numbers to name their tubing, but, these numbers no longer have any real significance. Once upon a time Reynolds 531 was given its name because it reflected the ratio of the secret alloying elements it was made from, that is 5:3:1. In later years, 531 was heat treated and it was re-named 753 and from this time onwards Reynolds’ numbers had no significance whatsoever! 853 was seen as a step up in quality from 753. In theory any of Reynolds’ tubes can be purchased in one of several different gauges (thicknesses)
We too use numbers to name our tubing. Our description of THORN tubing, for example 858, is an actual description of the thickness in mm of the wall of the three parts of the tube, ie.0.8mm at the end of the tube, 0.5mm in the middle of the tube and returning to 0.8mm at the other end of the tube. Experience has shown 0.8/0.5/0.8 is the thinnest gauge that can be built into a long-lasting frame.
Contrary to popular belief, there is no measurable difference in the weight of a specific volume of any of the types of steel. Higher quality steel is frequently used in thinner gauge which does give a weight saving.
We use our very high quality steel in a fairly thick gauge (969) for several of our frames, to give more strength and even more resistance to denting. Our frames are very strong for their given weight.
This section is less of an FAQ and more to include useful information we think it would help you to have!
Adventures on a Thorn Cycle
People take their Thorn cycles everywhere. Here are just a few stories that show just how robust these bikes really are!
How to turn a Mountain Bike into a Touring Bike
How to, in effect, own two different bikes for little more than the cost of one. We’ve considerable experience in making superbly handling, steelframed, touring bikes, with steel forks. We have also designed a fork, specifically to replace an 80 - 100mm travel suspension fork which turns a suitable mountain bike into a beautifully handling, rigid touring bike.