Manufacturers have to replace free of charge any defective components as a result of manufacturing defects - that's the law.
There is a difference when a component becomes defective. Broken spokes, pedals falling off or creaking. The question then arises: is it a manufacturing defect or not? if it is, then it must be covered. If not, then it may not be covered.
The point is, guarantee normally does not cover a defective component as a result of accidental dammage or misuse (like offroading, use of dongle) or lack of maintenance.
Your manual must explain the need for maintenance of that component, like keep the spokes tightenened, oil the pedals. So, as long as you maintain your bike as per your manual, the defective component must be covered.
Electric bikes need as much mechanical maintenance as normal bikes, if not slightly more so. If you ride 500 miles plus a year with your normal bike, you will inevitably have to maintain the bike yourself or pay a bike shop for it.
The Kudos website explains the position very well.
https://www.kudoscycles.com/information.php?info_id=3
Warranties
All products are subject to the terms of guarantees or warranties issued with them and you as the customer are reminded that you should complete all guarantee and/or warranty cards/documents immediately upon receipt of goods where appropriate.
Any advice given by agents or servants of Kudos Cycles during telephone/internet orders is based entirely upon information given by you the customer. Where advice is given after visual inspection by agents or servants of Kudos Cycles, such advice shall amount to an opinion only and Kudos Cycles shall not accept liability for any inaccuracies. Additionally, goods are supplied only to correspond to the purpose for which goods of that kind are commonly supplied and not alternative uses to which they may be put. No liability for failure can be accepted by Kudos Cycles for such alternative use, amendment or modification.
Compatibility of goods is not guaranteed where modifications or alterations have been made and, in such circumstances, any refunds to you the customer shall be at Kudos Cycles' sole discretion.
Where goods purchased by you are alleged to be defective, you agree to advise us of such defects within 7 days of the goods being delivered to you or the defect becoming apparent and you agree within 7 days thereafter (and in accordance with our Returns Policy) to arrange for the return of such goods to us for inspection and report (without us replacing the said goods prior to such inspection).
You further confirm that it shall be reasonable for us to inspect, repair or replace (at our option) such defective goods and allow our manufacturers or suppliers to undertake inspections so as to allow product methods to be modified. You also accept that it is reasonable to inform us of any interruption, defect or other failure prior to contacting independent third parties or incurring expenses and, in addition, to allow us to remedy the defect. Parts improperly fitted, assembled, modified or adapted by you shall no longer be warranted by us or any manufacturer or supplier to us, nor shall they or we be liable for any failures resulting subsequent to modification.
We shall accept no liability for death or personal injury unless caused directly by Kudos Cycles' negligence in circumstances where assembly has been effected otherwise than in strictly in accordance with the instructions set out in the manual and/or attached to the product or where modifications or alterations and/or poor or irregular servicing or maintenance to goods have been made. No liability is accepted by us where you attempt to modify or install components supplied where it is known or ought reasonably to be known that the part supplied is incorrectly supplied, defective or otherwise not in accordance with the order.
We accept no liability for accidental or consequential damage or loss of any other matters beyond our reasonable control or in respect of failure to supply or other interruptions caused by strikes, lockouts, civil disputes, acts of God, war or actions by third parties.
The bicycle is warranted against any manufacturing fault (1) year from invoice purchase date. Specifically the LiFePO4 battery is warranted for (2) years and LiMnO4 battery is warranted for (1) year.
Battery warranty is subject to appropriate battery care - batteries should ideally be stored 80%→30% capacity and below 40°C. Extended storage in high temperatures and/or fully discharged for more than (1) week can considerably reduce the life of the battery.
The warranty is offered only to the original purchaser and does not include labour, transportation costs or investigative costs in fault diagnosis.
Normal wear and tear, accident, abuse, misuse, neglect, poor maintenance, improper assembly and fitment of parts not consistent with the standard specification or use originally intended for the bicycle as sold, are not covered by this warranty.
The bending of frames, forks, stays, handlebars, seat posts, seat stems, mudguards, rims, is a sign of misuse of the bicycle inconsistent with the bike's intended use and therefore is not covered by this warranty.
E-bikes are generally heavier than normal cycles and thus are subject to greater stress. The e-bike is not intended for stunt riding, ramp jumping, bunny hops, acrobatics or extreme rough surface off-road riding, it is up to the rider to determine whether such activity exceeds the capacity of the bicycle.
Damage caused by an accident or deliberate malicious act is not covered by this warranty.
Metal fatigue
It is possible to design a structure, such as a bicycle so strong that fatigue life is nearly infinite.
This would involve a lot of materials and hence considerable weight. Any structure that must be light and strong will have a finite fatigue life - aircraft, race cars, motorcycles, bicycles, all have parts which have parts with finite fatigue lives. If you wanted a bicycle with an almost infinite fatigue life it would be so heavy as to be unpleasant to ride. So there has to be a trade off between weight and life, a fatigue crack on a bicycle is not a manufacturing defect, it is a sign that the part has worn out, a sign that the part has reached the end of its useful life and needs replacement.
The fatigue life of a bicycle will be considerably reduced if the rider is tall and/or heavy putting additional bending moment stresses into the seat post, seat stem, seat tube and subsequently the frame. Obviously the fatigue life is also reduced if the bicycle is subject to excessive off-road usage - though some bicycles are more suited to off-road than others.
Motor overheating
The motors fitted to e-bikes are pedal assist, EN15194, are restricted to 250 watts power, most leg power is 150→250 watts so some pedal assistance is required to avoid over stressing the motor.
In particular, allowing the motor to 'labour' at slow speed on steep hills is not good practice and can cause the motor to overheat.
Excessive use of the throttle without pedal assist is specifically to be avoided.
A motor which has failed due to excessive heat will not be covered by warranty and is considered misuse of the product.
Return to base
'Base' can either mean Kudos Cycles and/or its agents. A charge of £25.00 will be levied on collection of any bicycle for any reason whatsoever.
It is up to the sender to ensure that the bicycle is sent in a strong 'bicycle' box, properly packed and fully bubble wrapped/protected. It is the responsibility of the sender to avoid any damage in transit.
Consumables
Bicycle parts normally subject to wear, such as tyres, bulbs, chain and chainrings, brake pads, gear cassette, cables, pedals and handle grips are not covered by the warranty unless failure is a direct consequence of an original manufacturing defect.
Service
As with any mechanised vehicle, your Kudos cycle will perform better if subject to a planned maintenance schedule by a skilled bicycle engineer. As a minimum, the cycle should be inspected, maintained and adjusted once per annum.