BMX Build & Warranty
When purchasing a mafiabike. You will have chosen an excellent bicycle from a manufacturer that prides itself on the supply of the best quality bikes at the most affordable prices.
Please note, your bicycle has been supplied in a carton (box) in a semi-knock-down state. This means it requires some basic assembly & a thorough inspection by a competent experienced person prior to riding.
We strongly recommend that this inspection is carried out by a trained bicycle technician at a bicycle shop where they regularly build and service bicycles. It’s paramount for the safety of the rider that this bicycle is thoroughly checked over for any potential safety issues prior to riding. We will not accept any liability whatsoever for injury or death sustained as a result of improper assembly and inspection of your new bicycle.
If you should encounter any such issue during assembly/inspection please do not hesitate in contacting us using the appropriate wblog and instagram to arranty or returns form to be found at www.stomp-group.com
Servicing (1 week service)
For your safety and also to validate your warranty, your new bike needs to be serviced after approximately 1 week of riding or 50 miles (whichever comes sooner). This is because all moving parts are liable to bed-in and require adjustment e.g. crank bearings, wheel bearings & headset bearings. The chain may also require re-tensioning. All nuts & bolts should also be checked to ensure they are sufficiently tight along with wheel spokes (especially on BMX bikes which tend to be ridden much harder than other bikes).
All mafiabikes BMX’s are designed for use at an entry-level. This means small airs, jumps or hops (max 1 foot or 12 inches), which may incorporate basic tricks such as up to 360° spins). Foot jams, foot jam whips, bar spins or manuals. If you push your BMX beyond this level, you do so entirely at your own risk.
Should you wish to go beyond these limits we advise you to upgrade your bicycle to one that is built entirely of aftermarket parts. Servicing (continued) For your safety and for the optimum performance of your bicycle it should be checked thoroughly by a trained bicycle technician on a regular basis. This is especially true for BMX bikes, which may sustain regular immeasurable impacts.
For your safety and for the optimum performance of your bicycle it should be checked thoroughly by a trained bicycle technician on a regular basis. This is especially true for BMX bikes, which may sustain
regular immeasurable impacts.
A bicycle that has not been serviced correctly and is ridden in a manner which it may sustain regular immeasurable and unquantifiable impacts, may cause component failure and potential injury or death. Stomp Racing LTD will not be held liable in any way for any injury or death sustained as a result of improper/incorrect use, servicing or maintenance.
As a guide, we suggest a full inspection by a qualified person every 3 months however this is only a guide & is by no means exhaustible. It is your responsibility to ensure your bicycle is safe to ride at ALL TIMES.
If you ride your bicycle in an ‘extreme way’ i.e. to perform tricks such as. BMX, you should inspect your bicycle EVERY time you ride it and also during the period you are riding it. It is highly recommended that you carry any essential tools you may require for continued maintenance whilst
you are riding.
This is perfectly normal and accepted practice whilst riding BMX. E.g. an impact from a jump or air may cause your bars to move, also your cranks or your spokes could work loose. You should be prepared at all times to be in a position to rectify any servicing or maintenance issue which could potentially cause component failure, injury or death. Your safety is entirely your responsibility.
The majority of Mafiabikes are supplied for off-road use. If you intend to use your bicycle on the road, please ensure you have the appropriate legally required features to do so, such as front & rear brakes, chain guard, reflectors, bell.
If you do not have these items but you want to ride on the road, we can supply them free of charge.
Wherever you ride, you should take every precaution to protect yourself from potential injury. Always wear a protective helmet and gloves and make sure you stay visible to others by wearing brightly coloured clothing such as a reflective jacket.
If you are riding in a skate park or other off-road location, ensure you are always well protected. If performing tricks or riding difficult obstacles such
as ramps, curbs, rails or trails we strongly advise the use of a full-face helmet, protective gloves, elbow & knee pads, shin/ankle pads & protective shoes
MAFIA BMX SETUP GUIDE
The following is a guide for technically competent persons only, it is not a step-by-step ‘how-to’ guide. It is assumed that this guide is to be read by those who already understand the requirements of a bicycle pre-ride safety inspection. This guide may not be exhaustive.
- Loosen the 2 rear pinch bolts at the back of the handlebar stem
- Tighten the top bolt (centre of the stem top cap). Not too hard, the bolt simply preloads the bearings. You should be able to still turn the bars easily and smoothly. If they feel notchy then loosen the bolt slightly. If there is a movement back & forth in line with the frame, then tighten the bolt.
- Once satisfied, re-tighten the pinch bolts on the stem nice & tight to prevent the stem from slipping on the fork steer tube
- Your bars should normally be installed in line with your forks (looking from the side). However, if you are a little small for the bike you
may want them back towards you a touch. There is very little reason to angle your bars forward; this will simply affect the bikes geometry & thus performance making riding difficult.
- Make sure you install the faceplate for the stem evenly, with an equal gap to the top & bottom of the stem to the faceplate. Make sure the bolts have a little grease on them as this will allow you to tighten them more than without grease. Tighten the bolts diagonally top to bottom, and then switch to the opposing side. This will ensure even pressure on the bars. If your bars persist to slip, try roughing up the knurled section of the bar & also scratch grooves into the stem faceplate & body. This will help the two parts grip each other better.
Brake Pad Adjustment
1. Your brake(s) should be set by the factory, however as it beds in it may require adjustment. To adjust your brake pad, first loosen the allen bolt attaching it to the calliper enough that the shoe will move freely.
2. Next pull your brake lever so the pad makes firm flat contact with the wheel rim. Whilst holding the brake lever, adjust & position the pad so that it sits flat on the rim. Make sure the pad is away from the tyre. A rubbing pad on the tyre will cause the tyre sidewall to fail & the tube to blow out BANG. This can cause injury.
3. Once you are fully satisfied with the position of the pad, tighten the pad retaining bolt/nut whilst FIRMLY pulling the brake lever and preventing the pad from spinning (sometimes this requires 3 hands). This will give a nice flat pad adjustment & very effective braking performance. However, it may also cause the brake to squeal, especially if rim-protecting soft pads are being used (clear pads). To prevent brake squeal, attempt to angle the leading edge of the pad slightly into the rim. The rear of the pad should be approx 1-2 mm off the rim when the leading edge 1st touches the rim. Braking performance will still be good & hopefully, the SQUEAL is reduced or totally eliminated.
Note: if your brakes are not installed but supplied as a kit, please see the separate brake assembly instructions and online ‘how to’ install brake video.
U or V-brake adjustment
1, The U or V-brake utilises 2 separate levers to apply pressure to the wheel rims. Each lever has a spring which is adjustable in tension. In order for both levers to pull together & for the pads to make contact at the same time, the springs need to be adjusted for balanced movement. If one arm is moving more than the other, you must reduce it’s spring tension (usually as small allen key bolt in the side of the brake/pad lever)
2. Depending on the brake this can be either clockwise, or anticlockwise, therefore you will need to experiment. You are trying to achieve the brake levers to be in roughly the same position at rest & pull together at the same time when you pull the brake. A perfect set-up will see both pads hit the rim at the same time.
U-brake cable adjustment
Once your brake is set up correctly you may want to finally adjust the brake lever pull for your personal preference. There are normally 2 adjusters, 1 on the lever & 1 on the cable termination on the frame.
- Screw the cable adjuster anticlockwise to reduce cable pull i.e. in order that the pads hit the rim sooner for a give brake lever operation.
- If you have run out of adjustment it may be necessary to adjust the cable length at the cross-over junction or on the cross over cable itself. Simply loosen the cable connection & pull a small amount of cable through note: screw your cable adjusters clockwise until they are approx 1/3 from the hard stop before you carry this out. This will allow you to fine adjust your cable pull afterwards.
Brake lever position
- You can angle your brake lever however you like, however, the best angle is normally tending down pointing to the ground. This allows the lever to be out of the way whilst performing bar spins etc.
- To adjust, simply loosen the lever on the bar and slide/angle to your desired position. Note: if you do not fully tighten, it is less likely that the lever will be damaged whilst bailing a trick or jump as it will simply spin out of the way under the impact force. If fully tight, the lever may fail as a result of a given impact.
3-piece pinch bolt crank arm adjustment
Your cranks may come loose from time to time, if they do, this is how to tighten them:
1. Loosen the 2 pinch bolts (where fitted e.g mafia clip), next tighten the centre crank arm bolt (in line with crank axle) then re-tighten the pinch bolts.
2. If your cranks are still after tightening, it may be that you bearings are not fully pressed in. To ensure they are pressed in firmly, remove the crank arms fully & using a suitably sized large socket matching the outer race of the bearing unit, drift the bearing hard into place in the BB housing (using a hammer). Do this on both sides & then re-assemble the crank arms
Hubs & bearings
- most of our models use loose ball hubs unless specified otherwise e.g. bb-kush, kush, clip & Manhattan silver all use loose ball hubs. As the bearings bed in, it may be necessary to tighten the cone nuts from time to time.
- If there is wobble (side to side) your bearings could probably do with a slight tweak. Remove the wheel, loosen the cone locking nuts & carefully tighten the cone nuts. The wheel should spin freely, but there should be no side-to-side play.
- Once you are satisfied, re-tighten the locking nuts & replace the wheel. Note this can also be a good time to check there is plenty of grease in your bearings. If they are looking/feeling a bit dry, stuff in some fresh grease before adjusting the cone nuts
Tyre pressure is a personal preference. Some people like their tyres soft, others like them rock hard. Your tyres are only designed for pressures up to 60 psi, so always use a pressure gauge & never overdo the pressure. If you desire higher pressure we suggest you invest in some hi-pressure aftermarket tyres.
Your chain should be tight at all times. The reason for this is that a tight chain will make it easier for you to keep your pedals in the desired position whilst performing tricks where your feet leave the pedals e.g. foot-jam whip.
- To tighten your chain, 1st loosen your rear wheel nuts enough that the wheel only just moves in the rear dropouts (moves with a little force). Pull the rear wheel hardback keeping it inline in the frame.
- Next, pull the non-drive side back a tiny bit more than the now tight chain side & tighten the non-drive side wheel nut. The wheel will now be slightly out of line in the frame.
- Next, grab the tyre somewhere close to the seat tube & pull the wheel hard over towards the drive side until the wheel is centralised. Once you have it centralised tighten the drive side wheel nut. This procedure can be a little tricky & will take a few attempts to get the hang of, but the result is a very tight chain & pedals that stay put whilst performing tricks.
- When you rotate the pedals you may notice a very tight spot or a very loose spot. This is often caused by the chain wheel (front sprocket) not being centralised. In order to centralise it, try loosening the sprocket bolt (to the rear) a small amount & then spinning the crank arms. The chain wheel should centralise (note you should not fully loosen, only a little). Once centralised tighten the sprocket bolt.
Note: if this is all too complicated & you are not
interested in tight crank arms for tricks, simply align
your rear wheel centrally pulling back on the wheel
till the chain is tight, then tighten the wheel nuts.
- When you get your bike, the spokes have not been pre-stressed. Your wheels were built by automated machines and machines can sometimes make minor mistakes.
- Check all your spokes are tight. If any are very loose carefully tighten them.
- First remove the free play (wobble) from the spoke, then carefully tighten to a similar tension as that of the looser spokes in your wheel.Note: If you over tighten what was a loose spoke it can often cause the wheel to buckle
- As your wheels bed in, you may find some of the spokes become loose. The best way to deal with a wheels bedding in, is to regularly put a 1/4 turn on each spoke after riding (especially the rear wheel). This will keep them tight & your wheels true (running straight). Once the spokes have passed their bedding in stage (stretching) you should not have to tighten spokes very often.
- If your wheel is buckled you can true the wheel by finding the bend in the rim & applying tension to the correct spokes to pull the rim back in line. This is a relatively skilled procedure & we recommend that you at least follow some of the tutorial videos on youtube: search ‘true bicycle wheel’
Still, got questions? Email the technical team at
Mafia Bike Warranty
How to Claim
Warranty claims will only be handled through the appropriate channel which is our online form. If you do not supply all of the requested information, your claim may be rejected. Please go to the following
page & fill out the warranty enquiry form in full http://www.stomp-group.com/warranty-enquiry-form/
Completes & Parts
1-year manufacturers warranty. Covers unexpected failure/defect of all parts/components that may not be attributed to fair wear & tear or crash damage outside that considered normal use. The claimant must be the original owner/purchaser to produce a receipt to prove the date of purchase. The bicycle/parts/components must be free from modification including shot blasting non-standard parts and or painting/powder coating.
Please note, you automatically qualify for a 6 months statutory warranty, to extend to the full 1 year you must fill out the warranty registration form which can be found with your purchase or if not you can download a copy from our website www.mafiabikes.com
IMPORTANT – 1-week service
As your bike will have been sent to you via mail order, it is your responsibility to ensure it has been assembled correctly. If you do not have your 1-week service record (signed & stamped receipt), then your warranty is invalid. Please note: ‘Raw’ finished frames forks etc will be subject to corrosion at a faster rate than painted bikes.
This is simply because there is no rust protection applied to give the parts the ‘raw look’ i.e. where you can see the blueing of the tubes as a result of welding. Therefore, we cannot offer a warranty on the basis of corrosion. It is advised to minimise the potential for corrosion, that the bikes/parts are kept away from water and stored inside.
Examples of items not covered by your warranty:
• Buckled wheels
• Worn tyres
• Worn/Broken chains (unless clearly a
• Worn Sprockets
• Worn bearings or hub internals
• Bent forks / frame / bars / axles / cranks / pedals
Examples of items that are covered
where it is clear there has been no abuse or misuse (note: you will
need to supply photos of both sides of your bike & then may further be asked to return the failed component):
• Cracked or broken frames
• Cracked or broken forks
• Cracked or broken bars
• Cracked or broken hubs
• Internal axle failure BB/wheels
• Cracked or broken cranks
• Visible manufacturing defects to any part or component (should be reported as soon as noticed)
You are expected to keep your bike in serviceable condition. Any failure attributed to incorrect or lack of maintenance will be easily detected by our
engineers & in most cases rejected.
When you make a claim, you will be expected to provide photographic evidence of your complete bike (photos of both sides even if it is a single small component failure) including close up shots of the failed component(s).
In most instances, you will then be required to send the failed part/component back to our head office for inspection at your own cost.
For any warranty or return enquiry please fill out the relevant application form to be found here www.stomp-group.com