How to change your own tyres
29 November 2006 16:21
Why should I do it?
Because any project that involves just you will save you money. If you buy mail order tyres at a bargain price, you’ll have to find the nearest tyre-fitting service, and nine times out of 10 you’ll be charged the earth to have another supplier’s tyres fitted to your rims. It can also save a lot of time and grief carting loose wheels somewhere, then having to wait for them to be done, or pick them up later.
Don’t I need special kit?
As a rule of thumb, bikes with small rim sizes – say up to three-inch front and four-inch rear – only need muscle power to ‘break the beading’. That is, to break the airtight seal between the tyre and the wheel’s rim wall. Larger rims obviously run with bigger, wider tyres, and ideally a hydraulic bead-breaking machine should be used for this job – not the sort of device you’d find in every biker’s garage. But, as you’ll read here, there are cheaper ways to get round this.
What is required is a set of tyre levers that are suitable for the job and a tyre valve key (available from any car/bike spares shop) or pronged-type valve cap. Bicycle tyre levers aren’t man enough for the job. A half-decent set can be bought from a mail order firm for about £10 a pair – get friends to chip in, as levers are always in demand. Hard plastic rim protectors (£5 a pair) are a good investment too, as they prevent scratching the paint and the aluminium beneath.
As for your own ability, muscle power isn’t everything. Like most things in life, first-time anticipation is more worrying than the event itself. Practice makes perfect, so we respectfully suggest practising on something like a Honda C50/70/90 wheel first.
Tubed or tubeless?
Bikes with wire-spoked wheels (generally trail bikes and small commuter bikes) more often than not run with tubes – as wire-spoked rims aren’t airtight unless the spokes are mounted outside of the rim (as on some BMW GS models). More bikes today have cast or forged aluminium wheels that run tubeless-type tyres and while the fitting of these and tubed tyres is similar, the addition of a tube makes fitting trickier – more care is needed as ‘nipping’ a tube with a tyre lever and putting a hole in it is easily done.
1. Deflate the tyre by depressing the valve before removing it fully with a valve key – high pressure in the tyre can cause the valve to fly out and disappear. If a tube is fitted, loosen the valve’s securing nut but do not remove, just unwind it to the top of the valve, so the tube can move away from the rim and won’t be trapped by a tyre lever.
2. Several methods can be used to ‘break’ the rim/tyre seal. On small-sized tyres, the heel of a boot placed on the tyre, as close to the rim as possible, and forced downwards to push the tyre into the rim’s well (centre) while pulling up on a spoke will suffice. Turn wheel over and repeat. Put down carpet or cardboard to prevent damage to rim or disc.
3. Breaking the beading in a vice is a cheap and safer alternative, and more suitable for larger tyres. With the jaws open to the max, place the wheel in the vice so the top of the jaws are within 5mm of the rim. Holding the wheel in place, slowly and carefully (to avoid marking the rim) tighten the vice until the seal is broken. Repeat for the other side.
4. For around £60, a purpose-made bead breaker is the safest and easiest way to break any tyre rim seal without damage. They come in a variety of styles, ranging from elaborate scissor-like mechanisms to over-sized G-clamps. What may seem an unnecessary expense can quickly be recouped from friends, or even at trackdays.
5. Place the wheel flat on the floor, preferably on a mat to avoid any damage. With both hands either side of the tyre, squeeze hard to help the tyre drop in to the ‘well’ (middle) of the wheel. This makes fitting a tyre lever and removal of the tyre a lot easier – you won’t be trying to stretch the tyre off the rim.
6. With one tyre lever, carefully insert the tip between rim and tyre, push it away from you and fit a rim protector. Lift the lever so the lip of the tyre lifts over the rim. Hold this lever down with your knee and repeat with another lever 3-4 inches further along...
7. …Remove the first lever and lift the tyre lip another 3-4ins further along from the second lever. Work the levers and protectors round the tyre until its lip is clear of the rim. Stand the wheel up and feed a lever from the opposite side under the tyre and through to the rim (with protector) and lift the lever to push the tyre off the rim.
8. Take the new tyre and paint some lubricant on to the outer lips of both sides of the tyre to aid fitting – especially when blowing the tyre up – so it butts on to the rim easily. Professional tyre services use ‘tyre soap’. If this is not available, use a thick, soapy solution of liquid hand soap and water. Swarfega can be used if applied liberally.
9. Ensure the tyre’s rotation of direction arrow (marked on sidewall) matches with the wheel’s (cast on rim). Slide, pull and push one side of the tyre on to the rim by placing the rim on to the lower part of the tyre, holding it in place with a foot and pushing the rim into the tyre from the bottom – lubricant, levers and protectors are a must.
10. With the wheel flat on the floor and the open side of the tyre facing up, carefully feed in the tube (if fittred). Blow it up slightly to assume its circular shape so it doesn’t get trapped between tyre and rim. Don’t screw down the valve-securing nut yet as you need some slack when fitting the last part of the tyre on the rim.
11. Starting at 180° from the valve, carefully start to lift the tyre lip over and on to the rim, alternating from left to right, so the last part of the lip to go in to the rim is at the valve. Try to keep the fitted lip (underside) in the rim’s well to make fitting easier. When lifting the last part over, push the tube valve back into the rim to prevent it being trapped.
12. Inflating the tyre requires a compressor. Garage forecourt pumps are fine. Keep inflating the tyre until the sidewalls seat on the rim (moulded lines on the tyre will be visible all the way round, near the rim, and at an even distance). Finally, reset the pressure. Don’t ride until the wheel has been balanced.