Emergency mobile tyre fitting on the M48
Move left and stop, then get everyone out of the vehicle on the side away from traffic and behind the barrier. The M48 crosses the Severn on a sixty-year-old suspension bridge where the deck is narrow, so the approaches are far better places to stop than the span itself. Fitting begins at £120 with a tyre supplied.
If you are in a live lane, do not attempt a tyre change
Conventional throughout: no all-lane running anywhere, and no gantry lane signals. What this road has instead is a bridge governed by weather and weight. The crossing shuts in high winds, and since May 2025 lorries above 7.5 tonnes have gone round by the M4 while the main cables are worked on. Get the vehicle as far left as you can, leave by the nearside doors, stand behind the barrier up the embankment, and call National Highways on 0300 123 5000, or 999 if you cannot get out of the vehicle. They can close the lane above you from the control room. Book a fitter once you are behind a barrier, never before. Full guidance is on National Highways.
Steer left and stop clear of the running lanes, then get everybody out on the side away from traffic and behind the barrier. National Highways run this crossing and answer on 0300 123 5000, and 999 covers anyone trapped inside. A tyre on the M48 costs from £120 fitted.
Thirteen miles of the M48 link the M4 at J21 near Aust in England to the M4 again at J23 by Magor in Wales. Between those points come J1 at Aust, the Severn Bridge itself, a second span over the Wye, J2 for Chepstow and the A48, then a run west across the Monmouthshire levels.
It has not always carried this number. The road opened in 1966 as part of the M4, and only became the M48 in 1996 once the second crossing took the M4 designation downstream. Tolls came off both crossings in December 2018, and traffic on the older bridge rose accordingly.
The bridge dominates everything here. It is a suspension structure high above open water, without the wind shielding the newer crossing was given, so it restricts high-sided vehicles and then closes once gusts get strong enough. Since 27 May 2025 a further restriction applies: lorries over 7.5 tonnes are barred while the main cables are strengthened, diverted by way of the M4 Prince of Wales Bridge. Emergency vehicles, buses, coaches and recovery vehicles are exempt.
For tyres that mix matters. Heavy freight has largely left the M48 for now, so less shed lorry tread lies in lane one than this road used to collect. The crossing brings its own problems instead: expansion joints on a long span, crosswind loading, salt-laden air on wheel rims, and the plain fact that the deck is a bad place to stop.
Where M48 tyre failures concentrate
M48 Severn Bridge crossing, 13 miles, M4 J21 at Aust to M4 J23 at Magor, via J1 and J2, through South Gloucestershire and Monmouthshire, crossing the Severn and the Wye between England and Wales.
The Severn Bridge deck
A long exposed span where the carriageway is narrower than standard motorway, which is why maintenance there needs lane closures. Expansion joints punch impacts into a tyre while a crosswind loads the sidewalls sideways. It is the last place on this road you want to be stationary.
The Wye crossing and the run into J2
The second, shorter span and the approach to Chepstow. Traffic slows and sorts itself for the A466 and A48, and lane changes over whatever lies in the nearside are how sidewalls get opened.
J1 Aust and the services entry
Everything using Severn View turns in and out here, mixing stopping traffic with vehicles building speed for the bridge. Kerbing on the service slips is common, and the damage often only announces itself out on the span.
West of J2 across the levels
Open, low-lying country between Chepstow and Magor with farm access onto the connecting roads. Mud, flint and stone from field entrances end up on the carriageway, and stone is what cuts a tread block open.
The M4 J21 tie-in
The English end, where M48 traffic joins and leaves the M4. Short merges at differing speeds put nearside wheels over debris collected against the edge line.
M48 services we cover
If you can reach a service area safely, do. A fitter can work on you in a car park with no live traffic alongside, which is both faster and far safer than a hard shoulder.
| Service area | Between |
|---|---|
| Severn View | At J1 Aust, English side, accessible from both directions |
M48 junctions, services and where we can fit
Give the junction number when you book and the app does the rest. This is what sits at each one, and whether that stretch still has a hard shoulder to stop on.
| Junction | Meets | Serves | Nearest services | Hard shoulder |
|---|---|---|---|---|
| M4 J21 | M4 | Almondsbury, Bristol and the south | Severn View at J1 | Yes, conventional |
| J1 | A403 | Aust, Severn Beach and Avonmouth | Severn View, on the junction | Yes, conventional |
| J2 | A466 and A48 | Chepstow, Tintern and Gloucester | Severn View, back over the bridge | Yes, conventional |
| M4 J23 | M4 | Magor, Newport and Cardiff | Magor services at M4 J23A | Yes, conventional |
M48 tyre prices
None of these prices carry a callout on top, because reaching you is already covered. The tyre is charged at what it costs and itemised on screen before confirmation. The overnight window, 23:00 through 07:00, applies a 1.5x factor to the base rate, published plainly: 24 hour tyre fitting on the M48 often means a Severn crossing in the middle of the night.
| Service | Price | What is included |
|---|---|---|
| Mobile tyre change, supply and fit | From £120 | Plus the tyre at cost. Chepstow, Caldicot and the Bristol fringe all supply this corridor, though the estuary means stock is not always on the same side of the water as you are. |
| Fit the spare you already carry | From £80 | Where a roadworthy spare is travelling with you. On the bridge itself this is much the fastest way to clear the crossing. |
| Puncture repair | From £60 | Only where the puncture lies within the central repairable zone under BS AU159 with legal depth remaining. Bead corrosion from salt air is a separate fault and gets checked at the same time. |
| Locking wheel nut removal | From £70 | When the key has vanished or rounded. The nut comes off intact wherever the head allows it, and the wheel is torqued to figure afterwards. |
| TPMS sensor replacement | From £60 | One price per sensor, paired to the vehicle before the fitter packs up. Fitted as standard to virtually every car registered from 2014. |
| Recovery if it cannot be fitted | From £70 | For a wheel too damaged to take a tyre, or a stopping position on the bridge deck where working at the roadside is not appropriate. Priced on weight and towing distance. |
Flat tyre on the M48: what to do
Go left, and get off the span if you can
Come off the power gently rather than braking hard, and work towards the nearside. If it happens on the bridge and the car will still travel, carrying on slowly beats stopping on a deck with very little room.
Hazards on, front wheels away from the lanes
Warn the traffic behind you as early as you can. Once halted, swing the front wheels toward the edge, so a shunt shoves the car sideways off the running surface instead of across it.
Get safe: leave on the sheltered side
Everybody leaves through the doors furthest from moving traffic, the driver crossing the cabin rather than stepping into a lane. Get behind the barrier, stand forward of the car, and expect it to be far windier outside than it felt in.
Get help: make the call before anything else
A free orange SOS phone reports your location automatically wherever one is close enough to walk to. If not, National Highways operate the Severn crossings and take the call on 0300 123 5000. Dial 999 before either if somebody cannot leave the car.
Red X, and where the M4 differs
This road has no all-lane running of its own. On the M4 either side, a red X displayed above a lane closes it, and driving beneath one is an offence. Where all-lane running applies, the emergency areas replacing the shoulder are given blue signs bearing an orange SOS handset and set at intervals.
Then book the fitter
With everyone clear and the stop reported, place the booking in the app. Where the shoulder is usable and the spot sensible, the work happens where you stand. On the bridge deck the answer is usually recovery to Severn View.
The legal minimum tread depth in the UK is 1.6mm across the central three quarters of the tyre, and the fine is up to £2,500 and three penalty points per tyre. A fitter cannot legally refit a tyre below that, which is why a worn tyre becomes a replacement rather than a repair.
What drives the M48, and what fails
Cross-border commuters and day traffic
Since the tolls ended, the older bridge carries a great deal of ordinary travel between Bristol, Chepstow and Newport. These are everyday cars covering the same crossing repeatedly, and constant salt air ages wheels and valves faster than inland.
Vans and light commercials under the limit
With lorries above 7.5 tonnes diverted, the working traffic left here is mostly vans and small trucks. Those run high pressures on C-rated tyres, and a loaded van meeting an expansion joint on the span takes a much harder hit than a car.
Caravans, motorhomes and high-sided vehicles
Tourist traffic heading into Wales brings towed and tall vehicles onto an exposed crossing. High-sided vehicles are first to be restricted when the wind rises, and a caravan tyre stood on one spot all winter is exactly the kind that fails on its first long run.
M48 tyre failures through the year
Autumn and winter storms
The crossing is restricted to high-sided vehicles when the wind gets up and closed to everything when it worsens, so plans change at short notice. Standing water on the approaches adds aquaplaning to any tyre already down on depth.
Spring, potholes and joints
Freeze and thaw work on approach surfacing and on the joints of a long structure. Damage from that shows as a sidewall swelling instead of a hole, and swellings are never repairable.
Summer, tourist volume
Holiday traffic into Wales fills the road with laden cars and towed vans. Heat plus load is the classic combination behind a sudden failure, and a caravan just out of storage is most likely to supply one.
Getting a tyre near the M48
Severn View at J1 Aust is the M48's single service area, and it is well placed: English side, right by the bridge, reachable from both directions. Magor services on the M4 at J23A is the other option, just past the Welsh end.
The estuary is the complication. Chepstow, Caldicot, Thornbury and the Bristol fringe all support tyre trade, but a fitter on the wrong bank has either the bridge or a long detour ahead. Say which side of the water you are on and which way you were heading. The window you are quoted is a target and nothing firmer.
Responsibility is split, too. National Highways operate the Severn crossings and the English section, while the Welsh stretch beyond the Wye falls to the South Wales Trunk Road Agent. In an emergency that changes nothing about who you ring.
Tread, pressure and the law
Where the 1.6mm has to be
The legal depth is required over the tread's middle portion, three quarters of its breadth, and at all points around the circumference. Manufacturers cast small bridges of rubber into the groove floors at exactly that height, and tread level with those bridges has reached the limit rather than approached it.
Penalties add up per tyre
One worn tyre alone can cost £2,500 and three penalty points, and four of them add up to a ban rather than a fine.
Sidewalls, salt and the MOT
Any bulge, split or cord showing through a sidewall is an immediate MOT failure whatever the depth gauge says. On this crossing there is a second thing to watch: salt-laden air corrodes the rim where the tyre seals, producing slow leaks that get mistaken for punctures.
M48 tyre questions
Can a wheel be changed on the M48 hard shoulder?
On the approaches, yes. The M48 is conventional with a hard shoulder and no converted section, so a fitter will work at the roadside where the position is safe. The deck is the exception: narrow, exposed and busy, and recovery off the crossing is usually better.
Who do I call for a puncture on the M48?
National Highways operate the Severn crossings and take reports on 0300 123 5000, and an orange SOS phone does the same job where one stands close. Use 999 first if somebody cannot leave the car or it is blocking a running lane.
Is changing a wheel on a motorway an offence?
No law prohibits it. National Highways discourage it anyway, and the Severn Bridge shows why better than most places: there is little room on the deck, the wind is stronger than it looks from inside a car, and traffic passes close.
How much is a roadside tyre on the M48?
From £120 for a tyre supplied and fitted, from £80 to put on a spare you carry, £60 to mend one when the damage allows, and from £70 for recovery if fitting on site is not sensible. No callout is charged, and overnight everything is multiplied by 1.5.
Where do I stop if there is nowhere to pull in?
Everywhere on the M48 has a hard shoulder, so you do have somewhere, just not always a good one. On the bridge, keep going slowly until you are off the span. Otherwise get hard left, everybody out on the sheltered side and behind the barrier, then ring 999.
Is Severn View a better place to have the tyre done?
By a distance. Severn View sits at J1 on the English side and is reachable from both directions, so there is lighting, space and nothing travelling past at speed. If the car will still roll, aim for it rather than staying on the crossing.
What if the Severn Bridge closes while I am waiting?
It happens in strong winds, and it changes the route rather than the job. A fitter already on your bank carries on; one on the far side goes round by the M4 Prince of Wales Bridge, which adds distance. Another reason the time you are shown is a target.
Does the 7.5 tonne limit stop a recovery truck reaching me?
No. The restriction introduced in May 2025 bars goods vehicles over 7.5 tonnes while the main cables are strengthened, but National Highways list exemptions covering emergency vehicles, buses, coaches and recovery vehicles.
Book a M48 tyre fitter in the app
Your location comes from GPS, so you do not have to read a marker post. The price is fixed before you confirm and you track the fitter in.
Download free
iOS and Android from the 1st of October 2026. No membership, no annual fee and no account charge. You only pay when you book a job.
Book securely
The fixed price is shown before you confirm, not after the work. Card, Apple Pay and Google Pay are handled in-app, so no cash changes hands at the kerb.
Track the driver
Once a job is accepted you see the driver's name, vehicle and live position on the map, with an arrival time that updates as they travel.
Every operator is DBS checked, insured for hire and reward, and rated after each job. Prices are fixed before dispatch, never quoted as a range.
Own a van or recovery truck? Take jobs through the same appMobile tyre fitters wanted on the M48
Crossing the Severn either way puts you on the M48, and fitters in Chepstow, Caldicot, Thornbury or on the Bristol fringe are the ones who can reach the bridge from the correct side of the water. Fitters keep 90 percent of every job for their first twelve months, with no joining fee, no weekly subscription, no bidding and no charge for jobs you decline. You set your own radius and hours. We are signing up fitters along the M48 ahead of the 1st of October 2026 launch.
Cover the M48 with usTom Hargreaves - Head of Recovery Standards
Tom spent 12 years patrolling UK motorways with the AA before joining TowManVan. He signs off the roadside safety guidance and every price on this page. Questions? Email tom@towmanvan.co.uk.
Last updated 19 August 2026. Apps launch 1st of October 2026.