The position is critical. The tyre shop should have a diagram that shows the area where a repair is permissible. But the type of damage also matters, the hole created by a bolt is quite possibly too large to safely repair.

You really need to take the tyre to a well established independent for advice but for them to comment they would probablt need to remove the tyre to check for internal damage and that will not be free.

But surely if you can afford a Merc GLA you can afford a new tyre. They are after all safety critical, if it blows at speed the cost would without doubt exceed replacement and in some instances you could face a criminal prosecution.

Serious tyre damage should be left to tyre repair professionals, and your local tyre fitter is not qualified nor have the equipment nor expertise to tackle a major repair, minor tread punctures by nails are not major damage, but a bolt can be much worse, the problem is you have no idea what damage is done inside the casing by the item protruding inside.

There are very few tyre repair professionals about, there's a couple of places still going in Northants (this area specialised decades ago and as its a specialised small industry the long learned skills have stayed fairly local), and one in Ely that i'm aware of, there may be others but you'll have to find them for yourself.

Cost is the issue here, chances are that this major repair will be in the region of £25 to £35, and you'll have demount and remount fees from the tyre fitters so you'll probably be knocking on the door of £50 by the time its done, few people will want the hassle and i dare say these days that in the passenger tyre market very few tyre fitters even deal with these few major repairers...who run vans and small lorries going round the country collecting damaged tyres and redelivering the repaired item.

Their core business is lorry, agricultural and plant equipment tyres where damage is rife and the cost of tyres makes major repairs economic sense, its rare now for car tyres to be major repaired, only those in the know or living in the vicinity of these places (as i do, and i started my working life in one of these workshops) so able to mitigate cost and downtime would likely use them.

For most people, what are you going to do whilst your tyre is away for a week being repaired? especially if you have no spare at all or at best a wheelbarrow tyre, and its entirely possible the pro will scrap the tyre anyway if excessive cord damage or evidence of running flat is discovered.

Edited by gordonbennet on 29/08/2018 at 22:50