Blow outs after inflating tyre

amcalester

Hi All

Looking for some help here. Recently bought a bike on the cycle to work scheme, just a basic road bike. Problem I've been having is I keep getting punctures and I haven't even had it out yet.

I'll inflate the tyre and 10 minutes later it'll blow. I don't think I'm over inflating it (not accodring to the pump anyways), I've checked the inside of the tyre for anything that might be causing the punctures and couldnt find anything.

This is the first bike Ive owned since was a kid so Im fairly new to it all.

Its happened twice on the same tyre (front) but not on the rear tyre.

Any help would be appreciated.

Encrypted Pigeon

Have you checked that there isn't a spoke poking through on the rim, there should be rim tape to stop this, but safer to check, just in case.

Also, dumb question, are you sure you have the right tube for the tyre?

Beasty

Could be a tyre or rim issue. Try swapping front and back tyres - if you get another puncture you'll at least know which component is the issue, if you don't get one, problem solved

If you're still having problems, take it back to the retailer - they should sort it out FOC if it's a new bike

amcalester

Definitely the right size tyre and there are no spokes pushing through , I havent tried swapping the tyres. Will do that.

thanks for the help.

Dermot Illogical

Is it puncturing in the same place, and what PSI are you inflating it to?

Crow92

Are you getting tyre bulge? Sometimes people pull the valve further through the hole in the rim to get it longer to attatch the pump to it. This can cause the tube in inflate under the tyre and it won't be seated properly.

Are is the tyre coming off when if blows out?

Is there a hole in the tube or a rip?

If you haven't even been on it yet bring it back to where you bought it and they should fix it for free.

amcalester

Tyre says to inflate to between 110 and 130 so I've been going to about 125 and removing the valve.

Because its just the front tyre I dont think I'm over inflating it.

I've been checking for bulges as well and as far as I can see there haven't been any.

Each time it happens there's a hole not a rip and its what I would consider to be a big hole as in its easily seen when the tube is removed.

I'm going to try the advice above and that doesn't work I'll bring it back. Either way I'm learning.

Crow92

Just thought of a few things.

What kind of rimtape is on it? Is it s stretchy one or tough and hard on the edges? Sometimes if it's too hard it can cut the tube and if too soft it can still allow the tube to be burst by a spoke. (Ensure its one with reinforcing fibres in it).

Also where is the hole? Is it on the tyre side, the sidewall side of the spoke side of the tube?

Check for metal fragments in the rim from the manufacturing process incase there is any splinters.

midonogh

Crow92 wrote: »

Just thought of a few things.

What kind of rimtape is on it? Is it s stretchy one or tough and hard on the edges? Sometimes if it's too hard it can cut the tube and if too soft it can still allow the tube to be burst by a spoke. (Ensure its one with reinforcing fibres in it).

Also where is the hole? Is it on the tyre side, the sidewall side of the spoke side of the tube?

Check for metal fragments in the rim from the manufacturing process incase there is any splinters.

My bets are on this. I had exactly the same issue as OP when I got a new wheel built in a shop that specialised in MTB rather than road bikes. They used less durable rim tape and the high pressure forced a hole in the tape. The tube then expanded into the hole and as soon as I got on the bike or moved it the tube blew leaving a hole rather than a rip

kumate_champ07

125psi is alot for a front tyre on Irish roads. I'd use 100-110

rurs

Definitely change the rim tape for something better, if it's the rubbery, stretchy kind. I had a big blow-out at speed a few years ago, caused by rim tape failure.
It's only about €2 per wheel for the BBB ones.

As regards pressures, the max pressure listed on your tyre is in relation to the heaviest load (ie person+bike) it has to carry. According to this chart from Vittoria anyway.

Raymzor

i had similar experience after repairing a puncture. it is possible the tube is not fully in the tyre. the edge of the tyre may be pinching the tyre particularly where valve comes thru rim. before inflating push valve aprox 10mm back thru the rim. start pumping. stop after 4-5 strokes. push against side wall of tyre full circumference on both sides of tyre to make sure edge of tyre not pinching tube. if tube is vissible anywhere deflate again and push tube into tyre.

amcalester

Even at 125 psi theres no extra load on the bike as it is sitting upside down in my front room when the blow-outs happen. The bike hasn't made it onto a road yet.

I took the wheel off and removed the tyre to look at the tape, I couldn't see any spoke jutting through or anything wrong with the tape. What I did notice was 3 sets of punctures in the metal rim of the wheel, 1 puncture either side of the tape. It looks like the wheel has been pierced with something (like a sharp tuning fork) so I think this may be causing the blow outs.

I'm going to take it back to the shop, should I bring the bike or just the front wheel?

amcalester

Raymzor wrote: »

i had similar experience after repairing a puncture. it is possible the tube is not fully in the tyre. the edge of the tyre may be pinching the tyre particularly where valve comes thru rim. before inflating push valve aprox 10mm back thru the rim. start pumping. stop after 4-5 strokes. push against side wall of tyre full circumference on both sides of tyre to make sure edge of tyre not pinching tube. if tube is vissible anywhere deflate again and push tube into tyre.

I was checking for this too when inflating it and stopped a few times to check if the tube was fully in the tyre and it looked like it was.

I've had a similar problem on several occassions. It may be that at some point the tyre is not seated on the rim correctly. When inflated the tube lifts the tyre off the rim and pokes out, followed by a massive bang and a hiss. Then the tyre falls back on the rim and it's impossible to see where the problem was. Take the tyre off the wheel and reseat it, taking extra care to make sure that at no point is the tube pinched under the edge of the tyre. Then reinflate carefully looking for any evidence of the sidewall lifting off the rim anywhere.

johnnyros_gt

hi. i run a bike shop in roscommon and i have seen this happen a few times. as in 1 of the posts above, its more than likely that the tube isnt seated in the tyre fully and is gettin pinched between the rim and tyre. what i do normally is put a bit of pressure in the tube before installation and seat it in the tyre all the way around, then start putting the tyre back around the rim and when it gets a bit tight just let a small bit of air out of the tube until you get it on.id recommended tyre pressure to be around 120psi.

morana

rurs wrote: »

Definitely change the rim tape for something better, if it's the rubbery, stretchy kind. I had a big blow-out at speed a few years ago, caused by rim tape failure.
It's only about €2 per wheel for the BBB ones.

As regards pressures, the max pressure listed on your tyre is in relation to the heaviest load (ie person+bike) it has to carry. According to this chart from Vittoria anyway.

the best rim tape is insulation tape. Wrap it a few times round the rimand it lasts for years

souter

Deleted User wrote: »

I've had a similar problem on several occassions. It may be that at some point the tyre is not seated on the rim correctly. When inflated the tube lifts the tyre off the rim and pokes out, followed by a massive bang and a hiss. Then the tyre falls back on the rim and it's impossible to see where the problem was. Take the tyre off the wheel and reseat it, taking extra care to make sure that at no point is the tube pinched under the edge of the tyre. Then reinflate carefully looking for any evidence of the sidewall lifting off the rim anywhere.

+1, this happened to me, there would be a noise like a gunshot, between 10 mins to a couple hours after inflation, and a big hole ripped in the tube.

Didn't matter how carefully I inflated, it was a fundemental incompatability between the tyre and the rims, so I ended up getting different tyres.